Dramatiq

Changed

* Upgraded prometheus_client to 0.2.x.
* Bumped pika to version 0.12. Because of this change, the ``interrupt`` method on `Broker` and its usages within `Worker` have been dropped.
* There is no longer a max message delay.

Fixed

* `Broker`s can now be passed an empty list of middleware. ([90])
* Potential stack overflow when restarting Consumer threads. ([89])

[90]: https://github.com/Bogdanp/dramatiq/issues/90
[89]: https://github.com/Bogdanp/dramatiq/issues/89

Added

* Support for worker heartbeats to `RedisBroker`.
* `maintenance_chance` and `heartbeat_timeout` parameters to
`RedisBroker`.
* `Interrupt` base class for thread-interrupting exceptions. ([rpkilby])
* `ShutdownNotifications` middleware. ([rpkilby])

Changed

* `TimeLimitExceeded` is now a subclass of `Interrupt`.

Fixed

* `StubBroker.join` and `Worker.join` are now more reliable.
* Module import path is now prepended to search path rather than
appended. This fixes an issue where importing modules with the same
name as modules from site-packages would end up importing the
modules from site-packages. ([88])
* `Prometheus` middleware no longer wipes the prometheus data
directory on startup. This fixes an issue with exporting
application metrics along with worker metrics.

[88]: https://github.com/Bogdanp/dramatiq/issues/88
[rpkilby]: https://github.com/rpkilby