Add initial distributor CLI skeleton

internal/cli/root.go

@@ -0,0 +1,84 @@
+package cli
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/distributor/internal/app"
+)
+
+const (
+	exitOK    = 0
+	exitError = 1
+	exitUsage = 2
+)
+
+func Execute(ctx context.Context, args []string, stdout, stderr io.Writer) int {
+	if len(args) == 0 {
+		printRootHelp(stdout)
+		return exitOK
+	}
+
+	switch args[0] {
+	case "-h", "--help", "help":
+		printRootHelp(stdout)
+		return exitOK
+	case "version":
+		return versionCommand(ctx, args[1:], stdout, stderr)
+	case "run":
+		return runCommand(ctx, args[1:], stdout, stderr)
+	case "validate":
+		return validateCommand(ctx, args[1:], stdout, stderr)
+	case "inspect":
+		return inspectCommand(ctx, args[1:], stdout, stderr)
+	default:
+		fmt.Fprintf(stderr, "%s: unknown command %q\n\n", app.Name, args[0])
+		printRootHelp(stderr)
+		return exitUsage
+	}
+}
+
+func printRootHelp(w io.Writer) {
+	fmt.Fprintf(w, `%s validates and publishes manifested report bundles.
+
+Usage:
+  %s <command> [options]
+
+Commands:
+  version    Print version information
+  run        Run configured distribution pipelines
+  validate   Validate a source bundle or bundle tree
+  inspect    Inspect bundles or distributor state
+
+Use "%s <command> --help" for command-specific help.
+`, app.Name, app.Name, app.Name)
+}
+
+func hasHelp(args []string) bool {
+	for _, arg := range args {
+		if arg == "-h" || arg == "--help" {
+			return true
+		}
+	}
+	return false
+}
+
+func fail(stderr io.Writer, err error) int {
+	if errors.Is(err, app.ErrNotImplemented) {
+		fmt.Fprintf(stderr, "%s: %s\n", app.Name, err)
+		return exitError
+	}
+	fmt.Fprintf(stderr, "%s: %s\n", app.Name, err)
+	return exitError
+}
+
+func rejectExtraArgs(stderr io.Writer, command string, args []string) bool {
+	if len(args) == 0 {
+		return false
+	}
+	fmt.Fprintf(stderr, "%s: %s does not accept arguments: %s\n", app.Name, command, strings.Join(args, " "))
+	return true
+}