PostgreSQL driver, tests against DB backends, and general drivers cleanup (#2723)

* PostgreSQL driver and general drivers cleanup

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Make tests pass

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Add black --target-version flag in make.bat

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Rewrite postgres driver

Most of the logic is now in PL/pgSQL.

This completely avoids the use of Python f-strings to format identifiers into queries. Although an SQL-injection attack would have been impossible anyway (only the owner would have ever had the ability to do that), using PostgreSQL's format() is more reliable for unusual identifiers. Performance-wise, I'm not sure whether this is an improvement, but I highly doubt that it's worse.

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Reformat

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Fix PostgresDriver.delete_all_data()

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Clean up PL/pgSQL code

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* More PL/pgSQL cleanup

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* PL/pgSQL function optimisations

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Ensure compatibility with PostgreSQL 10 and below

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* More/better docstrings for PG functions

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Fix typo in docstring

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Return correct value on toggle()

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Use composite type for PG function parameters

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Fix JSON driver's Config.clear_all()

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Correct description for Mongo tox recipe

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Fix linting errors

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Update dep specification after merging bumpdeps

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Add towncrier entries

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Update from merge

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Mention [postgres] extra in install docs

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Support more connection options and use better defaults

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Actually pass PG env vars in tox

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

* Replace event trigger with manual DELETE queries

Signed-off-by: Toby Harradine <tobyharradine@gmail.com>

.travis.yml

@@ -5,14 +5,10 @@ notifications:
   email: false
 
 python:
-- 3.7.2
+- 3.7.3
 env:
   global:
     - PIPENV_IGNORE_VIRTUALENVS=1
-  matrix:
-    - TOXENV=py
-    - TOXENV=docs
-    - TOXENV=style
 
 install:
 - pip install --upgrade pip tox
@@ -22,6 +18,19 @@ script:
 
 jobs:
   include:
+    - env: TOXENV=py
+    - env: TOXENV=docs
+    - env: TOXENV=style
+    - env: TOXENV=postgres
+      services: postgresql
+      addons:
+        postgresql: "10"
+      before_script:
+        - psql -c 'create database red_db;' -U postgres
+    - env: TOXENV=mongo
+      services: mongodb
+      before_script:
+        - mongo red_db --eval 'db.createUser({user:"red",pwd:"red",roles:["readWrite"]});'
     # These jobs only occur on tag creation if the prior ones succeed
     - stage: PyPi Deployment
       if: tag IS present