fix!: Enforce mandatory space around condition operator (#382)

BREAKING CHANGE: The comparator in each condition must now be wrapped by a space (e.g. [STATUS] == 200) or the condition will not be valid.

core/condition.go

@@ -1,6 +1,7 @@
 package core
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -86,8 +87,17 @@ const (
 // Condition is a condition that needs to be met in order for an Endpoint to be considered healthy.
 type Condition string
 
+// Validate checks if the Condition is valid
+func (c Condition) Validate() error {
+	r := &Result{}
+	c.evaluate(r, false)
+	if len(r.Errors) != 0 {
+		return errors.New(r.Errors[0])
+	}
+	return nil
+}
+
 // evaluate the Condition with the Result of the health check
-// TODO: Add a mandatory space between each operators (e.g. " == " instead of "==") (BREAKING CHANGE)
 func (c Condition) evaluate(result *Result, dontResolveFailedConditions bool) bool {
 	condition := string(c)
 	success := false
@@ -129,7 +139,7 @@ func (c Condition) evaluate(result *Result, dontResolveFailedConditions bool) bo
 			conditionToDisplay = prettifyNumericalParameters(parameters, resolvedParameters, "<")
 		}
 	} else {
-		result.AddError(fmt.Sprintf("invalid condition '%s' has been provided", condition))
+		result.AddError(fmt.Sprintf("invalid condition: %s", condition))
 		return false
 	}
 	if !success {

core/condition_test.go

@@ -1,11 +1,48 @@
 package core
 
 import (
+	"errors"
+	"fmt"
 	"strconv"
 	"testing"
 	"time"
 )
 
+func TestCondition_Validate(t *testing.T) {
+	scenarios := []struct {
+		condition   Condition
+		expectedErr error
+	}{
+		{condition: "[STATUS] == 200", expectedErr: nil},
+		{condition: "[STATUS] != 200", expectedErr: nil},
+		{condition: "[STATUS] <= 200", expectedErr: nil},
+		{condition: "[STATUS] >= 200", expectedErr: nil},
+		{condition: "[STATUS] < 200", expectedErr: nil},
+		{condition: "[STATUS] > 200", expectedErr: nil},
+		{condition: "[STATUS] == any(200, 201, 202, 203)", expectedErr: nil},
+		{condition: "[STATUS] == [BODY].status", expectedErr: nil},
+		{condition: "[BODY].test == wat", expectedErr: nil},
+		{condition: "[BODY].test == wat", expectedErr: nil},
+		{condition: "[BODY].test.wat == wat", expectedErr: nil},
+		{condition: "[BODY].users[0].id == 1", expectedErr: nil},
+		{condition: "len([BODY].users) == 100", expectedErr: nil},
+		{condition: "has([BODY].users[0].name) == 100", expectedErr: nil},
+		{condition: "raw == raw", expectedErr: nil},
+		{condition: "[STATUS] ? 201", expectedErr: errors.New("invalid condition: [STATUS] ? 201")},
+		{condition: "[STATUS]==201", expectedErr: errors.New("invalid condition: [STATUS]==201")},
+		{condition: "[STATUS] = = 201", expectedErr: errors.New("invalid condition: [STATUS] = = 201")},
+		// FIXME: Should return an error, but doesn't because jsonpath isn't evaluated due to body being empty in Condition.Validate()
+		//{condition: "len([BODY].users == 100", expectedErr: nil},
+	}
+	for _, scenario := range scenarios {
+		t.Run(string(scenario.condition), func(t *testing.T) {
+			if err := scenario.condition.Validate(); fmt.Sprint(err) != fmt.Sprint(scenario.expectedErr) {
+				t.Errorf("expected err %v, got %v", scenario.expectedErr, err)
+			}
+		})
+	}
+}
+
 func TestCondition_evaluate(t *testing.T) {
 	scenarios := []struct {
 		Name                        string

core/endpoint.go

@@ -5,6 +5,7 @@ import (
 	"crypto/x509"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io"
 	"net"
 	"net/http"
@@ -60,6 +61,9 @@ var (
 	// ErrUnknownEndpointType is the error with which Gatus will panic if an endpoint has an unknown type
 	ErrUnknownEndpointType = errors.New("unknown endpoint type")
 
+	// ErrInvalidConditionFormat is the error with which Gatus will panic if a condition has an invalid format
+	ErrInvalidConditionFormat = errors.New("invalid condition format: does not match '<VALUE> <COMPARATOR> <VALUE>'")
+
 	// ErrInvalidEndpointIntervalForDomainExpirationPlaceholder is the error with which Gatus will panic if an endpoint
 	// has both an interval smaller than 5 minutes and a condition with DomainExpirationPlaceholder.
 	// This is because the free whois service we are using should not be abused, especially considering the fact that
@@ -202,11 +206,12 @@ func (endpoint *Endpoint) ValidateAndSetDefaults() error {
 	if len(endpoint.Conditions) == 0 {
 		return ErrEndpointWithNoCondition
 	}
-	if endpoint.Interval < 5*time.Minute {
-		for _, condition := range endpoint.Conditions {
-			if condition.hasDomainExpirationPlaceholder() {
+	for _, c := range endpoint.Conditions {
+		if endpoint.Interval < 5*time.Minute && c.hasDomainExpirationPlaceholder() {
 			return ErrInvalidEndpointIntervalForDomainExpirationPlaceholder
 		}
+		if err := c.Validate(); err != nil {
+			return fmt.Errorf("%v: %w", ErrInvalidConditionFormat, err)
 		}
 	}
 	if endpoint.DNS != nil {

core/endpoint_test.go

@@ -346,7 +346,9 @@ func TestEndpoint_ValidateAndSetDefaults(t *testing.T) {
 		Conditions: []Condition{Condition("[STATUS] == 200")},
 		Alerts:     []*alert.Alert{{Type: alert.TypePagerDuty}},
 	}
-	endpoint.ValidateAndSetDefaults()
+	if err := endpoint.ValidateAndSetDefaults(); err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
 	if endpoint.ClientConfig == nil {
 		t.Error("client configuration should've been set to the default configuration")
 	} else {
@@ -383,6 +385,17 @@ func TestEndpoint_ValidateAndSetDefaults(t *testing.T) {
 	}
 }
 
+func TestEndpoint_ValidateAndSetDefaultsWithInvalidCondition(t *testing.T) {
+	endpoint := Endpoint{
+		Name:       "invalid-condition",
+		URL:        "https://twin.sh/health",
+		Conditions: []Condition{"[STATUS] invalid 200"},
+	}
+	if err := endpoint.ValidateAndSetDefaults(); err == nil {
+		t.Error("endpoint validation should've returned an error, but didn't")
+	}
+}
+
 func TestEndpoint_ValidateAndSetDefaultsWithClientConfig(t *testing.T) {
 	endpoint := Endpoint{
 		Name:       "website-health",
@@ -605,26 +618,6 @@ func TestIntegrationEvaluateHealth(t *testing.T) {
 	}
 }
 
-func TestIntegrationEvaluateHealthWithInvalidCondition(t *testing.T) {
-	condition := Condition("[STATUS] invalid 200")
-	endpoint := Endpoint{
-		Name:       "invalid-condition",
-		URL:        "https://twin.sh/health",
-		Conditions: []Condition{condition},
-	}
-	if err := endpoint.ValidateAndSetDefaults(); err != nil {
-		// XXX: Should this really not return an error? After all, the condition is not valid and conditions are part of the endpoint...
-		t.Error("endpoint validation should've been successful, but wasn't")
-	}
-	result := endpoint.EvaluateHealth()
-	if result.Success {
-		t.Error("Because one of the conditions was invalid, result.Success should have been false")
-	}
-	if len(result.Errors) == 0 {
-		t.Error("There should've been an error")
-	}
-}
-
 func TestIntegrationEvaluateHealthWithErrorAndHideURL(t *testing.T) {
 	endpoint := Endpoint{
 		Name:       "invalid-url",