fix: cleanup consumed scheduler outbox rows

backend/internal/repository/scheduler_outbox_repo.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"strconv"
+	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )
@@ -16,6 +17,12 @@ type schedulerOutboxRepository struct {
 	db *sql.DB
 }
 
+type schedulerOutboxCleanupLease struct {
+	conn *sql.Conn
+}
+
+const schedulerOutboxDefaultCleanSize = 5000
+
 func NewSchedulerOutboxRepository(db *sql.DB) service.SchedulerOutboxRepository {
 	return &schedulerOutboxRepository{db: db}
 }
@@ -94,6 +101,60 @@ func (r *schedulerOutboxRepository) MaxID(ctx context.Context) (int64, error) {
 	return maxID, nil
 }
 
+func (r *schedulerOutboxRepository) DeleteConsumedUpTo(ctx context.Context, watermark int64, limit int) (int64, error) {
+	if watermark <= 0 {
+		return 0, nil
+	}
+	if limit <= 0 {
+		limit = schedulerOutboxDefaultCleanSize
+	}
+	result, err := r.db.ExecContext(ctx, `
+		WITH doomed AS (
+			SELECT id
+			FROM scheduler_outbox
+			WHERE id <= $1
+			ORDER BY id ASC
+			LIMIT $2
+		)
+		DELETE FROM scheduler_outbox o
+		USING doomed d
+		WHERE o.id = d.id
+	`, watermark, limit)
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected()
+}
+
+func (r *schedulerOutboxRepository) TryAcquireCleanupLock(ctx context.Context) (service.SchedulerOutboxCleanupLease, bool, error) {
+	conn, err := r.db.Conn(ctx)
+	if err != nil {
+		return nil, false, err
+	}
+
+	var acquired bool
+	if err := conn.QueryRowContext(ctx, "SELECT pg_try_advisory_lock(hashtext('scheduler_outbox_cleanup'))").Scan(&acquired); err != nil {
+		_ = conn.Close()
+		return nil, false, err
+	}
+	if !acquired {
+		_ = conn.Close()
+		return nil, false, nil
+	}
+	return &schedulerOutboxCleanupLease{conn: conn}, true, nil
+}
+
+func (l *schedulerOutboxCleanupLease) Release() {
+	if l == nil || l.conn == nil {
+		return
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	_, _ = l.conn.ExecContext(ctx, "SELECT pg_advisory_unlock(hashtext('scheduler_outbox_cleanup'))")
+	_ = l.conn.Close()
+	l.conn = nil
+}
+
 func enqueueSchedulerOutbox(ctx context.Context, exec sqlExecutor, eventType string, accountID *int64, groupID *int64, payload any) error {
 	if exec == nil {
 		return nil

backend/internal/repository/scheduler_outbox_repo_test.go

@@ -0,0 +1,91 @@
+package repository
+
+import (
+	"context"
+	"regexp"
+	"testing"
+
+	sqlmock "github.com/DATA-DOG/go-sqlmock"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSchedulerOutboxRepositoryDeleteConsumedUpToUsesBoundedCTE(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	require.NoError(t, err)
+	defer func() { _ = db.Close() }()
+
+	repo := &schedulerOutboxRepository{db: db}
+	const expectedSQL = `
+		WITH doomed AS (
+			SELECT id
+			FROM scheduler_outbox
+			WHERE id <= $1
+			ORDER BY id ASC
+			LIMIT $2
+		)
+		DELETE FROM scheduler_outbox o
+		USING doomed d
+		WHERE o.id = d.id
+	`
+	mock.ExpectExec(regexp.QuoteMeta(expectedSQL)).
+		WithArgs(int64(42), 5000).
+		WillReturnResult(sqlmock.NewResult(0, 17))
+
+	deleted, err := repo.DeleteConsumedUpTo(context.Background(), 42, 5000)
+
+	require.NoError(t, err)
+	require.EqualValues(t, 17, deleted)
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
+func TestSchedulerOutboxRepositoryDeleteConsumedUpToSkipsNonPositiveWatermark(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	require.NoError(t, err)
+	defer func() { _ = db.Close() }()
+
+	repo := &schedulerOutboxRepository{db: db}
+
+	deleted, err := repo.DeleteConsumedUpTo(context.Background(), 0, 5000)
+
+	require.NoError(t, err)
+	require.EqualValues(t, 0, deleted)
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
+func TestSchedulerOutboxRepositoryTryAcquireCleanupLock(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	require.NoError(t, err)
+	defer func() { _ = db.Close() }()
+
+	repo := &schedulerOutboxRepository{db: db}
+	mock.ExpectQuery(regexp.QuoteMeta("SELECT pg_try_advisory_lock(hashtext('scheduler_outbox_cleanup'))")).
+		WillReturnRows(sqlmock.NewRows([]string{"pg_try_advisory_lock"}).AddRow(true))
+	mock.ExpectExec(regexp.QuoteMeta("SELECT pg_advisory_unlock(hashtext('scheduler_outbox_cleanup'))")).
+		WillReturnResult(sqlmock.NewResult(0, 1))
+
+	lease, acquired, err := repo.TryAcquireCleanupLock(context.Background())
+	require.NoError(t, err)
+	require.True(t, acquired)
+	require.NotNil(t, lease)
+
+	lease.Release()
+
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
+func TestSchedulerOutboxRepositoryTryAcquireCleanupLockUnavailable(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	require.NoError(t, err)
+	defer func() { _ = db.Close() }()
+
+	repo := &schedulerOutboxRepository{db: db}
+	mock.ExpectQuery(regexp.QuoteMeta("SELECT pg_try_advisory_lock(hashtext('scheduler_outbox_cleanup'))")).
+		WillReturnRows(sqlmock.NewRows([]string{"pg_try_advisory_lock"}).AddRow(false))
+
+	lease, acquired, err := repo.TryAcquireCleanupLock(context.Background())
+	require.NoError(t, err)
+	require.False(t, acquired)
+	require.Nil(t, lease)
+
+	require.NoError(t, mock.ExpectationsWereMet())
+}