Retry Plugin should also retry responses with status 5xx

[dbu]

Q	A
Bug?	no
New Feature?	yes
Version	2

Actual Behavior

We only retry if there is an exception thrown.

Expected Behavior

We should also retry when a response arrives but the status is indicating a server error.

Possible Solutions

• a) Have an exception decider and a response decider (and same for delay)
• b) Expand the decider and delay functions to also pass them the response. This would be a hard BC break

[dbu]

i think i prefer a) to avoid the BC break. also, there will never be both exception and response and the retry plugin knows in which part it is.

i suggest keeping the names for the exception decider and delay and adding a response_decider and response_error_delay that have request and response as argument, and no exception.

[joelwurtz]

Prefer a) also

But would like to change the name and deprecate older ones for consistency

[dbu]

as we do version 2, i will change the name and hint with a comment in the code that the name changed (in addition to the changelog)