Cannot pass Chromium arguments with commas through RENDERING_ARGS (e.g., --host-resolver-rules), causes browser launch failure

[Bujupah]

What happened:
When setting Chromium launch arguments through the RENDERING_ARGS environment variable, if an argument contains a comma ,, such as --host-resolver-rules=MAP fonts.googleapis.com 127.0.0.1, MAP fonts.gstatic.com 127.0.0.1, the arguments are incorrectly split.

What you expected to happen:
Arguments passed through RENDERING_ARGS should be parsed safely even if they contain commas. Chromium should launch properly without splitting important arguments, and the renderer service should start successfully.

How to reproduce it (as minimally and precisely as possible):

1. Set the RENDERING_ARGS environment variable with Chromium flags, including --host-resolver-rules that contains a comma:

--no-sandbox,--disable-setuid-sandbox,--host-resolver-rules=MAP fonts.googleapis.com 127.0.0.1, MAP fonts.gstatic.com 127.0.0.1

2. Start the Grafana Image Renderer service.
3. Observe that the renderer fails to launch Chromium properly and crashes.

Anything else we need to know?:
The splitting logic inside the image renderer code incorrectly splits RENDERING_ARGS by commas without considering quoted arguments or escaping.

It is impossible to pass certain valid Chromium arguments (like --host-resolver-rules) safely without modifying the code.

A better approach would be to split the environment variable by newlines or provide another structured way to pass arguments (e.g., JSON array).

Environment:
Grafana Image Renderer version: Latest and any.
Grafana version: 10.x/11.x
Installed plugin or remote renderer service: Remote renderer service.
OS Grafana Image Renderer is installed on: Linux/Windows/Mac
User OS & Browser: N/A
Others: N/A

[Bujupah]

This condition in app.ts or rendering.ts (depends on version) it needs few changes

if (env['RENDERING_ARGS']) {
  const args = env['RENDERING_ARGS'] as string;
  if (args.length > 0) {
    const argsList = args.split(',');
    if (argsList.length > 0) {
      config.rendering.args = argsList;
    }
  }
}

Maybe would suggest support the split by \n instead of comma only ~ have both to keep it backward compatible...

if (env['RENDERING_ARGS']) {
  const args = env['RENDERING_ARGS'] as string;
  if (args.length > 0) {
    let argsList: string[] = [];

    if (args.includes('\n')) {
      // New style: split by newlines
      argsList = args.split('\n').map(arg => arg.trim()).filter(arg => arg.length > 0);
    } else {
      // Old style: split by commas
      argsList = args.split(',').map(arg => arg.trim()).filter(arg => arg.length > 0);
    }

    if (argsList.length > 0) {
      config.rendering.args = argsList;
    }
  }
}

and from env variable it will be supporting this way too:

env:
  - name: RENDERING_ARGS
    value: |
      --no-sandbox
      --disable-setuid-sandbox
      --host-resolver-rules=MAP fonts.googleapis.com 127.0.0.1, MAP fonts.gstatic.com 127.0.0.1

and so the comma only (old behavior)

[Bujupah]

I have raised a draft PR for this though please take a look, #631