chore: make psycopg2 optional

[jenhagg]

Purpose

Simplify local installation by removing psycopg2 from requirements.txt and separate the code that depends on it, to prevent import errors if psycopg2 is not installed.

What the code is doing

• Move psycopg2 to optional requirements
• Nothing is done with Pipfile, so tox will still run the associated sql tests. Anyone who needs to run those tests but isn't using pipenv will need to also install the optional requirements (or just pip install psycopg2).
• Remove psycopg2 from setup.py - this will cause dependent packages not to install it as well, so we could regenerate the Pipfile.lock in PostREISE and PreREISE.

Testing

tox

Time estimate

5 min

[jenhagg]

This is a funny artifact of the config.ini file I'm using with my other branch - it ends up overriding the DATA_ROOT_DIR with LOCAL_DIR, which is expected, but the trailing slash breaks a couple of tests here which use string concatenation to join paths for simplicity/readability. Real functionality uses os.path.join so this isn't a problem elsewhere.

[rouille]

You lost me. In your other branch, jon/windows I presume, you have a config.ini file where you set the path for the various variables, including DATA_ROOT_DIR. But for what reason it is overwritten by LOCAL_DIR?

[jenhagg]

The config.ini sets the deployment mode, which results in using a LocalConfig, where we default the DATA_ROOT_DIR to be equal to LOCAL_DIR since there is no need for separate locations. This caused a test failure since LOCAL_DIR has an extra / at the end. So this is just to make the tests work whether or not there is a config.ini causing this effect.

[rouille]

Looks good