How to set the browser window size when using `google-chrome --headless`?

Question

Tried setting the browser size on chrome --headless by using Selenium webdriver commands.

I get this webdriver error:

      - Failed: unknown error: cannot get automation extension
from unknown error: page could not be found: chrome-extension://aapnijgdinlhnhlmodcfapnahmbfebeb/_generated_background_page.html
  (Session info: headless chrome=58.0.3029.81)
  (Driver info: chromedriver=2.29.461571 (8a88bbe0775e2a23afda0ceaf2ef7ee74e822cc5),platform=Linux 4.4.0-72-generic x86_64) (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 10.07 seconds
Build info: version: '3.3.1', revision: '5234b32', time: '2017-03-10 09:04:52 -0800'
System info: host: '826f6a766112', ip: '172.17.0.2', os.name: 'Linux', os.arch: 'amd64', os.version: '4.4.0-72-generic', java.version: '1.8.0_121'
Driver info: org.openqa.selenium.chrome.ChromeDriver
Capabilities [{applicationCacheEnabled=false, rotatable=false, mobileEmulationEnabled=false, networkConnectionEnabled=false, chrome={chromedriverVersion=2.29.461571 (8a88bbe0775e2a23afda0ceaf2ef7ee74e822cc5), userDataDir=/tmp/.org.chromium.Chromium.cuymDL}, takesHeapSnapshot=true, pageLoadStrategy=normal, databaseEnabled=false, handlesAlerts=true, hasTouchScreen=false, version=58.0.3029.81, platform=LINUX, browserConnectionEnabled=false, nativeEvents=true, acceptSslCerts=true, locationContextEnabled=true, webStorageEnabled=true, browserName=chrome, takesScreenshot=true, javascriptEnabled=true, cssSelectorsEnabled=true, unexpectedAlertBehaviour=}]
Session ID: 9569e5ebd8f7540ce510b20647443baf

Answer 1

Found it, simply pass --window-size command line argument to Google Chrome, for example --window-size=1920,1080

In a Protractor config this would look like this:

capabilities: {
    browserName: 'chrome',
    chromeOptions: {
        args: ['headless', 'window-size=1920,1080']
    }
}

The cool thing is that the windows size is not limited to the current display, is truly headless meaning in can be as large as needed for the tests.

Java code:

options.addArguments("window-size=1920,1080");

I expand a bit more on this here: https://stackoverflow.com/a/43542416/511069

Answer 2

I realize this is a bit late, but why not just use the built in selenium?

    aDriver.manage().window().setSize(new Dimension(width, height));

Works like a champ. I've used it for FireFox, Chrome (even headless), and Edge.