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jeffbass / imagezmq

A set of Python classes that transport OpenCV images from one computer to another using PyZMQ messaging.
MIT License
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Possible bug setting "connect_to='localhost':5555" on ImageSender #38

Open sfrmattos opened 4 years ago

sfrmattos commented 4 years ago

Python 3.8.2 (Win10 x64) Imagezmq V 1.1.1

I noticed that when using:

sender = imagezmq.ImageSender(connect_to='tcp://localhost:5555', REQ_REP=False)

it fails with:

zmq.error.ZMQError: No such device.

With REQ_REP enabled, it works like a charm using "localhost":

sender = imagezmq.ImageSender(connect_to='tcp://localhost:5555')

Using 127.0.0.1:5555 or *:5555 with PUB/SUB also runs with no problems.

** I'm not a developer, so I'm sorry if this kind of reporting is not appropriate.

jeffbass commented 4 years ago

@sfrmattos, This is exactly the place to report this. Thanks! I don't use Windows, but I have had 2 other imageZMQ users report issues with Windows related to specifying the TCP address. I'm glad you found a workaround; I'd suggest just avoiding the "localhost" wording and just stick with 127.0.0.1:5555. I think this might be a problem with the interface between ZMQ and Windows. imageZMQ just passes the tcp address to ZMQ, and doesn't do any modification of it. So I suspect it may be related to how ZMQ sets up a PUB socket on Windows. ZMQ sets up PUB/SUB socket pairs differently than REQ/REP pairs. That may account for why using "localhost" works for one and not the other. Thanks for reporting this. I will leave this issue open for a while to see if it sparks any comment from others. You may also want to read some of the comments on issue #20.

sfrmattos commented 4 years ago

great! Thank you @jeffbass. Next week I'll try to debug and figure it out where exactly this error occurs and report back,.