Allow retention_days of 0 to mean retain forever (closes #79)

RetentionDays carried gorm:"default:30", so GORM substituted 30 for a
zero value while building the insert. A webhook could therefore never
be configured to keep its events indefinitely: the reaper's
retain-forever branch existed but was unreachable from the normal
create and edit flows.

Introduce database.RetentionForeverDays = 365 * 1000 as the sentinel
for "retain forever" and a Webhook.BeforeSave hook that rewrites any
non-positive RetentionDays to it. The rewrite has to live in the hook
rather than at the call sites: GORM applies the column default while
converting the model to insert values, which happens after BeforeSave,
so anything later loses that race. Putting it on the model also means
a future call site, such as the planned REST API, cannot bypass it.

The reaper now skips a webhook when Webhook.RetainsForever reports
true, which recognises the sentinel and keeps honouring the old <= 0
values for rows written before it existed. Without this the sentinel,
being positive, would have produced a cutoff a thousand years in the
past and a DELETE matching nothing on every sweep.

Form handling is shared by create and edit through parseRetentionDays
so the two cannot drift: an empty field keeps the previous behaviour
(default on create, unchanged on edit), 0 is honoured, and an
unparseable or negative value is a 400 that re-renders the form rather
than a silently substituted default.

The retention inputs drop max="365". That cap was not cosmetic: the
edit form pre-fills the stored value, so a retain-forever webhook
rendered 365000 into an input capped at 365 and browser validation
would have blocked saving any edit to it. min becomes 0 with a hint
explaining what 0 does, and the list and detail views render a
RetentionLabel of "forever" instead of a raw day count.

The 30-day default is consolidated into database.DefaultRetentionDays,
referenced from the handler and from the create form's pre-filled
value, with a test asserting it agrees with the struct tag that cannot
reference it.

internal/handlers/handlers.go

@@ -26,8 +26,6 @@ const (
 	maxBodyShift = 20
 	// recentEventLimit is the number of recent events to show.
 	recentEventLimit = 20
-	// defaultRetentionDays is the default event retention period.
-	defaultRetentionDays = 30
 	// paginationPerPage is the number of items per page.
 	paginationPerPage = 25
 

internal/handlers/source_management.go

@@ -25,6 +25,37 @@ type WebhookListItem struct {
 // errMissingURL signals that a required URL was not provided.
 var errMissingURL = errors.New("missing URL")
 
+// errInvalidRetention signals a retention_days form value that is not
+// a non-negative whole number.
+var errInvalidRetention = errors.New("invalid retention days")
+
+// retentionErrorMessage is what the create and edit forms show the user
+// when parseRetentionDays returns errInvalidRetention.
+const retentionErrorMessage = "Retention must be a whole number of " +
+	"days, or 0 to retain events forever."
+
+// parseRetentionDays interprets a retention_days form value.
+//
+// An empty value yields fallback, which lets the create path apply the
+// default and the edit path leave the stored value unchanged. A value
+// of 0 is returned as 0 and is rewritten to the retain-forever
+// sentinel by database.Webhook's BeforeSave hook, so no handler needs
+// to know the sentinel. Anything unparseable or negative is an error
+// rather than a silently substituted default.
+func parseRetentionDays(raw string, fallback int) (int, error) {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return fallback, nil
+	}
+
+	v, err := strconv.Atoi(raw)
+	if err != nil || v < 0 {
+		return 0, errInvalidRetention
+	}
+
+	return v, nil
+}
+
 // EventWithDeliveries holds an event and its deliveries.
 type EventWithDeliveries struct {
 	database.Event
@@ -106,11 +137,20 @@ func (h *Handlers) buildWebhookListItems(
 // HandleSourceCreate shows the form to create a new webhook.
 func (h *Handlers) HandleSourceCreate() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		data := map[string]any{
-			tmplKeyError: "",
-		}
+		h.renderTemplate(
+			w, r, "sources_new.html", newSourceFormData(""),
+		)
+	}
+}
 
-		h.renderTemplate(w, r, "sources_new.html", data)
+// newSourceFormData builds the template data for the webhook creation
+// form, carrying the retention default so the pre-filled value comes
+// from database.DefaultRetentionDays rather than being a third
+// hardcoded copy of the same policy.
+func newSourceFormData(errMsg string) map[string]any {
+	return map[string]any{
+		tmplKeyError:           errMsg,
+		"DefaultRetentionDays": database.DefaultRetentionDays,
 	}
 }
 
@@ -145,23 +185,26 @@ func (h *Handlers) HandleSourceCreateSubmit() http.HandlerFunc {
 		retentionStr := r.FormValue("retention_days")
 
 		if name == "" {
-			data := map[string]any{
-				tmplKeyError: "Name is required",
-			}
-
 			w.WriteHeader(http.StatusBadRequest)
-			h.renderTemplate(w, r, "sources_new.html", data)
+			h.renderTemplate(
+				w, r, "sources_new.html",
+				newSourceFormData("Name is required"),
+			)
 
 			return
 		}
 
-		retentionDays := defaultRetentionDays
+		retentionDays, retErr := parseRetentionDays(
+			retentionStr, database.DefaultRetentionDays,
+		)
+		if retErr != nil {
+			w.WriteHeader(http.StatusBadRequest)
+			h.renderTemplate(
+				w, r, "sources_new.html",
+				newSourceFormData(retentionErrorMessage),
+			)
 
-		if retentionStr != "" {
-			v, convErr := strconv.Atoi(retentionStr)
-			if convErr == nil && v > 0 {
-				retentionDays = v
-			}
+			return
 		}
 
 		h.createWebhookWithEntrypoint(
@@ -428,7 +471,25 @@ func (h *Handlers) applyWebhookEdit(
 
 	webhook.Name = name
 	webhook.Description = r.FormValue("description")
-	h.parseRetention(r, webhook)
+
+	// An empty field falls back to the stored value, so submitting the
+	// form without touching retention leaves the policy alone.
+	retentionDays, retErr := parseRetentionDays(
+		r.FormValue("retention_days"), webhook.RetentionDays,
+	)
+	if retErr != nil {
+		data := map[string]any{
+			tmplKeyWebhook: *webhook,
+			tmplKeyError:   retentionErrorMessage,
+		}
+
+		w.WriteHeader(http.StatusBadRequest)
+		h.renderTemplate(w, r, "source_edit.html", data)
+
+		return
+	}
+
+	webhook.RetentionDays = retentionDays
 
 	err := h.db.DB().Save(webhook).Error
 	if err != nil {
@@ -442,23 +503,6 @@ func (h *Handlers) applyWebhookEdit(
 	)
 }
 
-// parseRetention parses and applies retention_days from the
-// form.
-func (h *Handlers) parseRetention(
-	r *http.Request,
-	webhook *database.Webhook,
-) {
-	retStr := r.FormValue("retention_days")
-	if retStr == "" {
-		return
-	}
-
-	v, err := strconv.Atoi(retStr)
-	if err == nil && v > 0 {
-		webhook.RetentionDays = v
-	}
-}
-
 // HandleSourceDelete handles webhook deletion.
 func (h *Handlers) HandleSourceDelete() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {

internal/handlers/source_management_test.go

@@ -0,0 +1,481 @@
+package handlers_test
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/go-chi/chi"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/gorm/clause"
+	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/handlers"
+	"sneak.berlin/go/webhooker/internal/session"
+)
+
+const (
+	// sourceTestUserID is the session user id used by the webhook
+	// management tests.
+	sourceTestUserID = "source-test-user"
+	// sourceIDParam is the chi URL parameter naming a webhook.
+	sourceIDParam = "sourceID"
+)
+
+// formRequest builds an urlencoded POST to path carrying the given
+// cookies, plus any chi URL parameters the handler reads.
+func formRequest(
+	path string,
+	cookies []*http.Cookie,
+	form url.Values,
+	urlParams map[string]string,
+) *http.Request {
+	req := httptest.NewRequestWithContext(
+		context.Background(),
+		http.MethodPost,
+		path,
+		strings.NewReader(form.Encode()),
+	)
+	req.Header.Set(
+		"Content-Type", "application/x-www-form-urlencoded",
+	)
+
+	for _, c := range cookies {
+		req.AddCookie(c)
+	}
+
+	rctx := chi.NewRouteContext()
+	for k, v := range urlParams {
+		rctx.URLParams.Add(k, v)
+	}
+
+	return req.WithContext(
+		context.WithValue(req.Context(), chi.RouteCtxKey, rctx),
+	)
+}
+
+// getRequest builds a GET to path carrying the given cookies, plus any
+// chi URL parameters the handler reads.
+func getRequest(
+	t *testing.T,
+	path string,
+	cookies []*http.Cookie,
+	urlParams map[string]string,
+) *http.Request {
+	t.Helper()
+
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodGet, path, nil,
+	)
+
+	for _, c := range cookies {
+		req.AddCookie(c)
+	}
+
+	rctx := chi.NewRouteContext()
+	for k, v := range urlParams {
+		rctx.URLParams.Add(k, v)
+	}
+
+	return req.WithContext(
+		context.WithValue(req.Context(), chi.RouteCtxKey, rctx),
+	)
+}
+
+// submitCreate posts the webhook creation form with the given
+// retention_days value (omitted entirely when retention is nil) and
+// returns the recorder.
+func submitCreate(
+	t *testing.T,
+	h *handlers.Handlers,
+	cookies []*http.Cookie,
+	name string,
+	retention *string,
+) *httptest.ResponseRecorder {
+	t.Helper()
+
+	form := url.Values{}
+	form.Set("name", name)
+
+	if retention != nil {
+		form.Set("retention_days", *retention)
+	}
+
+	req := formRequest("/sources/new", cookies, form, nil)
+	w := httptest.NewRecorder()
+
+	h.HandleSourceCreateSubmit().ServeHTTP(w, req)
+
+	return w
+}
+
+// onlyWebhook loads the single webhook belonging to the test user.
+func onlyWebhook(
+	t *testing.T,
+	db *database.Database,
+) database.Webhook {
+	t.Helper()
+
+	var webhooks []database.Webhook
+
+	require.NoError(
+		t,
+		db.DB().Where("user_id = ?", sourceTestUserID).
+			Find(&webhooks).Error,
+	)
+	require.Len(t, webhooks, 1)
+
+	return webhooks[0]
+}
+
+// seedWebhook inserts a webhook owned by the test user with an exact
+// stored retention value, bypassing Webhook.BeforeSave via a
+// column-level update so that legacy rows can be planted too.
+func seedWebhook(
+	t *testing.T,
+	db *database.Database,
+	retentionDays int,
+) database.Webhook {
+	t.Helper()
+
+	wh := &database.Webhook{
+		UserID:        sourceTestUserID,
+		Name:          "seeded",
+		RetentionDays: retentionDays,
+	}
+	require.NoError(
+		t,
+		db.DB().Omit(clause.Associations).Create(wh).Error,
+	)
+	require.NoError(
+		t,
+		db.DB().Model(wh).
+			Update("retention_days", retentionDays).Error,
+	)
+
+	wh.RetentionDays = retentionDays
+
+	return *wh
+}
+
+// storedRetentionDays reads the retention_days column for a webhook.
+func storedRetentionDays(
+	t *testing.T,
+	db *database.Database,
+	id string,
+) int {
+	t.Helper()
+
+	var got int
+
+	require.NoError(
+		t,
+		db.DB().Model(&database.Webhook{}).
+			Where("id = ?", id).
+			Pluck("retention_days", &got).Error,
+	)
+
+	return got
+}
+
+// sourceTestEnv bundles the handler, session, and database a webhook
+// management test drives.
+type sourceTestEnv struct {
+	handlers *handlers.Handlers
+	db       *database.Database
+	cookies  []*http.Cookie
+}
+
+func setupSourceTest(t *testing.T) *sourceTestEnv {
+	t.Helper()
+
+	var h *handlers.Handlers
+
+	var sess *session.Session
+
+	var db *database.Database
+
+	app := newTestApp(t, &h, &sess, &db)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	return &sourceTestEnv{
+		handlers: h,
+		db:       db,
+		cookies: authenticatedCookies(
+			t, sess, sourceTestUserID, "sourceuser",
+		),
+	}
+}
+
+// TestHandleSourceCreateSubmit_ZeroRetentionPersistsForever is the core
+// regression test for the bug: the create form's 0 must reach the
+// database as the retain-forever sentinel rather than being replaced by
+// the column's default of 30.
+func TestHandleSourceCreateSubmit_ZeroRetentionPersistsForever(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	zero := "0"
+
+	w := submitCreate(t, env.handlers, env.cookies, "forever", &zero)
+	require.Equal(t, http.StatusSeeOther, w.Code)
+
+	wh := onlyWebhook(t, env.db)
+	assert.Equal(
+		t,
+		database.RetentionForeverDays,
+		storedRetentionDays(t, env.db, wh.ID),
+	)
+	assert.True(t, wh.RetainsForever())
+}
+
+func TestHandleSourceCreateSubmit_OmittedRetentionUsesDefault(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+
+	w := submitCreate(t, env.handlers, env.cookies, "defaulted", nil)
+	require.Equal(t, http.StatusSeeOther, w.Code)
+
+	wh := onlyWebhook(t, env.db)
+	assert.Equal(
+		t,
+		database.DefaultRetentionDays,
+		storedRetentionDays(t, env.db, wh.ID),
+	)
+}
+
+// TestHandleSourceCreate_PrefillsDefaultFromConstant keeps the create
+// form's pre-filled retention from becoming a third hardcoded copy of
+// the 30-day policy.
+func TestHandleSourceCreate_PrefillsDefaultFromConstant(t *testing.T) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+
+	w := httptest.NewRecorder()
+	env.handlers.HandleSourceCreate().ServeHTTP(
+		w, getRequest(t, "/sources/new", env.cookies, nil),
+	)
+
+	require.Equal(t, http.StatusOK, w.Code)
+
+	body := w.Body.String()
+
+	assert.Contains(
+		t, body,
+		`value="`+strconv.Itoa(database.DefaultRetentionDays)+`"`,
+	)
+	assert.NotContains(
+		t, body, `max="365"`,
+		"a max below the sentinel would block retain-forever",
+	)
+	assert.Contains(t, body, `min="0"`)
+}
+
+func TestHandleSourceCreateSubmit_InvalidRetentionIsRejected(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	for _, raw := range []string{"abc", "-1", "3.5"} {
+		t.Run(raw, func(t *testing.T) {
+			t.Parallel()
+
+			env := setupSourceTest(t)
+
+			w := submitCreate(
+				t, env.handlers, env.cookies, "bad", &raw,
+			)
+
+			assert.Equal(t, http.StatusBadRequest, w.Code)
+			assert.Contains(
+				t, w.Body.String(), "Retention must be",
+			)
+
+			var count int64
+
+			require.NoError(
+				t,
+				env.db.DB().Model(&database.Webhook{}).
+					Where("user_id = ?", sourceTestUserID).
+					Count(&count).Error,
+			)
+			assert.Zero(
+				t, count,
+				"no webhook may be created from a rejected form",
+			)
+		})
+	}
+}
+
+// submitEdit posts the webhook edit form for the given webhook.
+func submitEdit(
+	t *testing.T,
+	env *sourceTestEnv,
+	wh database.Webhook,
+	retention string,
+) *httptest.ResponseRecorder {
+	t.Helper()
+
+	form := url.Values{}
+	form.Set("name", wh.Name)
+	form.Set("description", wh.Description)
+	form.Set("retention_days", retention)
+
+	req := formRequest(
+		"/source/"+wh.ID+"/edit",
+		env.cookies,
+		form,
+		map[string]string{sourceIDParam: wh.ID},
+	)
+	w := httptest.NewRecorder()
+
+	env.handlers.HandleSourceEditSubmit().ServeHTTP(w, req)
+
+	return w
+}
+
+func TestHandleSourceEditSubmit_ZeroRetentionPersistsForever(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	wh := seedWebhook(t, env.db, database.DefaultRetentionDays)
+
+	w := submitEdit(t, env, wh, "0")
+	require.Equal(t, http.StatusSeeOther, w.Code)
+
+	assert.Equal(
+		t,
+		database.RetentionForeverDays,
+		storedRetentionDays(t, env.db, wh.ID),
+	)
+}
+
+func TestHandleSourceEditSubmit_InvalidRetentionIsRejected(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	wh := seedWebhook(t, env.db, database.DefaultRetentionDays)
+
+	w := submitEdit(t, env, wh, "not-a-number")
+
+	assert.Equal(t, http.StatusBadRequest, w.Code)
+	assert.Contains(t, w.Body.String(), "Retention must be")
+	assert.Equal(
+		t,
+		database.DefaultRetentionDays,
+		storedRetentionDays(t, env.db, wh.ID),
+		"a rejected form must not change the stored retention",
+	)
+}
+
+func TestHandleSourceEditSubmit_EmptyRetentionLeavesValueUnchanged(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	wh := seedWebhook(t, env.db, 7)
+
+	w := submitEdit(t, env, wh, "")
+	require.Equal(t, http.StatusSeeOther, w.Code)
+
+	assert.Equal(t, 7, storedRetentionDays(t, env.db, wh.ID))
+}
+
+// TestSourceEditForm_ForeverWebhookRoundTrips walks the exact path that
+// the removed max="365" cap used to break: render the edit form for a
+// retain-forever webhook, confirm the pre-filled sentinel is not capped
+// by browser validation, then submit that pre-filled value straight
+// back and confirm the retention policy survives untouched.
+func TestSourceEditForm_ForeverWebhookRoundTrips(t *testing.T) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	wh := seedWebhook(t, env.db, database.RetentionForeverDays)
+
+	req := getRequest(
+		t, "/source/"+wh.ID+"/edit", env.cookies,
+		map[string]string{sourceIDParam: wh.ID},
+	)
+	w := httptest.NewRecorder()
+	env.handlers.HandleSourceEdit().ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code)
+
+	sentinel := strconv.Itoa(database.RetentionForeverDays)
+	body := w.Body.String()
+
+	assert.Contains(
+		t, body, `value="`+sentinel+`"`,
+		"the edit form pre-fills the stored retention",
+	)
+	assert.NotContains(
+		t, body, `max="365"`,
+		"a max below the sentinel would block saving any edit",
+	)
+	assert.Contains(
+		t, body, "forever",
+		"the form explains what the sentinel means",
+	)
+
+	// Submit the pre-filled value back, exactly as a browser would.
+	post := submitEdit(t, env, wh, sentinel)
+	require.Equal(t, http.StatusSeeOther, post.Code)
+
+	assert.Equal(
+		t,
+		database.RetentionForeverDays,
+		storedRetentionDays(t, env.db, wh.ID),
+	)
+}
+
+// TestSourceListAndDetail_ShowForeverNotTheSentinelNumber checks that
+// the retain-forever value is never rendered to the user as a raw day
+// count on either read-only view.
+func TestSourceListAndDetail_ShowForeverNotTheSentinelNumber(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	wh := seedWebhook(t, env.db, database.RetentionForeverDays)
+	sentinel := strconv.Itoa(database.RetentionForeverDays)
+
+	listW := httptest.NewRecorder()
+	env.handlers.HandleSourceList().ServeHTTP(
+		listW, getRequest(t, "/sources", env.cookies, nil),
+	)
+
+	require.Equal(t, http.StatusOK, listW.Code)
+	assert.Contains(t, listW.Body.String(), "Retention: forever")
+	assert.NotContains(t, listW.Body.String(), sentinel)
+
+	detailW := httptest.NewRecorder()
+	env.handlers.HandleSourceDetail().ServeHTTP(
+		detailW,
+		getRequest(
+			t, "/source/"+wh.ID, env.cookies,
+			map[string]string{sourceIDParam: wh.ID},
+		),
+	)
+
+	require.Equal(t, http.StatusOK, detailW.Code)
+	assert.Contains(t, detailW.Body.String(), "Retention: forever")
+	assert.NotContains(t, detailW.Body.String(), sentinel)
+}