From 5f88e5da5d03adc5092c73e838af9e5025325513 Mon Sep 17 00:00:00 2001
From: Shin'ya Ueoka <ueokande@i-beam.org>
Date: Sun, 8 Nov 2020 09:56:11 +0900
Subject: [PATCH] Improve observability on FCM errors (#542)

A caller can now observe errors returned from FCM server such as
an unauthorized error (401).
---
 gorush/notification_fcm.go      | 28 ++++++++++++++++++++++++++++
 gorush/notification_fcm_test.go |  5 +++++
 2 files changed, 33 insertions(+)

diff --git a/gorush/notification_fcm.go b/gorush/notification_fcm.go
index ca28e05..8a3d155 100644
--- a/gorush/notification_fcm.go
+++ b/gorush/notification_fcm.go
@@ -141,6 +141,34 @@ Retry:
 	if err != nil {
 		// Send Message error
 		LogError.Error("FCM server send message error: " + err.Error())
+
+		if req.IsTopic() {
+			if PushConf.Core.Sync {
+				req.AddLog(getLogPushEntry(FailedPush, req.To, req, err))
+			} else if PushConf.Core.FeedbackURL != "" {
+				go func(logger *logrus.Logger, log LogPushEntry, url string, timeout int64) {
+					err := DispatchFeedback(log, url, timeout)
+					if err != nil {
+						logger.Error(err)
+					}
+				}(LogError, getLogPushEntry(FailedPush, req.To, req, err), PushConf.Core.FeedbackURL, PushConf.Core.FeedbackTimeout)
+			}
+			StatStorage.AddAndroidError(1)
+		} else {
+			for _, token := range req.Tokens {
+				if PushConf.Core.Sync {
+					req.AddLog(getLogPushEntry(FailedPush, token, req, err))
+				} else if PushConf.Core.FeedbackURL != "" {
+					go func(logger *logrus.Logger, log LogPushEntry, url string, timeout int64) {
+						err := DispatchFeedback(log, url, timeout)
+						if err != nil {
+							logger.Error(err)
+						}
+					}(LogError, getLogPushEntry(FailedPush, token, req, err), PushConf.Core.FeedbackURL, PushConf.Core.FeedbackTimeout)
+				}
+			}
+			StatStorage.AddAndroidError(int64(len(req.Tokens)))
+		}
 		return
 	}
 
diff --git a/gorush/notification_fcm_test.go b/gorush/notification_fcm_test.go
index 7a35610..530ef26 100644
--- a/gorush/notification_fcm_test.go
+++ b/gorush/notification_fcm_test.go
@@ -102,6 +102,7 @@ func TestPushToAndroidRightTokenForStringLog(t *testing.T) {
 func TestOverwriteAndroidAPIKey(t *testing.T) {
 	PushConf, _ = config.LoadConf("")
 
+	PushConf.Core.Sync = true
 	PushConf.Android.Enabled = true
 	PushConf.Android.APIKey = os.Getenv("ANDROID_API_KEY")
 
@@ -113,10 +114,14 @@ func TestOverwriteAndroidAPIKey(t *testing.T) {
 		Message:  "Welcome",
 		// overwrite android api key
 		APIKey: "1234",
+
+		log: &[]LogPushEntry{},
 	}
 
 	// FCM server error: 401 error: 401 Unauthorized (Wrong API Key)
 	PushToAndroid(req)
+
+	assert.Len(t, *req.log, 2)
 }
 
 func TestFCMMessage(t *testing.T) {