feat(metrics): serve /metrics endpoint with prometheus-save-to-file

.goreleaser-docker-only.yml

@@ -29,10 +29,8 @@ archives:
 
 dockers:
   - image_templates:
-      - "creativeprojects/resticprofile:latest-amd64"
-      - "creativeprojects/resticprofile:{{ .RawVersion }}-amd64"
-      - "ghcr.io/creativeprojects/resticprofile:latest-amd64"
-      - "ghcr.io/creativeprojects/resticprofile:{{ .RawVersion }}-amd64"
+      - "ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:latest-amd64"
+      - "ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:{{ .RawVersion }}-amd64"
     ids:
       - resticprofile_targz
     use: buildx
@@ -52,10 +50,8 @@ dockers:
       - "--build-arg=ARCH=amd64"
 
   - image_templates:
-      - "creativeprojects/resticprofile:latest-arm64v8"
-      - "creativeprojects/resticprofile:{{ .RawVersion }}-arm64v8"
-      - "ghcr.io/creativeprojects/resticprofile:latest-arm64v8"
-      - "ghcr.io/creativeprojects/resticprofile:{{ .RawVersion }}-arm64v8"
+      - "ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:latest-arm64v8"
+      - "ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:{{ .RawVersion }}-arm64v8"
     ids:
       - resticprofile_targz
     use: buildx
@@ -75,25 +71,15 @@ dockers:
       - "--build-arg=ARCH=arm64"
 
 docker_manifests:
-  - name_template: creativeprojects/resticprofile:{{ .RawVersion }}
+  - name_template: ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:{{ .RawVersion }}
     image_templates:
-      - creativeprojects/resticprofile:{{ .RawVersion }}-amd64
-      - creativeprojects/resticprofile:{{ .RawVersion }}-arm64v8
+      - ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:{{ .RawVersion }}-amd64
+      - ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:{{ .RawVersion }}-arm64v8
 
-  - name_template: creativeprojects/resticprofile:latest
+  - name_template: ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:latest
     image_templates:
-      - creativeprojects/resticprofile:latest-amd64
-      - creativeprojects/resticprofile:latest-arm64v8
-
-  - name_template: ghcr.io/creativeprojects/resticprofile:{{ .RawVersion }}
-    image_templates:
-      - ghcr.io/creativeprojects/resticprofile:{{ .RawVersion }}-amd64
-      - ghcr.io/creativeprojects/resticprofile:{{ .RawVersion }}-arm64v8
-
-  - name_template: ghcr.io/creativeprojects/resticprofile:latest
-    image_templates:
-      - ghcr.io/creativeprojects/resticprofile:latest-amd64
-      - ghcr.io/creativeprojects/resticprofile:latest-arm64v8
+      - ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:latest-amd64
+      - ghcr.io/{{ .Env.GITHUB_REPOSITORY }}:latest-arm64v8
 
 release:
   disable: true

commands.go

@@ -189,6 +189,18 @@ func getOwnCommands() []ownCommand {
 			hide:              true,
 			experimental:      true,
 		},
+		{
+			name:              "serve-metrics",
+			description:       "serve the profile's prometheus-save-to-file (and Go runtime metrics) on /metrics",
+			action:            serveMetricsCommand,
+			needConfiguration: true,
+			noProfile:         false,
+			hide:              true,
+			experimental:      true,
+			flags: map[string]string{
+				"--metrics-port": "port to expose /metrics on (overrides RESTICPROFILE_METRICS_PORT)",
+			},
+		},
 	}
 }
 

commands_schedule.go

@@ -4,8 +4,11 @@ import (
 	"errors"
 	"fmt"
 	"maps"
+	"os"
+	"os/signal"
 	"slices"
 	"strings"
+	"syscall"
 
 	"github.com/creativeprojects/clog"
 	"github.com/creativeprojects/resticprofile/config"
@@ -72,9 +75,92 @@ func createSchedule(ctx commandContext) error {
 		}
 	}
 
+	// Optional: if --metrics-port is set, keep the process alive and serve
+	// the profiles' prometheus-save-to-file on /metrics. This lets the schedule
+	// command double as a metrics sidecar when running under crond in a container.
+	if err := blockForMetricsServer(ctx); err != nil {
+		return err
+	}
+
 	return nil
 }
 
+// blockForMetricsServer starts a /metrics HTTP server for the prometheus-save-to-file
+// of the selected profiles, then blocks until SIGINT/SIGTERM. Returns nil immediately
+// (and the function returns) when --metrics-port is not set or no profile has a
+// prometheus-save-to-file configured. A warning is logged in the latter case so the
+// user knows metrics were requested but no file is available.
+func blockForMetricsServer(ctx commandContext) error {
+	if ctx.flags.metricsPort <= 0 {
+		return nil
+	}
+
+	metricFiles := collectPrometheusSaveToFiles(ctx)
+	if len(metricFiles) == 0 {
+		clog.Warningf("metrics server not started: no profile has prometheus-save-to-file set")
+		return nil
+	}
+
+	quit := make(chan os.Signal, 1)
+	signal.Notify(quit, os.Interrupt, syscall.SIGTERM)
+	defer signal.Stop(quit)
+
+	errCh := make(chan error, len(metricFiles))
+	for _, file := range metricFiles {
+		file := file
+		go func() {
+			if err := newMetricsServer(ctx.flags.metricsPort, file).run(quit); err != nil {
+				clog.Errorf("metrics server failed for %q: %v", file, err)
+				errCh <- err
+			}
+		}()
+	}
+
+	clog.Infof("schedule command will keep the process alive for the metrics server; send SIGINT/SIGTERM to stop")
+	select {
+	case <-quit:
+		clog.Info("shutting down metrics server (schedule)")
+		return nil
+	case err := <-errCh:
+		// best-effort: close quit so all running goroutines shut down
+		close(quit)
+		return err
+	}
+}
+
+// collectPrometheusSaveToFiles returns the unique non-empty prometheus-save-to-file
+// paths of all profiles selected by the schedule command (--all or a specific profile).
+// If a group is selected, the prometheus-save-to-file of each member profile is used.
+func collectPrometheusSaveToFiles(ctx commandContext) []string {
+	seen := make(map[string]struct{})
+	var files []string
+	args := ctx.request.arguments
+	add := func(name string) {
+		profile, err := ctx.config.GetProfile(name)
+		if err != nil || profile == nil || profile.PrometheusSaveToFile == "" {
+			return
+		}
+		if _, ok := seen[profile.PrometheusSaveToFile]; ok {
+			return
+		}
+		seen[profile.PrometheusSaveToFile] = struct{}{}
+		files = append(files, profile.PrometheusSaveToFile)
+	}
+
+	for _, name := range selectProfilesAndGroups(ctx.config, ctx.request.profile, args) {
+		if ctx.config.HasProfile(name) {
+			add(name)
+			continue
+		}
+		if group, err := ctx.config.GetProfileGroup(name); err == nil && group != nil {
+			for _, member := range group.Profiles {
+				add(member)
+			}
+		}
+	}
+	return files
+}
+
 func removeSchedule(ctx commandContext) error {
 	var err error
 	c := ctx.config

commands_schedule_test.go

@@ -298,3 +298,98 @@ func TestCreateScheduleOverwriteExistingIntegrationUsingCrontab(t *testing.T) {
 	assert.NotContains(t, output.String(), "Original form: *-*-* *:10,40:00") // previous one
 	t.Log(output.String())
 }
+
+func TestCollectPrometheusSaveToFiles(t *testing.T) {
+	const configYAML = `
+version: "2"
+
+groups:
+  group-a:
+    profiles:
+      - alpha
+      - beta
+
+profiles:
+  alpha:
+    prometheus-save-to-file: /var/metrics/alpha.prom
+  beta:
+    prometheus-save-to-file: /var/metrics/beta.prom
+  gamma:
+    prometheus-save-to-file: /var/metrics/shared.prom
+  delta:
+    prometheus-save-to-file: /var/metrics/shared.prom
+  epsilon: {}
+`
+	testCases := []struct {
+		name      string
+		arguments []string
+		profile   string
+		expected  []string
+		matcher   func(t assert.TestingT, expected, actual interface{}, msgAndArgs ...interface{}) bool
+	}{
+		{
+			name:      "single profile",
+			arguments: []string{"schedule"},
+			profile:   "alpha",
+			expected:  []string{"/var/metrics/alpha.prom"},
+			matcher:   assert.Equal,
+		},
+		{
+			name:      "all profiles dedups shared file",
+			arguments: []string{"schedule", "--all"},
+			profile:   "",
+			// Order is non-deterministic (viper map iteration); assert set
+			// membership via ElementsMatch so the test isn't order-sensitive.
+			expected: []string{"/var/metrics/shared.prom", "/var/metrics/alpha.prom", "/var/metrics/beta.prom"},
+			matcher:  assert.ElementsMatch,
+		},
+		{
+			name:      "group aggregates member files",
+			arguments: []string{"schedule"},
+			profile:   "group-a",
+			expected:  []string{"/var/metrics/alpha.prom", "/var/metrics/beta.prom"},
+			matcher:   assert.ElementsMatch,
+		},
+		{
+			name:      "profile without prometheus-save-to-file yields nothing",
+			arguments: []string{"schedule"},
+			profile:   "epsilon",
+			expected:  nil,
+			matcher:   assert.Equal,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg, err := config.Load(bytes.NewBufferString(configYAML), config.FormatYAML, config.WithConfigFile("config.yaml"))
+			require.NoError(t, err)
+
+			ctx := commandContext{
+				Context: Context{
+					config: cfg,
+					request: Request{
+						profile:   tc.profile,
+						arguments: tc.arguments,
+					},
+				},
+			}
+
+			got := collectPrometheusSaveToFiles(ctx)
+			tc.matcher(t, tc.expected, got)
+		})
+	}
+}
+
+func TestBlockForMetricsServerDisabledByDefault(t *testing.T) {
+	cfg, err := config.Load(bytes.NewBufferString("version: \"2\"\nprofiles:\n  alpha:\n    prometheus-save-to-file: /tmp/x.prom\n"), config.FormatYAML, config.WithConfigFile("config.yaml"))
+	require.NoError(t, err)
+
+	ctx := commandContext{
+		Context: Context{
+			config:  cfg,
+			request: Request{profile: "alpha"},
+			flags:   commandLineFlags{metricsPort: 0}, // explicitly disabled
+		},
+	}
+	assert.NoError(t, blockForMetricsServer(ctx))
+}

docs/content/changelog.md

@@ -5,6 +5,29 @@ title: Release Notes
 weight: 8
 ---
 
+# v0.34.0 (unreleased)
+
+## New Features
+
+### Prometheus metrics endpoint [EXPERIMENTAL]
+
+resticprofile can now expose the contents of a profile's `prometheus-save-to-file` on an HTTP endpoint, alongside the Go runtime metrics, so a sidecar Prometheus can scrape the last backup status from `schedule` and `serve-metrics` commands.
+
+Two ways to use it:
+
+- `resticprofile --metrics-port <port> schedule --all` — run `schedule` as usual; once the cron entries are installed the process blocks on SIGINT/SIGTERM, serving `/metrics` for every selected profile and group (textfile paths are de-duplicated).
+- `resticprofile --metrics-port <port> <profile> serve-metrics` — long-running sidecar serving a single profile's textfile. Useful when you can't or don't want to pass `--metrics-port` to the scheduler.
+
+Both honour `RESTICPROFILE_METRICS_PORT` and the `--metrics-port` flag is hidden from `--help` until the feature is stabilized.
+
+Response contract:
+
+- `200 OK` — runtime metrics + textfile body
+- `503 Service Unavailable` — textfile not yet created (e.g. first backup has not run). Prometheus treats this as `up == 0` rather than logging a 404 every scrape.
+- `500 Internal Server Error` — other I/O errors
+
+The `/metrics` endpoint binds on `0.0.0.0:<port>` for compatibility with container environments using `network_mode: host`.
+
 # v0.33.0 (2026-04-04)
 
 ## 🌸 Easter release 🥚

docs/content/monitoring/prometheus.md

@@ -229,4 +229,46 @@ root:
 {{< /tabs >}}
 
 
-This adds the `host` label to all your metrics.
+This adds the `host` label to all your metrics.
+
+## Exposing metrics over HTTP [EXPERIMENTAL]
+
+In addition to the file-based and push-based options, resticprofile can serve the latest metrics on an HTTP endpoint. The endpoint combines the Go runtime collector with the profile's `prometheus-save-to-file` body so a single sidecar can be scraped by Prometheus, Node Exporter's `--collector.textfile.directory`, or anything else that understands the Prometheus text exposition format.
+
+The feature is opt-in and hidden from `--help` until it stabilises. Enable it via the `--metrics-port` flag (or the `RESTICPROFILE_METRICS_PORT` environment variable) and select one of the following integration points:
+
+### `schedule` keeps the process alive and serves `/metrics`
+
+When `resticprofile` is used as the scheduler under `crond` (e.g. inside a container), it can double as a metrics sidecar. The scheduler registers all cron jobs as usual, then blocks on SIGINT/SIGTERM while serving `/metrics` for each profile that has `prometheus-save-to-file` set. Textfile paths are de-duplicated across profiles and groups, so several profiles writing to the same file share a single scrape target.
+
+```sh
+resticprofile --metrics-port 19302 schedule --all &
+crond -f
+```
+
+### `serve-metrics` as a stand-alone sidecar
+
+If you don't use `schedule` (or already have a separate scheduler), run a dedicated process:
+
+```sh
+resticprofile --metrics-port 19302 default serve-metrics
+```
+
+### Response contract
+
+- `200 OK` — Go runtime metrics followed by the textfile body.
+- `503 Service Unavailable` — the textfile does not exist yet (e.g. the first backup has not run). Prometheus reports the target as `up == 0` without logging a 404 on every scrape.
+- `500 Internal Server Error` — other I/O errors.
+
+The server binds on `0.0.0.0:<port>` for `network_mode: host` containers.
+
+### Scrape configuration
+
+```yaml
+scrape_configs:
+  - job_name: resticprofile
+    static_configs:
+      - targets: ['<host>:19302']
+        labels:
+          host: backup-server
+```

flags.go

@@ -39,6 +39,7 @@ type commandLineFlags struct {
 	ignoreOnBattery int
 	usagesHelp      string
 	remote          string // url of the remote server to download configuration files from
+	metricsPort     int    // port to expose /metrics on (0 = disabled)
 }
 
 func envValueOverride[T any](defaultValue T, keys ...string) T {
@@ -94,6 +95,7 @@ func loadFlags(args []string) (*pflag.FlagSet, commandLineFlags, error) {
 		wait:            envValueOverride(false, "RESTICPROFILE_WAIT"),
 		ignoreOnBattery: envValueOverride(0, "RESTICPROFILE_IGNORE_ON_BATTERY"),
 		remote:          envValueOverride("", "RESTICPROFILE_REMOTE"),
+		metricsPort:     envValueOverride(0, "RESTICPROFILE_METRICS_PORT"),
 	}
 
 	flagset.BoolVarP(&flags.help, "help", "h", flags.help, "display this help")
@@ -119,6 +121,9 @@ func loadFlags(args []string) (*pflag.FlagSet, commandLineFlags, error) {
 	// keep the "remote" flag hidden for now
 	_ = flagset.MarkHidden("remote")
 
+	flagset.IntVar(&flags.metricsPort, "metrics-port", flags.metricsPort, "port to expose /metrics on (overrides RESTICPROFILE_METRICS_PORT; 0 disables)")
+	_ = flagset.MarkHidden("metrics-port")
+
 	flagset.SetNormalizeFunc(func(f *pflag.FlagSet, name string) pflag.NormalizedName {
 		switch name {
 		case "profile":