fix: report failed backup monitoring when the backup never starts

docs/content/monitoring/prometheus.md

@@ -131,6 +131,13 @@ resticprofile_build_info{goversion="go1.24.3",profile="prom",version="0.31.0"} 1
 
 ```
 
+## Failure behavior
+
+The metrics reflects the most recent `backup` run, whether it succeeded or failed. A failed run is reported with `resticprofile_backup_status` set to `0`.
+This also applies to a backup that never started because a `run-before` command or a `stdin-command` exited with an error.
+
+The `*_bytes`, `*_files`, `*_dir` and `duration_seconds` gauges are derived from the summary that restic prints on completion. When a backup is aborted before restic prints that summary (for example when a `run-before` or `stdin-command` exits with an error), those gauges are written as `0`.
+
 ## Prometheus Pushgateway
 
 Prometheus Pushgateway uses the job label as a grouping key. Metrics with the same grouping key are replaced when pushed. To prevent overwriting metrics from different profiles, the default job label is set to `<profile_name>.<command>` (e.g., `root.backup`).
@@ -229,4 +236,4 @@ root:
 {{< /tabs >}}
 
 
-This adds the `host` label to all your metrics.
+This adds the `host` label to all your metrics.

wrapper.go

@@ -121,11 +121,14 @@ func (r *resticWrapper) summary(command string, summary monitor.Summary, stderr
 func (r *resticWrapper) runnerWithBeforeAndAfter(commands config.RunShellCommandsSection, command string, action func() error) func() error {
 	return func() (err error) {
 		err = r.runBeforeCommands(commands, command)
-
-		if err == nil {
-			err = action()
+		if err != nil {
+			// Report the failure so that a run aborted by a failing "run-before" command does not
+			// leave the previous (successful) result in the status file and the prometheus metrics.
+			r.summary(r.command, monitor.Summary{}, "", err)
+			return
 		}
 
+		err = action()
 		if err == nil {
 			err = r.runAfterCommands(commands, command)
 		}
@@ -558,7 +561,11 @@ func (r *resticWrapper) runCommand(command string) error {
 					rCommand.stdin = streamSource
 				}
 			} else {
-				return newCommandError(rCommand, "", fmt.Errorf("%s on profile '%s': %w", r.command, r.profile.Name, err))
+				// Report the failure so that a backup which never started does not leave the
+				// previous (successful) result in the status file and the prometheus metrics.
+				err = newCommandError(rCommand, "", fmt.Errorf("%s on profile '%s': %w", r.command, r.profile.Name, err))
+				r.summary(r.command, monitor.Summary{}, "", err)
+				return err
 			}
 		}
 

wrapper_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/creativeprojects/resticprofile/constants"
 	"github.com/creativeprojects/resticprofile/monitor"
 	"github.com/creativeprojects/resticprofile/monitor/mocks"
+	"github.com/creativeprojects/resticprofile/monitor/prom"
 	"github.com/creativeprojects/resticprofile/monitor/status"
 	"github.com/creativeprojects/resticprofile/platform"
 	"github.com/creativeprojects/resticprofile/restic"
@@ -240,6 +241,56 @@ func TestPostProfileScriptFail(t *testing.T) {
 	assert.EqualError(t, err, "run-after on profile 'name': exit status 1")
 }
 
+func TestRunBeforeFailureReportsMonitoring(t *testing.T) {
+	t.Parallel()
+
+	newWrapper := func(t *testing.T, runBefore *config.RunShellCommandsSection) (string, *resticWrapper) {
+		t.Helper()
+		profile := config.NewProfile(nil, "name")
+		profile.Backup = &config.BackupSection{}
+		if runBefore != nil {
+			profile.Backup.RunBefore = runBefore.RunBefore
+		}
+		promFile := filepath.Join(t.TempDir(), "metrics.prom")
+		profile.PrometheusSaveToFile = promFile
+		ctx := &Context{
+			binary:   mockBinary,
+			profile:  profile,
+			command:  constants.CommandBackup,
+			terminal: term.NewTerminal(),
+		}
+		wrapper := newResticWrapper(ctx)
+		wrapper.addProgress(prom.NewProgress(profile, prom.NewMetrics(profile.Name, "", version, "", nil)))
+		return promFile, wrapper
+	}
+
+	readStatus := func(t *testing.T, file string) string {
+		t.Helper()
+		content, err := os.ReadFile(file)
+		require.NoError(t, err, "prometheus metrics file should be written")
+		return string(content)
+	}
+
+	t.Run("ProfileRunBefore", func(t *testing.T) {
+		promFile, wrapper := newWrapper(t, nil)
+		wrapper.profile.RunBefore = []string{"exit 2"}
+
+		err := wrapper.runProfile()
+
+		require.Error(t, err)
+		assert.Contains(t, readStatus(t, promFile), `resticprofile_backup_status{profile="name"} 0`)
+	})
+
+	t.Run("SectionRunBefore", func(t *testing.T) {
+		promFile, wrapper := newWrapper(t, &config.RunShellCommandsSection{RunBefore: []string{"exit 2"}})
+
+		err := wrapper.runProfile()
+
+		require.Error(t, err)
+		assert.Contains(t, readStatus(t, promFile), `resticprofile_backup_status{profile="name"} 0`)
+	})
+}
+
 func TestRunEchoProfile(t *testing.T) {
 	t.Parallel()
 
@@ -768,6 +819,22 @@ func TestBackupWithStreamSource(t *testing.T) {
 		assert.EqualError(t, err, "stdin-test on profile 'name': 'stdin-command' on profile 'name': exit status 2")
 	})
 
+	t.Run("StreamSourceFailureReportsMonitoring", func(t *testing.T) {
+		profile, wrapper := profileAndWrapper(t)
+		wrapper.command = constants.CommandBackup
+		profile.PrometheusSaveToFile = filepath.Join(t.TempDir(), "metrics.prom")
+		profile.Backup.StdinCommand = []string{"exit 2"}
+		profile.ResolveConfiguration()
+		wrapper.addProgress(prom.NewProgress(profile, prom.NewMetrics(profile.Name, "", version, "", nil)))
+
+		err := wrapper.runCommand(constants.CommandBackup)
+
+		require.Error(t, err)
+		content, readErr := os.ReadFile(profile.PrometheusSaveToFile)
+		require.NoError(t, readErr, "prometheus metrics file should be written even if restic never started")
+		assert.Contains(t, string(content), "resticprofile_backup_status{profile=\"name\"} 0")
+	})
+
 	t.Run("StreamSourceWorksWithDryRun", func(t *testing.T) {
 		profile, wrapper := profileAndWrapper(t)
 		wrapper.dryRun = true