feat: Add todos-profile command

.gitignore

@@ -14,6 +14,13 @@
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
 
+# Go pprof files
+*.prof
+
+# binary names
+todos
+todos-profile
+
 # Dependency directories (remove the comment below to include it)
 vendor/
 node_modules/

internal/cmd/todos-profile/main.go

@@ -0,0 +1,48 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"runtime/pprof"
+
+	"github.com/urfave/cli/v2"
+
+	"github.com/ianlewis/todos/internal/cmd/todos/app"
+	"github.com/ianlewis/todos/internal/utils"
+)
+
+func main() {
+	f, err := os.Create("todos.prof")
+	if err != nil {
+		_ = utils.Must(fmt.Fprintf(os.Stderr, "%v", err))
+		os.Exit(1)
+	}
+	if err := pprof.StartCPUProfile(f); err != nil {
+		_ = utils.Must(fmt.Fprintf(os.Stderr, "%v", err))
+		os.Exit(1)
+	}
+	defer pprof.StopCPUProfile()
+
+	exit := cli.OsExiter
+	cli.OsExiter = func(code int) {
+		// Make sure profile is stopped even if os.Exit is called.
+		pprof.StopCPUProfile()
+		exit(code)
+	}
+
+	app.Main()
+}

internal/cmd/todos/app.go → internal/cmd/todos/app/app.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package main
+package app
 
 import (
 	"encoding/json"
@@ -55,8 +55,8 @@ var (
 	ErrWalk = errors.New("walking")
 )
 
-// newTODOsApp returns a new `todos` application.
-func newTODOsApp() *cli.App {
+// NewTODOsApp returns a new `todos` application.
+func NewTODOsApp() *cli.App {
 	return &cli.App{
 		Name:  filepath.Base(os.Args[0]),
 		Usage: "Search for TODOS in code.",
@@ -288,3 +288,14 @@ func walkerOptionsFromContext(c *cli.Context) (*walker.Options, error) {
 
 	return &o, nil
 }
+
+// Main is the main function of the `todos` command.
+func Main() {
+	// NOTE: Errors are generally handled in the app itself but Run could
+	// return errors if command line flags are incorrect etc. In this case neither
+	// Action nor ExitErrHandler are called.
+	todosApp := NewTODOsApp()
+	if err := todosApp.Run(os.Args); err != nil {
+		cli.OsExiter(ExitCodeUnknownError)
+	}
+}

internal/cmd/todos/app_test.go → internal/cmd/todos/app/app_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package main
+package app
 
 import (
 	"bytes"
@@ -47,7 +47,7 @@ func newContext(app *cli.App, args []string) *cli.Context {
 func Test_TODOsApp_version(t *testing.T) {
 	t.Parallel()
 
-	app := newTODOsApp()
+	app := NewTODOsApp()
 	var b strings.Builder
 	app.Writer = &b
 	c := newContext(app, []string{"--version"})
@@ -80,7 +80,7 @@ func Test_TODOsApp_Walk(t *testing.T) {
 	d := testutils.NewTempDir(files)
 	defer d.Cleanup()
 
-	app := newTODOsApp()
+	app := NewTODOsApp()
 	var b strings.Builder
 	app.Writer = &b
 	c := newContext(app, []string{d.Dir()})
@@ -106,7 +106,7 @@ func Test_TODOsApp_ExitErrHandler_ErrWalk(t *testing.T) {
 		cli.OsExiter = oldExiter
 	}()
 
-	app := newTODOsApp()
+	app := NewTODOsApp()
 	var b strings.Builder
 	app.ErrWriter = &b
 	c := newContext(app, nil)

internal/cmd/todos/main.go

@@ -15,17 +15,9 @@
 package main
 
 import (
-	"os"
-
-	"github.com/urfave/cli/v2"
+	"github.com/ianlewis/todos/internal/cmd/todos/app"
 )
 
 func main() {
-	// NOTE: Errors are generally handled in the app itself but Run could
-	// return errors if command line flags are incorrect etc. In this case neither
-	// Action nor ExitErrHandler are called.
-	app := newTODOsApp()
-	if err := app.Run(os.Args); err != nil {
-		cli.OsExiter(ExitCodeUnknownError)
-	}
+	app.Main()
 }