Alerting: Fix bug not creating filepath for silences/nflog if it does not exist (#39174)

We created this filepath just as we're about persist the templates - with the latest change, we now need to create it sooner.

pkg/services/ngalert/notifier/file_store.go

@@ -93,6 +93,12 @@ func (fs *FileStore) IsExists(fn string) bool {
 
 // WriteFileToDisk writes a file with the provided name and contents to the Alertmanager working directory with the default grafana permission.
 func (fs *FileStore) WriteFileToDisk(fn string, content []byte) error {
+	// Ensure the working directory is created
+	err := os.MkdirAll(fs.workingDirPath, 0750)
+	if err != nil {
+		return fmt.Errorf("unable to create the working directory %q: %s", fs.workingDirPath, err)
+	}
+
 	return os.WriteFile(fs.pathFor(fn), content, 0644)
 }
 

pkg/services/ngalert/notifier/file_store_test.go

@@ -10,6 +10,27 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func TestFileStore_FilepathFor_DirectoryNotExist(t *testing.T) {
+	store := newFakeKVStore(t)
+	workingDir := filepath.Join(t.TempDir(), "notexistdir")
+	fs := NewFileStore(1, store, workingDir)
+	filekey := "silences"
+	filePath := filepath.Join(workingDir, filekey)
+
+	// With a file already on the database and the path does not exist yet, it creates the path,
+	// writes the file to disk, then returns the filepath.
+	{
+		require.NoError(t, store.Set(context.Background(), 1, KVNamespace, filekey, encode([]byte("silence1,silence3"))))
+		r, err := fs.FilepathFor(context.Background(), filekey)
+		require.NoError(t, err)
+		require.Equal(t, filePath, r)
+		f, err := ioutil.ReadFile(filepath.Clean(filePath))
+		require.NoError(t, err)
+		require.Equal(t, "silence1,silence3", string(f))
+		require.NoError(t, os.Remove(filePath))
+		require.NoError(t, store.Del(context.Background(), 1, KVNamespace, filekey))
+	}
+}
 func TestFileStore_FilepathFor(t *testing.T) {
 	store := newFakeKVStore(t)
 	workingDir := t.TempDir()