RemoveEventListener cause connection leak about go-dockerclient

[fsouza]

Thanks for the detailed issue and for providing a reproducer!

Yeah, if nothing is listening for the events we should probably close the connection. I'll take a closer look at this on Thursday.

[yyuuttaaoo]

Is there a plan to fix this issue as there is an official alternative now?

[fsouza]

Is there a plan to fix this issue as there is an official alternative now?

Yeah I plan to get to it before the end of the Summer, just been away for a while.

[fsouza]

@yyuuttaaoo @shabicheng can you try #928?

[yyuuttaaoo]

After testing, this patch does not work. So I think the issue should be reopened.
First, let me fix a small bug in the test program. $(pidof docker) should be $(pidof dockerd).
Now we can use the test program to test.
We can see, the fd number is still climbing. Why? There are 2 reasons:

1. If there is no new event for some reason, the json.Decode will block forever.
2. res.Body.Close actually hangs forever if it is called before conn.Close.

There are 2 other problems in this solution:

1. There is a chance that eventChannel and errorChannel are closed before the last event was sent to the channel. This may cause panic.
2. If the last event was an error, it will cause reconnect regardless of the number of listeners.

So I have made another patch based on the current one.
#930

Note:

1. The patch still contains some debug printf code, because it is not fully tested.
2. I have not run any UT for regression yet.
3. I've only test it on Linux using unencrypted docker.sock. SSH/TLS are not tested. Windows platform is not tested.

@fsouza Would you help/coauthor to make the new patch complete?

[fsouza]

@yyuuttaaoo thank you for detailed explanation! I can definitely work on that patch, but this week is a bit busy. I can come around some time next week and look into that patch and make sure it's ready for prime time!