app: minor reorg

* add version number
* add more logging
* add command/subcommand

pkg/app/app.go

@@ -1,15 +1,25 @@
 package app
 
 import (
-	"apc-p15-tool/pkg/pkcs15"
+	"context"
+	"errors"
 	"os"
 
+	"github.com/peterbourgon/ff/v4"
+	"github.com/peterbourgon/ff/v4/ffhelp"
 	"go.uber.org/zap"
 )
 
+const (
+	appVersion = "0.1.0"
+
+	environmentVarPrefix = "APC_P15_TOOL"
+)
+
 // struct for receivers to use common app pieces
 type app struct {
 	logger *zap.SugaredLogger
+	cmd    *ff.Command
 	config *config
 }
 
@@ -27,52 +37,40 @@ func Start() {
 	// re-init logger with configured log level
 	app.logger = makeZapLogger(app.config.logLevel)
 
-	// break point for building additional alternate functions
+	// log start
+	app.logger.Infof("apc-p15-tool v%s", appVersion)
 
-	// function: make p15 from pem files
+	// get config
+	app.getConfig()
 
-	// Read in PEM files
-	keyPem, err := os.ReadFile(*app.config.keyPemFilePath)
+	// run it
+	exitCode := 0
+	err := app.cmd.ParseAndRun(context.Background(), os.Args[1:], ff.WithEnvVarPrefix(environmentVarPrefix))
 	if err != nil {
-		app.logger.Fatalf("failed to read key file (%s)", err)
-		// FATAL
+		exitCode = 1
+
+		if errors.Is(err, ff.ErrHelp) {
+			// help explicitly requested
+			exitCode = 0
+			app.logger.Info("\n\n", ffhelp.Command(app.cmd))
+
+		} else if errors.Is(err, ErrExtraArgs) {
+			// extra args (will log elsewhere, so no need to log err again)
+			app.logger.Info("\n\n", ffhelp.Command(app.cmd))
+
+		} else if errors.Is(err, ff.ErrDuplicateFlag) ||
+			errors.Is(err, ff.ErrUnknownFlag) ||
+			errors.Is(err, ff.ErrNoExec) {
+			// other error that suggests user needs to see help
+			app.logger.Error(err)
+			app.logger.Info("\n\n", ffhelp.Command(app.cmd))
+
+		} else {
+			// any other error
+			app.logger.Error(err)
+		}
 	}
 
-	certPem, err := os.ReadFile(*app.config.certPemFilePath)
-	if err != nil {
-		app.logger.Fatalf("failed to read cert file (%s)", err)
-		// FATAL
-	}
-
-	p15, err := pkcs15.ParsePEMToPKCS15(keyPem, certPem)
-	if err != nil {
-		app.logger.Fatalf("failed to parse pem files (%s)", err)
-		// FATAL
-	}
-
-	// TEMP TEMP TEMP
-	p15File, err := p15.ToP15File()
-	if err != nil {
-		app.logger.Fatalf("failed to make p15 file (%s)", err)
-		// FATAL
-	}
-
-	// app.logger.Debug(hex.EncodeToString(p15File))
-	// app.logger.Debug(base64.RawStdEncoding.EncodeToString(p15File))
-
-	apcHeader, err := makeFileHeader(p15File)
-	if err != nil {
-		app.logger.Fatalf("failed to make p15 file header (%s)", err)
-		// FATAL
-	}
-
-	apcFile := append(apcHeader, p15File...)
-
-	err = os.WriteFile("./apctool.p15", apcFile, 0777)
-	if err != nil {
-		app.logger.Fatalf("failed to write apc p15 file (%s)", err)
-		// FATAL
-	}
-
-	// TEMP TEMP TEMP
+	app.logger.Info("apc-p15-tool done")
+	os.Exit(exitCode)
 }

pkg/app/app_config.go

@@ -1,45 +0,0 @@
-package app
-
-import (
-	"os"
-
-	"github.com/peterbourgon/ff/v4"
-	"github.com/peterbourgon/ff/v4/ffhelp"
-)
-
-const (
-	environmentVarPrefix = "APC_P15_TOOL"
-)
-
-// app's config options from user
-type config struct {
-	logLevel        *string
-	keyPemFilePath  *string
-	certPemFilePath *string
-}
-
-// getConfig returns the app's configuration from either command line args,
-// or environment variables
-func (app *app) getConfig() {
-	// make config and flag set
-	cfg := &config{}
-	fs := ff.NewFlagSet("apc-p15-tool")
-
-	// define options
-	cfg.logLevel = fs.StringEnum('l', "loglevel", "log level: debug, info, warn, error, dpanic, panic, or fatal",
-		"info", "debug", "warn", "error", "dpanic", "panic", "fatal")
-
-	cfg.keyPemFilePath = fs.StringLong("keyfile", "", "path and filename of the rsa-2048 key in pem format")
-	cfg.certPemFilePath = fs.StringLong("certfile", "", "path and filename of the rsa-2048 key in pem format")
-	// TODO key and pem directly in a flag/env var
-
-	// parse using args and/or ENV vars
-	err := ff.Parse(fs, os.Args[1:], ff.WithEnvVarPrefix(environmentVarPrefix))
-	if err != nil {
-		app.logger.Fatal(ffhelp.Flags(fs))
-		// FATAL
-	}
-
-	// set app config
-	app.config = cfg
-}

pkg/app/cmd_create.go

@@ -0,0 +1,84 @@
+package app
+
+import (
+	"apc-p15-tool/pkg/pkcs15"
+	"context"
+	"errors"
+	"fmt"
+	"os"
+)
+
+const createDefaultOutFilePath = "apctool.p15"
+
+// cmdCreate is the app's command to create an apc p15 file from key and cert
+// pem files
+func (app *app) cmdCreate(_ context.Context, args []string) error {
+	// extra args == error
+	if len(args) != 0 {
+		app.logger.Errorf("create: failed, extra args (%d) present", len(args))
+		return ErrExtraArgs
+	}
+
+	// key must be specified
+	if app.config.create.keyPemFilePath == nil || *app.config.create.keyPemFilePath == "" {
+		return errors.New("create: failed, key not specified")
+	}
+
+	// cert must be specified
+	if app.config.create.certPemFilePath == nil || *app.config.create.certPemFilePath == "" {
+		return errors.New("create: failed, cert not specified")
+	}
+
+	// validation done
+	app.logger.Infof("create: making apc p15 file from pem files")
+
+	// Read in PEM files
+	keyPem, err := os.ReadFile(*app.config.create.keyPemFilePath)
+	if err != nil {
+		return fmt.Errorf("create: failed to read key file (%s)", err)
+	}
+
+	certPem, err := os.ReadFile(*app.config.create.certPemFilePath)
+	if err != nil {
+		return fmt.Errorf("create: failed to read cert file (%s)", err)
+	}
+
+	// make p15 struct
+	p15, err := pkcs15.ParsePEMToPKCS15(keyPem, certPem)
+	if err != nil {
+		return fmt.Errorf("create: failed to parse pem files (%s)", err)
+	}
+
+	app.logger.Infof("create: successfully loaded pem files")
+
+	// make file bytes
+	p15File, err := p15.ToP15File()
+	if err != nil {
+		return fmt.Errorf("create: failed to make p15 file (%s)", err)
+	}
+
+	// make header for file bytes
+	apcHeader, err := makeFileHeader(p15File)
+	if err != nil {
+		return fmt.Errorf("create: failed to make p15 file header (%s)", err)
+	}
+
+	// combine header with file
+	apcFile := append(apcHeader, p15File...)
+
+	// determine file name (should already be done by flag parsing, but avoid nil just in case)
+	fileName := createDefaultOutFilePath
+	if app.config.create.outFilePath != nil && *app.config.create.outFilePath != "" {
+		fileName = *app.config.create.outFilePath
+	}
+
+	// write file
+	err = os.WriteFile(fileName, apcFile, 0777)
+	if err != nil {
+		return fmt.Errorf("create: failed to write apc p15 file (%s)", err)
+	}
+
+	app.logger.Infof("create: apc p15 file %s written to disk", fileName)
+
+	return nil
+}

pkg/app/config.go

@@ -0,0 +1,67 @@
+package app
+
+import (
+	"errors"
+
+	"github.com/peterbourgon/ff/v4"
+)
+
+var (
+	ErrExtraArgs = errors.New("extra args present")
+)
+
+// app's config options from user
+type config struct {
+	logLevel *string
+	create   struct {
+		keyPemFilePath  *string
+		certPemFilePath *string
+		outFilePath     *string
+	}
+}
+
+// getConfig returns the app's configuration from either command line args,
+// or environment variables
+func (app *app) getConfig() {
+	// make config
+	cfg := &config{}
+
+	// commands:
+	// create
+	// TODO:
+	// upload
+	// unpack (both key & key+cert)
+
+	// apc-p15-tool -- root command
+	rootFlags := ff.NewFlagSet("apc-p15-tool")
+
+	cfg.logLevel = rootFlags.StringEnum('l', "loglevel", "log level: debug, info, warn, error, dpanic, panic, or fatal",
+		"info", "debug", "warn", "error", "dpanic", "panic", "fatal")
+
+	rootCmd := &ff.Command{
+		Name:  "apc-p15-tool",
+		Usage: "apc-p15-tool [FLAGS] SUBCOMMAND ...",
+		Flags: rootFlags,
+	}
+
+	// create -- subcommand
+	createFlags := ff.NewFlagSet("create").SetParent(rootFlags)
+
+	cfg.create.keyPemFilePath = createFlags.StringLong("keyfile", "", "path and filename of the rsa-2048 key in pem format")
+	cfg.create.certPemFilePath = createFlags.StringLong("certfile", "", "path and filename of the rsa-2048 key in pem format")
+	cfg.create.outFilePath = createFlags.StringLong("outfile", createDefaultOutFilePath, "path and filename to write the p15 file to")
+
+	createCmd := &ff.Command{
+		Name:      "create",
+		Usage:     "apc-p15-tool create --keyfile key.pem --certfile cert.pem [--outfile apctool.p15]",
+		ShortHelp: "create an apc p15 file from the specified key and cert pem files",
+		Flags:     createFlags,
+		Exec:      app.cmdCreate,
+	}
+
+	rootCmd.Subcommands = append(rootCmd.Subcommands, createCmd)
+
+	// set app cmd & cfg
+	app.cmd = rootCmd
+	app.config = cfg
+}