Consider setting MOZ_HEADLESS env var to 1

[McSneaky]

Without adding this environment variable every attempt to connect fails with error:

Error: no DISPLAY environment variable specified
1610804842426	webdriver::server	DEBUG	<- 500 Internal Server Error {"value":{"error":"unknown error","message":"Process unexpectedly closed with status 1","stacktrace":""}}

Not sure if it's intentional or not. Based on readme it feels like it should be headless and not require display output

[tyranron]

@McSneaky I wonder is it due to latest 0.29.0 upgrade or was true for previous versions too?

[McSneaky]

@McSneaky I wonder is it due to latest 0.29.0 upgrade or was true for previous versions too?

Sadly no idea 😐 . The day I made the issue was the first time I ever used it

[tyranron]

@McSneaky well, maybe a connection parameters should have some parameters to run in headless mode?

I don't know the webdriver specifics, but in our builds it works OK out-of-the-box:

docker run --rm -d --network=host --shm-size 512m \
	--name medea-webdriver-firefox \
	instrumentisto/geckodriver:84.0.2

GECKODRIVER_REMOTE="http://127.0.0.1:4444" \
WASM_BINDGEN_TEST_TIMEOUT=60 \
cargo test --target wasm32-unknown-unknown --features mockable
    Finished test [unoptimized + debuginfo] target(s) in 0.10s
     Running /home/runner/work/medea/medea/target/wasm32-unknown-unknown/debug/deps/medea_jason-870dc78cb583511a.wasm

Running headless tests in Firefox on `http://127.0.0.1:4444/`
Try find `webdriver.json` for configure browser's capabilities:
Ok
Starting new webdriver session...                 
Visiting http://127.0.0.1:42725...                
Loading page elements...                          
Waiting for test to finish...                     
                                                  
running 143 tests

Also, you can always use -e MOZ_HEADLESS=1 in docker run if your installation does require it.

I don't feel like it's something that should be baked into the image. But mentioning this issue in README makes sense. Would you like to submit a PR?

[McSneaky]

I don't know the webdriver specifics, but in our builds it works OK out-of-the-box:

@tyranron Hmm, that's odd

The command I used which caused problem: docker run --network=host instrumentisto/geckodriver
When running it with docker run --network=host -e MOZ_HEADLESS=1 instrumentisto/geckodriver then everything is good

Using copy-paste of that first example in https://github.com/jonhoo/fantoccini#examples to test

I'll file in PR to mention it in readme 👍

[tyranron]

@McSneaky yeah, the guess was right. wasm-bindgen explicitly requests headless mode when creates a new WebDriver session. Seems that fantoccini doesn't do that out-of-the-box, but you always may specify them explicitly via Client::with_capabilities().

Thanks for the PR!

[McSneaky]

Aah, that's cool! Didn't know about wasm-bindgen 😋

I think the issue can be closed, since there are already 2 solutions for it in here and there's no real need to keep it open anymore