better error info for browser downloader

abdihaikal · Sep 20, 2022 · b9c1f60 · b9c1f60
1 parent 0acf6e2
commit b9c1f60
Show file tree

Hide file tree

Showing 4 changed files with 33 additions and 11 deletions.
diff --git a/lib/launcher/browser.go b/lib/launcher/browser.go
@@ -237,7 +237,7 @@ func (lc *Browser) httpClient() *http.Client {
 func (lc *Browser) Get() (string, error) {
 	defer leakless.LockPort(lc.LockPort)()
 
-	if lc.Exists() {
+	if lc.Validate() == nil {
 		return lc.Destination(), nil
 	}
 
@@ -251,21 +251,25 @@ func (lc *Browser) MustGet() string {
 	return p
 }
 
-// Exists returns true if the browser executable path exists.
-// If the executable is malformed it will return false.
-func (lc *Browser) Exists() bool {
+// Validate returns nil if the browser executable valid.
+// If the executable is malformed it will return error.
+func (lc *Browser) Validate() error {
 	_, err := os.Stat(lc.Destination())
 	if err != nil {
-		return false
+		return err
 	}
 
 	cmd := exec.Command(lc.Destination(), "--headless", "--no-sandbox",
 		"--disable-gpu", "--dump-dom", "about:blank")
 	b, err := cmd.CombinedOutput()
 	if err != nil {
-		return false
+		return fmt.Errorf("failed to run the browser: %w\n%s", err, b)
 	}
-	return bytes.Contains(b, []byte(`<html><head></head><body></body></html>`))
+	if !bytes.Contains(b, []byte(`<html><head></head><body></body></html>`)) {
+		return errors.New("the browser executable doesn't support headless mode")
+	}
+
+	return nil
 }
 
 // LookPath searches for the browser executable from often used paths on current operating system.

diff --git a/lib/launcher/fixtures/chrome-empty/main.go b/lib/launcher/fixtures/chrome-empty/main.go
@@ -0,0 +1,4 @@
+// Package main ...
+package main
+
+func main() {}
diff --git a/lib/launcher/fixtures/chrome-exit-err/main.go b/lib/launcher/fixtures/chrome-exit-err/main.go
@@ -0,0 +1,8 @@
+// Package main ...
+package main
+
+import "os"
+
+func main() {
+	os.Exit(1)
+}
diff --git a/lib/launcher/launcher_test.go b/lib/launcher/launcher_test.go
@@ -11,6 +11,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"testing"
 	"time"
@@ -252,10 +253,15 @@ func TestBrowserExists(t *testing.T) {
 
 	b := launcher.NewBrowser()
 	b.Revision = 0
-	g.False(b.Exists())
+	g.Err(b.Validate())
 
-	// fake a broken executable
-	g.E(utils.Mkdir(b.Destination()))
+	g.E(utils.Mkdir(filepath.Base(b.Destination())))
 	g.Cleanup(func() { _ = os.RemoveAll(b.Destination()) })
-	g.False(b.Exists())
+
+	g.E(exec.Command("go", "build", "-o", b.Destination(), "./fixtures/chrome-exit-err").CombinedOutput())
+	g.Has(b.Validate().Error(), "failed to run the browser")
+
+	g.E(utils.Mkdir(filepath.Base(b.Destination())))
+	g.E(exec.Command("go", "build", "-o", b.Destination(), "./fixtures/chrome-empty").CombinedOutput())
+	g.Eq(b.Validate().Error(), "the browser executable doesn't support headless mode")
 }