Expose the maximum retry count for Seismic Store requests.

Expose the maximum retry count for Seismic Store requests.

This determines how long to wait before giving up on a transient error in the back-end. There is an exponential back-off between the first 7 or so requests an a fixed (currently 32 seconds) waiting time between subsequent retries.

The limit default to 10. It can be set in the IOContext or as an environment variable OPENZGY_SD_BACKOFF.

There are situations where Seismic Store cannot reliably report whether a problem is transient or not. This is where the setting is most useful, to avoid waiting several minutes before a human-readable error message can be displayed by the application.

Obviously the limit should not be set so low that actual transient errors cause the application to error out. So the optimal setting depends both on how well the application is connected to the server and whether the application is interactive or not.