add reason label to the numTotalFailedNotifications metric

notify/notify.go

@@ -262,7 +262,7 @@ func NewMetrics(r prometheus.Registerer) *Metrics {
 			Namespace: "alertmanager",
 			Name:      "notifications_failed_total",
 			Help:      "The total number of failed notifications.",
-		}, []string{"integration"}),
+		}, []string{"integration", "reason"}),
 		numNotificationRequestsTotal: prometheus.NewCounterVec(prometheus.CounterOpts{
 			Namespace: "alertmanager",
 			Name:      "notification_requests_total",
@@ -293,10 +293,13 @@ func NewMetrics(r prometheus.Registerer) *Metrics {
 		"telegram",
 	} {
 		m.numNotifications.WithLabelValues(integration)
-		m.numTotalFailedNotifications.WithLabelValues(integration)
 		m.numNotificationRequestsTotal.WithLabelValues(integration)
 		m.numNotificationRequestsFailedTotal.WithLabelValues(integration)
 		m.notificationLatencySeconds.WithLabelValues(integration)
+
+		for _, reason := range possibleFailureReasonCategory {
+			m.numTotalFailedNotifications.WithLabelValues(integration, reason)
+		}
 	}
 	r.MustRegister(
 		m.numNotifications, m.numTotalFailedNotifications,
@@ -662,8 +665,13 @@ func NewRetryStage(i Integration, groupName string, metrics *Metrics) *RetryStag
 func (r RetryStage) Exec(ctx context.Context, l log.Logger, alerts ...*types.Alert) (context.Context, []*types.Alert, error) {
 	r.metrics.numNotifications.WithLabelValues(r.integration.Name()).Inc()
 	ctx, alerts, err := r.exec(ctx, l, alerts...)
+
+	failureReason := DefaultReason.String()
 	if err != nil {
-		r.metrics.numTotalFailedNotifications.WithLabelValues(r.integration.Name()).Inc()
+		if e, ok := errors.Cause(err).(*ErrorWithReason); ok {
+			failureReason = e.Reason.String()
+		}
+		r.metrics.numTotalFailedNotifications.WithLabelValues(r.integration.Name(), failureReason).Inc()
 	}
 	return ctx, alerts, err
 }

notify/notify_test.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/prometheus/client_golang/prometheus"
+	prom_testutil "github.com/prometheus/client_golang/prometheus/testutil"
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v2"
@@ -422,6 +423,57 @@ func TestRetryStageWithError(t *testing.T) {
 	require.NotNil(t, resctx)
 }
 
+func TestRetryStageWithErrorCode(t *testing.T) {
+	testcases := map[string]struct {
+		isNewErrorWithReason bool
+		reason               Reason
+		reasonlabel          string
+		expectedCount        int
+	}{
+		"for clientError":     {isNewErrorWithReason: true, reason: ClientErrorReason, reasonlabel: ClientErrorReason.String(), expectedCount: 1},
+		"for serverError":     {isNewErrorWithReason: true, reason: ServerErrorReason, reasonlabel: ServerErrorReason.String(), expectedCount: 1},
+		"for unexpected code": {isNewErrorWithReason: false, reason: DefaultReason, reasonlabel: DefaultReason.String(), expectedCount: 1},
+	}
+	for _, testData := range testcases {
+		retry := false
+		testData := testData
+		i := Integration{
+			name: "test",
+			notifier: notifierFunc(func(ctx context.Context, alerts ...*types.Alert) (bool, error) {
+				if !testData.isNewErrorWithReason {
+					return retry, errors.New("fail to deliver notification")
+				}
+				return retry, NewErrorWithReason(testData.reason, errors.New("fail to deliver notification"))
+			}),
+			rs: sendResolved(false),
+		}
+		r := RetryStage{
+			integration: i,
+			metrics:     NewMetrics(prometheus.NewRegistry()),
+		}
+
+		alerts := []*types.Alert{
+			{
+				Alert: model.Alert{
+					EndsAt: time.Now().Add(time.Hour),
+				},
+			},
+		}
+
+		ctx := context.Background()
+		ctx = WithFiringAlerts(ctx, []uint64{0})
+
+		// Notify with a non-recoverable error.
+		resctx, _, err := r.Exec(ctx, log.NewNopLogger(), alerts...)
+		counter := r.metrics.numTotalFailedNotifications
+
+		require.Equal(t, testData.expectedCount, int(prom_testutil.ToFloat64(counter.WithLabelValues(r.integration.Name(), testData.reasonlabel))))
+
+		require.NotNil(t, err)
+		require.NotNil(t, resctx)
+	}
+}
+
 func TestRetryStageNoResolved(t *testing.T) {
 	sent := []*types.Alert{}
 	i := Integration{

notify/sns/sns.go

@@ -83,7 +83,10 @@ func (n *Notifier) Notify(ctx context.Context, alert ...*types.Alert) (bool, err
 	publishOutput, err := client.Publish(publishInput)
 	if err != nil {
 		if e, ok := err.(awserr.RequestFailure); ok {
-			return n.retrier.Check(e.StatusCode(), strings.NewReader(e.Message()))
+			retryable, error := n.retrier.Check(e.StatusCode(), strings.NewReader(e.Message()))
+
+			reasonErr := notify.NewErrorWithReason(notify.GetFailureReasonFromStatusCode(e.StatusCode()), error)
+			return retryable, reasonErr
 		}
 		return true, err
 	}

notify/util.go

@@ -245,3 +245,57 @@ func (r *Retrier) Check(statusCode int, body io.Reader) (bool, error) {
 	}
 	return retry, errors.New(s)
 }
+
+type ErrorWithReason struct {
+	Err error
+
+	Reason Reason
+}
+
+func NewErrorWithReason(reason Reason, err error) *ErrorWithReason {
+	return &ErrorWithReason{
+		Err:    err,
+		Reason: reason,
+	}
+}
+
+func (e *ErrorWithReason) Error() string {
+	return e.Err.Error()
+}
+
+// Reason is the failure reason.
+type Reason int
+
+const (
+	DefaultReason Reason = iota
+	ClientErrorReason
+	ServerErrorReason
+)
+
+func (s Reason) String() string {
+	switch s {
+	case DefaultReason:
+		return "other"
+	case ClientErrorReason:
+		return "clientError"
+	case ServerErrorReason:
+		return "serverError"
+	default:
+		panic(fmt.Sprintf("unknown Reason: %d", s))
+	}
+}
+
+// possibleFailureReasonCategory is a list of possible failure reason.
+var possibleFailureReasonCategory = []string{DefaultReason.String(), ClientErrorReason.String(), ServerErrorReason.String()}
+
+// GetFailureReasonFromStatusCode returns the reason for the failure based on the status code provided.
+func GetFailureReasonFromStatusCode(statusCode int) Reason {
+	if statusCode/100 == 4 {
+		return ClientErrorReason
+	}
+	if statusCode/100 == 5 {
+		return ServerErrorReason
+	}
+
+	return DefaultReason
+}