make a "src/common/" directory (package?) to share between server and acquisition code

[melange396]

to promote modularity and reduce code repetition, we should create a "./src/common/" directory (and potentially package too). this will require some changes to our docker definitions and maybe also other parts of our build process.

the first file/module to include here could be our structured logger code... see: #1027 (comment)_

[krivard]

Alternative: pull logger.py out of delphi_utils & into its own package, and include that in all three places (indicators, acquisition, server)

[melange396]

following up, these two files are now essentially identical:
./src/acquisition/covidcast/logger.py
./src/server/utils/logger.py

[krivard]

& the third one:
covidcast-indicators/_delphi_utils_python/delphi_utils/logger.py

[melange396]

a big part of the problem is that the server code cant "see" the acqusisition code but the acq can see the server.

the root of this lies in two different docker setups:

• these files preserve the module structure for the delphi_web_python docker image: all of the code tree is visible and happy.
• this definition for the delphi_web_epidata image keeps only src/server/ code: the non-server code gets chopped out completely.

fixing the server docker image might (almost) be as simple as something like this...
change this line to something like:

  RUN mkdir -p /app/delphi/epidata
  COPY ./src/* /app/delphi/epidata/

or perhaps just:

  RUN mkdir -p /app/delphi/epidata
  COPY ./src/server /app/delphi/epidata/
  COPY ./src/common /app/delphi/epidata/

then use environment variables $MODULE_NAME + $VARIABLE_NAME (or just $APP_MODULE) to run delphi.epidata.server.main:app as described here. (those env variables would need to be added to our dev Makefile, the github ci.yaml, and probably somewhere in our scheduler/automation system).

a nice bonus is that i think this will also let us turn all of the relative local imports in the server code into fully qualified ones.

[melange396]

in addition to the logging module[s] mentioned above, the newly extracted CovidcastRow (see #1044) is another great first candidates to go in the common/ tree. after that, we could pull stuff from src/server/utils/* , and probbly some of src/server/endpoints/covidcast_utils/*

[melange396]

this will probably also need to include some changes to deploy.json, similar to those recently seen in #1097