crossbario / crossbario/autobahn-python
maxConnection count relies on onClose not throwing an exception
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- Dominant language
- Python
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Description
maxConnections watches countConnections to determine remaining connections to allow. However, if an exception is thrown in onClose, the countConnections is not decremented. This means an error in onClose can easily starve your system of allowing connections.
The _onClose call from WebSocketProtocol's _connectionLost should either be wrapped in a try/finally to ensure countConnections is decremented, or the count should be decremented before calling the _connectionLost handler here: https://github.com/tavendo/AutobahnPython/blob/master/autobahn/websocket/protocol.py#L2759
Or it should be very very clear to folks implementing this that any exception in onClose could cause this to occur.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in autobahn/websocket/protocol.py around WebSocketProtocol._connectionLost at line 2759, and trace how maxConnections uses countConnections and onClose. Confirm the behavior when onClose raises, then ensure the connection count is still decremented and add or update regression coverage for that case.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- networking
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 38/100