age

commit e82447cddb6020f668e68457891fe147cf0b931f
parent c4269b618599be45fcc3fafe04a10216791ad84c
Author: Stephen Gregoratto <dev@sgregoratto.me>
Date:   Wed,  9 Oct 2019 15:14:27 +1100

Change flags, prefix logs, add usage func

- All command flags are now one rune long.
- Logs are prefixed with the program name similar to err(3).
- `flags.Usage` is replaced with a custom function.
- Log messages are converted to lowercase.

Diffstat:
M
cmd/age/age.go
 | 
119
++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------
M
go.mod
 | 
5
++++-
M
go.sum
 | 
3
++-

3 files changed, 87 insertions(+), 40 deletions(-)
diff --git a/cmd/age/age.go b/cmd/age/age.go
@@ -20,76 +20,119 @@ import (
 )
 
 func main() {
+	var (
+		gen     = flag.Bool("G", false, "generate a new age key pair")
+		dec     = flag.Bool("D", false, "decrypt the input")
+		help    = flag.Bool("h", false, "show this help")
+		inFile  = flag.String("i", "", "output file")
+		outFile = flag.String("o", "", "input file")
+
+		in       = os.Stdin
+		out      = os.Stdout
+		err      error
+		progname = filepath.Base(os.Args[0])
+	)
+
 	log.SetFlags(0)
+	log.SetPrefix(progname + ": ")
 
-	generateFlag := flag.Bool("generate", false, "generate a new age key pair")
-	decryptFlag := flag.Bool("d", false, "decrypt the input")
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr,
+			`usage:	%s [-o file] -G
+	%s [-i file] [-o file] recipient ...
+	%s [-i file] [-o file] -D [identity-file ... ]
+`, progname, progname, progname)
+		os.Exit(1)
+	}
 	flag.Parse()
+	args := flag.Args()
 
-	switch {
-	case *generateFlag:
-		if *decryptFlag {
-			log.Fatalf("Invalid flag combination")
+	if *help {
+		flag.Usage()
+	}
+
+	if *dec && *gen {
+		log.Printf("multiple modes selected")
+		flag.Usage()
+	}
+
+	if *inFile != "" {
+		if *gen {
+			log.Printf("-g takes no input")
+			flag.Usage()
+		}
+
+		in, err = os.Open(*inFile)
+		if err != nil {
+			log.Fatalf("cannot open file %q: %v", *inFile, err)
 		}
-		generate()
-	case *decryptFlag:
-		if *generateFlag {
-			log.Fatalf("Invalid flag combination")
+	}
+
+	if *outFile != "" {
+		out, err = os.Create(*outFile)
+		if err != nil {
+			log.Fatalf("cannot open file %q: %v", *outFile, err)
 		}
-		decrypt()
-	default:
-		encrypt()
 	}
-}
 
-func generate() {
-	if len(flag.Args()) != 0 {
-		log.Fatalf("-generate takes no arguments")
+	switch {
+	case *gen:
+		if len(args) != 0 {
+			log.Printf("-g takes no arguments")
+			flag.Usage()
+		}
+		generate(out)
+	case *dec:
+		decrypt(in, out, args)
+	default:
+		encrypt(in, out, args)
 	}
+}
 
+func generate(out *os.File) {
 	key := make([]byte, 32)
 	if _, err := rand.Read(key); err != nil {
-		log.Fatalf("Internal error: %v", err)
+		log.Fatalf("cannot get random bytes: %v", err)
 	}
 	k, err := age.NewX25519Identity(key)
 	if err != nil {
-		log.Fatalf("Internal error: %v", err)
+		log.Fatalf("cannot create new identity: %v", err)
 	}
 
-	fmt.Printf("# created: %s\n", time.Now().Format(time.RFC3339))
-	fmt.Printf("# %s\n", k.Recipient())
-	fmt.Printf("%s\n", k)
+	fmt.Fprintf(out, "# created: %s\n", time.Now().Format(time.RFC3339))
+	fmt.Fprintf(out, "# %s\n", k.Recipient())
+	fmt.Fprintf(out, "%s\n", k)
 }
 
-func encrypt() {
+func encrypt(in, out *os.File, args []string) {
 	var recipients []age.Recipient
-	for _, arg := range flag.Args() {
+	for _, arg := range args {
 		r, err := parseRecipient(arg)
 		if err != nil {
-			log.Fatalf("Error: %v", err)
+			log.Fatalf("cannot parse recipient %q: %v", arg, err)
 		}
 		recipients = append(recipients, r)
 	}
 	if len(recipients) == 0 {
-		log.Fatalf("Missing recipients!")
+		log.Printf("no recipients")
 	}
 
-	w, err := age.Encrypt(os.Stdout, recipients...)
+	w, err := age.Encrypt(out, recipients...)
 	if err != nil {
-		log.Fatalf("Error initializing encryption: %v", err)
+		log.Fatalf("cannot initialize encryption: %v", err)
 	}
-	if _, err := io.Copy(w, os.Stdin); err != nil {
-		log.Fatalf("Error encrypting the input: %v", err)
+	if _, err := io.Copy(w, in); err != nil {
+		log.Fatalf("cannot encrypt input: %v", err)
 	}
 	if err := w.Close(); err != nil {
-		log.Fatalf("Error finalizing encryption: %v", err)
+		log.Fatalf("cannot close output: %v", err)
 	}
 }
 
-func decrypt() {
+func decrypt(in, out *os.File, args []string) {
 	var identities []age.Identity
 	// TODO: use the default location if no arguments are provided.
-	for _, name := range flag.Args() {
+	for _, name := range args {
 		var (
 			ids []age.Identity
 			err error
@@ -102,16 +145,16 @@ func decrypt() {
 			ids, err = parseIdentitiesFile(name)
 		}
 		if err != nil {
-			log.Fatalf("Error: %v", err)
+			log.Fatalf("cannot parse identity %q: %v", name, err)
 		}
 		identities = append(identities, ids...)
 	}
 
-	r, err := age.Decrypt(os.Stdin, identities...)
+	r, err := age.Decrypt(in, identities...)
 	if err != nil {
-		log.Fatalf("Error initializing decryption: %v", err)
+		log.Fatalf("cannot initialize encryption: %v", err)
 	}
-	if _, err := io.Copy(os.Stdout, r); err != nil {
-		log.Fatalf("Error decrypting the input: %v", err)
+	if _, err := io.Copy(out, r); err != nil {
+		log.Fatalf("cannot decrypt input: %v", err)
 	}
 }
diff --git a/go.mod b/go.mod
@@ -2,4 +2,7 @@ module github.com/FiloSottile/age
 
 go 1.13
 
-require golang.org/x/crypto v0.0.0-20191002192127-34f69633bfdc
+require (
+	golang.org/x/crypto v0.0.0-20191002192127-34f69633bfdc
+	golang.org/x/sys v0.0.0-20191008105621-543471e840be // indirect
+)
diff --git a/go.sum b/go.sum
@@ -3,6 +3,7 @@ golang.org/x/crypto v0.0.0-20191002192127-34f69633bfdc h1:c0o/qxkaO2LF5t6fQrT4b5
 golang.org/x/crypto v0.0.0-20191002192127-34f69633bfdc/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191008105621-543471e840be h1:QAcqgptGM8IQBC9K/RC4o+O9YmqEm0diQn9QmZw/0mU=
+golang.org/x/sys v0.0.0-20191008105621-543471e840be/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=