adds throttle grace

README.md

@@ -1,6 +1,18 @@
-# go-alertnotification
-
-This library supports sending throttled alerts as email and as message card to Ms Teams channel.
+<p align="center">
+  <a href="https://github.com/rakutentech/go-alertnotification">
+    <img alt="go-alertnotification" src="logo.png" width="360">
+  </a>
+</p>
+
+<h3 align="center">Send Alert Notifications for Go Errors.<br>Notify when new error arrives.</h3>
+
+<p align="center">
+  Throttle notifications to avoid overwhelming your inbox.
+  <br>
+  Grace period to notify if the same error occurs.
+  <br>
+  Supports multiple Emails, MS Teams and proxy support.
+</p>
 
 ## Usage
 
@@ -10,48 +22,48 @@ go install github.com/rakutentech/go-alertnotification@latest
 
 ## Configurations
 
-* This package use golang env variables as settings.
+You need to set env variables to configure the alert notification behaviour.
 
 ### General Configs
 
 
-| Env Variable | default | Description                                                   |
-| :----------- | :------ | :------------------------------------------------------------ |
-| APP_ENV      |         | application environment to be appeared in email/teams message |
-| APP_NAME     |         | application name to be appeared in email/teams message        |
+| Env Variable | default | Description                  |
+| :----------- | :------ | :--------------------------- |
+| APP_ENV      |         | Appears in email/teams title |
+| APP_NAME     |         | Appears in email/teams body  |
 
 
 ### Email Configs
 
-| Env Variable        | default | Description                                                                     |
-| :------------------ | :------ | :------------------------------------------------------------------------------ |
-| **EMAIL_SENDER**    |         | **required** sender email address                                               |
-| **EMAIL_RECEIVERS** |         | **required** receiver email addresses. Eg. `[email protected]`,`[email protected]`  |
-| EMAIL_ALERT_ENABLED | false   | change to "true" to enable                                                      |
-| SMTP_HOST           |         | SMTP server hostname                                                            |
-| SMTP_PORT           |         | SMTP server port                                                                |
-| EMAIL_USERNAME      |         | SMTP username                                                                   |
-| EMAIL_PASSWORD      |         | SMTP password                                                                   |
+| Env Variable        | default | Description                                                              |
+| :------------------ | :------ | :----------------------------------------------------------------------- |
+| **EMAIL_SENDER**    |         | **Required** one mail address                                            |
+| **EMAIL_RECEIVERS** |         | **Required** multiple addresses. Eg. `[email protected]`,`[email protected]` |
+| EMAIL_ALERT_ENABLED | false   |                                                                          |
+| SMTP_HOST           |         |                                                                          |
+| SMTP_PORT           |         |                                                                          |
+| EMAIL_USERNAME      |         |                                                                          |
+| EMAIL_PASSWORD      |         |                                                                          |
 
 ### Ms Teams Configs
 
-| Env Variable           | default | Description                    |
-| :--------------------- | :------ | :----------------------------- |
-| **MS_TEAMS_WEBHOOK**   |         | **required** Ms Teams webhook. |
-| MS_TEAMS_ALERT_ENABLED | false   | change to "true" to enable     |
-| MS_TEAMS_CARD_SUBJECT  |         | MS teams card subject          |
-| ALERT_CARD_SUBJECT     |         | Alert MessageCard subject      |
-| ALERT_THEME_COLOR      |         | Themes color                   |
-| MS_TEAMS_PROXY_URL     |         | Work behind corporate proxy    |
+| Env Variable           | default | Description        |
+| :--------------------- | :------ | :----------------- |
+| **MS_TEAMS_WEBHOOK**   |         | **Required**       |
+| MS_TEAMS_ALERT_ENABLED | false   |                    |
+| MS_TEAMS_CARD_SUBJECT  |         |                    |
+| ALERT_CARD_SUBJECT     |         |                    |
+| ALERT_THEME_COLOR      |         |                    |
+| MS_TEAMS_PROXY_URL     |         | HTTP proxy, if any |
 
 ### Throttling Configs
 
-| Env Variable           | default                                      | Explanation                    |
-| :--------------------- | :------------------------------------------- | :----------------------------- |
-| THROTTLE_DURATION      | 7                                            | throttling duration in minutes |
-| THROTTLE_GRACE_SECONDS | 0                                            | throttling grace in seconds    |
-| THROTTLE_DISKCACHE_DIR | `/tmp/cache/{APP_NAME}_throttler_disk_cache` | disk location for throttling   |
-| THROTTLE_ENABLED       | true                                         | Disable all together           |
+| Env Variable           | default                         | Explanation                      |
+| :--------------------- | :------------------------------ | :------------------------------- |
+| THROTTLE_DURATION      | 7                               | Throttling duration in (minutes) |
+| THROTTLE_GRACE_SECONDS | 0                               | Throttling grace in (seconds)    |
+| THROTTLE_DISKCACHE_DIR | `/tmp/cache/{APP_NAME}_thro...` | Disk location for cache          |
+| THROTTLE_ENABLED       | true                            | Disable all together             |
 
 ## Usage
 

throttler.go

@@ -49,6 +49,13 @@ func (t *Throttler) IsThrottled(ocError error) bool {
 	if err != nil {
 		return false
 	}
+
+	gracedTime, gracedSeconds := getGracePeriod(dc, ocError)
+
+	if isWithinGracePeriod(string(gracedTime), gracedSeconds) {
+		return true
+	}
+
 	cachedTime, throttled := dc.Get(ocError.Error())
 
 	if throttled && !isOverThrottleDuration(string(cachedTime), t.ThrottleDuration) {
@@ -63,6 +70,35 @@ func (t *Throttler) IsThrottled(ocError error) bool {
 	return false
 }
 
+func getGracePeriod(dc *diskache.Diskache, ocError error) ([]byte, int) {
+	graceKeyPrefix := "GRACE-"
+	now := time.Now().Format(time.RFC3339)
+	gracedTime, gracedCached := dc.Get(graceKeyPrefix + ocError.Error())
+	gracedSeconds, err := strconv.Atoi(os.Getenv("THROTTLE_GRACE_SECONDS"))
+	if err != nil {
+		return []byte{}, 0 // no grace period
+	}
+
+	if !gracedCached {
+		gracedTime = []byte(now)
+		err = dc.Set(graceKeyPrefix+ocError.Error(), gracedTime)
+		if err != nil {
+			return []byte{}, 0 // no grace period
+		}
+	}
+	return gracedTime, gracedSeconds
+}
+
+func isWithinGracePeriod(cachedTime string, gracedSeconds int) bool {
+	gracedTime, err := time.Parse(time.RFC3339, string(cachedTime))
+	if err != nil {
+		return false
+	}
+	now := time.Now()
+	diff := int(now.Sub(gracedTime).Seconds())
+	return diff < gracedSeconds
+}
+
 func isOverThrottleDuration(cachedTime string, throttleDuration int) bool {
 	throttledTime, err := time.Parse(time.RFC3339, string(cachedTime))
 	if err != nil {

throttler_test.go

@@ -113,6 +113,96 @@ func TestThrottler_IsThrottled(t *testing.T) {
 		})
 	}
 }
+func TestThrottler_IsThrottledGraced(t *testing.T) {
+	type fields struct {
+		CacheOpt         string
+		ThrottleDuration int
+	}
+	type args struct {
+		ocError error
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   bool
+	}{
+		{
+			name: "default",
+			fields: fields{
+				CacheOpt:         fmt.Sprintf("/tmp/cache/%v_throttler_disk_cache", os.Getenv("APP_NAME")),
+				ThrottleDuration: 5,
+			},
+			args: args{
+				ocError: errors.New("test_throttling"),
+			},
+			want: true,
+		},
+	}
+
+	os.Setenv("THROTTLE_GRACE_SECONDS", "10")
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			th := &Throttler{
+				CacheOpt:         tt.fields.CacheOpt,
+				ThrottleDuration: tt.fields.ThrottleDuration,
+			}
+			if got := th.IsThrottled(tt.args.ocError); got != tt.want {
+				t.Errorf("Throttler.IsThrottled() = %v, want %v", got, tt.want)
+			}
+			err := th.CleanThrottlingCache()
+			if err != nil {
+				t.Errorf("Cannot clean after test. %+v", err)
+			}
+
+		})
+	}
+}
+func TestThrottler_IsThrottledOverGraced(t *testing.T) {
+	type fields struct {
+		CacheOpt         string
+		ThrottleDuration int
+	}
+	type args struct {
+		ocError error
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   bool
+	}{
+		{
+			name: "default",
+			fields: fields{
+				CacheOpt:         fmt.Sprintf("/tmp/cache/%v_throttler_disk_cache", os.Getenv("APP_NAME")),
+				ThrottleDuration: 5,
+			},
+			args: args{
+				ocError: errors.New("test_throttling"),
+			},
+			want: false,
+		},
+	}
+
+	os.Setenv("THROTTLE_GRACE_SECONDS", "0")
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			th := &Throttler{
+				CacheOpt:         tt.fields.CacheOpt,
+				ThrottleDuration: tt.fields.ThrottleDuration,
+			}
+			if got := th.IsThrottled(tt.args.ocError); got != tt.want {
+				t.Errorf("Throttler.IsThrottled() = %v, want %v", got, tt.want)
+			}
+			err := th.CleanThrottlingCache()
+			if err != nil {
+				t.Errorf("Cannot clean after test. %+v", err)
+			}
+
+		})
+	}
+}
 
 func TestThrottler_ThrottleError(t *testing.T) {
 	type fields struct {