Add docs command (#13429)

Signed-off-by: jolheiser <john.olheiser@gmail.com>

cmd/docs.go

@@ -0,0 +1,61 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/urfave/cli"
+)
+
+// CmdDocs represents the available docs sub-command.
+var CmdDocs = cli.Command{
+	Name:        "docs",
+	Usage:       "Output CLI documentation",
+	Description: "A command to output Gitea's CLI documentation, optionally to a file.",
+	Action:      runDocs,
+	Flags: []cli.Flag{
+		&cli.BoolFlag{
+			Name:  "man",
+			Usage: "Output man pages instead",
+		},
+		&cli.StringFlag{
+			Name:  "output, o",
+			Usage: "Path to output to instead of stdout (will overwrite if exists)",
+		},
+	},
+}
+
+func runDocs(ctx *cli.Context) error {
+	docs, err := ctx.App.ToMarkdown()
+	if ctx.Bool("man") {
+		docs, err = ctx.App.ToMan()
+	}
+	if err != nil {
+		return err
+	}
+
+	if !ctx.Bool("man") {
+		// Clean up markdown. The following bug was fixed in v2, but is present in v1.
+		// It affects markdown output (even though the issue is referring to man pages)
+		// https://github.com/urfave/cli/issues/1040
+		docs = docs[strings.Index(docs, "#"):]
+	}
+
+	out := os.Stdout
+	if ctx.String("output") != "" {
+		fi, err := os.Create(ctx.String("output"))
+		if err != nil {
+			return err
+		}
+		defer fi.Close()
+		out = fi
+	}
+
+	_, err = fmt.Fprintln(out, docs)
+	return err
+}

main.go

@@ -69,6 +69,7 @@ arguments - which can alternatively be run by running the subcommand web.`
 		cmd.CmdManager,
 		cmd.Cmdembedded,
 		cmd.CmdMigrateStorage,
+		cmd.CmdDocs,
 	}
 	// Now adjust these commands to add our global configuration options