Configuring retries

[jennybc]

So far, I haven't exposed many of the dials and knobs re: retries. In particular, I'm thinking of the minimum and maximum backoff.

Further down the road, there's the question of specifying different actions based on the response (error, really). I.e. we wouldn't want to remain so narrowly focused on the current 429 quota exhaustion problem.

[jennybc]

I see that @MarkEdmondson1234 has also done some analysis of this and retries on a larger set of codes (all 500s, 429, 408).

https://github.com/MarkEdmondson1234/googleAuthR/blob/73221f3cf5a561cbb17fe04943ce85e2130204ff/R/generator.R#L297

MarkEdmondson1234/googleAuthR#199

Retries on 408, 429, 500, 502, 503:

googleapis/nodejs-storage#833

https://github.com/googleapis/nodejs-common/blob/56764dc58634d151f27b67869d38a7ef97708b6c/src/util.ts#L513-L515

[jennybc]

httr2 is going to offer much more retry support than httr, so that definitely changes the shape of what might happen in gargle. I will leave this open, but I'm not going to implement any changes in the near-term. Ideally, the next time I really work on retries, I am also switching over to httr2.

https://httr2.r-lib.org/reference/req_retry.html

[jennybc]

I'm going to collect relevant errors I see here, just to have more data re: which retryable codes come up, what the error messages are, etc.

From googlesheets4 CI (test coverage):

Error: Error: Server error: (500) INTERNAL
* Internal server error. Typically a server bug.
* Internal error encountered.

[jennybc]

Went ahead and expanded the set of codes. This will still change whenever we switch to httr2, but it will be nice to accumulate some experience with expanded retries in the meantime.