Add per-job backup retention

internal/model/model.go

@@ -74,9 +74,10 @@ type Consistency struct {
 }
 
 type Retention struct {
-	Daily   int `json:"daily"`
-	Weekly  int `json:"weekly"`
-	Monthly int `json:"monthly"`
+	KeepWithinDays int `json:"keepWithinDays,omitempty"`
+	Daily          int `json:"daily"`
+	Weekly         int `json:"weekly"`
+	Monthly        int `json:"monthly"`
 }
 
 type Repository struct {

internal/model/validate.go

@@ -87,9 +87,12 @@ func ValidateJob(j Job) error {
 	if j.Consistency.Mode != "live" && j.Consistency.Mode != "stop" {
 		return errors.New("consistency mode must be live or stop")
 	}
-	if j.Retention.Daily < 0 || j.Retention.Weekly < 0 || j.Retention.Monthly < 0 {
+	if j.Retention.KeepWithinDays < 0 || j.Retention.Daily < 0 || j.Retention.Weekly < 0 || j.Retention.Monthly < 0 {
 		return errors.New("retention values cannot be negative")
 	}
+	if j.Retention.KeepWithinDays == 0 && j.Retention.Daily == 0 && j.Retention.Weekly == 0 && j.Retention.Monthly == 0 {
+		return errors.New("retention must keep at least one age or calendar policy")
+	}
 	for _, exclude := range j.Excludes {
 		if strings.ContainsAny(exclude, "\x00\r\n") {
 			return errors.New("exclude contains forbidden control characters")

internal/model/validate_test.go

@@ -36,7 +36,7 @@ func TestRepositoryCannotBeSharedByJobs(t *testing.T) {
 }
 
 func TestDockerJobRequiresWorkloadSources(t *testing.T) {
-	job := Job{SchemaVersion: 1, ID: "docker-job", Name: "Docker", Type: JobDocker, RepositoryID: "repo", Sources: []Source{{Path: "/mnt/user/appdata"}}, Consistency: Consistency{Mode: "live"}, Compression: "auto"}
+	job := Job{SchemaVersion: 1, ID: "docker-job", Name: "Docker", Type: JobDocker, RepositoryID: "repo", Sources: []Source{{Path: "/mnt/user/appdata"}}, Consistency: Consistency{Mode: "live"}, Compression: "auto", Retention: Retention{KeepWithinDays: 30}}
 	if err := ValidateJob(job); err == nil {
 		t.Fatal("docker path source accepted without workload selection")
 	}
@@ -45,3 +45,14 @@ func TestDockerJobRequiresWorkloadSources(t *testing.T) {
 		t.Fatalf("valid docker workload rejected: %v", err)
 	}
 }
+
+func TestRetentionRequiresAtLeastOneRule(t *testing.T) {
+	job := Job{SchemaVersion: 1, ID: "job", Name: "Share", Type: JobShare, RepositoryID: "repo", Sources: []Source{{Path: "/mnt/user/data"}}, Consistency: Consistency{Mode: "live"}, Compression: "auto"}
+	if err := ValidateJob(job); err == nil {
+		t.Fatal("empty retention policy accepted")
+	}
+	job.Retention.KeepWithinDays = 30
+	if err := ValidateJob(job); err != nil {
+		t.Fatalf("age retention rejected: %v", err)
+	}
+}

internal/restic/restic.go

@@ -58,7 +58,19 @@ func (r *Runner) Backup(ctx context.Context, repo model.Repository, job model.Jo
 }
 
 func (r *Runner) Forget(ctx context.Context, repo model.Repository, job model.Job) error {
-	args := []string{"forget", "--tag", "job:" + job.ID, "--keep-daily", fmt.Sprint(job.Retention.Daily), "--keep-weekly", fmt.Sprint(job.Retention.Weekly), "--keep-monthly", fmt.Sprint(job.Retention.Monthly)}
+	args := []string{"forget", "--tag", "job:" + job.ID}
+	if job.Retention.KeepWithinDays > 0 {
+		args = append(args, "--keep-within", fmt.Sprintf("%dd", job.Retention.KeepWithinDays))
+	}
+	if job.Retention.Daily > 0 {
+		args = append(args, "--keep-daily", fmt.Sprint(job.Retention.Daily))
+	}
+	if job.Retention.Weekly > 0 {
+		args = append(args, "--keep-weekly", fmt.Sprint(job.Retention.Weekly))
+	}
+	if job.Retention.Monthly > 0 {
+		args = append(args, "--keep-monthly", fmt.Sprint(job.Retention.Monthly))
+	}
 	return r.run(ctx, repo, args, nil, nil)
 }
 

internal/restic/restic_test.go

@@ -45,3 +45,28 @@ func TestBackupUsesPasswordFileAndStructuredArguments(t *testing.T) {
 		t.Fatal("password file was not provided")
 	}
 }
+
+func TestForgetUsesAgeAndCalendarRetention(t *testing.T) {
+	dir := t.TempDir()
+	argsPath := filepath.Join(dir, "args")
+	script := filepath.Join(dir, "restic")
+	body := fmt.Sprintf("#!/bin/sh\nprintf '%%s\\n' \"$@\" > '%s'\n", argsPath)
+	if err := os.WriteFile(script, []byte(body), 0700); err != nil {
+		t.Fatal(err)
+	}
+	runner := &Runner{Binary: script, RuntimeDir: dir, Secrets: fakeSecrets{"password": "secret"}}
+	repo := model.Repository{Type: model.RepositoryLocal, Location: "/repo", PasswordRef: "password"}
+	job := model.Job{ID: "job", Retention: model.Retention{KeepWithinDays: 30, Weekly: 4, Monthly: 12}}
+	if err := runner.Forget(context.Background(), repo, job); err != nil {
+		t.Fatal(err)
+	}
+	args, _ := os.ReadFile(argsPath)
+	for _, expected := range []string{"--keep-within", "30d", "--keep-weekly", "4", "--keep-monthly", "12"} {
+		if !strings.Contains(string(args), expected) {
+			t.Fatalf("retention arguments missing %q: %s", expected, args)
+		}
+	}
+	if strings.Contains(string(args), "--keep-daily") {
+		t.Fatalf("disabled daily retention was included: %s", args)
+	}
+}