Separate head and pop (allow peeking)

[akiross]

Hello,
I am using janus, very happily, to mix async and threaded code, and it works great.

I have just a little suggestion about the API: I think you should provide a head() or peek() method, that allows to get the first element in the queue without removing it. Although this is not really necessary (also, you provide a PriorityQueue), I think it's a great addition which could make user code easier.

The current get() method could be implemented using head() + removal, so code should stay reasonably similar to the current.

This would allow to take decisions earlier, without messing with queue order.

[asvetlov]

It's not very helpful because of concurrent nature: a value returned by peek() could be different from the value from subsequent get() call if the queue has multiple consumers.

Standard queue.Queue and asyncio.Queue have no peek() methods exactly for the same reason.

[akiross]

You're right! But it's helpful when there is a single consumer :) In my use case, I have multiple producing threads and a single (async) consumer. But I get your point, I'm still happy with janus even if you won't include it.

[asvetlov]

Unfortunately not -- I'd like to keep janus API in sync with queues from stdlib.