Baseplate

Backport of tracing changes:

* The debug flag is now passed into the span data sent to the trace aggregator.
* Trace observer log entries are now WARNING instead of ERROR level.

This backports a fix for a Python 3 compressed memcached serialization.

This fixes Python 2.7 compatibility for the GC reference cycle fix in v0.30.2.

This release backports fixes for some reference cycles in the core framework. The changes should reduce garbage collector pressure in your application.

**Use v0.30.3 instead if you're on Python 2.7**

This is a bugfix release with two changes:

* Properly do a graceful shutdown when the infrastructure informs us we are about to be shut down. If requests finish up fast enough, they won't be cut off in flight.
* Limit the size of the internal queue in the Kombu QueueConsumer. Previously, if the remote queue had a lot of messages this internal queue would fill up without bound and potentially consume excessive memory.

Target version: v1.0 (1.0 series)

✓ Updated baseplate to 1.0 in requirements.txt
✓ Updated cassandra-driver to 3.18.0 in requirements.txt
✓ Updated requests to 2.22.0 in requirements.txt
✓ Refactored ./setup.py
✓ Refactored ./tests/cache_tests.py
✓ Refactored ./thing/__init__.py
✓ Refactored ./thing/cache.py
! Line 16 of ./thing/cassandra_context.py: 'baseplate._compat' does not exist
anymore. Remove references to it.
✓ Refactored ./thing/cassandra_context.py
! Line 23 of ./thing/memcache_lib.py: 'baseplate._compat' does not exist
anymore. Remove references to it.
! Line 23 of ./thing/memcache_lib.py: 'baseplate._compat' does not exist
anymore. Remove references to it.
✓ Refactored ./thing/memcache_lib.py

Automatic upgrade successful!
There's more to do:
• Review the logs above.
• Review the diff in your application.
• Apply code formatters to clean up refactored code.
• Thoroughly test your application.
• Commit the changes.


The tool may warn you about some things that you will have to manually update. Once you've done all the changes and tested your service, you should be good to go!

Note that this only upgrades breaking changes. If you want to fully take advantage of Baseplate 1.0, check out the `configure_context` and `configure_observers` functions to simplify your application's wireup.