is there any right way to interrupt a started server?

[polymorphm]

• I'm submitting a ...
  [x] bug report
  [ ] feature request
  [ ] question about the decisions made in the repository

• Do you want to request a feature or report a bug?

bug? or may be it is a feature request?... no.. I think it is a bug (I don't know)

• What is the current behavior?

the method server.interrupt [of class cherrot.Server] seems like useless.

I can not invoke the method server._set_interrupt() [the property server.interrupt] from the same thread where I just invoked server.start(), because the method server.start() is blocking the thread.

and I can not invoke server.interrupt() in another thread, because server._set_interrupt() invokes server.stop() inside himself. but server.stop() isn't threadsafe!

the method server.stop() isn't threadsafe -- because it has a race condition with the method server.start(). and there isn't a way how to wait for the moment when the method server.start() will pass his initialization (dangerous) point.

how can I use right way to interrupt a server?

I've found the way (the workaround?) like this:

### thread A ###
try:
    server.start()
except MyStopError:
    pass
finally:
    server.stop() # ---- will be invoked always after ``server.start()`` and always in the same thread

### thread B ###
server._interrupt = MyStopError() # ---- doesn't do anything except setting a flag

i.e I've tried to avoid using server._set_interrupt(), so I've got ability to invoke the method server.stop() inside the thread A after invoking the method server.start() in the same thread (the race condition wouldn't happen).

• What is the expected behavior?

if the method server.start() an server.stop() would be use synchronization primitives -- it would NOT fix the problem(!) . because in this case the race contition with server.stop() will still happen at moment before starting the method server.start() (in detail: in thread B we can at random invoke stop() before invoking start(), so the stop() will not stop anything).

and of course -- I can not set server.ready = False in the thread B, because I still have race condition for this variable with the method server.start() invoked in the thread A. it is the real problem..

I think one of the way -- it is to split the method server.start() to two separated methods:

• the first method for a start-initialization phase (not blocking method)
• the second method for a serving phase (blocking method).

this separation will allow to know that you can correctly invoke the method server.stop() -- after the start-initialization phase is done.

thank you in advance!

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[webknjaz]

I need to find time to dig into it.
@jaraco do you have any comments on this post?

[jaraco]

I haven't experienced this issue, but the analysis seems sound.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jaraco]

@polymorphm Would you consider putting together a pull request implementing the approach you've outlined?

[polymorphm]

I would be glad to make a pull request (in some days. at this weakend!).

but I'm afraid that the names of new-functions may turn out to be not very good :-) .

[polymorphm]

I've made pull #98 ..

it seems, I've to do pull's "Checklist" :-) ..