Make headless browsers available.

[lpeabody]

Changes

• Makes the following SeleniumHQ-supported headless browsers available for usage within Docksal:
  • Chrome
  • Firefox
  • Edge
• Browsers can be CPU intensive, so they are disabled by default (even if you've extended them into your docksal.yml file). You must explicitly add COMPOSE_PROFILES="testing" to either docksal.env or docksal-local.env and then run fin up.

[lpeabody]

The chrome browser presents some issues. You may receive a couple of errors immediately:

Tab crash (error is generated from PHPUnit test):

...
WebDriver\Exception\UnknownError: unknown error: session deleted because of page crash
from unknown error: cannot determine loading status
from tab crashed
  (Session info: chrome=84.0.4147.105)
...

Blocked connection (Docker logs from browser service):

...
browser_1    | Only local connections are allowed.
browser_1    | Please see https://chromedriver.chromium.org/security-considerations for suggestions on keeping ChromeDriver safe.
browser_1    | [Ch1romeD6r2i0v2e3r0 8w1a6s. 5s8t4a]r[tSeEdV EsRuEc]c:e sbsifnudl(l)y .f
browser_1    | ailed: Cannot assign requested address (99)
...

Both of the errors above, based on my testing locally, can be resolved by updating the browser service definition like so:

browser:
    hostname: browser
    image: selenium/standalone-chrome
    environment:
      JAVA_OPTS: "-Dwebdriver.chrome.whitelistedIps="
    shm_size: '512M'
    dns:
      - ${DOCKSAL_DNS1}
      - ${DOCKSAL_DNS2}

Setting shm_size addresses the tab crash, and adding the JAVA_OPTS whitelist equal to nothing allows all remote connections. If we wanted to be more secure we could make the browser service dependent on the cli service and figure out a way to pass the IP address of the cli service on the project network.

For more details regarding the shm_size property usage in the context of the selenium-chrome image, see https://stackoverflow.com/a/53970825/664881.