Add port validation checks for HTTP streaming #315
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| // Function to find an open port starting from a specified port | ||
| function findOpenPort(callback: (port: number) => void): void { | ||
| const server = net.createServer(); |
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Why are we creating a new server? Can 't we use server already created?
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The server we created is already listening in on port 0. We could use that one, but it would be closing and re-listening a lot. I created a new one to keep the logic cleaner and because using net.createServer() should be faster when just checking the ports.
| const server = net.createServer(); | ||
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| function tryPort(port: number) { | ||
| server.once('error', () => { |
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I think we should have a retry limit. If the vnet has blocked all ports, this will lead to stack overflow.
| const server = net.createServer(); | ||
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| function tryPort(port: number) { | ||
| server.once('error', () => { |
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This will retry finding a new port for all errors. How about we check if (err.code === 'EADDRINUSE') and then find the next port.
| const randomPort = getRandomPort(); | ||
| tryPort(randomPort); | ||
| }); | ||
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Add server.removeAllListeners(); . This is to remove all listeners for each recursive call.
https://nodejs.org/api/events.html#nodeeventtargetremovealllistenerstype
For HTTP streaming, the port is selected by the platform. However, there was no logic that checks if the selected port is valid and available. In the case where the OS is Windows and VNET integration is enabled, the platform defaults to port 0. Port 0 isn't valid, so any proxy requests fail, and the function execution times out.
This fix adds validation on the selected port value. If the port value is 0, the worker will search for and bind to an available port. It first starts searching at port 55000, and if that port isn't available, it will pick a random port between 55000 and 65535 (max port value) and search again. It continues this process until a port is found.
There are no behavioral changes if the selected port value is not 0. The only scenario this change affects then is for Windows + VNET integration enabled.