Add configuration values for address and port

Add (non-mandatory) configuration values to set address and port on which the web frontent will be served. If not set defaults will be applied.

.gitignore

@@ -1,2 +1,3 @@
 bin
-.idea
+.idea
+.vscode

README.md

@@ -133,6 +133,8 @@ Note that you can also add environment variables in the configuration file (i.e.
 | `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`        |
+| `web.address`                            | Address to listen on                                                          | `0.0.0.0`      |
+| `web.port`                               | Port to listen on                                                             | `8080`         |
 
 For Kubernetes configuration, see [Kubernetes](#kubernetes-alpha)
 

config/config.go

@@ -2,8 +2,10 @@ package config
 
 import (
 	"errors"
+	"fmt"
 	"io/ioutil"
 	"log"
+	"math"
 	"os"
 
 	"github.com/TwinProduction/gatus/alerting"
@@ -22,6 +24,12 @@ const (
 	// DefaultFallbackConfigurationFilePath is the default fallback path that will be used to search for the
 	// configuration file if DefaultConfigurationFilePath didn't work
 	DefaultFallbackConfigurationFilePath = "config/config.yml"
+
+	// DefaultAddress is the default address the service will bind to
+	DefaultAddress = "0.0.0.0"
+
+	// DefaultPort is the default port the service will listen on
+	DefaultPort = 8080
 )
 
 var (
@@ -64,6 +72,9 @@ type Config struct {
 
 	// Kubernetes is the Kubernetes configuration
 	Kubernetes *k8s.Config `yaml:"kubernetes"`
+
+	// webConfig is the optional configuration of the web listener providing the frontend UI
+	Web *webConfig `yaml:"web"`
 }
 
 // Get returns the configuration, or panics if the configuration hasn't loaded yet
@@ -127,10 +138,20 @@ func parseAndValidateConfigBytes(yamlBytes []byte) (config *Config, err error) {
 		validateSecurityConfig(config)
 		validateServicesConfig(config)
 		validateKubernetesConfig(config)
+		validateAddressAndPortConfig(config)
 	}
 	return
 }
 
+func validateAddressAndPortConfig(config *Config) {
+	if config.Web == nil {
+		config.Web = &webConfig{Address: DefaultAddress, Port: DefaultPort}
+	} else {
+		config.Web.validateAndSetDefaults()
+	}
+
+}
+
 func validateKubernetesConfig(config *Config) {
 	if config.Kubernetes != nil && config.Kubernetes.AutoDiscover {
 		if config.Kubernetes.ServiceTemplate == nil {
@@ -237,3 +258,27 @@ func GetAlertingProviderByAlertType(config *Config, alertType core.AlertType) pr
 	}
 	return nil
 }
+
+// webConfig is the structure which supports the configuration of the endpoint
+// which provides access to the web frontend
+type webConfig struct {
+	// Address to listen on (defaults to 0.0.0.0 specified by DefaultAddress)
+	Address string `yaml:"address"`
+
+	// Port to listen on (default to 8080 specified by DefaultPort)
+	Port int `yaml:"port"`
+}
+
+// validateAndSetDefaults checks and sets missing values based on the defaults
+// in given in DefaultAddress and DefaultPort if necessary
+func (web *webConfig) validateAndSetDefaults() {
+	if len(web.Address) == 0 {
+		web.Address = DefaultAddress
+	}
+
+	if web.Port == 0 {
+		web.Port = DefaultPort
+	} else if web.Port < 0 || web.Port > math.MaxUint16 {
+		panic(fmt.Sprintf("port has an invalid value %d shoud be between %d - %d\r\n", web.Port, 0, math.MaxUint16))
+	}
+}

config/config_test.go

@@ -103,6 +103,120 @@ services:
 	if config.Services[0].Interval != 60*time.Second {
 		t.Errorf("Interval should have been %s, because it is the default value", 60*time.Second)
 	}
+
+	if config.Web.Address != DefaultAddress {
+		t.Errorf("Bind address should have been %s, because it is the default value", DefaultAddress)
+	}
+
+	if config.Web.Port != DefaultPort {
+		t.Errorf("Port should have been %d, because it is the default value", DefaultPort)
+	}
+}
+
+func TestParseAndValidateConfigBytesWithAddress(t *testing.T) {
+	config, err := parseAndValidateConfigBytes([]byte(`
+web:
+  address: 127.0.0.1
+services:
+  - name: twinnation
+    url: https://twinnation.org/actuator/health
+    conditions:
+      - "[STATUS] == 200"
+`))
+	if err != nil {
+		t.Error("No error should've been returned")
+	}
+	if config == nil {
+		t.Fatal("Config shouldn't have been nil")
+	}
+	if config.Metrics {
+		t.Error("Metrics should've been false by default")
+	}
+	if config.Services[0].URL != "https://twinnation.org/actuator/health" {
+		t.Errorf("URL should have been %s", "https://twinnation.org/actuator/health")
+	}
+	if config.Services[0].Interval != 60*time.Second {
+		t.Errorf("Interval should have been %s, because it is the default value", 60*time.Second)
+	}
+
+	if config.Web.Address != "127.0.0.1" {
+		t.Errorf("Bind address should have been %s, because it is specified in config", "127.0.0.1")
+	}
+
+	if config.Web.Port != DefaultPort {
+		t.Errorf("Port should have been %d, because it is the default value", DefaultPort)
+	}
+}
+
+func TestParseAndValidateConfigBytesWithPort(t *testing.T) {
+	config, err := parseAndValidateConfigBytes([]byte(`
+web:
+  port: 12345
+services:
+  - name: twinnation
+    url: https://twinnation.org/actuator/health
+    conditions:
+      - "[STATUS] == 200"
+`))
+	if err != nil {
+		t.Error("No error should've been returned")
+	}
+	if config == nil {
+		t.Fatal("Config shouldn't have been nil")
+	}
+	if config.Metrics {
+		t.Error("Metrics should've been false by default")
+	}
+	if config.Services[0].URL != "https://twinnation.org/actuator/health" {
+		t.Errorf("URL should have been %s", "https://twinnation.org/actuator/health")
+	}
+	if config.Services[0].Interval != 60*time.Second {
+		t.Errorf("Interval should have been %s, because it is the default value", 60*time.Second)
+	}
+
+	if config.Web.Address != DefaultAddress {
+		t.Errorf("Bind address should have been %s, because it is the default value", DefaultAddress)
+	}
+
+	if config.Web.Port != 12345 {
+		t.Errorf("Port should have been %d, because it is specified in config", 12345)
+	}
+}
+
+func TestParseAndValidateConfigBytesWithPortAndHost(t *testing.T) {
+	config, err := parseAndValidateConfigBytes([]byte(`
+web:
+  port: 12345
+  address: 127.0.0.1
+services:
+  - name: twinnation
+    url: https://twinnation.org/actuator/health
+    conditions:
+      - "[STATUS] == 200"
+`))
+	if err != nil {
+		t.Error("No error should've been returned")
+	}
+	if config == nil {
+		t.Fatal("Config shouldn't have been nil")
+	}
+	if config.Metrics {
+		t.Error("Metrics should've been false by default")
+	}
+	if config.Services[0].URL != "https://twinnation.org/actuator/health" {
+		t.Errorf("URL should have been %s", "https://twinnation.org/actuator/health")
+	}
+	if config.Services[0].Interval != 60*time.Second {
+		t.Errorf("Interval should have been %s, because it is the default value", 60*time.Second)
+	}
+
+	if config.Web.Address != "127.0.0.1" {
+		t.Errorf("Bind address should have been %s, because it is specified in config", "127.0.0.1")
+	}
+
+	if config.Web.Port != 12345 {
+		t.Errorf("Port should have been %d, because it is specified in config", 12345)
+	}
 }
 
 func TestParseAndValidateConfigBytesWithMetrics(t *testing.T) {
@@ -129,6 +243,51 @@ services:
 	if config.Services[0].Interval != 60*time.Second {
 		t.Errorf("Interval should have been %s, because it is the default value", 60*time.Second)
 	}
+
+	if config.Web.Address != DefaultAddress {
+		t.Errorf("Bind address should have been %s, because it is specified in config", DefaultAddress)
+	}
+
+	if config.Web.Port != DefaultPort {
+		t.Errorf("Port should have been %d, because it is specified in config", DefaultPort)
+	}
+}
+
+func TestParseAndValidateConfigBytesWithMetricsAndHostAndPort(t *testing.T) {
+	config, err := parseAndValidateConfigBytes([]byte(`
+metrics: true
+services:
+  - name: twinnation
+    url: https://twinnation.org/actuator/health
+    conditions:
+      - "[STATUS] == 200"
+web:
+  address: 192.168.0.1
+  port: 9090
+`))
+	if err != nil {
+		t.Error("No error should've been returned")
+	}
+	if config == nil {
+		t.Fatal("Config shouldn't have been nil")
+	}
+	if !config.Metrics {
+		t.Error("Metrics should have been true")
+	}
+	if config.Services[0].URL != "https://twinnation.org/actuator/health" {
+		t.Errorf("URL should have been %s", "https://twinnation.org/actuator/health")
+	}
+	if config.Services[0].Interval != 60*time.Second {
+		t.Errorf("Interval should have been %s, because it is the default value", 60*time.Second)
+	}
+
+	if config.Web.Address != "192.168.0.1" {
+		t.Errorf("Bind address should have been %s, because it is the default value", "192.168.0.1")
+	}
+
+	if config.Web.Port != 9090 {
+		t.Errorf("Port should have been %d, because it is specified in config", 9090)
+	}
 }
 
 func TestParseAndValidateBadConfigBytes(t *testing.T) {

main.go

@@ -8,7 +8,6 @@ import (
 	"log"
 	"net/http"
 	"os"
-	"strconv"
 	"strings"
 	"time"
 
@@ -24,38 +23,8 @@ var (
 	cachedServiceResults          []byte
 	cachedServiceResultsGzipped   []byte
 	cachedServiceResultsTimestamp time.Time
-	port                          int
-	host                          string
 )
 
-func init() {
-	// Customizing priority:
-	// (1) command line parameters will be preferred over
-	// (2) environment variables will be preferred over
-	// (3) application defaults
-
-	// set defaults for the case that neither an environment variable nor a
-	// command line parameter is passed
-	var defaultHost = ""
-	var defaultPort = 8080
-
-	// assume set if the is a valid port number
-	if p, err := strconv.Atoi(os.Getenv("GATUS_CONFIG_PORT")); err == nil && p > 0 {
-		defaultPort = p
-	}
-
-	// explicitly asked if the user has set a the environment variable to
-	// blank / empty in order to allow listening on all interfaces
-	if h, set := os.LookupEnv("GATUS_CONFIG_HOST"); set == true {
-		defaultHost = h
-	}
-
-	flag.IntVar(&port, "port", defaultPort, "port to listen (default: 8080)")
-	flag.IntVar(&port, "p", defaultPort, "port to listen (default: 8080 ; shorthand)")
-	flag.StringVar(&host, "host", defaultHost, "host to listen on (default all interfaces on host)")
-	flag.StringVar(&host, "h", defaultHost, "host to listen on (default all interfaces on host; shorthand)")
-}
-
 func main() {
 	flag.Parse()
 
@@ -71,9 +40,9 @@ func main() {
 		http.Handle("/metrics", promhttp.Handler())
 	}
 
-	log.Printf("[main][main] Listening on %s:%d", host, port)
+	log.Printf("[main][main] Listening on %s:%d\r\n", cfg.Web.Address, cfg.Web.Port)
 	go watchdog.Monitor(cfg)
-	log.Fatal(http.ListenAndServe(fmt.Sprintf("%s:%d", host, port), nil))
+	log.Fatal(http.ListenAndServe(fmt.Sprintf("%s:%d", cfg.Web.Address, cfg.Web.Port), nil))
 }
 
 func loadConfiguration() *config.Config {