cmd: Add `caddy fmt` command. (#3090)

This takes the config file as input and formats it.
Prints the result to stdout. Can write changes to
file if `--write` flag is passed.

Fixes #3020

Signed-off-by: Vaibhav <vrongmeal@gmail.com>

2 files changed, 48 insertions, 0 deletions

diff --git a/cmd/commandfuncs.go b/cmd/commandfuncs.go
index a2c8e3d..4f86aa8 100644
--- a/cmd/commandfuncs.go
+++ b/cmd/commandfuncs.go
@@ -34,6 +34,7 @@ import (
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddyconfig"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
 	"github.com/mholt/certmagic"
 	"go.uber.org/zap"
 )
@@ -538,6 +539,35 @@ func cmdValidateConfig(fl Flags) (int, error) {
 	return caddy.ExitCodeSuccess, nil
 }
 
+func cmdFormatConfig(fl Flags) (int, error) {
+	// Default path of file is Caddyfile
+	formatCmdConfigFile := fl.Arg(0)
+	if formatCmdConfigFile == "" {
+		formatCmdConfigFile = "Caddyfile"
+	}
+
+	formatCmdWriteFlag := fl.Bool("write")
+
+	input, err := ioutil.ReadFile(formatCmdConfigFile)
+	if err != nil {
+		return caddy.ExitCodeFailedStartup,
+			fmt.Errorf("reading input file: %v", err)
+	}
+
+	output := caddyfile.Format(input)
+
+	if formatCmdWriteFlag {
+		err = ioutil.WriteFile(formatCmdConfigFile, output, 0644)
+		if err != nil {
+			return caddy.ExitCodeFailedStartup, nil
+		}
+	} else {
+		fmt.Print(string(output))
+	}
+
+	return caddy.ExitCodeSuccess, nil
+}
+
 func cmdHelp(fl Flags) (int, error) {
 	const fullDocs = `Full documentation is available at:
 https://caddyserver.com/docs/command-line`
diff --git a/cmd/commands.go b/cmd/commands.go
index 87ded60..37ede3a 100644
--- a/cmd/commands.go
+++ b/cmd/commands.go
@@ -242,6 +242,24 @@ provisioning stages.`,
 		}(),
 	})
 
+	RegisterCommand(Command{
+		Name:  "fmt",
+		Func:  cmdFormatConfig,
+		Usage: "[--write] [<path>]",
+		Short: "Formats a Caddyfile",
+		Long: `
+Formats the Caddyfile by adding proper indentation and spaces to improve
+human readability. It prints the result to stdout.
+
+If --write is specified, the output will be written to the config file
+directly instead of printing it.`,
+		Flags: func() *flag.FlagSet {
+			fs := flag.NewFlagSet("format", flag.ExitOnError)
+			fs.Bool("write", false, "Over-write the output to specified file")
+			return fs
+		}(),
+	})
+
 }
 
 // RegisterCommand registers the command cmd.