do not start a browser in headless mode by default

Fixes #845
chromedp · Jul 13, 2021 · a2ec9e1 · a2ec9e1
1 parent e43a192
commit a2ec9e1
Show file tree

Hide file tree

Showing 4 changed files with 81 additions and 25 deletions.
diff --git a/README.md b/README.md
@@ -23,11 +23,6 @@ full page screenshots.
 
 ## Frequently Asked Questions
 
-> I can't see any Chrome browser window
-
-By default, Chrome is run in headless mode. See `DefaultExecAllocatorOptions`, and
-[an example][goref-chromedp-exec-allocator] to override the default options.
-
 > I'm seeing "context canceled" errors
 
 When the connection to the browser is lost, `chromedp` cancels the context, and
@@ -64,7 +59,17 @@ chromedp.Run(ctx, chromedp.ActionFunc(func(ctx context.Context) error {
 The simplest way is to run the Go program that uses chromedp inside the
 [chromedp/headless-shell][docker-headless-shell] image. That image contains
 `headless-shell`, a smaller headless build of Chrome, which `chromedp` is able
-to find out of the box.
+to find out of the box. If other browser is used in the headless environment,
+don't forget to set the `--headless` option like this:
+
+```go
+opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+allocCtx, allocCancel := chromedp.NewExecAllocator(context.Background(), opts...)
+defer allocCancel()
+ctx, cancel := chromedp.NewContext(allocCtx)
+defer cancel()
+// use the ctx
+```
 
 ## Resources
 

diff --git a/allocate.go b/allocate.go
@@ -54,7 +54,6 @@ func setupExecAllocator(opts ...ExecAllocatorOption) *ExecAllocator {
 var DefaultExecAllocatorOptions = [...]ExecAllocatorOption{
 	NoFirstRun,
 	NoDefaultBrowserCheck,
-	Headless,
 
 	// After Puppeteer's default behavior.
 	Flag("disable-background-networking", true),

diff --git a/chromedp_test.go b/chromedp_test.go
@@ -57,8 +57,8 @@ func init() {
 	// and can slightly speed up the tests on other systems.
 	allocOpts = append(allocOpts, DisableGPU)
 
-	if noHeadless := os.Getenv("CHROMEDP_NO_HEADLESS"); noHeadless != "" && noHeadless != "false" {
-		allocOpts = append(allocOpts, Flag("headless", false))
+	if noHeadless := os.Getenv("CHROMEDP_NO_HEADLESS"); noHeadless == "" || noHeadless == "false" {
+		allocOpts = append(allocOpts, Headless)
 	}
 
 	// Find the exec path once at startup.
@@ -310,6 +310,7 @@ func TestPrematureCancelAllocator(t *testing.T) {
 
 	// To ensure we don't actually fire any Chrome processes.
 	allocCtx, cancel := NewExecAllocator(context.Background(),
+		Headless,
 		ExecPath("/do-not-run-chrome"))
 	// Cancel before the browser is allocated.
 	cancel()
@@ -326,6 +327,7 @@ func TestConcurrentCancel(t *testing.T) {
 
 	// To ensure we don't actually fire any Chrome processes.
 	allocCtx, cancel := NewExecAllocator(context.Background(),
+		Headless,
 		ExecPath("/do-not-run-chrome"))
 	defer cancel()
 
@@ -555,7 +557,10 @@ func TestLogOptions(t *testing.T) {
 		bufMu.Unlock()
 	}
 
-	ctx, cancel := NewContext(context.Background(),
+	opts := append(DefaultExecAllocatorOptions[:], Headless)
+	ctx, cancel := NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = NewContext(ctx,
 		WithErrorf(fn),
 		WithLogf(fn),
 		WithDebugf(fn),
@@ -728,6 +733,8 @@ func TestGracefulBrowserShutdown(t *testing.T) {
 func TestAttachingToWorkers(t *testing.T) {
 	t.Parallel()
 
+	opts := append(DefaultExecAllocatorOptions[:], Headless)
+
 	for _, tc := range []struct {
 		desc, pageJS, wantSelf string
 	}{
@@ -754,7 +761,9 @@ func TestAttachingToWorkers(t *testing.T) {
 			ts := httptest.NewServer(mux)
 			defer ts.Close()
 
-			ctx, cancel := NewContext(context.Background())
+			ctx, cancel := NewExecAllocator(context.Background(), opts...)
+			defer cancel()
+			ctx, cancel = NewContext(ctx)
 			defer cancel()
 
 			ch := make(chan target.ID, 1)

diff --git a/example_test.go b/example_test.go
@@ -31,7 +31,10 @@ func writeHTML(content string) http.Handler {
 }
 
 func ExampleTitle() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	ts := httptest.NewServer(writeHTML(`
@@ -58,7 +61,10 @@ func ExampleTitle() {
 }
 
 func ExampleRunResponse() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	// This server simply shows the URL path as the page title, and contains
@@ -123,6 +129,7 @@ func ExampleExecAllocator() {
 	defer os.RemoveAll(dir)
 
 	opts := append(chromedp.DefaultExecAllocatorOptions[:],
+		chromedp.Headless,
 		chromedp.DisableGPU,
 		chromedp.UserDataDir(dir),
 	)
@@ -169,7 +176,10 @@ func ExampleNewContext_reuseBrowser() {
 	defer ts.Close()
 
 	// create a new browser
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	// start the browser without a timeout
@@ -200,8 +210,11 @@ func ExampleNewContext_reuseBrowser() {
 }
 
 func ExampleNewContext_manyTabs() {
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
 	// new browser, first tab
-	ctx1, cancel := chromedp.NewContext(context.Background())
+	ctx1, cancel := chromedp.NewContext(ctx)
 	defer cancel()
 
 	// ensure the first tab is created
@@ -229,7 +242,10 @@ func ExampleNewContext_manyTabs() {
 }
 
 func ExampleListenTarget_consoleLog() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	ts := httptest.NewServer(writeHTML(`
@@ -276,7 +292,10 @@ func ExampleListenTarget_consoleLog() {
 }
 
 func ExampleWaitNewTarget() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	mux := http.NewServeMux()
@@ -311,7 +330,10 @@ func ExampleWaitNewTarget() {
 }
 
 func ExampleListenTarget_acceptAlert() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	mux := http.NewServeMux()
@@ -346,7 +368,10 @@ func ExampleListenTarget_acceptAlert() {
 }
 
 func Example_retrieveHTML() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	ts := httptest.NewServer(writeHTML(`
@@ -383,7 +408,10 @@ function changeText() {
 }
 
 func ExampleEmulate() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	var buf []byte
@@ -405,7 +433,10 @@ func ExampleEmulate() {
 }
 
 func ExamplePrintToPDF() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	var buf []byte
@@ -431,7 +462,10 @@ func ExamplePrintToPDF() {
 }
 
 func ExampleByJSPath() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	ts := httptest.NewServer(writeHTML(`
@@ -466,7 +500,10 @@ func ExampleByJSPath() {
 }
 
 func ExampleFromNode() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	ts := httptest.NewServer(writeHTML(`
@@ -514,7 +551,10 @@ func ExampleFromNode() {
 }
 
 func Example_documentDump() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	ts := httptest.NewServer(writeHTML(`<!doctype html>
@@ -571,7 +611,10 @@ func Example_documentDump() {
 }
 
 func ExampleFullScreenshot() {
-	ctx, cancel := chromedp.NewContext(context.Background())
+	opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Headless)
+	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
+	defer cancel()
+	ctx, cancel = chromedp.NewContext(ctx)
 	defer cancel()
 
 	var buf []byte