feat: allow specifying formatters in cli

Closes #9

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/charmbracelet/log v0.3.1
 	github.com/gobwas/glob v0.2.3
 	github.com/juju/errors v1.0.0
+	github.com/otiai10/copy v1.14.0
 	github.com/stretchr/testify v1.8.4
 	github.com/vmihailenco/msgpack/v5 v5.4.1
 	github.com/ztrue/shutdown v0.1.1

go.sum

@@ -40,6 +40,10 @@ github.com/muesli/reflow v0.3.0 h1:IFsN6K9NfGtjeggFP+68I4chLZV2yIKsXJFNZ+eWh6s=
 github.com/muesli/reflow v0.3.0/go.mod h1:pbwTDkVPibjO2kyvBQRBxTWEEGDGq0FlB1BIKtnHY/8=
 github.com/muesli/termenv v0.15.2 h1:GohcuySI0QmI3wN8Ok9PtKGkgkFIk7y6Vpb5PvrY+Wo=
 github.com/muesli/termenv v0.15.2/go.mod h1:Epx+iuz8sNs7mNKhxzH4fWXGNpZwUaJKRS1noLXviQ8=
+github.com/otiai10/copy v1.14.0 h1:dCI/t1iTdYGtkvCuBG2BgR6KZa83PTclw4U5n2wAllU=
+github.com/otiai10/copy v1.14.0/go.mod h1:ECfuL02W+/FkTWZWgQqXPWZgW9oeKCSQ5qVfSc4qc4w=
+github.com/otiai10/mint v1.5.1 h1:XaPLeE+9vGbuyEHem1JNk3bYc7KKqyI/na0/mLd/Kks=
+github.com/otiai10/mint v1.5.1/go.mod h1:MJm72SBthJjz8qhefc4z1PYEieWmy8Bku7CjcAqyUSM=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=

internal/cli/cli.go

@@ -1,20 +1,23 @@
 package cli
 
-import "github.com/charmbracelet/log"
+import (
+	"github.com/charmbracelet/log"
+)
 
 var Cli = Options{}
 
 type Options struct {
-	AllowMissingFormatter bool   `default:"false" help:"Do not exit with error if a configured formatter is missing"`
-	ClearCache            bool   `short:"c" help:"Reset the evaluation cache. Use in case the cache is not precise enough"`
-	ConfigFile            string `type:"existingfile" default:"./treefmt.toml"`
-	TreeRoot              string `type:"existingdir" default:"."`
-	Verbosity             int    `name:"verbose" short:"v" type:"counter" default:"0" env:"LOG_LEVEL" help:"Set the verbosity of logs e.g. -vv"`
+	AllowMissingFormatter bool     `default:"false" help:"Do not exit with error if a configured formatter is missing"`
+	ClearCache            bool     `short:"c" help:"Reset the evaluation cache. Use in case the cache is not precise enough"`
+	ConfigFile            string   `type:"existingfile" default:"./treefmt.toml"`
+	Formatters            []string `help:"Specify formatters to apply. Defaults to all formatters"`
+	TreeRoot              string   `type:"existingdir" default:"."`
+	Verbosity             int      `name:"verbose" short:"v" type:"counter" default:"0" env:"LOG_LEVEL" help:"Set the verbosity of logs e.g. -vv"`
 
 	Format Format `cmd:"" default:"."`
 }
 
-func (c *Options) ConfigureLogger() {
+func (c *Options) Configure() {
 	log.SetReportTimestamp(false)
 
 	if c.Verbosity == 0 {

internal/cli/format.go

@@ -19,7 +19,7 @@ type Format struct{}
 func (f *Format) Run() error {
 	start := time.Now()
 
-	Cli.ConfigureLogger()
+	Cli.Configure()
 
 	l := log.WithPrefix("format")
 
@@ -42,8 +42,34 @@ func (f *Format) Run() error {
 		return errors.Annotate(err, "failed to read config file")
 	}
 
+	// create optional formatter filter set
+	formatterSet := make(map[string]bool)
+	for _, name := range Cli.Formatters {
+		_, ok := cfg.Formatters[name]
+		if !ok {
+			return errors.Errorf("formatter not found in config: %v", name)
+		}
+		formatterSet[name] = true
+	}
+
+	includeFormatter := func(name string) bool {
+		if len(formatterSet) == 0 {
+			return true
+		} else {
+			_, include := formatterSet[name]
+			return include
+		}
+	}
+
 	// init formatters
 	for name, formatter := range cfg.Formatters {
+		if !includeFormatter(name) {
+			// remove this formatter
+			delete(cfg.Formatters, name)
+			l.Debugf("formatter %v is not in formatter list %v, skipping", name, Cli.Formatters)
+			continue
+		}
+
 		err = formatter.Init(name)
 		if err == format.ErrFormatterNotFound && Cli.AllowMissingFormatter {
 			l.Debugf("formatter not found: %v", name)
@@ -126,7 +152,7 @@ func (f *Format) Run() error {
 		}
 		changes += count
 
-		println(fmt.Sprintf("%v files changed in %v", changes, time.Now().Sub(start)))
+		fmt.Printf("%v files changed in %v", changes, time.Now().Sub(start))
 		return nil
 	})
 

internal/cli/format_test.go

@@ -1,12 +1,16 @@
 package cli
 
 import (
+	"io"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"git.numtide.com/numtide/treefmt/internal/format"
 	"github.com/BurntSushi/toml"
 	"github.com/alecthomas/kong"
+	"github.com/juju/errors"
+	cp "github.com/otiai10/copy"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -37,10 +41,56 @@ func newKong(t *testing.T, cli interface{}, options ...kong.Option) *kong.Kong {
 	return parser
 }
 
-func newCli(t *testing.T, args ...string) (*kong.Context, error) {
+func tempFile(t *testing.T, path string) *os.File {
 	t.Helper()
+	file, err := os.Create(path)
+	if err != nil {
+		t.Fatalf("failed to create temporary file: %v", err)
+	}
+	return file
+}
+
+func cmd(t *testing.T, args ...string) ([]byte, error) {
+	t.Helper()
+
+	// create a new kong context
 	p := newKong(t, &Cli)
-	return p.Parse(args)
+	ctx, err := p.Parse(args)
+	if err != nil {
+		return nil, err
+	}
+
+	tempDir := t.TempDir()
+	tempOut := tempFile(t, filepath.Join(tempDir, "combined_output"))
+
+	// capture standard outputs before swapping them
+	stdout := os.Stdout
+	stderr := os.Stderr
+
+	// swap them temporarily
+	os.Stdout = tempOut
+	os.Stderr = tempOut
+
+	// run the command
+	if err = ctx.Run(); err != nil {
+		return nil, err
+	}
+
+	// reset and read the temporary output
+	if _, err = tempOut.Seek(0, 0); err != nil {
+		return nil, errors.Annotate(err, "failed to reset temp output for reading")
+	}
+
+	out, err := io.ReadAll(tempOut)
+	if err != nil {
+		return nil, errors.Annotate(err, "failed to read temp output")
+	}
+
+	// swap outputs back
+	os.Stdout = stdout
+	os.Stderr = stderr
+
+	return out, nil
 }
 
 func TestAllowMissingFormatter(t *testing.T) {
@@ -57,12 +107,59 @@ func TestAllowMissingFormatter(t *testing.T) {
 		},
 	})
 
-	ctx, err := newCli(t, "--config-file", configPath, "--tree-root", tempDir)
-	as.NoError(err)
-	as.Error(ctx.Run(), format.ErrFormatterNotFound)
+	_, err := cmd(t, "--config-file", configPath, "--tree-root", tempDir)
+	as.ErrorIs(err, format.ErrFormatterNotFound)
 
-	ctx, err = newCli(t, "--config-file", configPath, "--tree-root", tempDir, "--allow-missing-formatter")
+	_, err = cmd(t, "--config-file", configPath, "--tree-root", tempDir, "--allow-missing-formatter")
 	as.NoError(err)
-
-	as.NoError(ctx.Run())
+}
+
+func TestSpecifyingFormatters(t *testing.T) {
+	as := require.New(t)
+
+	tempDir := t.TempDir()
+	configPath := tempDir + "/treefmt.toml"
+
+	as.NoError(cp.Copy("../../test/examples", tempDir), "failed to copy test data to temp dir")
+
+	writeConfig(t, configPath, format.Config{
+		Formatters: map[string]*format.Formatter{
+			"elm": {
+				Command:  "echo",
+				Includes: []string{"*.elm"},
+			},
+			"nix": {
+				Command:  "echo",
+				Includes: []string{"*.nix"},
+			},
+			"ruby": {
+				Command:  "echo",
+				Includes: []string{"*.rb"},
+			},
+		},
+	})
+
+	out, err := cmd(t, "--clear-cache", "--config-file", configPath, "--tree-root", tempDir)
+	as.NoError(err)
+	as.Contains(string(out), "3 files changed")
+
+	out, err = cmd(t, "--clear-cache", "--config-file", configPath, "--tree-root", tempDir, "--formatters", "elm,nix")
+	as.NoError(err)
+	as.Contains(string(out), "2 files changed")
+
+	out, err = cmd(t, "--clear-cache", "--config-file", configPath, "--tree-root", tempDir, "--formatters", "ruby,nix")
+	as.NoError(err)
+	as.Contains(string(out), "2 files changed")
+
+	out, err = cmd(t, "--clear-cache", "--config-file", configPath, "--tree-root", tempDir, "--formatters", "nix")
+	as.NoError(err)
+	as.Contains(string(out), "1 files changed")
+
+	// test bad names
+
+	out, err = cmd(t, "--clear-cache", "--config-file", configPath, "--tree-root", tempDir, "--formatters", "foo")
+	as.Errorf(err, "formatter not found in config: foo")
+
+	out, err = cmd(t, "--clear-cache", "--config-file", configPath, "--tree-root", tempDir, "--formatters", "bar,foo")
+	as.Errorf(err, "formatter not found in config: bar")
 }