Function RunShell

server/shell.go:20–133

RunShell starts an interactive SQL shell with a fully initialized DuckDB connection. It uses the same CreateDBConnection path as the PostgreSQL server, so extensions, DuckLake, and pg_catalog views are all available.

(cfg Config)

// It uses the same CreateDBConnection path as the PostgreSQL server, so extensions,
// DuckLake, and pg_catalog views are all available.
func RunShell(cfg Config) {
	sem := make(chan struct{}, 1)
	if err := bootstrapBundledExtensions(cfg.DataDir); err != nil {
		slog.Error("Failed to bootstrap bundled DuckDB extensions.", "source", bundledDuckDBExtensionsDir, "extension_directory", filepath.Join(cfg.DataDir, "extensions"), "error", err)
		os.Exit(1)
	}
	db, err := CreateDBConnection(cfg, sem, "shell", processStartTime, processVersion)
	if err != nil {
		slog.Error("Failed to create database connection.", "error", err)
		os.Exit(1)
	}
	defer func() { _ = db.Close() }()

	stopRefresh := StartCredentialRefresh(db, cfg.DuckLake)
	defer stopRefresh()

	fmt.Fprintln(os.Stderr, "Duckgres shell (type \\q to exit)")

	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]byte, bufio.MaxScanTokenSize), 1024*1024) // 1MB max line

	var buf strings.Builder
	promptPrimary := "duckgres> "
	promptContinuation := "       -> "

	// mu protects queryCancel and buf from concurrent access
	// between the main goroutine and the signal goroutine.
	var mu sync.Mutex
	var queryCancel context.CancelFunc

	// Channel for query cancellation via Ctrl+C
	cancelCh := make(chan os.Signal, 1)
	signal.Notify(cancelCh, syscall.SIGINT)

	done := make(chan struct{})
	go func() {
		for {
			select {
			case <-cancelCh:
				mu.Lock()
				cancel := queryCancel
				if cancel != nil {
					mu.Unlock()
					cancel()
				} else {
					// Not in a query -- clear the current input buffer.
					buf.Reset()
					mu.Unlock()
					fmt.Fprint(os.Stderr, "\n"+promptPrimary)
				}
			case <-done:
				return
			}
		}
	}()

	defer func() {
		signal.Stop(cancelCh)