Retry logic for running pub [get, etc]

[sethladd]

Looking at the logs, I see SSL errors as a reason for build failures. Check out:

Handshake error in client (OS Error: SSL peer reports incorrect Message Authentication Code., errno = -12272)

in http://www.dartdocs.org/buildlogs/b-ae6665f19488c940fa2c1f1f024e5-startupscript.log

and SSL received a record with an incorrect Message Authentication Code. error -12273 in http://www.dartdocs.org/buildlogs/b-5f914e95e441991c8315e4992b9d8-startupscript.log

I wonder if we can retry the pub cache or pub get logic in buildDocumentationCacheSync ?

Basically, how do we handle transient issues?

[adam-singer]

could try using the retry_wrapper in the https://github.com/financeCoding/dart-carte-du-jour/blob/master/lib/multi_package_startup_script.mustache boot script for pub. I'm not aware of exit codes on that error on pub. If it sets the exit code correctly then should be easy enough to replace https://github.com/financeCoding/dart-carte-du-jour/blob/master/lib/multi_package_startup_script.mustache#L80 with retry logic with the pub install