* ZK retries have been cleaned up. We will now retry after every error
EXCEPT when we have a badly formed path.
* ZK library has been reworked with optional arguments pattern to not be
so intertwined with the cluster.json file.
* Timeout error has been re-implemented as RetryError. RetryError
behaves like a Timeout error but is used exclusively to add more context
privately. This allows us to have unit tests that check our retry
mechanism is actually retrying.
* Additional logging has been added to retry mechanisms as well as to
the Zookeeper library we use.
* Deleting permament error as it doesn't make sense. Just return a plain old error and that will be considered permanent.
* Removing double closure at as it's unmaintainable and can be error prone. Separated back offs into a generic one and a thrift call specific one.
* ZK leader finder now returns a temporary error instead of constantly no leader found and quitting. It could be that the leader info is being propagated so it's worth trying another time.
* Adding more logging to the retry.
* Wrapping lock and unlock in an anonymous function so that we can use defer on unlock such that it is called in the case of a panic.
* fixed semantics. Earlier mentioned that 'Pystachio does yet support...'. Changed now to mention 'Pystachio does not yet support...'
* fixed grammatical mistake.
* Ran gofmt on project.
* Code cleanup: Deleted multiple functions which have become stale. Removed cluster example as we replaced the need to create the Cluster object.
* Cleaned up ZK connection code by using the backoff function. Added a test to the end to end to test that we're getting the host correctly from ZK. Changed clusters test to be an outside package.
* Added LeaderFromZKURL test to end to end tests.
* Added logger to realisConfig so that users can attach their own Loggers to the client. Logger is an interface that shadows most popular logging libraries. Only Print, Println, and Printf are needed to be a realis.Logger type. Example in the client uses the std library log.
* Moved most fmt.Print* calls to be redirected to user provided logger. Logger by default is a no-op logger.
* Adding CreateService to realis interface. Uses the StartJobUpdate API to create services instead of the createJobs API.
* Bumping up version number inside client in anticipation of new release.
Some tests included for making sure the JSON blob pulled from Zookeeper
is correct.
Updated client to be able to take Zookeeper json cluster config that is
currently being used in aurora (clusters.json usually located at
/etc/aurora/cluster.json).
Changed error messages to no longer have a period at the end as that was
throwing off printing of the error.
Modified samuel's ZK library slightly to stop verbose logging using a
NoOpLogger from stackoverflow.
