From 51cad8ca17f252dbf376fbb245ec972c0e5c16a5 Mon Sep 17 00:00:00 2001
From: Dominik Guhr <dominik.guhr@innoq.com>
Date: Sat, 17 Feb 2024 17:10:10 +0100
Subject: [PATCH] Possible fix for #129 - Check if mention - configvalues are
 containing non-empty values

only add to builder when they are not empty.
---
 receivers/slack/slack.go      |  8 +++-
 receivers/slack/slack_test.go | 82 +++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/receivers/slack/slack.go b/receivers/slack/slack.go
index 1aad87f5..8f3d8ead 100644
--- a/receivers/slack/slack.go
+++ b/receivers/slack/slack.go
@@ -368,14 +368,18 @@ func (sn *Notifier) createSlackMessage(ctx context.Context, alerts []*types.Aler
 	if len(sn.settings.MentionGroups) > 0 {
 		appendSpace()
 		for _, g := range sn.settings.MentionGroups {
-			mentionsBuilder.WriteString(fmt.Sprintf("<!subteam^%s>", tmpl(g)))
+			if strings.TrimSpace(g) != "" {
+				mentionsBuilder.WriteString(fmt.Sprintf("<!subteam^%s>", tmpl(g)))
+			}
 		}
 	}
 
 	if len(sn.settings.MentionUsers) > 0 {
 		appendSpace()
 		for _, u := range sn.settings.MentionUsers {
-			mentionsBuilder.WriteString(fmt.Sprintf("<@%s>", tmpl(u)))
+			if strings.TrimSpace(u) != "" {
+				mentionsBuilder.WriteString(fmt.Sprintf("<@%s>", tmpl(u)))
+			}
 		}
 	}
 
diff --git a/receivers/slack/slack_test.go b/receivers/slack/slack_test.go
index 5ea6446d..a1942671 100644
--- a/receivers/slack/slack_test.go
+++ b/receivers/slack/slack_test.go
@@ -508,6 +508,88 @@ func TestNotify_PostMessage(t *testing.T) {
 				},
 			},
 		},
+	}, {
+		name: "Message is sent without mentions when only empty values are in mention config",
+		settings: Config{
+			EndpointURL:    "https://example.com/api",
+			URL:            "https://example.com/api",
+			Token:          "1234",
+			Recipient:      "#test",
+			Text:           templates.DefaultMessageEmbed,
+			Title:          templates.DefaultMessageTitleEmbed,
+			Username:       "Grafana",
+			IconEmoji:      ":emoji:",
+			IconURL:        "",
+			MentionChannel: "",
+			MentionUsers:   []string{""},
+			MentionGroups:  []string{"", " ", "     "},
+		},
+		alerts: []*types.Alert{{
+			Alert: model.Alert{
+				Labels:      model.LabelSet{"alertname": "alert1", "lbl1": "val1"},
+				Annotations: model.LabelSet{"ann1": "annv1"},
+			},
+		}},
+		expectedMessage: &slackMessage{
+			Channel:   "#test",
+			Username:  "Grafana",
+			IconEmoji: ":emoji:",
+			Attachments: []attachment{
+				{
+					Title:      "[FIRING:1]  (val1)",
+					TitleLink:  "http://localhost/alerting/list",
+					Text:       "**Firing**\n\nValue: [no value]\nLabels:\n - alertname = alert1\n - lbl1 = val1\nAnnotations:\n - ann1 = annv1\nSilence: http://localhost/alerting/silence/new?alertmanager=grafana&matcher=alertname%3Dalert1&matcher=lbl1%3Dval1\n",
+					Fallback:   "[FIRING:1]  (val1)",
+					Fields:     nil,
+					Footer:     "Grafana v" + appVersion,
+					FooterIcon: "https://grafana.com/static/assets/img/fav32.png",
+					Color:      "#D63232",
+					Pretext:    "",
+					MrkdwnIn:   []string(nil),
+				},
+			},
+		},
+	}, {
+		name: "Message is sent with right mention when empty and non-empty values are used",
+		settings: Config{
+			EndpointURL:    "https://example.com/api",
+			URL:            "https://example.com/api",
+			Token:          "1234",
+			Recipient:      "#test",
+			Text:           templates.DefaultMessageEmbed,
+			Title:          templates.DefaultMessageTitleEmbed,
+			Username:       "Grafana",
+			IconEmoji:      ":emoji:",
+			IconURL:        "",
+			MentionChannel: "",
+			MentionUsers:   []string{"Test User", " "},
+			MentionGroups:  []string{"", " ", "Team Test"},
+		},
+		alerts: []*types.Alert{{
+			Alert: model.Alert{
+				Labels:      model.LabelSet{"alertname": "alert1", "lbl1": "val1"},
+				Annotations: model.LabelSet{"ann1": "annv1"},
+			},
+		}},
+		expectedMessage: &slackMessage{
+			Channel:   "#test",
+			Username:  "Grafana",
+			IconEmoji: ":emoji:",
+			Attachments: []attachment{
+				{
+					Title:      "[FIRING:1]  (val1)",
+					TitleLink:  "http://localhost/alerting/list",
+					Text:       "**Firing**\n\nValue: [no value]\nLabels:\n - alertname = alert1\n - lbl1 = val1\nAnnotations:\n - ann1 = annv1\nSilence: http://localhost/alerting/silence/new?alertmanager=grafana&matcher=alertname%3Dalert1&matcher=lbl1%3Dval1\n",
+					Fallback:   "[FIRING:1]  (val1)",
+					Fields:     nil,
+					Footer:     "Grafana v" + appVersion,
+					FooterIcon: "https://grafana.com/static/assets/img/fav32.png",
+					Color:      "#D63232",
+					Pretext:    "<!subteam^Team Test> <@Test User>",
+					MrkdwnIn:   []string{"pretext"},
+				},
+			},
+		},
 	}}
 
 	for _, test := range tests {