Expose maxRetries & totalTimeoutMillis to gapic layer

[stephenplusplus]

We'll need a way to honor maxRetries with requests made through the generated API. We will need to wrap each outbound call to implement our own exponential backoff retry strategy.

@callmehiphop will retryRequest work here, or will this require any extra work to be compatible with the promise API?

[callmehiphop]

I think all our gapic files still are using callback mode, so integrating with retryRequest then decorating the methods via promisify should work just fine.

We will probably need to rethink our strategy once gapic methods start returning promises, but I vote we cross that bridge once we get to it.

[stephenplusplus]

I think the bridge is pretty close, @jmuk promise support is landed in gax, right? We just need the Language & Speech APIs regenerated. Let me know if I'm mistaken!

[stephenplusplus]

Together with the gax team, we've decided to expose both maxRetries and totalTimeoutMillis to google-cloud users for 1.0.

[stephenplusplus]

@callmehiphop since this isn't blocking beta like I originally thought, it's not a big 🚨. But, if you have time soon, can you go over the methods that we would need to add an options argument to, just to be absolutely sure we won't have to break the API to support this configuration?

[callmehiphop]

@stephenplusplus are we only worried about APIs currently using GAPIC? I did a quick run through of those APIs and I didn't see any methods that didn't have some kind of options/config parameter.

[stephenplusplus]

I think we need to do all APIs that are gax-equipped now or later (basically, anything that is using gRPC). If we wait until we implement gax to realize we missed one, that would be a breaking change to add support.

[jmuk]

Found this through bug triage, I think this is done already. Am I right?