From 0b2d994698a23daf75ffaaeec74b68db1494c9b1 Mon Sep 17 00:00:00 2001 From: Chris Koch Date: Sat, 24 Feb 2024 00:48:51 +0000 Subject: [PATCH] Basic CLI Signed-off-by: Chris Koch --- cli/cli.go | 93 +++++++++++++++++++++++++++++++ cli/cli_test.go | 145 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 238 insertions(+) create mode 100644 cli/cli.go create mode 100644 cli/cli_test.go diff --git a/cli/cli.go b/cli/cli.go new file mode 100644 index 0000000..efd15be --- /dev/null +++ b/cli/cli.go @@ -0,0 +1,93 @@ +// Copyright 2024 the u-root Authors. All rights reserved +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package cli provides a bare bones CLI with commands. +// +// cli supports standard Go flags. +package cli + +import ( + "flag" + "fmt" + "io" + "os" + "slices" + "strings" + "text/tabwriter" +) + +// Command is a CLI command. +type Command struct { + // Name or Aliases are used to match argv[1] and select this command. + Name string + Aliases []string + + // Short is a one-line description for the command. + Short string + + // Run is called if argv[1] matches the command. Flags are parsed before Run is called. + Run func(args []string) + + flags *flag.FlagSet +} + +func (c *Command) Flags() *flag.FlagSet { + if c.flags == nil { + c.flags = flag.NewFlagSet(c.Name, flag.ContinueOnError) + } + return c.flags +} + +// An App is composed of many commands. +type App []Command + +// Help returns the app's help string. +func (a App) Help() string { + var s strings.Builder + w := tabwriter.NewWriter(&s, 1, 2, 4, ' ', 0) + fmt.Fprintf(w, "Commands:\n\n") + for _, cmd := range a { + fmt.Fprintf(w, "\t%s\t%s\n", cmd.Name, cmd.Short) + } + w.Flush() + return s.String() +} + +func (a App) commandFor(args []string) *Command { + if len(args) == 0 { + return nil + } + for _, cmd := range a { + if args[0] == cmd.Name || slices.Contains(cmd.Aliases, args[0]) { + return &cmd + } + } + return nil +} + +func (a App) run(errW io.Writer, args []string) int { + if len(args) == 0 { + fmt.Fprintf(errW, "No program name provided\n") + return 1 + } + cmd := a.commandFor(args[1:]) + if cmd == nil { + fmt.Fprintf(errW, "%s", a.Help()) + return 1 + } + + cmd.Flags().SetOutput(errW) + if err := cmd.Flags().Parse(args[2:]); err != nil { + cmd.Flags().Output() + return 1 + } + + cmd.Run(cmd.Flags().Args()) + return 0 +} + +// Run runs the app. Expects program name as the first arg, and an optional command name next. +func (a App) Run(args []string) { + os.Exit(a.run(os.Stderr, args)) +} diff --git a/cli/cli_test.go b/cli/cli_test.go new file mode 100644 index 0000000..e91781b --- /dev/null +++ b/cli/cli_test.go @@ -0,0 +1,145 @@ +// Copyright 2024 the u-root Authors. All rights reserved +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package cli + +import ( + "reflect" + "strings" + "testing" +) + +func TestCLI(t *testing.T) { + type flags struct { + output string + input string + } + var f flags + var cmd string + var cmdArgs []string + + makeCmd := Command{ + Name: "make", + Short: "create uimage", + Run: func(args []string) { + cmdArgs = args + cmd = "make" + }, + } + makeCmd.Flags().StringVar(&f.output, "o", "", "Output") + makeCmd.Flags().StringVar(&f.input, "i", "", "Input") + + listCmd := Command{ + Name: "list", + Short: "list uimage", + Aliases: []string{"ls", "l"}, + Run: func(args []string) { + cmdArgs = args + cmd = "list" + }, + } + app := App{makeCmd, listCmd} + + for _, tt := range []struct { + name string + args []string + wantCmd string + wantCmdArgs []string + wantFlags flags + wantExit int + wantPrint string + }{ + { + name: "cmd with flag", + args: []string{"uimage", "make", "-o", "high", "foobar", "bla"}, + wantCmdArgs: []string{"foobar", "bla"}, + wantCmd: "make", + wantFlags: flags{ + output: "high", + }, + wantExit: 0, + wantPrint: "", + }, + { + name: "not exist", + args: []string{"uimage", "notmake", "-o", "low"}, + wantExit: 1, + wantPrint: "Commands:\n\n make create uimage\n list list uimage\n", + }, + { + name: "cmd exist but flag doesn't", + args: []string{"uimage", "list", "-o", "low"}, + wantExit: 1, + wantPrint: "flag provided but not defined: -o\nUsage of list:\n", + }, + { + name: "cmd with no flags", + args: []string{"uimage", "list", "anything"}, + wantExit: 0, + wantCmd: "list", + wantCmdArgs: []string{"anything"}, + }, + { + name: "alias", + args: []string{"uimage", "ls", "anything"}, + wantExit: 0, + wantCmd: "list", + wantCmdArgs: []string{"anything"}, + }, + { + name: "no program name", + wantExit: 1, + wantPrint: "No program name provided\n", + }, + { + name: "no command name", + args: []string{"uimage"}, + wantExit: 1, + wantPrint: "Commands:\n\n make create uimage\n list list uimage\n", + }, + { + name: "cmd help", + args: []string{"uimage", "make", "-h"}, + wantExit: 1, + wantPrint: "Usage of make:\n -i string\n \tInput\n -o string\n \tOutput\n", + }, + { + name: "app help", + args: []string{"uimage", "-h"}, + wantExit: 1, + wantPrint: "Commands:\n\n make create uimage\n list list uimage\n", + }, + { + name: "app help 2", + args: []string{"uimage", "help"}, + wantExit: 1, + wantPrint: "Commands:\n\n make create uimage\n list list uimage\n", + }, + } { + t.Run(tt.name, func(t *testing.T) { + f = flags{} + cmd = "" + cmdArgs = nil + + var s strings.Builder + exitCode := app.run(&s, tt.args) + t.Logf("App:\n%s", s.String()) + if exitCode != tt.wantExit { + t.Errorf("run = %d, want %d", exitCode, tt.wantExit) + } + if cmd != tt.wantCmd { + t.Errorf("run = cmd %s, want cmd %s", cmd, tt.wantCmd) + } + if !reflect.DeepEqual(cmdArgs, tt.wantCmdArgs) { + t.Errorf("run = args %+v, want %+v", cmdArgs, tt.wantCmdArgs) + } + if !reflect.DeepEqual(f, tt.wantFlags) { + t.Errorf("run = flags %+v, want %+v", f, tt.wantFlags) + } + if got := s.String(); got != tt.wantPrint { + t.Errorf("run = %#v, want %#v", got, tt.wantPrint) + } + }) + } +}