fix(alerting): Limit minimum-reminder-interval to >5m (#1290)

README.md

@@ -712,13 +712,13 @@ individual endpoints with configurable descriptions and thresholds.
 Alerts are configured at the endpoint level like so:
 
 | Parameter                            | Description                                                                                                                                               | Default       |
-|:-------------------------------------|:-------------------------------------------------------------------------------------------------------------------------------|:--------------|
+|:-------------------------------------|:----------------------------------------------------------------------------------------------------------------------------------------------------------|:--------------|
 | `alerts`                             | List of all alerts for a given endpoint.                                                                                                                  | `[]`          |
 | `alerts[].type`                      | Type of alert. <br />See table below for all valid types.                                                                                                 | Required `""` |
 | `alerts[].enabled`                   | Whether to enable the alert.                                                                                                                              | `true`        |
 | `alerts[].failure-threshold`         | Number of failures in a row needed before triggering the alert.                                                                                           | `3`           |
 | `alerts[].success-threshold`         | Number of successes in a row before an ongoing incident is marked as resolved.                                                                            | `2`           |
-| `alerts[].minimum-reminder-interval` | Minimum time interval between alert reminders. E.g. `"30m"`, `"1h45m30s"` or `"24h"`. If empty or `0`, reminders are disabled. | `0`           |
+| `alerts[].minimum-reminder-interval` | Minimum time interval between alert reminders. E.g. `"30m"`, `"1h45m30s"` or `"24h"`. If empty or `0`, reminders are disabled. Cannot be lower than `5m`. | `0`           |
 | `alerts[].send-on-resolved`          | Whether to send a notification once a triggered alert is marked as resolved.                                                                              | `false`       |
 | `alerts[].description`               | Description of the alert. Will be included in the alert sent.                                                                                             | `""`          |
 | `alerts[].provider-override`         | Alerting provider configuration override for the given alert type                                                                                         | `{}`          |

alerting/alert/alert.go

@@ -15,6 +15,8 @@ import (
 var (
 	// ErrAlertWithInvalidDescription is the error with which Gatus will panic if an alert has an invalid character
 	ErrAlertWithInvalidDescription = errors.New("alert description must not have \" or \\")
+
+	ErrAlertWithInvalidMinimumReminderInterval = errors.New("minimum-reminder-interval must be either omitted or be at least 5m")
 )
 
 // Alert is endpoint.Endpoint's alert configuration
@@ -78,6 +80,9 @@ func (alert *Alert) ValidateAndSetDefaults() error {
 	if alert.SuccessThreshold <= 0 {
 		alert.SuccessThreshold = 2
 	}
+	if alert.MinimumReminderInterval != 0 && alert.MinimumReminderInterval < 5*time.Minute {
+		return ErrAlertWithInvalidMinimumReminderInterval
+	}
 	if strings.ContainsAny(alert.GetDescription(), "\"\\") {
 		return ErrAlertWithInvalidDescription
 	}

alerting/alert/alert_test.go

@@ -3,6 +3,7 @@ package alert
 import (
 	"errors"
 	"testing"
+	"time"
 )
 
 func TestAlert_ValidateAndSetDefaults(t *testing.T) {
@@ -36,6 +37,61 @@ func TestAlert_ValidateAndSetDefaults(t *testing.T) {
 			expectedFailureThreshold: 10,
 			expectedSuccessThreshold: 5,
 		},
+		{
+			name: "valid-minimum-reminder-interval-0",
+			alert: Alert{
+				MinimumReminderInterval: 0,
+				FailureThreshold:        10,
+				SuccessThreshold:        5,
+			},
+			expectedError:            nil,
+			expectedFailureThreshold: 10,
+			expectedSuccessThreshold: 5,
+		},
+		{
+			name: "valid-minimum-reminder-interval-5m",
+			alert: Alert{
+				MinimumReminderInterval: 5 * time.Minute,
+				FailureThreshold:        10,
+				SuccessThreshold:        5,
+			},
+			expectedError:            nil,
+			expectedFailureThreshold: 10,
+			expectedSuccessThreshold: 5,
+		},
+		{
+			name: "valid-minimum-reminder-interval-10m",
+			alert: Alert{
+				MinimumReminderInterval: 10 * time.Minute,
+				FailureThreshold:        10,
+				SuccessThreshold:        5,
+			},
+			expectedError:            nil,
+			expectedFailureThreshold: 10,
+			expectedSuccessThreshold: 5,
+		},
+		{
+			name: "invalid-minimum-reminder-interval-1m",
+			alert: Alert{
+				MinimumReminderInterval: 1 * time.Minute,
+				FailureThreshold:        10,
+				SuccessThreshold:        5,
+			},
+			expectedError:            ErrAlertWithInvalidMinimumReminderInterval,
+			expectedFailureThreshold: 10,
+			expectedSuccessThreshold: 5,
+		},
+		{
+			name: "invalid-minimum-reminder-interval-1s",
+			alert: Alert{
+				MinimumReminderInterval: 1 * time.Second,
+				FailureThreshold:        10,
+				SuccessThreshold:        5,
+			},
+			expectedError:            ErrAlertWithInvalidMinimumReminderInterval,
+			expectedFailureThreshold: 10,
+			expectedSuccessThreshold: 5,
+		},
 	}
 	for _, scenario := range scenarios {
 		t.Run(scenario.name, func(t *testing.T) {

watchdog/alerting_test.go

@@ -648,7 +648,7 @@ func TestHandleAlertingWithMinimumReminderInterval(t *testing.T) {
 				SuccessThreshold:        3,
 				SendOnResolved:          &enabled,
 				Triggered:               false,
-				MinimumReminderInterval: 1 * time.Second,
+				MinimumReminderInterval: 5 * time.Minute,
 			},
 		},
 	}