Add async job runner and GET /api/v1/jobs/{id}

internal/jobs persists jobs in the jobs table, which is also the queue: a
bounded pool of workers claims queued jobs oldest first. Handlers are
registered per kind before Start with typed payloads and results, and can
publish partial results to the row while they run. Only typed results and
*jobs.Failure messages are stored; any other handler error is logged and
stored as "internal error", so dependency error text cannot surface a
secret. Start fails jobs a previous process left running with
"interrupted by restart" before any worker runs.

GET /api/v1/jobs/{id} returns {id, kind, status, result, error} inside the
protected /api/v1 group; an unknown id is a 404 not_found.

Migration 0003_jobs_status rebuilds jobs with status queued, running,
succeeded, failed, mapping legacy pending and done rows.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/server/jobs.go

@@ -0,0 +1,29 @@
+package server
+
+import (
+	"errors"
+	"log/slog"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
+)
+
+// getJob serves GET /api/v1/jobs/{id}: the job's id, kind, status, latest
+// result and error.
+func getJob(logger *slog.Logger, runner *jobs.Runner) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		job, err := runner.Get(r.Context(), chi.URLParam(r, "id"))
+		if errors.Is(err, jobs.ErrNotFound) {
+			writeError(w, r, logger, http.StatusNotFound, "not_found", "job not found")
+			return
+		}
+		if err != nil {
+			logger.ErrorContext(r.Context(), "get job", "error", err)
+			writeError(w, r, logger, http.StatusInternalServerError, "internal", "internal error")
+			return
+		}
+		writeJSON(w, r, logger, http.StatusOK, job)
+	}
+}

internal/server/jobs_test.go

@@ -0,0 +1,151 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"maps"
+	"net/http"
+	"net/http/httptest"
+	"slices"
+	"testing"
+	"time"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
+)
+
+type draftPayload struct{}
+
+type draftResult struct {
+	Days int `json:"days"`
+}
+
+// startedRunner registers a "draft" kind that publishes {"days":1}, waits
+// for release and returns {"days":7}, or fails with a *jobs.Failure when
+// fail is closed first. It starts the runner and stops it when the test ends.
+func startedRunner(t *testing.T, release, fail <-chan struct{}) (*jobs.Runner, *jobs.Kind[draftPayload]) {
+	t.Helper()
+	runner := newTestRunner(t)
+	kind, err := jobs.Register(runner, "draft", func(ctx context.Context, _ draftPayload, publish func(draftResult) error) (draftResult, error) {
+		if err := publish(draftResult{Days: 1}); err != nil {
+			return draftResult{}, err
+		}
+		select {
+		case <-release:
+			return draftResult{Days: 7}, nil
+		case <-fail:
+			return draftResult{}, &jobs.Failure{Message: "no Regulars to plan from"}
+		case <-ctx.Done():
+			return draftResult{}, ctx.Err()
+		}
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	if err := runner.Start(ctx); err != nil {
+		cancel()
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		cancel()
+		runner.Wait()
+	})
+	return runner, kind
+}
+
+// pollJob GETs the job until want accepts the body, failing after five
+// seconds.
+func pollJob(t *testing.T, h http.Handler, id string, want func(map[string]any) bool) map[string]any {
+	t.Helper()
+	deadline := time.Now().Add(5 * time.Second)
+	for {
+		rec, body := serve(t, h, signedIn(http.MethodGet, "/api/v1/jobs/"+id, nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200: %s", rec.Code, rec.Body)
+		}
+		if want(body) {
+			if keys := slices.Sorted(maps.Keys(body)); !slices.Equal(keys, []string{"error", "id", "kind", "result", "status"}) {
+				t.Errorf("body fields = %v, want id, kind, status, result, error", keys)
+			}
+			return body
+		}
+		if time.Now().After(deadline) {
+			t.Fatalf("job %s never reached the expected state; last %v", id, body)
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+}
+
+func resultDays(body map[string]any) float64 {
+	result, _ := body["result"].(map[string]any)
+	days, _ := result["days"].(float64)
+	return days
+}
+
+func TestGetJobShowsProgressThenResult(t *testing.T) {
+	t.Parallel()
+	release := make(chan struct{})
+	runner, kind := startedRunner(t, release, nil)
+	router := newTestRouterWith(t, "dev", newTestSettings(t), runner)
+	id, err := kind.Enqueue(context.Background(), draftPayload{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mid := pollJob(t, router, id, func(b map[string]any) bool { return resultDays(b) == 1 })
+	if mid["id"] != id || mid["kind"] != "draft" || mid["status"] != "running" || mid["error"] != nil {
+		t.Errorf("mid-run body = %v, want running draft job %s with no error", mid, id)
+	}
+
+	close(release)
+	done := pollJob(t, router, id, func(b map[string]any) bool { return b["status"] == "succeeded" })
+	if resultDays(done) != 7 || done["error"] != nil {
+		t.Errorf("finished body = %v, want result {\"days\":7} and no error", done)
+	}
+}
+
+func TestGetJobShowsFailure(t *testing.T) {
+	t.Parallel()
+	fail := make(chan struct{})
+	close(fail)
+	runner, kind := startedRunner(t, nil, fail)
+	router := newTestRouterWith(t, "dev", newTestSettings(t), runner)
+	id, err := kind.Enqueue(context.Background(), draftPayload{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	body := pollJob(t, router, id, func(b map[string]any) bool { return b["status"] == "failed" })
+	if body["error"] != "no Regulars to plan from" {
+		t.Errorf("error = %v, want the Failure message", body["error"])
+	}
+}
+
+func TestGetJobUnknownIDIsNotFound(t *testing.T) {
+	t.Parallel()
+	router := newTestRouter(t, "dev")
+
+	rec, _ := serve(t, router, signedIn(http.MethodGet, "/api/v1/jobs/"+store.NewID(), nil))
+	if rec.Code != http.StatusNotFound {
+		t.Fatalf("status = %d, want 404", rec.Code)
+	}
+	var body errorBody
+	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
+		t.Fatal(err)
+	}
+	if want := (errorBody{Error: apiError{Code: "not_found", Message: "job not found"}}); body != want {
+		t.Errorf("body = %+v, want %+v", body, want)
+	}
+}
+
+func TestGetJobRequiresSession(t *testing.T) {
+	t.Parallel()
+	router := newTestRouter(t, "dev")
+
+	rec := httptest.NewRecorder()
+	router.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/api/v1/jobs/"+store.NewID(), nil))
+	if rec.Code != http.StatusUnauthorized {
+		t.Errorf("status = %d, want 401", rec.Code)
+	}
+}

internal/server/login_test.go

@@ -83,7 +83,7 @@ func newLoginRouter(t *testing.T, issuer string) http.Handler {
 		t.Fatal(err)
 	}
 	r, err := NewRouter(logger, "dev", trusted, flow, sessions, newTestSettings(t),
-		fstest.MapFS{"index.html": {Data: []byte(fixtureIndex)}})
+		newTestRunner(t), fstest.MapFS{"index.html": {Data: []byte(fixtureIndex)}})
 	if err != nil {
 		t.Fatal(err)
 	}

internal/server/origin_test.go

@@ -45,7 +45,7 @@ func newOriginRouter(t *testing.T, logs io.Writer) http.Handler {
 	}
 	logger := slog.New(forwarded.LogHandler(slog.NewJSONHandler(logs, nil)))
 	r, err := NewRouter(logger, "dev", trusted, probeAuth{}, stubSessions{}, newTestSettings(t),
-		fstest.MapFS{"index.html": {Data: []byte(fixtureIndex)}})
+		newTestRunner(t), fstest.MapFS{"index.html": {Data: []byte(fixtureIndex)}})
 	if err != nil {
 		t.Fatal(err)
 	}

internal/server/server.go

@@ -13,6 +13,7 @@ import (
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/forwarded"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/frontend"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/household"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
 )
 
 // reservedPrefixes are owned by the API router and are never answered with the
@@ -28,13 +29,17 @@ type RouteMounter interface {
 // has its client address and scheme resolved, honouring forwarded headers
 // only from a peer in trusted (see resolveOrigin). version is reported by
 // GET /health; auth mounts the /auth routes; sessions guards /api/v1 and
-// /media; settings serves /api/v1/settings/household; assets is the web build
+// /media; settings serves /api/v1/settings/household; runner serves
+// /api/v1/jobs/{id}; assets is the web build
 // served for every other GET. /health, /auth and the web build are public.
 // Requests to /api/v1 other than GET also need the session's CSRF token in CSRFHeader.
-func NewRouter(logger *slog.Logger, version string, trusted forwarded.Trusted, auth RouteMounter, sessions SessionLookup, settings *household.SettingsService, assets fs.FS) (http.Handler, error) {
+func NewRouter(logger *slog.Logger, version string, trusted forwarded.Trusted, auth RouteMounter, sessions SessionLookup, settings *household.SettingsService, runner *jobs.Runner, assets fs.FS) (http.Handler, error) {
 	if settings == nil {
 		return nil, errors.New("server: nil household settings service")
 	}
+	if runner == nil {
+		return nil, errors.New("server: nil job runner")
+	}
 	notFound := apiErrorHandler(logger, http.StatusNotFound, "not_found", "not found")
 	methodNotAllowed := apiErrorHandler(logger, http.StatusMethodNotAllowed, "method_not_allowed", "method not allowed")
 
@@ -63,6 +68,7 @@ func NewRouter(logger *slog.Logger, version string, trusted forwarded.Trusted, a
 	apiV1.Get("/me", me(logger))
 	apiV1.Get("/settings/household", getHouseholdSettings(logger, settings))
 	apiV1.Patch("/settings/household", patchHouseholdSettings(logger, settings))
+	apiV1.Get("/jobs/{id}", getJob(logger, runner))
 	r.Route("/api", func(r chi.Router) {
 		r.MethodNotAllowed(methodNotAllowed)
 		r.NotFound(notFound)

internal/server/server_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/go-chi/chi/v5"
 
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/household"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/migrations"
 )
@@ -27,17 +28,17 @@ const (
 
 func newTestRouter(t *testing.T, version string) http.Handler {
 	t.Helper()
-	return newTestRouterWith(t, version, newTestSettings(t))
+	return newTestRouterWith(t, version, newTestSettings(t), newTestRunner(t))
 }
 
-func newTestRouterWith(t *testing.T, version string, settings *household.SettingsService) http.Handler {
+func newTestRouterWith(t *testing.T, version string, settings *household.SettingsService, runner *jobs.Runner) http.Handler {
 	t.Helper()
 	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
 	assets := fstest.MapFS{
 		"index.html":             {Data: []byte(fixtureIndex)},
 		"assets/index-AbC123.js": {Data: []byte(fixtureAsset)},
 	}
-	r, err := NewRouter(logger, version, nil, stubAuth{}, stubSessions{}, settings, assets)
+	r, err := NewRouter(logger, version, nil, stubAuth{}, stubSessions{}, settings, runner, assets)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -70,9 +71,8 @@ func TestAuthRoutesMounted(t *testing.T) {
 	}
 }
 
-// newTestSettings returns a settings service over a migrated temp database
-// seeded with zone America/New_York.
-func newTestSettings(t *testing.T) *household.SettingsService {
+// newTestStore returns a migrated temp database, closed when the test ends.
+func newTestStore(t *testing.T) *store.Store {
 	t.Helper()
 	ctx := context.Background()
 	st, err := store.Open(ctx, t.TempDir())
@@ -87,21 +87,49 @@ func newTestSettings(t *testing.T) *household.SettingsService {
 	if err := store.Migrate(ctx, st.Writer, migrations.FS); err != nil {
 		t.Fatal(err)
 	}
-	if err := household.SeedSettings(ctx, st, "America/New_York"); err != nil {
+	return st
+}
+
+// newTestSettings returns a settings service over a migrated temp database
+// seeded with zone America/New_York.
+func newTestSettings(t *testing.T) *household.SettingsService {
+	t.Helper()
+	st := newTestStore(t)
+	if err := household.SeedSettings(context.Background(), st, "America/New_York"); err != nil {
 		t.Fatal(err)
 	}
 	return household.NewSettingsService(st)
 }
 
+// newTestRunner returns an unstarted job runner over a migrated temp
+// database.
+func newTestRunner(t *testing.T) *jobs.Runner {
+	t.Helper()
+	runner, err := jobs.NewRunner(newTestStore(t), slog.New(slog.NewTextHandler(io.Discard, nil)), 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return runner
+}
+
 func TestNewRouterRequiresSettings(t *testing.T) {
 	t.Parallel()
 
 	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
-	if _, err := NewRouter(logger, "dev", nil, stubAuth{}, stubSessions{}, nil, fstest.MapFS{"index.html": {}}); err == nil {
+	if _, err := NewRouter(logger, "dev", nil, stubAuth{}, stubSessions{}, nil, newTestRunner(t), fstest.MapFS{"index.html": {}}); err == nil {
 		t.Fatal("NewRouter accepted a nil settings service")
 	}
 }
 
+func TestNewRouterRequiresJobRunner(t *testing.T) {
+	t.Parallel()
+
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+	if _, err := NewRouter(logger, "dev", nil, stubAuth{}, stubSessions{}, newTestSettings(t), nil, fstest.MapFS{"index.html": {}}); err == nil {
+		t.Fatal("NewRouter accepted a nil job runner")
+	}
+}
+
 func TestHealth(t *testing.T) {
 	t.Parallel()
 

internal/server/settings_test.go

@@ -84,7 +84,7 @@ func TestGetHouseholdSettings(t *testing.T) {
 func TestPatchHouseholdSettings(t *testing.T) {
 	t.Parallel()
 	settings := newTestSettings(t)
-	router := newTestRouterWith(t, "dev", settings)
+	router := newTestRouterWith(t, "dev", settings, newTestRunner(t))
 
 	var notified []household.Settings
 	settings.Subscribe(func(s household.Settings) { notified = append(notified, s) })
@@ -146,7 +146,7 @@ func TestPatchHouseholdSettingsRejected(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			settings := newTestSettings(t)
-			router := newTestRouterWith(t, "dev", settings)
+			router := newTestRouterWith(t, "dev", settings, newTestRunner(t))
 			notified := 0
 			settings.Subscribe(func(household.Settings) { notified++ })
 
@@ -216,7 +216,7 @@ func TestHouseholdSettingsWithRealSession(t *testing.T) {
 	}
 	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
 	router, err := NewRouter(logger, "dev", nil, stubAuth{}, sessions, household.NewSettingsService(st),
-		fstest.MapFS{"index.html": {Data: []byte(fixtureIndex)}})
+		newTestRunner(t), fstest.MapFS{"index.html": {Data: []byte(fixtureIndex)}})
 	if err != nil {
 		t.Fatal(err)
 	}