Will not connect to browser

[Freffles]

Will not connect to browser on windows. Tried with Chrome and Firefox, same issue. Spent way too long trying to figure this out.

[zamalali]

If you're encountering issues with connecting to the browser while using FastAPI and Playwright on Windows, and you've already tried different browsers like Chrome and Firefox without success, the problem is likely due to the --reload flag in FastAPI.

The Problem
On Windows, using the --reload flag with FastAPI can cause conflicts with Playwright's ability to launch browser subprocesses. This is because --reload spawns a subprocess to monitor file changes, which interferes with Playwright's asyncio.create_subprocess_exec, resulting in errors like NotImplementedError.

To resolve this issue, simply run the FastAPI server without the --reload flag. Here's the updated command:

uvicorn app.main:app --port 8000

[govindsinghrawat]

@Freffles - I was able to replicate the issue on Mac. This seems to be playwright not finding the right chromium or browser version in the /Users/"yourUserName"/Library/Caches/ms-playwright/ .

This pull request #11

has a fix to it which adds playwright to package.json. You can try with the appropriate playwright version and then do the "playwright install". Added the step of playwright install in the readme as well.

Hope it resolves the issue

[Freffles]

I was able to get a browser connection but that is kind of where it stopped. Got the browser window opened but when I entered a prompt and clicked send, the send button would briefly turn to "thinking" and I could see the page elements being selected by nothing else happened and there were no errors in the console.

Download the React DevTools for a better development experience: https://react.dev/link/react-devtools react-dom-client.development.js:24650
Attempting to connect... page.tsx:18:14
Response status: 200 page.tsx:27:14
Connection successful, redirecting... page.tsx:34:14
[Fast Refresh] rebuilding hot-reloader-client.tsx:364:14
[Fast Refresh] done in 4658ms hot-reloader-client.tsx:99:10

[hrithikkoduri]

Hey @Freffles ,
Have you by any chance implemented langsmith tracing? If you did can you share the screenshot of the trace?

[govindsinghrawat]

@Freffles

I was able to get a browser connection but that is kind of where it stopped.

Did the package.json update for playwright and "playwright install" solve it or you had to do something else?

Got the browser window opened but when I entered a prompt and clicked send, the send button would briefly turn to "thinking" and I could see the page elements being selected by nothing else happened and there were no errors in the console.

As @hrithikkoduri mentioned if there is any tracing available it will be helpful to debug further if you are hitting some form of limit.

Also if you can try curl https://api.openai.com/v1/models -H "Authorization: Bearer your_gpt_key" and check if response has "gpt-4o" model in it or not, as not having "gpt-4o" can be another point where agent just gets stuck "thinking" and does noting.

[Freffles]

I figured it out. Was the cut and paste from the readme on environment variables. The official langchain structure was this. You will note there are no commas at the end of each line.

LANGSMITH_TRACING=true
LANGSMITH_ENDPOINT="https://api.smith.langchain.com"
LANGSMITH_API_KEY=""
LANGSMITH_PROJECT="pr-juicy-restoration-70"
OPENAI_API_KEY=""

[govindsinghrawat]

I figured it out. Was the cut and paste from the readme on environment variables.

Created a PR for updating readme. Thanks for pointing that out.
#12