Remote debugging for Foxx services

[tomterl]

Is it planned, or even possible, to allow remote debugging via the V8 debug protocol, or swank.js (a node module), or another (homegrown) solution like a dbgP implementation?

[dothebart]

Interesting Idea. One would probably have to run the test database with only 1 js context to make this working properly (else you can't tell which context your foxx is going to run in). I can't promise a time frame for this yet.

[tomterl]

If it's under consideration, I'm content 👍

[tomterl]

Nota Bene: Would this be extendible to user supplied aql-functions?

[dothebart]

probably yes.

[pilot4u]

Is there any progress with this request?
Will it be possible to attach debugger to Foxx service?

[tomterl]

As our foxx services get more elaborate, attaching a real debugger would really help in analyzing aberrant runtime behavior in a more timely fashion -- is there light at the end of the tunnel? Or are we stuck with console.log() for good (or bad...)?

[pluma]

The JS debugger protocol is based on websockets. It would also probably require running ArangoDB with a single V8 thread. Although the main use case is debugging Foxx services, this is actually not at all related to Foxx implementation-wise.

[pavelsevcik]

@pluma thank you for valuable insight

to move forward, questions are

• Q1: would be possible to allocate some time to this issue, as it's blocker for broader adoption of Foxx, especially for more complex solutions, as lack of modern debugging significantly reduces benefits like performance and scaleability of Foxx over more complex setups like node+express+arangojs? Questions asking about debugging goes back to 2014 and I personaly heard and felt few times, that without debugging is Foxx too painful to develop with, aka not usable
• Q2: is it possible to implement some sort of combination of arangod option like --javascript.inspect true which would set also --javascript.v8-contexts 1 to enable inspector agent like nodejs does?
• Q3: if (Q2) { return {priority, ETA} }

Thanks, looking forward for RE

[pluma]

@pavelsevcik I feel your pain but this is a fairly large feature and will likely require very gradual iteration to become feasible. I think the biggest blocker is websocket support, as the debugger protocol depends on it. I suggest also following #602, which is likely a related problem.