refactor: move UI layer code to main.go

Author: tyru

main.go

@@ -4,15 +4,100 @@ package main
 
 import (
 	"os"
+	"os/user"
+	"runtime"
 
+	"github.com/pkg/errors"
+	"github.com/vim-volt/volt/config"
+	"github.com/vim-volt/volt/lockjson"
 	"github.com/vim-volt/volt/logger"
 	"github.com/vim-volt/volt/subcmd"
 )
 
 func main() {
-	err := subcmd.Run(os.Args, subcmd.DefaultRunner)
+	code, msg := run(os.Args)
+	if code != 0 {
+		logger.Error(msg)
+		os.Exit(code)
+	}
+}
+
+func run(args []string) (int, string) {
+	if os.Getenv("VOLT_DEBUG") != "" {
+		logger.SetLevel(logger.DebugLevel)
+	}
+
+	if len(args) <= 1 {
+		args = append(args, "help")
+	}
+	subCmd := args[1]
+	args = args[2:]
+
+	// Expand subcommand alias
+	subCmd, args, err := expandAlias(subCmd, args)
 	if err != nil {
-		logger.Error(err.Msg)
-		os.Exit(err.Code)
+		return 1, err.Error()
+	}
+
+	c := subcmd.LookUpCmd(subCmd)
+	if c == nil {
+		return 3, "Unknown command '" + subCmd + "'"
+	}
+
+	// Disallow executing the commands which may modify files in root priviledge
+	if c.ProhibitRootExecution(args) {
+		err := detectPriviledgedUser()
+		if err != nil {
+			return 4, err.Error()
+		}
+	}
+
+	lockJSON, err := lockjson.Read()
+	if err != nil {
+		return 20, errors.Wrap(err, "failed to read lock.json").Error()
+	}
+
+	cfg, err := config.Read()
+	if err != nil {
+		return 30, errors.Wrap(err, "failed to read config.toml").Error()
+	}
+
+	result := c.Run(&subcmd.CmdContext{
+		Args:     args,
+		LockJSON: lockJSON,
+		Config:   cfg,
+	})
+	return result.Code, result.Msg
+}
+
+func expandAlias(subCmd string, args []string) (string, []string, error) {
+	cfg, err := config.Read()
+	if err != nil {
+		return "", nil, errors.Wrap(err, "could not read config.toml")
+	}
+	if newArgs, exists := cfg.Alias[subCmd]; exists && len(newArgs) > 0 {
+		subCmd = newArgs[0]
+		args = append(newArgs[1:], args...)
+	}
+	return subCmd, args, nil
+}
+
+// On Windows, this function always returns nil.
+// Because if even administrator user creates a file, the file can be
+// overwritten by normal user.
+// On Linux, if current user's uid == 0, returns non-nil error.
+func detectPriviledgedUser() error {
+	if runtime.GOOS == "windows" {
+		return nil
+	}
+	u, err := user.Current()
+	if err != nil {
+		return errors.Wrap(err, "cannot get current user")
+	}
+	if u.Uid == "0" {
+		return errors.New(
+			"cannot run this sub command with root priviledge. " +
+				"Please run as normal user")
 	}
+	return nil
 }

subcmd/cmd.go

@@ -2,19 +2,18 @@ package subcmd
 
 import (
 	"flag"
-	"os"
-	"os/user"
-	"runtime"
-
-	"github.com/pkg/errors"
 
 	"github.com/vim-volt/volt/config"
 	"github.com/vim-volt/volt/lockjson"
-	"github.com/vim-volt/volt/logger"
 )
 
 var cmdMap = make(map[string]Cmd)
 
+// LookUpCmd looks up subcommand by name.
+func LookUpCmd(cmd string) Cmd {
+	return cmdMap[cmd]
+}
+
 // Cmd represents volt's subcommand interface.
 // All subcommands must implement this.
 type Cmd interface {
@@ -30,10 +29,6 @@ type CmdContext struct {
 	Config   *config.Config
 }
 
-// RunnerFunc invokes c with args.
-// On unit testing, a mock function was given.
-type RunnerFunc func(c Cmd, cmdctx *CmdContext) *Error
-
 // Error is a command error.
 // It also has a exit code.
 type Error struct {
@@ -44,88 +39,3 @@ type Error struct {
 func (e *Error) Error() string {
 	return e.Msg
 }
-
-// DefaultRunner simply runs command with args
-func DefaultRunner(c Cmd, cmdctx *CmdContext) *Error {
-	return c.Run(cmdctx)
-}
-
-// Run is invoked by main(), each argument means 'volt {subcmd} {args}'.
-func Run(args []string, cont RunnerFunc) *Error {
-	if os.Getenv("VOLT_DEBUG") != "" {
-		logger.SetLevel(logger.DebugLevel)
-	}
-
-	if len(args) <= 1 {
-		args = append(args, "help")
-	}
-	subCmd := args[1]
-	args = args[2:]
-
-	// Expand subcommand alias
-	subCmd, args, err := expandAlias(subCmd, args)
-	if err != nil {
-		return &Error{Code: 1, Msg: err.Error()}
-	}
-
-	c, exists := cmdMap[subCmd]
-	if !exists {
-		return &Error{Code: 3, Msg: "Unknown command '" + subCmd + "'"}
-	}
-
-	// Disallow executing the commands which may modify files in root priviledge
-	if c.ProhibitRootExecution(args) {
-		err := detectPriviledgedUser()
-		if err != nil {
-			return &Error{Code: 4, Msg: err.Error()}
-		}
-	}
-
-	lockJSON, err := lockjson.Read()
-	if err != nil {
-		return &Error{Code: 20, Msg: errors.Wrap(err, "failed to read lock.json").Error()}
-	}
-
-	cfg, err := config.Read()
-	if err != nil {
-		return &Error{Code: 30, Msg: errors.Wrap(err, "failed to read config.toml").Error()}
-	}
-
-	return cont(c, &CmdContext{
-		Args:     args,
-		LockJSON: lockJSON,
-		Config:   cfg,
-	})
-}
-
-func expandAlias(subCmd string, args []string) (string, []string, error) {
-	cfg, err := config.Read()
-	if err != nil {
-		return "", nil, errors.Wrap(err, "could not read config.toml")
-	}
-	if newArgs, exists := cfg.Alias[subCmd]; exists && len(newArgs) > 0 {
-		subCmd = newArgs[0]
-		args = append(newArgs[1:], args...)
-	}
-	return subCmd, args, nil
-}
-
-// On Windows, this function always returns nil.
-// Because if even administrator user creates a file, the file can be
-// overwritten by normal user.
-// On Linux, if current user's uid == 0, returns non-nil error.
-func detectPriviledgedUser() error {
-	if runtime.GOOS == "windows" {
-		return nil
-	}
-	u, err := user.Current()
-	if err != nil {
-		return errors.Wrap(err, "cannot get current user")
-	}
-	if u.Uid == "0" {
-		return errors.New(
-			"cannot run this sub command with root priviledge. " +
-				"Please run as normal user")
-	}
-	return nil
-}