feat: complete IM P0 and P1 reliability work

server/push/fcm/push_fcm.go

@@ -70,6 +70,14 @@ func (Handler) Init(jsonconf json.RawMessage) (bool, error) {
 		return false, errors.New("failed to parse config: " + err.Error())
 	}
 
+	if raw := strings.TrimSpace(os.Getenv("IM_FCM_CREDENTIALS_JSON")); raw != "" {
+		config.Credentials = json.RawMessage(raw)
+		config.Enabled = true
+	}
+	if path := strings.TrimSpace(os.Getenv("IM_FCM_CREDENTIALS_FILE")); path != "" {
+		config.CredentialsFile = path
+		config.Enabled = true
+	}
 	if !config.Enabled {
 		return false, nil
 	}