Don't close connections twice after join completes #217
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euank
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Half closed tcp connections are a mess, go does not make dealing with them easy, and I think this PR is doing something that is right on some technical level, but will cause some unfortunate regressions in practice...
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After @andrewryno's update, I think (unless I'm missing something) this covers both Ryno's needs and Euan's concerns, so I'm going to go ahead and approve
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lgtm, though I'd also suggest editing the PR title to match the new commit message.
Thanks!
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This fixes a data race in the forwarder which can be hit by reading/writing data during a call to
(ngrok.Endpoint).CloseWithContext()and(ngrok.Agent).Disconnect().I've been unsuccessfully trying to get a small test to demonstrate it since I ran into it in a rather complex setup for an internal test. I'll see if I can get one working. However, my internal tests are now working perfectly fine with this fix and I'm no longer getting any races.
The underlying problem is that when a muxado stream is closed it does internal writes, but the
io.Copystill might be doing reads which races. This closes writes but waits for all reads to finish fromio.Copybefore entirely closing the connection. There was also some additionalClosecalls that are unnecessary sincejoincan handle them all.Investigated/written with the help of Amp, but it took a long time to get there lol.