reduce main package

cli.go

@@ -0,0 +1,64 @@
+package gobump
+
+import (
+	"flag"
+	"fmt"
+	"io"
+)
+
+// Run the gobump
+func Run(argv []string, outStream, errStream io.Writer) error {
+	gb := &Gobump{
+		OutStream: outStream,
+	}
+	fs := flag.NewFlagSet("gobump", flag.ContinueOnError)
+	fs.BoolVar(&gb.Write, "w", false, "write result to (source) file instead of stdout")
+	fs.BoolVar(&gb.Verbose, "v", false, "show the resulting version values")
+	fs.BoolVar(&gb.Raw, "r", false, "output in raw text instead of JSON when output exists")
+	fs.Usage = func() {
+		out := errStream
+		fs.SetOutput(out)
+		fmt.Fprintln(out, `Usage: gobump (major|minor|patch|set <version>) [-w] [-v] [<path>]
+
+Commands:
+  major             bump major version up
+  minor             bump minor version up
+  patch             bump patch version up
+  set <version>     set exact version (no increments)
+  show              only show the versions (implies -v)
+Flags:`)
+		fs.PrintDefaults()
+	}
+
+	if len(argv) < 1 {
+		return fmt.Errorf("please specify subcommand. `gobump -h` for more details")
+	}
+
+	parseOffset := 1
+	switch argv[0] {
+	case "major":
+		gb.Config.MajorDelta = 1
+	case "minor":
+		gb.Config.MinorDelta = 1
+	case "patch":
+		gb.Config.PatchDelta = 1
+	case "set":
+		if len(argv) < 2 {
+			return fmt.Errorf("please specify a version to set")
+		}
+		gb.Config.Exact = argv[1]
+		parseOffset = 2
+	case "show":
+		gb.Show = true
+	case "-h", "-help", "--help":
+		parseOffset = 0
+	default:
+		return fmt.Errorf("unknown subcommand %q. `gobump -h` for more details", argv[0])
+	}
+	if err := fs.Parse(argv[parseOffset:]); err != nil {
+		return err
+	}
+
+	gb.Target = fs.Arg(0)
+	return gb.Run()
+}

cmd/gobump/main.go

@@ -18,131 +18,18 @@ Flags:
 package main
 
 import (
-	"encoding/json"
 	"flag"
-	"fmt"
+	"log"
 	"os"
 
-	"go/parser"
-	"go/printer"
-	"go/token"
-
 	"github.com/motemen/gobump"
 )
 
 func main() {
-	var (
-		write   = flag.Bool("w", false, "write result to (source) file instead of stdout")
-		verbose = flag.Bool("v", false, "show the resulting version values")
-		raw     = flag.Bool("r", false, "output in raw text instead of JSON when output exists")
-	)
-	flag.Usage = func() {
-		fmt.Fprintln(os.Stderr, "Usage: gobump (major|minor|patch|set <version>) [-w] [-v] [<path>]")
-		fmt.Fprintln(os.Stderr, "")
-		fmt.Fprintln(os.Stderr, `Commands:
-  major             bump major version up
-  minor             bump minor version up
-  patch             bump patch version up
-  set <version>     set exact version (no increments)
-  show              only show the versions (implies -v)
-`)
-		fmt.Fprintln(os.Stderr, "Flags:")
-		flag.PrintDefaults()
-		os.Exit(2)
-	}
-
-	shift := func() string {
-		if len(os.Args) < 2 {
-			flag.Usage()
-		}
-
-		arg := os.Args[1]
-		os.Args = append(os.Args[:1], os.Args[2:]...)
-
-		return arg
-	}
-
-	conf := gobump.Config{}
-
-	var noWrite bool
-
-	command := shift()
-	switch command {
-	case "major":
-		conf.MajorDelta = 1
-	case "minor":
-		conf.MinorDelta = 1
-	case "patch":
-		conf.PatchDelta = 1
-	case "set":
-		conf.Exact = shift()
-	case "show":
-		noWrite = true
-		*verbose = true
-	default:
-		flag.Usage()
-	}
-
-	flag.Parse()
-
-	target := flag.Arg(0)
-	if target == "" {
-		target = "."
-	}
-
-	fset := token.NewFileSet()
-	pkgs, err := parser.ParseDir(fset, target, nil, parser.ParseComments)
-	dieIf(err)
-
-	found := false
-	for _, pkg := range pkgs {
-		for _, f := range pkg.Files {
-			vers, err := conf.ProcessNode(fset, f)
-			dieIf(err)
-
-			// rewrote successfully
-			if vers != nil {
-				found = true
-
-				if *verbose {
-					if *raw {
-						for _, v := range vers {
-							fmt.Println(v)
-						}
-					} else {
-						json.NewEncoder(os.Stdout).Encode(vers)
-					}
-				}
-
-				if noWrite {
-					continue
-				}
-
-				out := os.Stdout
-				if *write {
-					file, err := os.Create(fset.File(f.Pos()).Name())
-					dieIf(err)
-
-					out = file
-				}
-
-				conf := &printer.Config{
-					Mode:     printer.UseSpaces | printer.TabIndent,
-					Tabwidth: 8,
-				}
-				conf.Fprint(out, fset, f)
-			}
-		}
-	}
-
-	if found == false {
-		os.Exit(1)
-	}
-}
-
-func dieIf(err error) {
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
+	log.SetFlags(0)
+	err := gobump.Run(os.Args[1:], os.Stdout, os.Stderr)
+	if err != nil && err != flag.ErrHelp {
+		log.Println(err)
 		os.Exit(1)
 	}
 }

gobump.go

@@ -2,7 +2,10 @@ package gobump
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
+	"io"
+	"os"
 	"regexp"
 	"strconv"
 
@@ -15,6 +18,84 @@ import (
 	"github.com/blang/semver"
 )
 
+// Gobump is main application struct
+type Gobump struct {
+	Write, Verbose, Raw, Show bool
+	Target                    string
+
+	Config    Config
+	OutStream io.Writer
+}
+
+// Run the gobump
+func (gb *Gobump) Run() error {
+	if gb.OutStream == nil {
+		gb.OutStream = os.Stdout
+	}
+	if gb.Target == "" {
+		gb.Target = "."
+	}
+
+	fset := token.NewFileSet()
+	pkgs, err := parser.ParseDir(fset, gb.Target, nil, parser.ParseComments)
+	if err != nil {
+		return err
+	}
+
+	found := false
+	for _, pkg := range pkgs {
+		for _, f := range pkg.Files {
+			vers, err := gb.Config.ProcessNode(fset, f)
+			if err != nil {
+				return err
+			}
+			if vers == nil {
+				continue
+			}
+
+			found = true
+			if gb.Verbose || gb.Show {
+				if gb.Raw {
+					for _, v := range vers {
+						fmt.Fprintln(gb.OutStream, v)
+					}
+				} else {
+					json.NewEncoder(gb.OutStream).Encode(vers)
+				}
+			}
+			if gb.Show {
+				continue
+			}
+			if err := gb.out(fset, f); err != nil {
+				return err
+			}
+		}
+	}
+
+	if found == false {
+		return fmt.Errorf("version not found")
+	}
+	return nil
+}
+
+func (gb *Gobump) out(fset *token.FileSet, f *ast.File) error {
+	out := gb.OutStream
+	if gb.Write {
+		file, err := os.Create(fset.File(f.Pos()).Name())
+		if err != nil {
+			return err
+		}
+		defer file.Close()
+		out = file
+	}
+
+	conf := &printer.Config{
+		Mode:     printer.UseSpaces | printer.TabIndent,
+		Tabwidth: 8,
+	}
+	return conf.Fprint(out, fset, f)
+}
+
 var defaultNamePattern = regexp.MustCompile(`^(?i)version$`)
 
 // Config is the entrypoint of gobump.