From 9464ffa86b0c0140460fcb9afb269b7335f05369 Mon Sep 17 00:00:00 2001
From: "Grot (@grafanabot)" <43478413+grafanabot@users.noreply.github.com>
Date: Wed, 2 Feb 2022 14:48:27 +0100
Subject: [PATCH] Fix Discord Webhook URL for invalid template (#44763)
 (#44772)

This commit fixes an issue where an invalid template for Discord would change the Webhook URL to "" and cause "unsupported protocol scheme" errors.
---
 pkg/services/ngalert/notifier/channels/discord.go      | 1 +
 pkg/services/ngalert/notifier/channels/discord_test.go | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/pkg/services/ngalert/notifier/channels/discord.go b/pkg/services/ngalert/notifier/channels/discord.go
index 83900e964e7..f4a83e044c2 100644
--- a/pkg/services/ngalert/notifier/channels/discord.go
+++ b/pkg/services/ngalert/notifier/channels/discord.go
@@ -101,6 +101,7 @@ func (d DiscordNotifier) Notify(ctx context.Context, as ...*types.Alert) (bool,
 	u := tmpl(d.WebhookURL)
 	if tmplErr != nil {
 		d.log.Warn("failed to template Discord message", "err", tmplErr.Error())
+		return false, tmplErr
 	}
 
 	body, err := json.Marshal(bodyJSON)
diff --git a/pkg/services/ngalert/notifier/channels/discord_test.go b/pkg/services/ngalert/notifier/channels/discord_test.go
index b14be659713..82a55e74a03 100644
--- a/pkg/services/ngalert/notifier/channels/discord_test.go
+++ b/pkg/services/ngalert/notifier/channels/discord_test.go
@@ -3,6 +3,7 @@ package channels
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"net/url"
 	"testing"
 
@@ -100,6 +101,14 @@ func TestDiscordNotifier(t *testing.T) {
 			settings:     `{}`,
 			expInitError: `failed to validate receiver "discord_testing" of type "discord": could not find webhook url property in settings`,
 		},
+		{
+			name: "Invalid template returns error",
+			settings: `{
+				"url": "http://localhost",
+				"message": "{{ template \"invalid.template\" }}"
+			}`,
+			expMsgError: errors.New("template: :1:12: executing \"\" at <{{template \"invalid.template\"}}>: template \"invalid.template\" not defined"),
+		},
 		{
 			name: "Default config with one alert, use default discord username",
 			settings: `{