[TIP] Run Playwright Tests on unsupported Linux distributions

[pavelfeldman]

To run Playwright on unsupported Linux distribution, you run run Playwright server in Docker while keeping your tests running on the host system:

Run Playwright Server in Docker

docker run -p 3000:3000 --rm --init -it mcr.microsoft.com/playwright:v1.41.0-jammy /bin/sh -c "cd /home/pwuser && npx -y playwright@1.41.0 run-server --port 3000 --host 0.0.0.0"

It will output following when ready

Listening on ws://127.0.0.1:3000/

Point Playwright client to the server on Docker

If running @playwright/test, use environment variable, no other changes are needed.

PW_TEST_CONNECT_WS_ENDPOINT=ws://127.0.0.1:3000/ npx playwright test

Alternatively, for other applications and language ports, use browserType.connect API to use remote Playwright.

const browser = await playwright['chromium'].connect('ws://127.0.0.1:3000/');

Network

Make sure that the host network is available in your Docker container if you are testing local servers:

docker run --add-host=hostmachine:host-gateway

This will make hostmachine point to the host's localhost. Note that all the tests would also need to use hostmachine in the URLs to access servers on the host. Alternatively, you can follow unconventional route and do docker run --add-host=localhost:host-gateway at your own risk.

[jasonparallel]

Really cool. Should sandboxing work in the container?

@aslushnikov thanks for pointing this our over on #9199

[mhchaudhry]

This is great, exactly what we needed, but the first thing that happens when you start the playwright server is that it goes out to npmjs to install the playwright-core dependency. Which doesn't work in say a CI/CD env with no outbound internet access.

Ideally, the container should be self-contained. Why not install that dependency when creating the container so that it is fully self-contained and works in an offline environment?

[akoidan]

There are always difficulties with network_mode: host that only works on Linux distros. Alternatively you can use --add-host=hostmachine:host-gateway, but could also lead to issues.

You can apply a small hack which allows playwright to listen 0.0.0.0. Since by default playwright server is not capable for that

: yarn playwright run-server --help
yarn run v1.22.19
$ node_modules/.bin/playwright run-server --help
Usage: yarn playwright run-server [options]

Options:
  --port <port>               Server port
  --path <path>               Endpoint Path (default: "/")
  --max-clients <maxClients>  Maximum clients
  --mode <mode>               Server mode, either "default" or "extension"
  -h, --help                  display help for command

You can manually patch

node_modules/playwright-core/lib/remote/playwrightServer.js

Replacing

-     server.listen(port, () => {
+     server.listen(port, '0.0.0.0', () => {

And run docker with docker run -p 3000:3000

If you need to automate that you can use patch-package

Also note, that when you run playwright from docker it has to have access to your webserver. Which means you need to run it inside same docker container as playwright. Otherwise you're stuck to an option that PO described with --add-host=hostmachine:host-gateway

[atollk]

Unfortunately, the container doesn't work at all for me.
I have a fresh setup of Playwright with npm init playwright@latest and followed the instructions above. The container starts fine (Listening on ws://127.0.0.1:3000/) but the tests are just stuck.

>  PW_TEST_CONNECT_WS_ENDPOINT=ws://127.0.0.1:3000/ npx playwright test       
Running 6 tests using 6 workers
[6/6] [chromium] › example.spec.ts:10:5 › get started link

When running npx playwright test by itself, the command finishes almost immediately and has 4 of 6 passing tests (webkit failing due to missing dependencies).

6.5.9-arch2-1 Linux

[kencloudbeds]

Hello, I have an odd issue. I tried using the docker image inside Rocky Linux and it worked perfectly, webkit passed no problem. What I noticed is that if after running it on a specific port, if I reboot the server, it will no longer work on the same port. I actually have to change the port to get it to work again. If I reboot again, now the new port I used won't work, but if I switch back to the original port, now that will work again. The error I get is as follows:

Error: browserType.connect: WebSocket error: connect EHOSTUNREACH 127.0.0.1:10700 =========================== logs =========================== <ws connecting> ws://127.0.0.1:10700/ <ws error> ws://127.0.0.1:10700/ error connect EHOSTUNREACH 127.0.0.1:10700 <ws connect error> ws://127.0.0.1:10700/ connect EHOSTUNREACH 127.0.0.1:10700 <ws disconnected> ws://127.0.0.1:10700/ code=1006 reason= ============================================================

The command I use is :

docker run -p 10700:10700 --rm --init -it mcr.microsoft.com/playwright:v1.39.0-jammy /bin/sh -c "cd /home/pwuser && npx -y playwright@1.39.0 run-server --port 10700"

So, every time I reboot, I have to keep switching back and forth between two ports 10700 and 10600. Do you have any idea why this would be happening?

Even if I re-download the docker image it still will not work using the previous port used prior to reboot.

Seems like some sort of cache issue.

Any help is appreciated.

[k1w1m8]

I have CentOS 7, which is definitely unsupported.

Then I found this issue which described how we can use playwright-java as the client and playwright docker as the server which should work on unsupported OS.

So I tried it using PW 1.40. I found that before you can call browserType.connect per the instructions in this issue, you need a Playwright instance. To get that, you can Playwright.create(), but this creates a temporary node instance using /tmp and that doesn't work on unsupported OS.

/tmp/playwright-java-7742446124117836956/node: /lib64/libm.so.6: version `GLIBC_2.27' not found (required by /tmp/playwright-java-7742446124117836956/node)

So seems the instructions in this issue are incorrect (or at least incomplete) for Java. It can be made to work, but not with the instructions as given.

After bit more searching I found microsoft/playwright-java#1016 and was able to use it to use my own host node rather than the PW supplied one which does not work. I installed node manually on CentOS and then set system property "playwright.nodejs.path" to point to it, and it seemed the local node could be started.

After that I set env PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=true to prevent PW trying to download and install browsers on the host (that I didn't need and won't work on the unsupported OS).

It would be much cleaner and simpler if the playwright-java API could be extended to allow connection to a previously started driver in Linux, avoiding Playwright.create() and local node altogether, similar to Selenium RemoteWebDriver.

Anyway. here is the working test case. I think it should be adaptable to any OS which can run Java and Node.

@Test
public void testSomething() {

    // Playwright will try and download and install node AND browsers automagically.
    // These do not work on CentOS7, as not supported O/S. So, we need another approach.
    // Playwright provide a docker container with correct node and browsers inside.
    // However, playwright-java requires a host node purely to "bounce" to the docker node.
    // So we have to install host node, point PW at it, and tell PW not to download browsers too.

    // Install node on the host, e.g. in CentOS
    //   sudo yum install nodejs
    // Find the install location of host node and use it to set the following variable
    //   which node
    String hostNodePath = "/usr/bin/node";

    // Start PW docker as per https://github.com/microsoft/playwright/issues/26482

    // Tell PW to use our host node for the "bounce" to Docker node
    System.setProperty("playwright.nodejs.path", hostNodePath);

    // Tell PW not to install host browsers, as we'll be using browsers from Docker container
    Map<String, String> env = new HashMap<String, String>() {{
       put("PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD", "true");
    }};

    Playwright.CreateOptions options = new Playwright.CreateOptions().setEnv(env);
    try (Playwright playwright = Playwright.create(options)) {
        // Connect to the node (driver) inside of docker
        Browser browser = playwright.chromium().connect("ws://127.0.0.1:3000/");
        // Test as usual
        Page page = browser.newPage();
        page.navigate("http://playwright.dev");
        System.out.println(page.title());
    }
}

My usage would be much easier if I can avoid installing native software on the host. So I might raise an issue on playwright-java to see if they can help with a pure Java client API.

microsoft/playwright-java#1446