Name each database target's archive for its webhook and target (closes #376)

Each database target now has its own archive file,
archive-WEBHOOKNAME-TARGETNAME-TARGETID.db, instead of one
archive-WEBHOOKID.db per webhook. delivery.ArchiveFileName builds the
name: each name is lowercased, keeps ASCII letters and digits, turns
every other run of characters into one dash, and is cut to 40
characters.

Renaming a webhook or a target renames its archive files under the
archive writer's lock, before the new name is saved, and back again if
the save fails. Deleting a target evicts only that target's writer.
Archive files are never deleted, and nothing looks for files under the
old name.

Model: opus-5-5

internal/handlers/source_delete_test.go

@@ -15,6 +15,7 @@ import (
 	"gorm.io/gorm"
 	"gorm.io/gorm/clause"
 	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/delivery"
 	"sneak.berlin/go/webhooker/internal/handlers"
 	"sneak.berlin/go/webhooker/internal/session"
 )
@@ -147,18 +148,19 @@ func failDeleteOnTable(
 }
 
 // archivePathFor returns the archive database path the
-// delivery engine would use for a webhook: beside the webhook's
-// event database in the data directory.
+// delivery engine would use for a database target: beside the
+// webhook's event database in the data directory.
 func archivePathFor(
 	t *testing.T,
 	mgr *database.WebhookDBManager,
-	webhookID string,
+	wh *database.Webhook,
+	tgt *database.Target,
 ) string {
 	t.Helper()
 
 	return filepath.Join(
-		filepath.Dir(mgr.DBPath(webhookID)),
-		"archive-"+webhookID+".db",
+		filepath.Dir(mgr.DBPath(wh.ID)),
+		delivery.ArchiveFileName(wh.Name, tgt.Name, tgt.ID),
 	)
 }
 
@@ -195,8 +197,8 @@ func postRequest(
 
 // TestHandleSourceDelete_EvictsArchiveWriter proves that
 // deleting a webhook reaches the delivery engine and releases
-// the webhook's archive writer, exercised through the real
-// deletion handler rather than by calling the evictor directly.
+// the webhook's archive writers, exercised through the real
+// deletion handler rather than by calling the engine directly.
 func TestHandleSourceDelete_EvictsArchiveWriter(t *testing.T) {
 	t.Parallel()
 
@@ -204,7 +206,7 @@ func TestHandleSourceDelete_EvictsArchiveWriter(t *testing.T) {
 		h    *handlers.Handlers
 		sess *session.Session
 		db   *database.Database
-		ev   *recordingEvictor
+		ev   *recordingArchives
 	)
 
 	app := newTestApp(t, &h, &sess, &db, &ev)
@@ -254,9 +256,10 @@ func TestHandleSourceDelete_KeepsArchiveFile(t *testing.T) {
 	t.Cleanup(app.RequireStop)
 
 	wh := seedWebhook(t, db)
+	tgt := seedTarget(t, db, wh.ID, database.TargetTypeDatabase)
 
 	// Place an archive file where the delivery engine would.
-	archivePath := archivePathFor(t, mgr, wh.ID)
+	archivePath := archivePathFor(t, mgr, wh, tgt)
 	require.NoError(
 		t,
 		writeArchivePlaceholder(archivePath),
@@ -435,68 +438,17 @@ func TestHandleSourceDelete_RemovesConfigAndEventDatabase(
 	)
 }
 
-// TestHandleTargetDelete_EvictsWhenLastDatabaseTargetGone
-// proves that removing the last database target releases the
-// archive writer.
-func TestHandleTargetDelete_EvictsWhenLastDatabaseTargetGone(
-	t *testing.T,
-) {
+// TestHandleTargetDelete_EvictsThatTarget proves that deleting a
+// database target releases that target's archive writer and no
+// other: the webhook's other database target keeps its own.
+func TestHandleTargetDelete_EvictsThatTarget(t *testing.T) {
 	t.Parallel()
 
 	var (
 		h    *handlers.Handlers
 		sess *session.Session
 		db   *database.Database
-		ev   *recordingEvictor
-	)
-
-	app := newTestApp(t, &h, &sess, &db, &ev)
-	app.RequireStart()
-
-	t.Cleanup(app.RequireStop)
-
-	wh := seedWebhook(t, db)
-	tgt := seedTarget(
-		t, db, wh.ID, database.TargetTypeDatabase,
-	)
-
-	cookies := authenticatedCookies(
-		t, sess, deleteTestUserID, deleteTestUsername,
-	)
-
-	req := postRequest(
-		"/hook/"+wh.ID+"/targets/"+tgt.ID+"/delete",
-		cookies,
-		map[string]string{
-			paramSourceID: wh.ID,
-			paramTargetID: tgt.ID,
-		},
-	)
-	w := httptest.NewRecorder()
-
-	h.HandleTargetDelete().ServeHTTP(w, req)
-
-	require.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Equal(
-		t, []string{wh.ID}, ev.Evicted(),
-		"removing the last database target should evict",
-	)
-}
-
-// TestHandleTargetDelete_KeepsWriterWhenDatabaseTargetRemains
-// proves that deleting one of several database targets leaves
-// the still-needed archive writer alone: the surviving target
-// keeps archiving to the same file, so the writer must stay.
-func TestHandleTargetDelete_KeepsWriterWhenDatabaseTargetRemains(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	var (
-		h    *handlers.Handlers
-		sess *session.Session
-		db   *database.Database
-		ev   *recordingEvictor
+		ev   *recordingArchives
 	)
 
 	app := newTestApp(t, &h, &sess, &db, &ev)
@@ -527,17 +479,17 @@ func TestHandleTargetDelete_KeepsWriterWhenDatabaseTargetRemains(
 	h.HandleTargetDelete().ServeHTTP(w, req)
 
 	require.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Empty(
-		t, ev.Evicted(),
-		"a second database target still needs the writer",
+	assert.Equal(
+		t, []string{doomed.ID}, ev.EvictedTargets(),
+		"deleting a database target should evict its writer",
 	)
+	assert.Empty(t, ev.Evicted(), "the webhook is not deleted")
 }
 
-// TestHandleTargetDelete_KeepsWriterWhenOtherTypeDeleted proves
-// that deleting a target of an unrelated type leaves a
-// still-needed archive writer alone: the webhook's database
-// target is untouched, so its writer must stay.
-func TestHandleTargetDelete_KeepsWriterWhenOtherTypeDeleted(
+// TestHandleTargetDelete_IgnoresAnotherWebhooksTarget proves that
+// a target id from the URL that is not a target of the webhook
+// deletes nothing and so evicts nothing.
+func TestHandleTargetDelete_IgnoresAnotherWebhooksTarget(
 	t *testing.T,
 ) {
 	t.Parallel()
@@ -546,7 +498,7 @@ func TestHandleTargetDelete_KeepsWriterWhenOtherTypeDeleted(
 		h    *handlers.Handlers
 		sess *session.Session
 		db   *database.Database
-		ev   *recordingEvictor
+		ev   *recordingArchives
 	)
 
 	app := newTestApp(t, &h, &sess, &db, &ev)
@@ -555,19 +507,20 @@ func TestHandleTargetDelete_KeepsWriterWhenOtherTypeDeleted(
 	t.Cleanup(app.RequireStop)
 
 	wh := seedWebhook(t, db)
-	seedTarget(t, db, wh.ID, database.TargetTypeDatabase)
-	other := seedTarget(t, db, wh.ID, database.TargetTypeLog)
+	elsewhere := seedTarget(
+		t, db, seedWebhook(t, db).ID, database.TargetTypeDatabase,
+	)
 
 	cookies := authenticatedCookies(
 		t, sess, deleteTestUserID, deleteTestUsername,
 	)
 
 	req := postRequest(
-		"/hook/"+wh.ID+"/targets/"+other.ID+"/delete",
+		"/hook/"+wh.ID+"/targets/"+elsewhere.ID+"/delete",
 		cookies,
 		map[string]string{
 			paramSourceID: wh.ID,
-			paramTargetID: other.ID,
+			paramTargetID: elsewhere.ID,
 		},
 	)
 	w := httptest.NewRecorder()
@@ -576,7 +529,7 @@ func TestHandleTargetDelete_KeepsWriterWhenOtherTypeDeleted(
 
 	require.Equal(t, http.StatusSeeOther, w.Code)
 	assert.Empty(
-		t, ev.Evicted(),
-		"a surviving database target must keep its writer",
+		t, ev.EvictedTargets(),
+		"another webhook's target must not be evicted",
 	)
 }