#29: Automatically reload on configuration file update

README.md

@@ -49,6 +49,7 @@ core applications: https://status.twinnation.org/
   - [Monitoring a service using DNS queries](#monitoring-a-service-using-dns-queries)
   - [Basic authentication](#basic-authentication)
   - [disable-monitoring-lock](#disable-monitoring-lock)
+  - [Reloading configuration on the fly](#reloading-configuration-on-the-fly)
   - [Service groups](#service-groups)
   - [Exposing Gatus on a custom port](#exposing-gatus-on-a-custom-port)
   - [Uptime Badges (ALPHA)](#uptime-badges)
@@ -153,6 +154,7 @@ Note that you can also use environment variables in the configuration file (e.g.
 | `security.basic.username`                | Username for Basic authentication                                             | Required `""`  |
 | `security.basic.password-sha512`         | Password's SHA512 hash for Basic authentication                               | Required `""`  |
 | `disable-monitoring-lock`                | Whether to [disable the monitoring lock](#disable-monitoring-lock)            | `false`        |
+| `skip-invalid-config-update`             | Whether to ignore invalid configuration update. See [Reloading configuration on the fly](#reloading-configuration-on-the-fly).
 | `web`                                    | Web configuration                                                             | `{}`           |
 | `web.address`                            | Address to listen on                                                          | `0.0.0.0`      |
 | `web.port`                               | Port to listen on                                                             | `8080`         |
@@ -818,6 +820,30 @@ technically, if you create 100 services with a 1 seconds interval, Gatus will se
 - You want to test multiple services at very short interval (< 5s)
 
 
+### Reloading configuration on the fly
+
+For the sake on convenience, Gatus automatically reloads the configuration on the fly if the loaded configuration file
+is updated while Gatus is running.
+
+By default, the application will exit if the updating configuration is invalid, but you can configure
+Gatus to continue running if the configuration file is updated with an invalid configuration by
+setting `skip-invalid-config-update` to `true`.
+
+Keep in mind that it is in your best interest to ensure the validity of the configuration file after each update you
+apply to the configuration file while Gatus is running by looking at the log and making sure that you do not see the
+following message:
+```
+The configuration file was updated, but it is not valid. The old configuration will continue being used.
+```
+Failure to do so may result in Gatus being unable to start if the application is restarted for whatever reason.
+
+I recommend not setting `skip-invalid-config-update` to `true` to avoid a situation like this, but the choice is yours
+to make.
+
+Note that if you are not using a file storage, updating the configuration while Gatus is running is effectively
+the same as restarting the application.
+
+
 ### Service groups
 
 Service groups are used for grouping multiple services together on the dashboard.

alerting/alert/alert.go

@@ -1,9 +1,9 @@
-package core
+package alert
 
 // Alert is the service's alert configuration
 type Alert struct {
 	// Type of alert (required)
-	Type AlertType `yaml:"type"`
+	Type Type `yaml:"type"`
 
 	// Enabled defines whether or not the alert is enabled
 	//
@@ -67,33 +67,3 @@ func (alert Alert) IsSendingOnResolved() bool {
 	}
 	return *alert.SendOnResolved
 }
-
-// AlertType is the type of the alert.
-// The value will generally be the name of the alert provider
-type AlertType string
-
-const (
-	// CustomAlert is the AlertType for the custom alerting provider
-	CustomAlert AlertType = "custom"
-
-	// DiscordAlert is the AlertType for the discord alerting provider
-	DiscordAlert AlertType = "discord"
-
-	// MattermostAlert is the AlertType for the mattermost alerting provider
-	MattermostAlert AlertType = "mattermost"
-
-	// MessagebirdAlert is the AlertType for the messagebird alerting provider
-	MessagebirdAlert AlertType = "messagebird"
-
-	// PagerDutyAlert is the AlertType for the pagerduty alerting provider
-	PagerDutyAlert AlertType = "pagerduty"
-
-	// SlackAlert is the AlertType for the slack alerting provider
-	SlackAlert AlertType = "slack"
-
-	// TelegramAlert is the AlertType for the telegram alerting provider
-	TelegramAlert AlertType = "telegram"
-
-	// TwilioAlert is the AlertType for the twilio alerting provider
-	TwilioAlert AlertType = "twilio"
-)

alerting/alert/alert_test.go

@@ -1,4 +1,4 @@
-package core
+package alert
 
 import "testing"
 

alerting/alert/type.go

@@ -0,0 +1,31 @@
+package alert
+
+// Type is the type of the alert.
+// The value will generally be the name of the alert provider
+type Type string
+
+const (
+	// TypeCustom is the Type for the custom alerting provider
+	TypeCustom Type = "custom"
+
+	// TypeDiscord is the Type for the discord alerting provider
+	TypeDiscord Type = "discord"
+
+	// TypeMattermost is the Type for the mattermost alerting provider
+	TypeMattermost Type = "mattermost"
+
+	// TypeMessagebird is the Type for the messagebird alerting provider
+	TypeMessagebird Type = "messagebird"
+
+	// TypePagerDuty is the Type for the pagerduty alerting provider
+	TypePagerDuty Type = "pagerduty"
+
+	// TypeSlack is the Type for the slack alerting provider
+	TypeSlack Type = "slack"
+
+	// TypeTelegram is the Type for the telegram alerting provider
+	TypeTelegram Type = "telegram"
+
+	// TypeTwilio is the Type for the twilio alerting provider
+	TypeTwilio Type = "twilio"
+)

alerting/config.go

@@ -1,6 +1,8 @@
 package alerting
 
 import (
+	"github.com/TwinProduction/gatus/alerting/alert"
+	"github.com/TwinProduction/gatus/alerting/provider"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/alerting/provider/discord"
 	"github.com/TwinProduction/gatus/alerting/provider/mattermost"
@@ -37,3 +39,58 @@ type Config struct {
 	// Twilio is the configuration for the twilio alerting provider
 	Twilio *twilio.AlertProvider `yaml:"twilio"`
 }
+
+// GetAlertingProviderByAlertType returns an provider.AlertProvider by its corresponding alert.Type
+func (config Config) GetAlertingProviderByAlertType(alertType alert.Type) provider.AlertProvider {
+	switch alertType {
+	case alert.TypeCustom:
+		if config.Custom == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Custom
+	case alert.TypeDiscord:
+		if config.Discord == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Discord
+	case alert.TypeMattermost:
+		if config.Mattermost == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Mattermost
+	case alert.TypeMessagebird:
+		if config.Messagebird == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Messagebird
+	case alert.TypePagerDuty:
+		if config.PagerDuty == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.PagerDuty
+	case alert.TypeSlack:
+		if config.Slack == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Slack
+	case alert.TypeTelegram:
+		if config.Telegram == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Telegram
+	case alert.TypeTwilio:
+		if config.Twilio == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Twilio
+	}
+	return nil
+}

alerting/provider/custom/custom.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/client"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -24,7 +25,7 @@ type AlertProvider struct {
 	Placeholders map[string]map[string]string `yaml:"placeholders,omitempty"`
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -33,7 +34,7 @@ func (provider *AlertProvider) IsValid() bool {
 }
 
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, result *core.Result, resolved bool) *AlertProvider {
 	return provider
 }
 
@@ -117,6 +118,6 @@ func (provider *AlertProvider) Send(serviceName, alertDescription string, resolv
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/custom/custom_test.go

@@ -4,6 +4,7 @@ import (
 	"io/ioutil"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -60,7 +61,7 @@ func TestAlertProvider_buildHTTPRequestWhenTriggered(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProvider(t *testing.T) {
 	provider := AlertProvider{URL: "http://example.com"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

alerting/provider/discord/discord.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -13,7 +14,7 @@ type AlertProvider struct {
 	WebhookURL string `yaml:"webhook-url"`
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -22,7 +23,7 @@ func (provider *AlertProvider) IsValid() bool {
 }
 
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
 	var message, results string
 	var colorCode int
 	if resolved {
@@ -66,6 +67,6 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/discord/discord_test.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -22,7 +23,7 @@ func TestAlertProvider_IsValid(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 	provider := AlertProvider{WebhookURL: "http://example.com"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -44,7 +45,7 @@ func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 	provider := AlertProvider{WebhookURL: "http://example.com"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

alerting/provider/mattermost/mattermost.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -14,7 +15,7 @@ type AlertProvider struct {
 	Insecure   bool   `yaml:"insecure,omitempty"`
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -23,7 +24,7 @@ func (provider *AlertProvider) IsValid() bool {
 }
 
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
 	var message string
 	var color string
 	if resolved {
@@ -78,6 +79,6 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/mattermost/mattermost_test.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -22,7 +23,7 @@ func TestAlertProvider_IsValid(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 	provider := AlertProvider{WebhookURL: "http://example.org"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -44,7 +45,7 @@ func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 	provider := AlertProvider{WebhookURL: "http://example.org"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

alerting/provider/messagebird/messagebird.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -19,7 +20,7 @@ type AlertProvider struct {
 	Recipients string `yaml:"recipients"`
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -29,7 +30,7 @@ func (provider *AlertProvider) IsValid() bool {
 
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
 // Reference doc for messagebird https://developers.messagebird.com/api/sms-messaging/#send-outbound-sms
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
 	var message string
 	if resolved {
 		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.GetDescription())
@@ -53,6 +54,6 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/messagebird/messagebird_test.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -30,7 +31,7 @@ func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 		Originator: "1",
 		Recipients: "1",
 	}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -56,7 +57,7 @@ func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 		Originator: "1",
 		Recipients: "1",
 	}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

alerting/provider/pagerduty/pagerduty.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -13,7 +14,7 @@ type AlertProvider struct {
 	IntegrationKey string `yaml:"integration-key"`
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -24,7 +25,7 @@ func (provider *AlertProvider) IsValid() bool {
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
 //
 // relevant: https://developer.pagerduty.com/docs/events-api-v2/trigger-events/
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
 	var message, eventAction, resolveKey string
 	if resolved {
 		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.GetDescription())
@@ -55,6 +56,6 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/pagerduty/pagerduty_test.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -22,7 +23,7 @@ func TestAlertProvider_IsValid(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 	provider := AlertProvider{IntegrationKey: "00000000000000000000000000000000"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -44,7 +45,7 @@ func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 	provider := AlertProvider{IntegrationKey: "00000000000000000000000000000000"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

alerting/provider/provider.go

@@ -1,6 +1,7 @@
 package provider
 
 import (
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/alerting/provider/discord"
 	"github.com/TwinProduction/gatus/alerting/provider/mattermost"
@@ -18,14 +19,14 @@ type AlertProvider interface {
 	IsValid() bool
 
 	// ToCustomAlertProvider converts the provider into a custom.AlertProvider
-	ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider
+	ToCustomAlertProvider(service *core.Service, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider
 
 	// GetDefaultAlert returns the provider's default alert configuration
-	GetDefaultAlert() *core.Alert
+	GetDefaultAlert() *alert.Alert
 }
 
 // ParseWithDefaultAlert parses a service alert by using the provider's default alert as a baseline
-func ParseWithDefaultAlert(providerDefaultAlert, serviceAlert *core.Alert) {
+func ParseWithDefaultAlert(providerDefaultAlert, serviceAlert *alert.Alert) {
 	if providerDefaultAlert == nil || serviceAlert == nil {
 		return
 	}

alerting/provider/provider_test.go

@@ -3,13 +3,13 @@ package provider
 import (
 	"testing"
 
-	"github.com/TwinProduction/gatus/core"
+	"github.com/TwinProduction/gatus/alerting/alert"
 )
 
 func TestParseWithDefaultAlert(t *testing.T) {
 	type Scenario struct {
 		Name                                            string
-		DefaultAlert, ServiceAlert, ExpectedOutputAlert *core.Alert
+		DefaultAlert, ServiceAlert, ExpectedOutputAlert *alert.Alert
 	}
 	enabled := true
 	disabled := false
@@ -18,18 +18,18 @@ func TestParseWithDefaultAlert(t *testing.T) {
 	scenarios := []Scenario{
 		{
 			Name: "service-alert-type-only",
-			DefaultAlert: &core.Alert{
+			DefaultAlert: &alert.Alert{
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &firstDescription,
 				FailureThreshold: 5,
 				SuccessThreshold: 10,
 			},
-			ServiceAlert: &core.Alert{
-				Type: core.DiscordAlert,
+			ServiceAlert: &alert.Alert{
+				Type: alert.TypeDiscord,
 			},
-			ExpectedOutputAlert: &core.Alert{
-				Type:             core.DiscordAlert,
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &firstDescription,
@@ -39,23 +39,23 @@ func TestParseWithDefaultAlert(t *testing.T) {
 		},
 		{
 			Name: "service-alert-overwrites-default-alert",
-			DefaultAlert: &core.Alert{
+			DefaultAlert: &alert.Alert{
 				Enabled:          &disabled,
 				SendOnResolved:   &disabled,
 				Description:      &firstDescription,
 				FailureThreshold: 5,
 				SuccessThreshold: 10,
 			},
-			ServiceAlert: &core.Alert{
-				Type:             core.TelegramAlert,
+			ServiceAlert: &alert.Alert{
+				Type:             alert.TypeTelegram,
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &secondDescription,
 				FailureThreshold: 6,
 				SuccessThreshold: 11,
 			},
-			ExpectedOutputAlert: &core.Alert{
-				Type:             core.TelegramAlert,
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeTelegram,
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &secondDescription,
@@ -65,22 +65,22 @@ func TestParseWithDefaultAlert(t *testing.T) {
 		},
 		{
 			Name: "service-alert-partially-overwrites-default-alert",
-			DefaultAlert: &core.Alert{
+			DefaultAlert: &alert.Alert{
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &firstDescription,
 				FailureThreshold: 5,
 				SuccessThreshold: 10,
 			},
-			ServiceAlert: &core.Alert{
-				Type:             core.DiscordAlert,
+			ServiceAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
 				Enabled:          nil,
 				SendOnResolved:   nil,
 				FailureThreshold: 6,
 				SuccessThreshold: 11,
 			},
-			ExpectedOutputAlert: &core.Alert{
-				Type:             core.DiscordAlert,
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &firstDescription,
@@ -90,19 +90,19 @@ func TestParseWithDefaultAlert(t *testing.T) {
 		},
 		{
 			Name: "default-alert-type-should-be-ignored",
-			DefaultAlert: &core.Alert{
-				Type:             core.TelegramAlert,
+			DefaultAlert: &alert.Alert{
+				Type:             alert.TypeTelegram,
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &firstDescription,
 				FailureThreshold: 5,
 				SuccessThreshold: 10,
 			},
-			ServiceAlert: &core.Alert{
-				Type: core.DiscordAlert,
+			ServiceAlert: &alert.Alert{
+				Type: alert.TypeDiscord,
 			},
-			ExpectedOutputAlert: &core.Alert{
-				Type:             core.DiscordAlert,
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
 				Enabled:          &enabled,
 				SendOnResolved:   &enabled,
 				Description:      &firstDescription,
@@ -112,8 +112,8 @@ func TestParseWithDefaultAlert(t *testing.T) {
 		},
 		{
 			Name: "no-default-alert",
-			DefaultAlert: &core.Alert{
-				Type:             core.DiscordAlert,
+			DefaultAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
 				Enabled:          nil,
 				SendOnResolved:   nil,
 				Description:      &firstDescription,

alerting/provider/slack/slack.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -13,7 +14,7 @@ type AlertProvider struct {
 	WebhookURL string `yaml:"webhook-url"` // Slack webhook URL
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -22,7 +23,7 @@ func (provider *AlertProvider) IsValid() bool {
 }
 
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
 	var message, color, results string
 	if resolved {
 		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", service.Name, alert.SuccessThreshold)
@@ -66,6 +67,6 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/slack/slack_test.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -22,7 +23,7 @@ func TestAlertProvider_IsValid(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 	provider := AlertProvider{WebhookURL: "http://example.com"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -44,7 +45,7 @@ func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 	provider := AlertProvider{WebhookURL: "http://example.com"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

alerting/provider/telegram/telegram.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -14,7 +15,7 @@ type AlertProvider struct {
 	ID    string `yaml:"id"`
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -23,7 +24,7 @@ func (provider *AlertProvider) IsValid() bool {
 }
 
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
 	var message, results string
 	if resolved {
 		message = fmt.Sprintf("An alert for *%s* has been resolved:\\n—\\n    _healthcheck passing successfully %d time(s) in a row_\\n—  ", service.Name, alert.FailureThreshold)
@@ -54,6 +55,6 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/telegram/telegram_test.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -23,7 +24,7 @@ func TestAlertProvider_IsValid(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 	provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -47,7 +48,7 @@ func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 	provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "0123456789"}
 	description := "Healthcheck Successful"
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{Description: &description}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{Description: &description}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -69,7 +70,7 @@ func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 
 func TestAlertProvider_ToCustomAlertProviderWithDescription(t *testing.T) {
 	provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "0123456789"}
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

alerting/provider/twilio/twilio.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/url"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -18,7 +19,7 @@ type AlertProvider struct {
 	To    string `yaml:"to"`
 
 	// DefaultAlert is the default alert configuration to use for services with an alert of the appropriate type
-	DefaultAlert *core.Alert `yaml:"default-alert"`
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -27,7 +28,7 @@ func (provider *AlertProvider) IsValid() bool {
 }
 
 // ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *alert.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
 	var message string
 	if resolved {
 		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.GetDescription())
@@ -50,6 +51,6 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 }
 
 // GetDefaultAlert returns the provider's default alert configuration
-func (provider AlertProvider) GetDefaultAlert() *core.Alert {
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert
 }

alerting/provider/twilio/twilio_test.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
@@ -32,7 +33,7 @@ func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
 		To:    "4",
 	}
 	description := "alert-description"
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{Name: "service-name"}, &core.Alert{Description: &description}, &core.Result{}, true)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{Name: "service-name"}, &alert.Alert{Description: &description}, &core.Result{}, true)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}
@@ -58,7 +59,7 @@ func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
 		To:    "1",
 	}
 	description := "alert-description"
-	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{Name: "service-name"}, &core.Alert{Description: &description}, &core.Result{}, false)
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{Name: "service-name"}, &alert.Alert{Description: &description}, &core.Result{}, false)
 	if customAlertProvider == nil {
 		t.Fatal("customAlertProvider shouldn't have been nil")
 	}

config/config.go

@@ -5,8 +5,10 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
+	"time"
 
 	"github.com/TwinProduction/gatus/alerting"
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider"
 	"github.com/TwinProduction/gatus/core"
 	"github.com/TwinProduction/gatus/k8s"
@@ -39,13 +41,8 @@ var (
 	// ErrConfigFileNotFound is an error returned when the configuration file could not be found
 	ErrConfigFileNotFound = errors.New("configuration file not found")
 
-	// ErrConfigNotLoaded is an error returned when an attempt to Get() the configuration before loading it is made
-	ErrConfigNotLoaded = errors.New("configuration is nil")
-
 	// ErrInvalidSecurityConfig is an error returned when the security configuration is invalid
 	ErrInvalidSecurityConfig = errors.New("invalid security configuration")
-
-	config *Config
 )
 
 // Config is the main configuration structure
@@ -56,6 +53,10 @@ type Config struct {
 	// Metrics Whether to expose metrics at /metrics
 	Metrics bool `yaml:"metrics"`
 
+	// SkipInvalidConfigUpdate Whether to make the application ignore invalid configuration
+	// if the configuration file is updated while the application is running
+	SkipInvalidConfigUpdate bool `yaml:"skip-invalid-config-update"`
+
 	// DisableMonitoringLock Whether to disable the monitoring lock
 	// The monitoring lock is what prevents multiple services from being processed at the same time.
 	// Disabling this may lead to inaccurate response times
@@ -78,47 +79,57 @@ type Config struct {
 
 	// Web is the configuration for the web listener
 	Web *WebConfig `yaml:"web"`
+
+	filePath        string    // path to the file from which config was loaded from
+	lastFileModTime time.Time // last modification time
 }
 
-// Get returns the configuration, or panics if the configuration hasn't loaded yet
-func Get() *Config {
-	if config == nil {
-		panic(ErrConfigNotLoaded)
+// HasLoadedConfigurationFileBeenModified returns whether the file that the
+// configuration has been loaded from has been modified since it was last read
+func (config Config) HasLoadedConfigurationFileBeenModified() bool {
+	if fileInfo, err := os.Stat(config.filePath); err == nil {
+		if !fileInfo.ModTime().IsZero() {
+			return config.lastFileModTime.Unix() != fileInfo.ModTime().Unix()
+		}
 	}
-	return config
+	return false
 }
 
-// Set sets the configuration
-// Used only for testing
-func Set(cfg *Config) {
-	config = cfg
+// UpdateLastFileModTime refreshes Config.lastFileModTime
+func (config *Config) UpdateLastFileModTime() {
+	if fileInfo, err := os.Stat(config.filePath); err == nil {
+		if !fileInfo.ModTime().IsZero() {
+			config.lastFileModTime = fileInfo.ModTime()
+		}
+	}
 }
 
 // Load loads a custom configuration file
 // Note that the misconfiguration of some fields may lead to panics. This is on purpose.
-func Load(configFile string) error {
+func Load(configFile string) (*Config, error) {
 	log.Printf("[config][Load] Reading configuration from configFile=%s", configFile)
 	cfg, err := readConfigurationFile(configFile)
 	if err != nil {
 		if os.IsNotExist(err) {
-			return ErrConfigFileNotFound
+			return nil, ErrConfigFileNotFound
 		}
-		return err
+		return nil, err
 	}
-	config = cfg
-	return nil
+	cfg.filePath = configFile
+	cfg.UpdateLastFileModTime()
+	return cfg, nil
 }
 
 // LoadDefaultConfiguration loads the default configuration file
-func LoadDefaultConfiguration() error {
-	err := Load(DefaultConfigurationFilePath)
+func LoadDefaultConfiguration() (*Config, error) {
+	cfg, err := Load(DefaultConfigurationFilePath)
 	if err != nil {
 		if err == ErrConfigFileNotFound {
 			return Load(DefaultFallbackConfigurationFilePath)
 		}
-		return err
+		return nil, err
 	}
-	return nil
+	return cfg, nil
 }
 
 func readConfigurationFile(fileName string) (config *Config, err error) {
@@ -144,23 +155,33 @@ func parseAndValidateConfigBytes(yamlBytes []byte) (config *Config, err error) {
 	} else {
 		// Note that the functions below may panic, and this is on purpose to prevent Gatus from starting with
 		// invalid configurations
-		validateAlertingConfig(config)
-		validateSecurityConfig(config)
-		validateServicesConfig(config)
-		validateKubernetesConfig(config)
-		validateWebConfig(config)
-		validateStorageConfig(config)
+		validateAlertingConfig(config.Alerting, config.Services, config.Debug)
+		if err := validateSecurityConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateServicesConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateKubernetesConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateWebConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateStorageConfig(config); err != nil {
+			return nil, err
+		}
 	}
 	return
 }
 
-func validateStorageConfig(config *Config) {
+func validateStorageConfig(config *Config) error {
 	if config.Storage == nil {
 		config.Storage = &storage.Config{}
 	}
 	err := storage.Initialize(config.Storage)
 	if err != nil {
-		panic(err)
+		return err
 	}
 	// Remove all ServiceStatus that represent services which no longer exist in the configuration
 	var keys []string
@@ -171,44 +192,52 @@ func validateStorageConfig(config *Config) {
 	if numberOfServiceStatusesDeleted > 0 {
 		log.Printf("[config][validateStorageConfig] Deleted %d service statuses because their matching services no longer existed", numberOfServiceStatusesDeleted)
 	}
+	return nil
 }
 
-func validateWebConfig(config *Config) {
+func validateWebConfig(config *Config) error {
 	if config.Web == nil {
 		config.Web = &WebConfig{Address: DefaultAddress, Port: DefaultPort}
 	} else {
-		config.Web.validateAndSetDefaults()
+		return config.Web.validateAndSetDefaults()
 	}
+	return nil
 }
 
-func validateKubernetesConfig(config *Config) {
+// deprecated
+// I don't like the current implementation.
+func validateKubernetesConfig(config *Config) error {
 	if config.Kubernetes != nil && config.Kubernetes.AutoDiscover {
 		if config.Kubernetes.ServiceTemplate == nil {
-			panic("kubernetes.service-template cannot be nil")
+			return errors.New("kubernetes.service-template cannot be nil")
 		}
 		if config.Debug {
 			log.Println("[config][validateKubernetesConfig] Automatically discovering Kubernetes services...")
 		}
 		discoveredServices, err := k8s.DiscoverServices(config.Kubernetes)
 		if err != nil {
-			panic(err)
+			return err
 		}
 		config.Services = append(config.Services, discoveredServices...)
 		log.Printf("[config][validateKubernetesConfig] Discovered %d Kubernetes services", len(discoveredServices))
 	}
+	return nil
 }
 
-func validateServicesConfig(config *Config) {
+func validateServicesConfig(config *Config) error {
 	for _, service := range config.Services {
 		if config.Debug {
 			log.Printf("[config][validateServicesConfig] Validating service '%s'", service.Name)
 		}
-		service.ValidateAndSetDefaults()
+		if err := service.ValidateAndSetDefaults(); err != nil {
+			return err
+		}
 	}
 	log.Printf("[config][validateServicesConfig] Validated %d services", len(config.Services))
+	return nil
 }
 
-func validateSecurityConfig(config *Config) {
+func validateSecurityConfig(config *Config) error {
 	if config.Security != nil {
 		if config.Security.IsValid() {
 			if config.Debug {
@@ -217,44 +246,45 @@ func validateSecurityConfig(config *Config) {
 		} else {
 			// If there was an attempt to configure security, then it must mean that some confidential or private
 			// data are exposed. As a result, we'll force a panic because it's better to be safe than sorry.
-			panic(ErrInvalidSecurityConfig)
+			return ErrInvalidSecurityConfig
 		}
 	}
+	return nil
 }
 
 // validateAlertingConfig validates the alerting configuration
 // Note that the alerting configuration has to be validated before the service configuration, because the default alert
 // returned by provider.AlertProvider.GetDefaultAlert() must be parsed before core.Service.ValidateAndSetDefaults()
 // sets the default alert values when none are set.
-func validateAlertingConfig(config *Config) {
-	if config.Alerting == nil {
+func validateAlertingConfig(alertingConfig *alerting.Config, services []*core.Service, debug bool) {
+	if alertingConfig == nil {
 		log.Printf("[config][validateAlertingConfig] Alerting is not configured")
 		return
 	}
-	alertTypes := []core.AlertType{
-		core.CustomAlert,
-		core.DiscordAlert,
-		core.MattermostAlert,
-		core.MessagebirdAlert,
-		core.PagerDutyAlert,
-		core.SlackAlert,
-		core.TelegramAlert,
-		core.TwilioAlert,
+	alertTypes := []alert.Type{
+		alert.TypeCustom,
+		alert.TypeDiscord,
+		alert.TypeMattermost,
+		alert.TypeMessagebird,
+		alert.TypePagerDuty,
+		alert.TypeSlack,
+		alert.TypeTelegram,
+		alert.TypeTwilio,
 	}
-	var validProviders, invalidProviders []core.AlertType
+	var validProviders, invalidProviders []alert.Type
 	for _, alertType := range alertTypes {
-		alertProvider := GetAlertingProviderByAlertType(config, alertType)
+		alertProvider := alertingConfig.GetAlertingProviderByAlertType(alertType)
 		if alertProvider != nil {
 			if alertProvider.IsValid() {
 				// Parse alerts with the provider's default alert
 				if alertProvider.GetDefaultAlert() != nil {
-					for _, service := range config.Services {
-						for alertIndex, alert := range service.Alerts {
-							if alertType == alert.Type {
-								if config.Debug {
+					for _, service := range services {
+						for alertIndex, serviceAlert := range service.Alerts {
+							if alertType == serviceAlert.Type {
+								if debug {
 									log.Printf("[config][validateAlertingConfig] Parsing alert %d with provider's default alert for provider=%s in service=%s", alertIndex, alertType, service.Name)
 								}
-								provider.ParseWithDefaultAlert(alertProvider.GetDefaultAlert(), alert)
+								provider.ParseWithDefaultAlert(alertProvider.GetDefaultAlert(), serviceAlert)
 							}
 						}
 					}
@@ -270,58 +300,3 @@ func validateAlertingConfig(config *Config) {
 	}
 	log.Printf("[config][validateAlertingConfig] configuredProviders=%s; ignoredProviders=%s", validProviders, invalidProviders)
 }
-
-// GetAlertingProviderByAlertType returns an provider.AlertProvider by its corresponding core.AlertType
-func GetAlertingProviderByAlertType(config *Config, alertType core.AlertType) provider.AlertProvider {
-	switch alertType {
-	case core.CustomAlert:
-		if config.Alerting.Custom == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Custom
-	case core.DiscordAlert:
-		if config.Alerting.Discord == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Discord
-	case core.MattermostAlert:
-		if config.Alerting.Mattermost == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Mattermost
-	case core.MessagebirdAlert:
-		if config.Alerting.Messagebird == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Messagebird
-	case core.PagerDutyAlert:
-		if config.Alerting.PagerDuty == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.PagerDuty
-	case core.SlackAlert:
-		if config.Alerting.Slack == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Slack
-	case core.TelegramAlert:
-		if config.Alerting.Telegram == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Telegram
-	case core.TwilioAlert:
-		if config.Alerting.Twilio == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Twilio
-	}
-	return nil
-}

config/config_test.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/TwinProduction/gatus/alerting"
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/alerting/provider/discord"
 	"github.com/TwinProduction/gatus/alerting/provider/mattermost"
@@ -20,31 +21,15 @@ import (
 	v1 "k8s.io/api/core/v1"
 )
 
-func TestGetBeforeConfigIsLoaded(t *testing.T) {
-	defer func() { recover() }()
-	Get()
-	t.Fatal("Should've panicked because the configuration hasn't been loaded yet")
-}
-
-func TestSet(t *testing.T) {
-	if config != nil {
-		t.Fatal("config should've been nil")
-	}
-	Set(&Config{})
-	if config == nil {
-		t.Fatal("config shouldn't have been nil")
-	}
-}
-
 func TestLoadFileThatDoesNotExist(t *testing.T) {
-	err := Load("file-that-does-not-exist.yaml")
+	_, err := Load("file-that-does-not-exist.yaml")
 	if err == nil {
 		t.Error("Should've returned an error, because the file specified doesn't exist")
 	}
 }
 
 func TestLoadDefaultConfigurationFile(t *testing.T) {
-	err := LoadDefaultConfiguration()
+	_, err := LoadDefaultConfiguration()
 	if err == nil {
 		t.Error("Should've returned an error, because there's no configuration files at the default path nor the default fallback path")
 	}
@@ -419,8 +404,8 @@ services:
 		t.Fatal("There should've been 7 alerts configured")
 	}
 
-	if config.Services[0].Alerts[0].Type != core.SlackAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.SlackAlert, config.Services[0].Alerts[0].Type)
+	if config.Services[0].Alerts[0].Type != alert.TypeSlack {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeSlack, config.Services[0].Alerts[0].Type)
 	}
 	if !config.Services[0].Alerts[0].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -432,8 +417,8 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[0].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[1].Type != core.PagerDutyAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.PagerDutyAlert, config.Services[0].Alerts[1].Type)
+	if config.Services[0].Alerts[1].Type != alert.TypePagerDuty {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypePagerDuty, config.Services[0].Alerts[1].Type)
 	}
 	if config.Services[0].Alerts[1].GetDescription() != "Healthcheck failed 7 times in a row" {
 		t.Errorf("The description of the alert should've been %s, but it was %s", "Healthcheck failed 7 times in a row", config.Services[0].Alerts[1].GetDescription())
@@ -445,8 +430,8 @@ services:
 		t.Errorf("The success threshold of the alert should've been %d, but it was %d", 5, config.Services[0].Alerts[1].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[2].Type != core.MattermostAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.MattermostAlert, config.Services[0].Alerts[2].Type)
+	if config.Services[0].Alerts[2].Type != alert.TypeMattermost {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeMattermost, config.Services[0].Alerts[2].Type)
 	}
 	if !config.Services[0].Alerts[2].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -458,15 +443,15 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[2].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[3].Type != core.MessagebirdAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.MessagebirdAlert, config.Services[0].Alerts[3].Type)
+	if config.Services[0].Alerts[3].Type != alert.TypeMessagebird {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeMessagebird, config.Services[0].Alerts[3].Type)
 	}
 	if config.Services[0].Alerts[3].IsEnabled() {
 		t.Error("The alert should've been disabled")
 	}
 
-	if config.Services[0].Alerts[4].Type != core.DiscordAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.DiscordAlert, config.Services[0].Alerts[4].Type)
+	if config.Services[0].Alerts[4].Type != alert.TypeDiscord {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeDiscord, config.Services[0].Alerts[4].Type)
 	}
 	if !config.Services[0].Alerts[4].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -478,8 +463,8 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[4].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[5].Type != core.TelegramAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.TelegramAlert, config.Services[0].Alerts[5].Type)
+	if config.Services[0].Alerts[5].Type != alert.TypeTelegram {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeTelegram, config.Services[0].Alerts[5].Type)
 	}
 	if !config.Services[0].Alerts[5].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -491,8 +476,8 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[5].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[6].Type != core.TwilioAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.TwilioAlert, config.Services[0].Alerts[6].Type)
+	if config.Services[0].Alerts[6].Type != alert.TypeTwilio {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeTwilio, config.Services[0].Alerts[6].Type)
 	}
 	if !config.Services[0].Alerts[6].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -633,7 +618,7 @@ services:
 	if config.Alerting.Discord.WebhookURL != "http://example.org" {
 		t.Errorf("Discord webhook should've been %s, but was %s", "http://example.org", config.Alerting.Discord.WebhookURL)
 	}
-	if GetAlertingProviderByAlertType(config, core.DiscordAlert) != config.Alerting.Discord {
+	if config.Alerting.GetAlertingProviderByAlertType(alert.TypeDiscord) != config.Alerting.Discord {
 		t.Error("expected discord configuration")
 	}
 
@@ -670,8 +655,8 @@ services:
 		t.Fatal("There should've been 7 alerts configured")
 	}
 
-	if config.Services[0].Alerts[0].Type != core.SlackAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.SlackAlert, config.Services[0].Alerts[0].Type)
+	if config.Services[0].Alerts[0].Type != alert.TypeSlack {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeSlack, config.Services[0].Alerts[0].Type)
 	}
 	if !config.Services[0].Alerts[0].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -683,8 +668,8 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[0].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[1].Type != core.PagerDutyAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.PagerDutyAlert, config.Services[0].Alerts[1].Type)
+	if config.Services[0].Alerts[1].Type != alert.TypePagerDuty {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypePagerDuty, config.Services[0].Alerts[1].Type)
 	}
 	if config.Services[0].Alerts[1].GetDescription() != "default description" {
 		t.Errorf("The description of the alert should've been %s, but it was %s", "default description", config.Services[0].Alerts[1].GetDescription())
@@ -696,8 +681,8 @@ services:
 		t.Errorf("The success threshold of the alert should've been %d, but it was %d", 5, config.Services[0].Alerts[1].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[2].Type != core.MattermostAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.MattermostAlert, config.Services[0].Alerts[2].Type)
+	if config.Services[0].Alerts[2].Type != alert.TypeMattermost {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeMattermost, config.Services[0].Alerts[2].Type)
 	}
 	if !config.Services[0].Alerts[2].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -709,8 +694,8 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[2].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[3].Type != core.MessagebirdAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.MessagebirdAlert, config.Services[0].Alerts[3].Type)
+	if config.Services[0].Alerts[3].Type != alert.TypeMessagebird {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeMessagebird, config.Services[0].Alerts[3].Type)
 	}
 	if config.Services[0].Alerts[3].IsEnabled() {
 		t.Error("The alert should've been disabled")
@@ -719,8 +704,8 @@ services:
 		t.Error("The alert should be sending on resolve")
 	}
 
-	if config.Services[0].Alerts[4].Type != core.DiscordAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.DiscordAlert, config.Services[0].Alerts[4].Type)
+	if config.Services[0].Alerts[4].Type != alert.TypeDiscord {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeDiscord, config.Services[0].Alerts[4].Type)
 	}
 	if !config.Services[0].Alerts[4].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -732,8 +717,8 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[4].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[5].Type != core.TelegramAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.TelegramAlert, config.Services[0].Alerts[5].Type)
+	if config.Services[0].Alerts[5].Type != alert.TypeTelegram {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeTelegram, config.Services[0].Alerts[5].Type)
 	}
 	if !config.Services[0].Alerts[5].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -745,8 +730,8 @@ services:
 		t.Errorf("The default success threshold of the alert should've been %d, but it was %d", 2, config.Services[0].Alerts[5].SuccessThreshold)
 	}
 
-	if config.Services[0].Alerts[6].Type != core.TwilioAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.TwilioAlert, config.Services[0].Alerts[6].Type)
+	if config.Services[0].Alerts[6].Type != alert.TypeTwilio {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeTwilio, config.Services[0].Alerts[6].Type)
 	}
 	if !config.Services[0].Alerts[6].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -800,14 +785,14 @@ services:
 	if len(config.Services) != 1 {
 		t.Error("There should've been 2 services")
 	}
-	if config.Services[0].Alerts[0].Type != core.SlackAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.SlackAlert, config.Services[0].Alerts[0].Type)
+	if config.Services[0].Alerts[0].Type != alert.TypeSlack {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeSlack, config.Services[0].Alerts[0].Type)
 	}
-	if config.Services[0].Alerts[1].Type != core.SlackAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.SlackAlert, config.Services[0].Alerts[1].Type)
+	if config.Services[0].Alerts[1].Type != alert.TypeSlack {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeSlack, config.Services[0].Alerts[1].Type)
 	}
-	if config.Services[0].Alerts[2].Type != core.SlackAlert {
-		t.Errorf("The type of the alert should've been %s, but it was %s", core.SlackAlert, config.Services[0].Alerts[2].Type)
+	if config.Services[0].Alerts[2].Type != alert.TypeSlack {
+		t.Errorf("The type of the alert should've been %s, but it was %s", alert.TypeSlack, config.Services[0].Alerts[2].Type)
 	}
 	if !config.Services[0].Alerts[0].IsEnabled() {
 		t.Error("The alert should've been enabled")
@@ -1209,40 +1194,38 @@ kubernetes:
 }
 
 func TestGetAlertingProviderByAlertType(t *testing.T) {
-	cfg := &Config{
-		Alerting: &alerting.Config{
-			Custom:      &custom.AlertProvider{},
-			Discord:     &discord.AlertProvider{},
-			Mattermost:  &mattermost.AlertProvider{},
-			Messagebird: &messagebird.AlertProvider{},
-			PagerDuty:   &pagerduty.AlertProvider{},
-			Slack:       &slack.AlertProvider{},
-			Telegram:    &telegram.AlertProvider{},
-			Twilio:      &twilio.AlertProvider{},
-		},
+	alertingConfig := &alerting.Config{
+		Custom:      &custom.AlertProvider{},
+		Discord:     &discord.AlertProvider{},
+		Mattermost:  &mattermost.AlertProvider{},
+		Messagebird: &messagebird.AlertProvider{},
+		PagerDuty:   &pagerduty.AlertProvider{},
+		Slack:       &slack.AlertProvider{},
+		Telegram:    &telegram.AlertProvider{},
+		Twilio:      &twilio.AlertProvider{},
 	}
-	if GetAlertingProviderByAlertType(cfg, core.CustomAlert) != cfg.Alerting.Custom {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypeCustom) != alertingConfig.Custom {
 		t.Error("expected Custom configuration")
 	}
-	if GetAlertingProviderByAlertType(cfg, core.DiscordAlert) != cfg.Alerting.Discord {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypeDiscord) != alertingConfig.Discord {
 		t.Error("expected Discord configuration")
 	}
-	if GetAlertingProviderByAlertType(cfg, core.MattermostAlert) != cfg.Alerting.Mattermost {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypeMattermost) != alertingConfig.Mattermost {
 		t.Error("expected Mattermost configuration")
 	}
-	if GetAlertingProviderByAlertType(cfg, core.MessagebirdAlert) != cfg.Alerting.Messagebird {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypeMessagebird) != alertingConfig.Messagebird {
 		t.Error("expected Messagebird configuration")
 	}
-	if GetAlertingProviderByAlertType(cfg, core.PagerDutyAlert) != cfg.Alerting.PagerDuty {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypePagerDuty) != alertingConfig.PagerDuty {
 		t.Error("expected PagerDuty configuration")
 	}
-	if GetAlertingProviderByAlertType(cfg, core.SlackAlert) != cfg.Alerting.Slack {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypeSlack) != alertingConfig.Slack {
 		t.Error("expected Slack configuration")
 	}
-	if GetAlertingProviderByAlertType(cfg, core.TelegramAlert) != cfg.Alerting.Telegram {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypeTelegram) != alertingConfig.Telegram {
 		t.Error("expected Telegram configuration")
 	}
-	if GetAlertingProviderByAlertType(cfg, core.TwilioAlert) != cfg.Alerting.Twilio {
+	if alertingConfig.GetAlertingProviderByAlertType(alert.TypeTwilio) != alertingConfig.Twilio {
 		t.Error("expected Twilio configuration")
 	}
 }

config/web.go

@@ -16,7 +16,7 @@ type WebConfig struct {
 }
 
 // validateAndSetDefaults checks and sets the default values for fields that are not set
-func (web *WebConfig) validateAndSetDefaults() {
+func (web *WebConfig) validateAndSetDefaults() error {
 	// Validate the Address
 	if len(web.Address) == 0 {
 		web.Address = DefaultAddress
@@ -25,8 +25,9 @@ func (web *WebConfig) validateAndSetDefaults() {
 	if web.Port == 0 {
 		web.Port = DefaultPort
 	} else if web.Port < 0 || web.Port > math.MaxUint16 {
-		panic(fmt.Sprintf("invalid port: value should be between %d and %d", 0, math.MaxUint16))
+		return fmt.Errorf("invalid port: value should be between %d and %d", 0, math.MaxUint16)
 	}
+	return nil
 }
 
 // SocketAddress returns the combination of the Address and the Port

controller/controller.go

@@ -44,20 +44,19 @@ func init() {
 }
 
 // Handle creates the router and starts the server
-func Handle() {
-	cfg := config.Get()
-	var router http.Handler = CreateRouter(cfg)
+func Handle(securityConfig *security.Config, webConfig *config.WebConfig, enableMetrics bool) {
+	var router http.Handler = CreateRouter(securityConfig, enableMetrics)
 	if os.Getenv("ENVIRONMENT") == "dev" {
 		router = developmentCorsHandler(router)
 	}
 	server = &http.Server{
-		Addr:         fmt.Sprintf("%s:%d", cfg.Web.Address, cfg.Web.Port),
+		Addr:         fmt.Sprintf("%s:%d", webConfig.Address, webConfig.Port),
 		Handler:      router,
 		ReadTimeout:  15 * time.Second,
 		WriteTimeout: 15 * time.Second,
 		IdleTimeout:  15 * time.Second,
 	}
-	log.Println("[controller][Handle] Listening on " + cfg.Web.SocketAddress())
+	log.Println("[controller][Handle] Listening on " + webConfig.SocketAddress())
 	if os.Getenv("ROUTER_TEST") == "true" {
 		return
 	}
@@ -73,15 +72,15 @@ func Shutdown() {
 }
 
 // CreateRouter creates the router for the http server
-func CreateRouter(cfg *config.Config) *mux.Router {
+func CreateRouter(securityConfig *security.Config, enabledMetrics bool) *mux.Router {
 	router := mux.NewRouter()
-	if cfg.Metrics {
+	if enabledMetrics {
 		router.Handle("/metrics", promhttp.Handler()).Methods("GET")
 	}
 	router.Handle("/health", health.Handler().WithJSON(true)).Methods("GET")
 	router.HandleFunc("/favicon.ico", favIconHandler).Methods("GET")
-	router.HandleFunc("/api/v1/statuses", secureIfNecessary(cfg, serviceStatusesHandler)).Methods("GET") // No GzipHandler for this one, because we cache the content
-	router.HandleFunc("/api/v1/statuses/{key}", secureIfNecessary(cfg, GzipHandlerFunc(serviceStatusHandler))).Methods("GET")
+	router.HandleFunc("/api/v1/statuses", secureIfNecessary(securityConfig, serviceStatusesHandler)).Methods("GET") // No GzipHandler for this one, because we cache the content
+	router.HandleFunc("/api/v1/statuses/{key}", secureIfNecessary(securityConfig, GzipHandlerFunc(serviceStatusHandler))).Methods("GET")
 	router.HandleFunc("/api/v1/badges/uptime/{duration}/{identifier}", badgeHandler).Methods("GET")
 	// SPA
 	router.HandleFunc("/services/{service}", spaHandler).Methods("GET")
@@ -90,9 +89,9 @@ func CreateRouter(cfg *config.Config) *mux.Router {
 	return router
 }
 
-func secureIfNecessary(cfg *config.Config, handler http.HandlerFunc) http.HandlerFunc {
-	if cfg.Security != nil && cfg.Security.IsValid() {
-		return security.Handler(handler, cfg.Security)
+func secureIfNecessary(securityConfig *security.Config, handler http.HandlerFunc) http.HandlerFunc {
+	if securityConfig != nil && securityConfig.IsValid() {
+		return security.Handler(handler, securityConfig)
 	}
 	return handler
 }

controller/controller_test.go

@@ -105,7 +105,7 @@ func TestCreateRouter(t *testing.T) {
 	}
 	watchdog.UpdateServiceStatuses(cfg.Services[0], &core.Result{Success: true, Duration: time.Millisecond, Timestamp: time.Now()})
 	watchdog.UpdateServiceStatuses(cfg.Services[1], &core.Result{Success: false, Duration: time.Second, Timestamp: time.Now()})
-	router := CreateRouter(cfg)
+	router := CreateRouter(cfg.Security, cfg.Metrics)
 	type Scenario struct {
 		Name         string
 		Path         string
@@ -235,12 +235,10 @@ func TestHandle(t *testing.T) {
 			},
 		},
 	}
-	config.Set(cfg)
-	defer config.Set(nil)
 	_ = os.Setenv("ROUTER_TEST", "true")
 	_ = os.Setenv("ENVIRONMENT", "dev")
 	defer os.Clearenv()
-	Handle()
+	Handle(cfg.Security, cfg.Web, cfg.Metrics)
 	defer Shutdown()
 	request, _ := http.NewRequest("GET", "/health", nil)
 	responseRecorder := httptest.NewRecorder()
@@ -273,7 +271,7 @@ func TestServiceStatusesHandler(t *testing.T) {
 	// Can't be bothered dealing with timezone issues on the worker that runs the automated tests
 	firstResult.Timestamp = time.Time{}
 	secondResult.Timestamp = time.Time{}
-	router := CreateRouter(&config.Config{})
+	router := CreateRouter(nil, false)
 
 	type Scenario struct {
 		Name         string

core/dns.go

@@ -29,16 +29,17 @@ type DNS struct {
 	QueryName string `yaml:"query-name"`
 }
 
-func (d *DNS) validateAndSetDefault() {
+func (d *DNS) validateAndSetDefault() error {
 	if len(d.QueryName) == 0 {
-		panic(ErrDNSWithNoQueryName)
+		return ErrDNSWithNoQueryName
 	}
 	if !strings.HasSuffix(d.QueryName, ".") {
 		d.QueryName += "."
 	}
 	if _, ok := dns.StringToType[d.QueryType]; !ok {
-		panic(ErrDNSWithInvalidQueryType)
+		return ErrDNSWithInvalidQueryType
 	}
+	return nil
 }
 
 func (d *DNS) query(url string, result *Result) {

core/service.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/client"
 )
 
@@ -72,7 +73,7 @@ type Service struct {
 	Conditions []*Condition `yaml:"conditions"`
 
 	// Alerts is the alerting configuration for the service in case of failure
-	Alerts []*Alert `yaml:"alerts"`
+	Alerts []*alert.Alert `yaml:"alerts"`
 
 	// Insecure is whether to skip verifying the server's certificate chain and host name
 	Insecure bool `yaml:"insecure,omitempty"`
@@ -85,7 +86,7 @@ type Service struct {
 }
 
 // ValidateAndSetDefaults validates the service's configuration and sets the default value of fields that have one
-func (service *Service) ValidateAndSetDefaults() {
+func (service *Service) ValidateAndSetDefaults() error {
 	// Set default values
 	if service.Interval == 0 {
 		service.Interval = 1 * time.Minute
@@ -105,32 +106,32 @@ func (service *Service) ValidateAndSetDefaults() {
 	if _, contentTypeHeaderExists := service.Headers[ContentTypeHeader]; !contentTypeHeaderExists && service.GraphQL {
 		service.Headers[ContentTypeHeader] = "application/json"
 	}
-	for _, alert := range service.Alerts {
-		if alert.FailureThreshold <= 0 {
-			alert.FailureThreshold = 3
+	for _, serviceAlert := range service.Alerts {
+		if serviceAlert.FailureThreshold <= 0 {
+			serviceAlert.FailureThreshold = 3
 		}
-		if alert.SuccessThreshold <= 0 {
-			alert.SuccessThreshold = 2
+		if serviceAlert.SuccessThreshold <= 0 {
+			serviceAlert.SuccessThreshold = 2
 		}
 	}
 	if len(service.Name) == 0 {
-		panic(ErrServiceWithNoName)
+		return ErrServiceWithNoName
 	}
 	if len(service.URL) == 0 {
-		panic(ErrServiceWithNoURL)
+		return ErrServiceWithNoURL
 	}
 	if len(service.Conditions) == 0 {
-		panic(ErrServiceWithNoCondition)
+		return ErrServiceWithNoCondition
 	}
 	if service.DNS != nil {
-		service.DNS.validateAndSetDefault()
-		return
+		return service.DNS.validateAndSetDefault()
 	}
 	// Make sure that the request can be created
 	_, err := http.NewRequest(service.Method, service.URL, bytes.NewBuffer([]byte(service.Body)))
 	if err != nil {
-		panic(err)
+		return err
 	}
+	return nil
 }
 
 // EvaluateHealth sends a request to the service's URL and evaluates the conditions of the service.
@@ -155,8 +156,8 @@ func (service *Service) EvaluateHealth() *Result {
 }
 
 // GetAlertsTriggered returns a slice of alerts that have been triggered
-func (service *Service) GetAlertsTriggered() []Alert {
-	var alerts []Alert
+func (service *Service) GetAlertsTriggered() []alert.Alert {
+	var alerts []alert.Alert
 	if service.NumberOfFailuresInARow == 0 {
 		return alerts
 	}

core/service_test.go

@@ -5,6 +5,8 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/TwinProduction/gatus/alerting/alert"
 )
 
 func TestService_ValidateAndSetDefaults(t *testing.T) {
@@ -13,7 +15,7 @@ func TestService_ValidateAndSetDefaults(t *testing.T) {
 		Name:       "twinnation-health",
 		URL:        "https://twinnation.org/health",
 		Conditions: []*Condition{&condition},
-		Alerts:     []*Alert{{Type: PagerDutyAlert}},
+		Alerts:     []*alert.Alert{{Type: alert.TypePagerDuty}},
 	}
 	service.ValidateAndSetDefaults()
 	if service.Method != "GET" {
@@ -98,7 +100,7 @@ func TestService_GetAlertsTriggered(t *testing.T) {
 		Name:       "twinnation-health",
 		URL:        "https://twinnation.org/health",
 		Conditions: []*Condition{&condition},
-		Alerts:     []*Alert{{Type: PagerDutyAlert, Enabled: &enabled}},
+		Alerts:     []*alert.Alert{{Type: alert.TypePagerDuty, Enabled: &enabled}},
 	}
 	service.ValidateAndSetDefaults()
 	if service.NumberOfFailuresInARow != 0 {

main.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 
 	"github.com/TwinProduction/gatus/config"
 	"github.com/TwinProduction/gatus/controller"
@@ -13,37 +14,75 @@ import (
 )
 
 func main() {
-	cfg := loadConfiguration()
-	go watchdog.Monitor(cfg)
-	go controller.Handle()
+	cfg, err := loadConfiguration()
+	if err != nil {
+		panic(err)
+	}
+	start(cfg)
 	// Wait for termination signal
-	sig := make(chan os.Signal, 1)
+	signalChannel := make(chan os.Signal, 1)
 	done := make(chan bool, 1)
-	signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
+	signal.Notify(signalChannel, os.Interrupt, syscall.SIGTERM)
 	go func() {
-		<-sig
+		<-signalChannel
 		log.Println("Received termination signal, attempting to gracefully shut down")
-		controller.Shutdown()
-		err := storage.Get().Save()
-		if err != nil {
-			log.Println("Failed to save storage provider:", err.Error())
-		}
+		stop()
+		save()
 		done <- true
 	}()
 	<-done
 	log.Println("Shutting down")
 }
 
-func loadConfiguration() *config.Config {
-	var err error
+func stop() {
+	watchdog.Shutdown()
+	controller.Shutdown()
+}
+
+func save() {
+	err := storage.Get().Save()
+	if err != nil {
+		log.Println("Failed to save storage provider:", err.Error())
+	}
+}
+
+func start(cfg *config.Config) {
+	go controller.Handle(cfg.Security, cfg.Web, cfg.Metrics)
+	watchdog.Monitor(cfg)
+	go listenToConfigurationFileChanges(cfg)
+}
+
+func loadConfiguration() (cfg *config.Config, err error) {
 	customConfigFile := os.Getenv("GATUS_CONFIG_FILE")
 	if len(customConfigFile) > 0 {
-		err = config.Load(customConfigFile)
+		cfg, err = config.Load(customConfigFile)
 	} else {
-		err = config.LoadDefaultConfiguration()
+		cfg, err = config.LoadDefaultConfiguration()
+	}
+	return
+}
+
+func listenToConfigurationFileChanges(cfg *config.Config) {
+	for {
+		time.Sleep(30 * time.Second)
+		if cfg.HasLoadedConfigurationFileBeenModified() {
+			log.Println("[main][listenToConfigurationFileChanges] Configuration file has been modified")
+			save()
+			updatedConfig, err := loadConfiguration()
+			if err != nil {
+				if cfg.SkipInvalidConfigUpdate {
+					log.Println("[main][listenToConfigurationFileChanges] Failed to load new configuration:", err.Error())
+					log.Println("[main][listenToConfigurationFileChanges] The configuration file was updated, but it is not valid. The old configuration will continue being used.")
+					// Update the last file modification time to avoid trying to process the same invalid configuration again
+					cfg.UpdateLastFileModTime()
+					continue
+				} else {
+					panic(err)
+				}
+			}
+			stop()
+			start(updatedConfig)
+			return
+		}
 	}
-	if err != nil {
-		panic(err)
-	}
-	return config.Get()
 }

metric/metric.go

@@ -5,7 +5,6 @@ import (
 	"strconv"
 	"sync"
 
-	"github.com/TwinProduction/gatus/config"
 	"github.com/TwinProduction/gatus/core"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
@@ -19,18 +18,16 @@ var (
 // PublishMetricsForService publishes metrics for the given service and its result.
 // These metrics will be exposed at /metrics if the metrics are enabled
 func PublishMetricsForService(service *core.Service, result *core.Result) {
-	if config.Get().Metrics {
-		rwLock.Lock()
-		gauge, exists := gauges[fmt.Sprintf("%s_%s", service.Name, service.URL)]
-		if !exists {
-			gauge = promauto.NewGaugeVec(prometheus.GaugeOpts{
-				Subsystem:   "gatus",
-				Name:        "tasks",
-				ConstLabels: prometheus.Labels{"service": service.Name, "url": service.URL},
-			}, []string{"status", "success"})
-			gauges[fmt.Sprintf("%s_%s", service.Name, service.URL)] = gauge
-		}
-		rwLock.Unlock()
-		gauge.WithLabelValues(strconv.Itoa(result.HTTPStatus), strconv.FormatBool(result.Success)).Inc()
+	rwLock.Lock()
+	gauge, exists := gauges[fmt.Sprintf("%s_%s", service.Name, service.URL)]
+	if !exists {
+		gauge = promauto.NewGaugeVec(prometheus.GaugeOpts{
+			Subsystem:   "gatus",
+			Name:        "tasks",
+			ConstLabels: prometheus.Labels{"service": service.Name, "url": service.URL},
+		}, []string{"status", "success"})
+		gauges[fmt.Sprintf("%s_%s", service.Name, service.URL)] = gauge
 	}
+	rwLock.Unlock()
+	gauge.WithLabelValues(strconv.Itoa(result.HTTPStatus), strconv.FormatBool(result.Success)).Inc()
 }

storage/storage.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"context"
 	"log"
 	"time"
 
@@ -15,6 +16,9 @@ var (
 	// Because store.Store is an interface, a nil check wouldn't be sufficient, so instead of doing reflection
 	// every single time Get is called, we'll just lazily keep track of its existence through this variable
 	initialized bool
+
+	ctx        context.Context
+	cancelFunc context.CancelFunc
 )
 
 // Get retrieves the storage provider
@@ -40,24 +44,34 @@ func Initialize(cfg *Config) error {
 			return err
 		}
 	} else {
+		if cancelFunc != nil {
+			// Stop the active autoSave task
+			cancelFunc()
+		}
+		ctx, cancelFunc = context.WithCancel(context.Background())
 		log.Printf("[storage][Initialize] Creating storage provider with file=%s", cfg.File)
 		provider, err = memory.NewStore(cfg.File)
 		if err != nil {
 			return err
 		}
-		go autoSave(7 * time.Minute)
+		go autoSave(7*time.Minute, ctx)
 	}
 	return nil
 }
 
-// autoSave automatically calls the Save function of the provider at every interval
-func autoSave(interval time.Duration) {
+// autoSave automatically calls the SaveFunc function of the provider at every interval
+func autoSave(interval time.Duration, ctx context.Context) {
 	for {
-		time.Sleep(interval)
-		log.Printf("[storage][autoSave] Saving")
-		err := provider.Save()
-		if err != nil {
-			log.Println("[storage][autoSave] Save failed:", err.Error())
+		select {
+		case <-ctx.Done():
+			log.Printf("[storage][autoSave] Stopping active job")
+			return
+		case <-time.After(interval):
+			log.Printf("[storage][autoSave] Saving")
+			err := provider.Save()
+			if err != nil {
+				log.Println("[storage][autoSave] Save failed:", err.Error())
+			}
 		}
 	}
 }

watchdog/alerting.go

@@ -4,96 +4,96 @@ import (
 	"encoding/json"
 	"log"
 
-	"github.com/TwinProduction/gatus/config"
+	"github.com/TwinProduction/gatus/alerting"
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/core"
 )
 
 // HandleAlerting takes care of alerts to resolve and alerts to trigger based on result success or failure
-func HandleAlerting(service *core.Service, result *core.Result) {
-	cfg := config.Get()
-	if cfg.Alerting == nil {
+func HandleAlerting(service *core.Service, result *core.Result, alertingConfig *alerting.Config, debug bool) {
+	if alertingConfig == nil {
 		return
 	}
 	if result.Success {
-		handleAlertsToResolve(service, result, cfg)
+		handleAlertsToResolve(service, result, alertingConfig, debug)
 	} else {
-		handleAlertsToTrigger(service, result, cfg)
+		handleAlertsToTrigger(service, result, alertingConfig, debug)
 	}
 }
 
-func handleAlertsToTrigger(service *core.Service, result *core.Result, cfg *config.Config) {
+func handleAlertsToTrigger(service *core.Service, result *core.Result, alertingConfig *alerting.Config, debug bool) {
 	service.NumberOfSuccessesInARow = 0
 	service.NumberOfFailuresInARow++
-	for _, alert := range service.Alerts {
-		// If the alert hasn't been triggered, move to the next one
-		if !alert.IsEnabled() || alert.FailureThreshold > service.NumberOfFailuresInARow {
+	for _, serviceAlert := range service.Alerts {
+		// If the serviceAlert hasn't been triggered, move to the next one
+		if !serviceAlert.IsEnabled() || serviceAlert.FailureThreshold > service.NumberOfFailuresInARow {
 			continue
 		}
-		if alert.Triggered {
-			if cfg.Debug {
-				log.Printf("[watchdog][handleAlertsToTrigger] Alert for service=%s with description='%s' has already been TRIGGERED, skipping", service.Name, alert.GetDescription())
+		if serviceAlert.Triggered {
+			if debug {
+				log.Printf("[watchdog][handleAlertsToTrigger] Alert for service=%s with description='%s' has already been TRIGGERED, skipping", service.Name, serviceAlert.GetDescription())
 			}
 			continue
 		}
-		alertProvider := config.GetAlertingProviderByAlertType(cfg, alert.Type)
+		alertProvider := alertingConfig.GetAlertingProviderByAlertType(serviceAlert.Type)
 		if alertProvider != nil && alertProvider.IsValid() {
-			log.Printf("[watchdog][handleAlertsToTrigger] Sending %s alert because alert for service=%s with description='%s' has been TRIGGERED", alert.Type, service.Name, alert.GetDescription())
-			customAlertProvider := alertProvider.ToCustomAlertProvider(service, alert, result, false)
+			log.Printf("[watchdog][handleAlertsToTrigger] Sending %s serviceAlert because serviceAlert for service=%s with description='%s' has been TRIGGERED", serviceAlert.Type, service.Name, serviceAlert.GetDescription())
+			customAlertProvider := alertProvider.ToCustomAlertProvider(service, serviceAlert, result, false)
 			// TODO: retry on error
 			var err error
 			// We need to extract the DedupKey from PagerDuty's response
-			if alert.Type == core.PagerDutyAlert {
+			if serviceAlert.Type == alert.TypePagerDuty {
 				var body []byte
-				if body, err = customAlertProvider.Send(service.Name, alert.GetDescription(), false); err == nil {
+				if body, err = customAlertProvider.Send(service.Name, serviceAlert.GetDescription(), false); err == nil {
 					var response pagerDutyResponse
 					if err = json.Unmarshal(body, &response); err != nil {
 						log.Printf("[watchdog][handleAlertsToTrigger] Ran into error unmarshaling pagerduty response: %s", err.Error())
 					} else {
-						alert.ResolveKey = response.DedupKey
+						serviceAlert.ResolveKey = response.DedupKey
 					}
 				}
 			} else {
-				// All other alert types don't need to extract anything from the body, so we can just send the request right away
-				_, err = customAlertProvider.Send(service.Name, alert.GetDescription(), false)
+				// All other serviceAlert types don't need to extract anything from the body, so we can just send the request right away
+				_, err = customAlertProvider.Send(service.Name, serviceAlert.GetDescription(), false)
 			}
 			if err != nil {
-				log.Printf("[watchdog][handleAlertsToTrigger] Failed to send an alert for service=%s: %s", service.Name, err.Error())
+				log.Printf("[watchdog][handleAlertsToTrigger] Failed to send an serviceAlert for service=%s: %s", service.Name, err.Error())
 			} else {
-				alert.Triggered = true
+				serviceAlert.Triggered = true
 			}
 		} else {
-			log.Printf("[watchdog][handleAlertsToResolve] Not sending alert of type=%s despite being TRIGGERED, because the provider wasn't configured properly", alert.Type)
+			log.Printf("[watchdog][handleAlertsToResolve] Not sending serviceAlert of type=%s despite being TRIGGERED, because the provider wasn't configured properly", serviceAlert.Type)
 		}
 	}
 }
 
-func handleAlertsToResolve(service *core.Service, result *core.Result, cfg *config.Config) {
+func handleAlertsToResolve(service *core.Service, result *core.Result, alertingConfig *alerting.Config, debug bool) {
 	service.NumberOfSuccessesInARow++
-	for _, alert := range service.Alerts {
-		if !alert.IsEnabled() || !alert.Triggered || alert.SuccessThreshold > service.NumberOfSuccessesInARow {
+	for _, serviceAlert := range service.Alerts {
+		if !serviceAlert.IsEnabled() || !serviceAlert.Triggered || serviceAlert.SuccessThreshold > service.NumberOfSuccessesInARow {
 			continue
 		}
-		// Even if the alert provider returns an error, we still set the alert's Triggered variable to false.
+		// Even if the serviceAlert provider returns an error, we still set the serviceAlert's Triggered variable to false.
 		// Further explanation can be found on Alert's Triggered field.
-		alert.Triggered = false
-		if !alert.IsSendingOnResolved() {
+		serviceAlert.Triggered = false
+		if !serviceAlert.IsSendingOnResolved() {
 			continue
 		}
-		alertProvider := config.GetAlertingProviderByAlertType(cfg, alert.Type)
+		alertProvider := alertingConfig.GetAlertingProviderByAlertType(serviceAlert.Type)
 		if alertProvider != nil && alertProvider.IsValid() {
-			log.Printf("[watchdog][handleAlertsToResolve] Sending %s alert because alert for service=%s with description='%s' has been RESOLVED", alert.Type, service.Name, alert.GetDescription())
-			customAlertProvider := alertProvider.ToCustomAlertProvider(service, alert, result, true)
+			log.Printf("[watchdog][handleAlertsToResolve] Sending %s serviceAlert because serviceAlert for service=%s with description='%s' has been RESOLVED", serviceAlert.Type, service.Name, serviceAlert.GetDescription())
+			customAlertProvider := alertProvider.ToCustomAlertProvider(service, serviceAlert, result, true)
 			// TODO: retry on error
-			_, err := customAlertProvider.Send(service.Name, alert.GetDescription(), true)
+			_, err := customAlertProvider.Send(service.Name, serviceAlert.GetDescription(), true)
 			if err != nil {
-				log.Printf("[watchdog][handleAlertsToResolve] Failed to send an alert for service=%s: %s", service.Name, err.Error())
+				log.Printf("[watchdog][handleAlertsToResolve] Failed to send an serviceAlert for service=%s: %s", service.Name, err.Error())
 			} else {
-				if alert.Type == core.PagerDutyAlert {
-					alert.ResolveKey = ""
+				if serviceAlert.Type == alert.TypePagerDuty {
+					serviceAlert.ResolveKey = ""
 				}
 			}
 		} else {
-			log.Printf("[watchdog][handleAlertsToResolve] Not sending alert of type=%s despite being RESOLVED, because the provider wasn't configured properly", alert.Type)
+			log.Printf("[watchdog][handleAlertsToResolve] Not sending serviceAlert of type=%s despite being RESOLVED, because the provider wasn't configured properly", serviceAlert.Type)
 		}
 	}
 	service.NumberOfFailuresInARow = 0

watchdog/alerting_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/TwinProduction/gatus/alerting"
+	"github.com/TwinProduction/gatus/alerting/alert"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/alerting/provider/pagerduty"
 	"github.com/TwinProduction/gatus/config"
@@ -24,13 +25,12 @@ func TestHandleAlerting(t *testing.T) {
 			},
 		},
 	}
-	config.Set(cfg)
 	enabled := true
 	service := &core.Service{
 		URL: "http://example.com",
-		Alerts: []*core.Alert{
+		Alerts: []*alert.Alert{
 			{
-				Type:             core.CustomAlert,
+				Type:             alert.TypeCustom,
 				Enabled:          &enabled,
 				FailureThreshold: 2,
 				SuccessThreshold: 3,
@@ -41,50 +41,40 @@ func TestHandleAlerting(t *testing.T) {
 	}
 
 	verify(t, service, 0, 0, false, "The alert shouldn't start triggered")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 1, 0, false, "The alert shouldn't have triggered")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 2, 0, true, "The alert should've triggered")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 3, 0, true, "The alert should still be triggered")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 4, 0, true, "The alert should still be triggered")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, true, "The alert should still be triggered (because service.Alerts[0].SuccessThreshold is 3)")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 2, true, "The alert should still be triggered (because service.Alerts[0].SuccessThreshold is 3)")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 3, false, "The alert should've been resolved")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 4, false, "The alert should no longer be triggered")
 }
 
 func TestHandleAlertingWhenAlertingConfigIsNil(t *testing.T) {
 	_ = os.Setenv("MOCK_ALERT_PROVIDER", "true")
 	defer os.Clearenv()
-
-	cfg := &config.Config{
-		Debug:    true,
-		Alerting: nil,
-	}
-	config.Set(cfg)
-	HandleAlerting(nil, nil)
+	HandleAlerting(nil, nil, nil, true)
 }
 
 func TestHandleAlertingWithBadAlertProvider(t *testing.T) {
 	_ = os.Setenv("MOCK_ALERT_PROVIDER", "true")
 	defer os.Clearenv()
 
-	cfg := &config.Config{
-		Alerting: &alerting.Config{},
-	}
-	config.Set(cfg)
 	enabled := true
 	service := &core.Service{
 		URL: "http://example.com",
-		Alerts: []*core.Alert{
+		Alerts: []*alert.Alert{
 			{
-				Type:             core.CustomAlert,
+				Type:             alert.TypeCustom,
 				Enabled:          &enabled,
 				FailureThreshold: 1,
 				SuccessThreshold: 1,
@@ -95,9 +85,9 @@ func TestHandleAlertingWithBadAlertProvider(t *testing.T) {
 	}
 
 	verify(t, service, 0, 0, false, "The alert shouldn't start triggered")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, &alerting.Config{}, false)
 	verify(t, service, 1, 0, false, "The alert shouldn't have triggered")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, &alerting.Config{}, false)
 	verify(t, service, 2, 0, false, "The alert shouldn't have triggered, because the provider wasn't configured properly")
 }
 
@@ -114,13 +104,12 @@ func TestHandleAlertingWhenTriggeredAlertIsAlmostResolvedButServiceStartFailingA
 			},
 		},
 	}
-	config.Set(cfg)
 	enabled := true
 	service := &core.Service{
 		URL: "http://example.com",
-		Alerts: []*core.Alert{
+		Alerts: []*alert.Alert{
 			{
-				Type:             core.CustomAlert,
+				Type:             alert.TypeCustom,
 				Enabled:          &enabled,
 				FailureThreshold: 2,
 				SuccessThreshold: 3,
@@ -132,7 +121,7 @@ func TestHandleAlertingWhenTriggeredAlertIsAlmostResolvedButServiceStartFailingA
 	}
 
 	// This test simulate an alert that was already triggered
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 2, 0, true, "The alert was already triggered at the beginning of this test")
 }
 
@@ -149,14 +138,13 @@ func TestHandleAlertingWhenTriggeredAlertIsResolvedButSendOnResolvedIsFalse(t *t
 			},
 		},
 	}
-	config.Set(cfg)
 	enabled := true
 	disabled := false
 	service := &core.Service{
 		URL: "http://example.com",
-		Alerts: []*core.Alert{
+		Alerts: []*alert.Alert{
 			{
-				Type:             core.CustomAlert,
+				Type:             alert.TypeCustom,
 				Enabled:          &enabled,
 				FailureThreshold: 1,
 				SuccessThreshold: 1,
@@ -167,7 +155,7 @@ func TestHandleAlertingWhenTriggeredAlertIsResolvedButSendOnResolvedIsFalse(t *t
 		NumberOfFailuresInARow: 1,
 	}
 
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, false, "The alert should've been resolved")
 }
 
@@ -183,13 +171,12 @@ func TestHandleAlertingWhenTriggeredAlertIsResolvedPagerDuty(t *testing.T) {
 			},
 		},
 	}
-	config.Set(cfg)
 	enabled := true
 	service := &core.Service{
 		URL: "http://example.com",
-		Alerts: []*core.Alert{
+		Alerts: []*alert.Alert{
 			{
-				Type:             core.PagerDutyAlert,
+				Type:             alert.TypePagerDuty,
 				Enabled:          &enabled,
 				FailureThreshold: 1,
 				SuccessThreshold: 1,
@@ -200,10 +187,10 @@ func TestHandleAlertingWhenTriggeredAlertIsResolvedPagerDuty(t *testing.T) {
 		NumberOfFailuresInARow: 0,
 	}
 
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 1, 0, true, "")
 
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, false, "The alert should've been resolved")
 }
 
@@ -220,13 +207,12 @@ func TestHandleAlertingWithProviderThatReturnsAnError(t *testing.T) {
 			},
 		},
 	}
-	config.Set(cfg)
 	enabled := true
 	service := &core.Service{
 		URL: "http://example.com",
-		Alerts: []*core.Alert{
+		Alerts: []*alert.Alert{
 			{
-				Type:             core.CustomAlert,
+				Type:             alert.TypeCustom,
 				Enabled:          &enabled,
 				FailureThreshold: 2,
 				SuccessThreshold: 2,
@@ -237,32 +223,32 @@ func TestHandleAlertingWithProviderThatReturnsAnError(t *testing.T) {
 	}
 
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "true")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 1, 0, false, "")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 2, 0, false, "The alert should have failed to trigger, because the alert provider is returning an error")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 3, 0, false, "The alert should still not be triggered, because the alert provider is still returning an error")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 4, 0, false, "The alert should still not be triggered, because the alert provider is still returning an error")
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "false")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 5, 0, true, "The alert should've been triggered because the alert provider is no longer returning an error")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, true, "The alert should've still been triggered")
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "true")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 2, false, "The alert should've been resolved DESPITE THE ALERT PROVIDER RETURNING AN ERROR. See Alert.Triggered for further explanation.")
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "false")
 
 	// Make sure that everything's working as expected after a rough patch
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 1, 0, false, "")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 2, 0, true, "The alert should have triggered")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, true, "The alert should still be triggered")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 2, false, "The alert should have been resolved")
 }
 
@@ -279,13 +265,12 @@ func TestHandleAlertingWithProviderThatOnlyReturnsErrorOnResolve(t *testing.T) {
 			},
 		},
 	}
-	config.Set(cfg)
 	enabled := true
 	service := &core.Service{
 		URL: "http://example.com",
-		Alerts: []*core.Alert{
+		Alerts: []*alert.Alert{
 			{
-				Type:             core.CustomAlert,
+				Type:             alert.TypeCustom,
 				Enabled:          &enabled,
 				FailureThreshold: 1,
 				SuccessThreshold: 1,
@@ -295,27 +280,27 @@ func TestHandleAlertingWithProviderThatOnlyReturnsErrorOnResolve(t *testing.T) {
 		},
 	}
 
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 1, 0, true, "")
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "true")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, false, "")
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "false")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 1, 0, true, "")
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "true")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, false, "")
 	_ = os.Setenv("MOCK_ALERT_PROVIDER_ERROR", "false")
 
 	// Make sure that everything's working as expected after a rough patch
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 1, 0, true, "")
-	HandleAlerting(service, &core.Result{Success: false})
+	HandleAlerting(service, &core.Result{Success: false}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 2, 0, true, "")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 1, false, "")
-	HandleAlerting(service, &core.Result{Success: true})
+	HandleAlerting(service, &core.Result{Success: true}, cfg.Alerting, cfg.Debug)
 	verify(t, service, 0, 2, false, "")
 }
 

watchdog/watchdog.go

@@ -1,10 +1,12 @@
 package watchdog
 
 import (
+	"context"
 	"log"
 	"sync"
 	"time"
 
+	"github.com/TwinProduction/gatus/alerting"
 	"github.com/TwinProduction/gatus/config"
 	"github.com/TwinProduction/gatus/core"
 	"github.com/TwinProduction/gatus/metric"
@@ -15,48 +17,65 @@ var (
 	// monitoringMutex is used to prevent multiple services from being evaluated at the same time.
 	// Without this, conditions using response time may become inaccurate.
 	monitoringMutex sync.Mutex
+
+	ctx        context.Context
+	cancelFunc context.CancelFunc
 )
 
 // Monitor loops over each services and starts a goroutine to monitor each services separately
 func Monitor(cfg *config.Config) {
+	ctx, cancelFunc = context.WithCancel(context.Background())
 	for _, service := range cfg.Services {
 		// To prevent multiple requests from running at the same time, we'll wait for a little bit before each iteration
 		time.Sleep(1111 * time.Millisecond)
-		go monitor(service)
+		go monitor(service, cfg.Alerting, cfg.DisableMonitoringLock, cfg.Metrics, cfg.Debug, ctx)
 	}
 }
 
 // monitor monitors a single service in a loop
-func monitor(service *core.Service) {
-	cfg := config.Get()
+func monitor(service *core.Service, alertingConfig *alerting.Config, disableMonitoringLock, enabledMetrics, debug bool, ctx context.Context) {
+	// Run it immediately on start
+	execute(service, alertingConfig, disableMonitoringLock, enabledMetrics, debug)
+	// Loop for the next executions
 	for {
-		if !cfg.DisableMonitoringLock {
-			// By placing the lock here, we prevent multiple services from being monitored at the exact same time, which
-			// could cause performance issues and return inaccurate results
-			monitoringMutex.Lock()
+		select {
+		case <-ctx.Done():
+			log.Printf("[watchdog][monitor] Canceling current execution of group=%s; service=%s", service.Group, service.Name)
+			return
+		case <-time.After(service.Interval):
+			execute(service, alertingConfig, disableMonitoringLock, enabledMetrics, debug)
 		}
-		if cfg.Debug {
-			log.Printf("[watchdog][monitor] Monitoring group=%s; service=%s", service.Group, service.Name)
-		}
-		result := service.EvaluateHealth()
+	}
+}
+
+func execute(service *core.Service, alertingConfig *alerting.Config, disableMonitoringLock, enabledMetrics, debug bool) {
+	if !disableMonitoringLock {
+		// By placing the lock here, we prevent multiple services from being monitored at the exact same time, which
+		// could cause performance issues and return inaccurate results
+		monitoringMutex.Lock()
+	}
+	if debug {
+		log.Printf("[watchdog][execute] Monitoring group=%s; service=%s", service.Group, service.Name)
+	}
+	result := service.EvaluateHealth()
+	if enabledMetrics {
 		metric.PublishMetricsForService(service, result)
-		UpdateServiceStatuses(service, result)
-		log.Printf(
-			"[watchdog][monitor] Monitored group=%s; service=%s; success=%v; errors=%d; duration=%s",
-			service.Group,
-			service.Name,
-			result.Success,
-			len(result.Errors),
-			result.Duration.Round(time.Millisecond),
-		)
-		HandleAlerting(service, result)
-		if cfg.Debug {
-			log.Printf("[watchdog][monitor] Waiting for interval=%s before monitoring group=%s service=%s again", service.Interval, service.Group, service.Name)
-		}
-		if !cfg.DisableMonitoringLock {
-			monitoringMutex.Unlock()
-		}
-		time.Sleep(service.Interval)
+	}
+	UpdateServiceStatuses(service, result)
+	log.Printf(
+		"[watchdog][execute] Monitored group=%s; service=%s; success=%v; errors=%d; duration=%s",
+		service.Group,
+		service.Name,
+		result.Success,
+		len(result.Errors),
+		result.Duration.Round(time.Millisecond),
+	)
+	HandleAlerting(service, result, alertingConfig, debug)
+	if debug {
+		log.Printf("[watchdog][execute] Waiting for interval=%s before monitoring group=%s service=%s again", service.Interval, service.Group, service.Name)
+	}
+	if !disableMonitoringLock {
+		monitoringMutex.Unlock()
 	}
 }
 
@@ -64,3 +83,8 @@ func monitor(service *core.Service) {
 func UpdateServiceStatuses(service *core.Service, result *core.Result) {
 	storage.Get().Insert(service, result)
 }
+
+// Shutdown stops monitoring all services
+func Shutdown() {
+	cancelFunc()
+}