Enable SO_REUSEPORT socket option.

[smilliken]

Needs:

• Testing on Python <2.7.9 and 3.*
• Configuration option.
• Testing on non-linux systems?

[berkerpeksag]

I'd use errno.ENOPROTOOPT instead of 92.

[berkerpeksag]

Also, perhaps we should raise the exception if exc.errno is not 92.

[benoitc]

@berkerpeksag in which case it isn't?

[berkerpeksag]

Even if it returns other than ENOPROTOOPT (e.g. EBADF, EINVAL), we could catch them in line 40 so ignore my last comment :)

[benoitc]

@smilliken interested by making these changes?

[tilgovi]

There's been some silence here from @smilliken. If we're happy with this, we should just make the small changes and merge a copy of it, with attribution.

[berkerpeksag]

+1

[pypeng]

+1

[benoitc]

which changes are needed? If someone can update the PR so we can merge it it would be helpful :)

[wooparadog]

I have some doubt about adding reuseport support for gunicorn.

SO_REUSEPORT is primarily used for using the same listening port for two unrelated processes. But in gunicorn's case, all workers are forked from master, AFTER master opening the listening port, so all workers are already using the same port.

The only use case I can think of is (even more) graceful restart(starting another gunicorn process tree, using SO_REUSEPORT, then kill the old one), but gunicorn already has support for reloading worker processes...

But of course, adding SO_REUSEPORT won't hurt..

[berkerpeksag]

Superseded by #1344.