From c16f1f5e99def9e0136170605368ab33e31e80a1 Mon Sep 17 00:00:00 2001
From: Matthew Jacobson <matthew.jacobson@grafana.com>
Date: Fri, 2 Jun 2023 15:47:43 -0400
Subject: [PATCH] Alerting: Fix provisioned templates being ignored by
 alertmanager (#69485)

* Alerting: Fix provisioned templates being ignored by alertmanager

Template provisioning sets the template in cfg.TemplateFiles while a recent change
made it so that alertmanager reads cfg.AlertmanagerConfig.Templates instead.

This change fixes the issue on both ends, by having provisioning set boths fields and
reverts the change on the alertmanager side so that it uses cfg.TemplateFiles.
---
 pkg/services/ngalert/notifier/alertmanager.go  | 4 ++--
 pkg/services/ngalert/notifier/config.go        | 4 ++--
 pkg/services/ngalert/notifier/config_test.go   | 5 -----
 pkg/services/ngalert/provisioning/templates.go | 5 +++++
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/pkg/services/ngalert/notifier/alertmanager.go b/pkg/services/ngalert/notifier/alertmanager.go
index cb9df23ee88..32293d6707c 100644
--- a/pkg/services/ngalert/notifier/alertmanager.go
+++ b/pkg/services/ngalert/notifier/alertmanager.go
@@ -260,13 +260,13 @@ func (am *Alertmanager) applyConfig(cfg *apimodels.PostableUserConfig, rawConfig
 		cfg.TemplateFiles = map[string]string{}
 	}
 	cfg.TemplateFiles["__default__.tmpl"] = alertingTemplates.DefaultTemplateString
-	cfg.AlertmanagerConfig.Templates = append(cfg.AlertmanagerConfig.Templates, "__default__.tmpl")
 
 	// next, we need to make sure we persist the templates to disk.
-	_, templatesChanged, err := PersistTemplates(am.logger, cfg, am.Base.WorkingDirectory())
+	paths, templatesChanged, err := PersistTemplates(am.logger, cfg, am.Base.WorkingDirectory())
 	if err != nil {
 		return false, err
 	}
+	cfg.AlertmanagerConfig.Templates = paths
 
 	// If neither the configuration nor templates have changed, we've got nothing to do.
 	if !amConfigChanged && !templatesChanged {
diff --git a/pkg/services/ngalert/notifier/config.go b/pkg/services/ngalert/notifier/config.go
index c1e97bb8942..86dfb404049 100644
--- a/pkg/services/ngalert/notifier/config.go
+++ b/pkg/services/ngalert/notifier/config.go
@@ -32,7 +32,7 @@ func PersistTemplates(logger log.Logger, cfg *api.PostableUserConfig, path strin
 		}
 
 		file := filepath.Join(path, name)
-		pathSet[file] = struct{}{}
+		pathSet[name] = struct{}{}
 
 		// Check if the template file already exists and if it has changed
 		// We can safely ignore gosec here as we've previously checked the filename is clean
@@ -60,7 +60,7 @@ func PersistTemplates(logger log.Logger, cfg *api.PostableUserConfig, path strin
 	}
 	for _, existingFile := range existingFiles {
 		p := filepath.Join(path, existingFile.Name())
-		_, ok := pathSet[p]
+		_, ok := pathSet[existingFile.Name()]
 		if !ok {
 			templatesChanged = true
 			err := os.Remove(p)
diff --git a/pkg/services/ngalert/notifier/config_test.go b/pkg/services/ngalert/notifier/config_test.go
index b11140b9b53..c39b4f2b2be 100644
--- a/pkg/services/ngalert/notifier/config_test.go
+++ b/pkg/services/ngalert/notifier/config_test.go
@@ -96,11 +96,6 @@ func TestPersistTemplates(t *testing.T) {
 				files[f.Name()] = string(content)
 			}
 
-			// Given we use a temporary directory in tests, we need to prepend the expected paths with it.
-			for i, p := range tt.expectedPaths {
-				tt.expectedPaths[i] = filepath.Join(dir, p)
-			}
-
 			require.Equal(t, tt.expectedError, persistErr)
 			require.ElementsMatch(t, tt.expectedPaths, paths)
 			require.Equal(t, tt.expectedChange, changed)
diff --git a/pkg/services/ngalert/provisioning/templates.go b/pkg/services/ngalert/provisioning/templates.go
index a05bb48105b..0e655224eb1 100644
--- a/pkg/services/ngalert/provisioning/templates.go
+++ b/pkg/services/ngalert/provisioning/templates.go
@@ -53,6 +53,11 @@ func (t *TemplateService) SetTemplate(ctx context.Context, orgID int64, tmpl def
 		revision.cfg.TemplateFiles = map[string]string{}
 	}
 	revision.cfg.TemplateFiles[tmpl.Name] = tmpl.Template
+	tmpls := make([]string, 0, len(revision.cfg.TemplateFiles))
+	for name := range revision.cfg.TemplateFiles {
+		tmpls = append(tmpls, name)
+	}
+	revision.cfg.AlertmanagerConfig.Templates = tmpls
 
 	serialized, err := serializeAlertmanagerConfig(*revision.cfg)
 	if err != nil {