Code review comment for lp:~wallyworld/juju-core/provisioner-retry

Reviewers: mp+212768_code.launchpad.net,

Message:
Please take a look.

Description:
Provisioner retries failed machines

Introduce a new watcher - WatchMachineErrorRetry. This
watcher fires when the provisioner task should attempt
to re-provision any machines with transient errors. It
is done as a separate watcher to avoid changing the
semantics of the exisitng machine watcher close to
cutting a release, and to more easily allow the
flexibility of doing things like queuing retries
separately with different priorities etc. It's still
early days and the implemenation is still evolving
because the watcher currently just triggers every minute.
It's an internal implementation detail so can be changed
if required. Future work needs to make the watcher smarter
and able to interpret errors returned by the providers
in order to know when to retry.

https://code.launchpad.net/~wallyworld/juju-core/provisioner-retry/+merge/212768

Requires:
https://code.launchpad.net/~wallyworld/juju-core/machineswithtransienterrors-api/+merge/212749

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/80340043/

Affected files (+286, -26 lines):
   A [revision details]
   M state/api/provisioner/provisioner.go
   A state/apiserver/provisioner/machineerror.go
   M state/apiserver/provisioner/provisioner.go
   M state/apiserver/provisioner/provisioner_test.go
   M worker/provisioner/provisioner.go
   M worker/provisioner/provisioner_task.go
   M worker/provisioner/provisioner_test.go