Implemented automatic caching for the discovery documents.

[tmatsuo]

Added 2 keyword arguments; cache_discovery and cache. You can suppress caching by setting cache_discovery=False. You can inject your own caching module via the cache kwarg.

It automatically uses app engine memcache if it's detected. It's not a hard dependency. Then fall back to file based caching.

fixes#110

[tmatsuo]

@nathanielmanistaatgoogle I'd appreciate it if you could take a look.

[tmatsuo]

@dhermes FYI

[dhermes]

Wow. So happy this is coming (3 years later)!

/cc @wescpy This is what we talked about at SFPython

[nathanielmanistaatgoogle]

Please squash commits.

[tmatsuo]

Thanks for the comment @nathanielmanistaatgoogle

All addressed, PTAL

[tmatsuo]

Let me write some tests. I'll update here once done.

[tmatsuo]

I added some tests in test_discovery. PTAL

[nathanielmanistaatgoogle]

@dhermes are you also reviewing this or just excited about it happening?

[dhermes]

I am not reviewing.

[tmatsuo]

@nathanielmanistaatgoogle
I addressed your comments. PTAL

[nathanielmanistaatgoogle]

Looks good. Are there more unit tests still to come or is this what you'd like to have merged?

[tmatsuo]

@nathanielmanistaatgoogle Thanks!
I would like to add some unit tests for the cache module. I will likely write those early next week.

[nathanielmanistaatgoogle]

Great; I'll hold steady until I hear more from you.

[tmatsuo]

I have just added a unit test for the file cache, which discovered several bugs in my code!

@nathanielmanistaatgoogle Now I'm confident to say "let's merge this". PTAL

[nathanielmanistaatgoogle]

Thanks for the contribution!

[tmatsuo]

Thanks for the review! I'm wondering when it goes to pypi distribution so that everyone can benefit from it.

[nathanielmanistaatgoogle]

Likely not this week; we're swamped with other things. Perhaps toward the end of next week? Would that be acceptable? Otherwise "sometime in September"?

[tmatsuo]

Yeah, sounds good, thanks

[tmatsuo]

Ok, will you be able to do the release this week? If you still have other things, maybe I can do the release, especially if there's how-to doc. Let me know if you want me to do.

[tmatsuo]

To clarify, I have uploaded a small library to pypi before, so I know the basic. My username on pypi is tmatsuo, so maybe you can add me to the owners list of this package on pypi so that I can do the release?

My current guess for how to release is that:

1. Create a release on github
2. upload the package to testpypi first and do the sanity check
3. upload it to pypi

[tmatsuo]

JFYI it's released.
https://pypi.python.org/pypi/google-api-python-client/1.4.2

[tmatsuo]

@dhermes I haven't seen any issues with the new release for a week, so I removed your original article about cache on App Engine. Thanks!

[dhermes]

You could have just marked it deprecated. Now I have one less imprint on Google Developers 😞

[tmatsuo]

Yeah, in that sense, I initially tried to mark it as deprecated, but tech writers don't like it. You're doing a greater work on gcloud-python, so I thought you're ok, but let me know if you want it back strongly.

[dhermes]

Ha no worries Takashi! I was just giving you a hard time. Thanks!