Dramatiq

This is a big one!


Added

* Barriers.

Changed

* `cli.main` now takes an optional argument namespace so that users
may define their own entrypoints. ([140], [maerteijn])
* Actor "message received" and "completed in x ms" log messages are
now logged with the `DEBUG` level instead of `INFO` level. This
improves throughput and makes logging much less verbose.
* The `TimeLimit` middleware no longer uses signals to trigger time
limit handling. Instead it uses a background thread per worker
process.
* Dramatiq now shuts itself down if any of the workers die
unexpectedly (for example, if one of them is killed by the OOM
killer).
* Windows is now supported (with some caveats)! ([119], [ryansm1])

Fixed

* Allow `pipe_ignore` option to be set at the actor level. ([100])
* Result encoder now defaults to the global encoder. ([108], [xdmiodz])
* Dot characters are now allowed in queue names. ([111])
* Tests are now run on Windows. ([113], [ryansm1])

[100]: https://github.com/Bogdanp/dramatiq/issues/100
[108]: https://github.com/Bogdanp/dramatiq/issues/108
[111]: https://github.com/Bogdanp/dramatiq/issues/111
[113]: https://github.com/Bogdanp/dramatiq/issues/113
[119]: https://github.com/Bogdanp/dramatiq/issues/119
[140]: https://github.com/Bogdanp/dramatiq/issues/140
[maerteijn]: https://github.com/maerteijn
[ryansm1]: https://github.com/ryansm1
[xdmiodz]: https://github.com/xdmiodz

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