Add speech api streaming sample.

[jerjou]

/cc @jonparrott @waprin

[jerjou]

Oh wait I should write a test shouldn't I...

[jerjou]

Okay, added tests.
However, the sample doesn't seem to work in python3 (it segfaults). After digging around a bunch, I think the problem is in the generated grpc lib. I skipped the test for python 3 for now..

PTAL

[theacodes]

This could cause some weirdness with clashing dependency versions. I'm okay with this for now, but we should be careful.

[jerjou]

Yeah - I think we should move to a world where, instead of having a global requirements-py[23].txt at the top level, each sample module would have its own smaller requirements.txt, and the global one would be either empty, or only include the stuff needed for pytest.

[jerjou]

Oh I see what you mean - the virtualenvs are split by session, not by subdir.
Hrm... that's a puzzle... perhaps we could have a separate virtualenv for each subdir that contains a requirements.txt?

Pros:

• Also tests that requirements.txt are valid

Cons:

• Adds overhead to testing

The con might be mitigated if we could run the tests in parallel..

[theacodes]

I tried that originally, and it's dreadfully slow. :/

[theacodes]

Finished first review pass. In general, I like this but I'm unsure about the control flow. It seems weird to me, but most threaded things are. hmm..

[jerjou]

Updated.

Re: control flow - yeah, I had an iteration where I made the request stream a class that was an iterator, with a stop method. It's probably the Right Way to do it, but it looked uglier / harder to explain, because then I had to deal with the record_audio context around the iteration.. so I figured this was better just because it's easier to see what's going on, even if the control flow is a bit icky.

(something like:

class RequestStream:
    def __init__(self):
        self.stop_audio = threading.Event()
        self.audio_stream = record_audio(..)
        self.is_first_request = True
    def __iter__(self):
        self.audio_stream.__enter__()
    def __next__(self):
        if self.is_first_request:
            self.is_first_request = False
            # ... do the special thing
        else if not self.stop_audio.is_set():
            # do the normal thing
        else:
            self.audio_stream.__exit__()
            raise StopIteration()

Just seemed like a lot of different pieces were interleaved.
I dunno - open to suggestions.

Travis is having trouble pulling down grpcio... will look into that.

[theacodes]

Please rebase, but otherwise I suppose this LGTM. I would appreciate some more time put into the control flow. Perhaps we can chat about it in person next week?

[jerjou]

Rebased.

What do you have in mind for the control flow? At this point it's not a matter of time so much as lack of better ideas.

[theacodes]

What do you have in mind for the control flow? At this point it's not a matter of time so much as lack of better ideas.

Not sure, I'd have to more deeply understand a few things. Much better to discuss in person. Feel free to merge.