Traefik can pass the subject and issuer in a 'cert-infos'
header, so I am adding an authentication backend to use that.

Non-priority production containers will use the master for
writes and a read-replica database for reads. This commit adds
functionality for getting the replica's information from
environment variables and sets up a database routing scheme.

Thomas Downes authored 6 years ago and Tanner Prestegard committed 6 years ago

ENABLE_SHIBD environment variable is set to "true" (default="false")

As shown here: emfollow/userguide!23

As requested here: emfollow/gwcelery!359

Have seen issues with "column 'filename' cannot be null" warnings
in the logs recently.  Found the issue in the events API, but
it's not obvious why this started now.  Possibly the upgrade to
Django 1.11.18?  Could have been a MariaDB upgrade too, but haven't
checked the logs to see if that happened.

Have to use 'get_or_create()' for Tag creation in unit tests.
Previously any tags that were created by data migrations were
always wiped after the initial migrations ran to set up the test
database due to the fact that we use MyISAM.  Now initial data
seems to be cleared only after the first test class runs.  So if
you run the full set of unit tests, it works fine, but if you only
run a class which includes creating a "real" Tag which is part
of the data migrations, it fails since the Tag is already in the
database.

I don't know when this changed - I tried using a previous tag of
the code (2.2.0) and the last version of Django that we used
(1.11.16), but no luck.  Really the solution should be to go away
from MyISAM or even MySQL altogether, but that will have to come
at a later date.

Lots of failovers seemed to be leaving lots of open connections
to the LVAlert server, so it seems that the connection wasn't being
closed properly. Looks like abort() is the method that should
be called instead of disconnect().

Have to use mock to properly modify throttles for unit testing
since 'override_settings' doesn't really work with the API
settings used by rest_framework.

The settings for gracedb-playground are no longer on a separate
branch and are just included in master. They can be selected
simply by settings the DJANGO_SETTINGS_MODULE environment variable
appropriately.  This should be much easier to maintain than a
completely separate branch.

All throttles now use a database-backed cache since that is the
only way to do centralized throttling (important for production
deployment with multiple workers). We also add default throttles
for anonymous users for the entire API.

Various javascript functionalities and forms in the web interface
make calls to the API to get or process data. The current
Apache configuration (verify a certificate IF presented on /api/*)
causes pop-ups for users who have certificates in their browsers
if they visit any pages which have these functionalities. So we have
changed all of those URLs to use /apiweb/ for now to prevent the
certificate challenge.  This will be resolved in the future by
getting away from certificate-based authentication.

Previously if an Event did not have a Search, no 'search'
key was included in the serialized event dictionary. Now we include
one and set it to None if the Event has no Search.

Not sure why this started happening all of a sudden since we have
been using 2.5.2 for quite a while.  But trying to pip install
python-ldap when building a Docker image keeps giving a
UnicodeDecodeError. Updating to version 3.1.0 seems to resolve it.

The format (which is staying the same) is like 'ID-N-TYPE', but for
retractions, TYPE was like "TYPE-OF-PREVIOUS-VOEVENT"-Retraction
(ex: Update-Retraction).  Now we just use TYPE=Retraction.