article-rec-db 0.0.1

Database models and imgrations for the Local News Lab's article recommendation system

This branch houses the effort to move our DB code to a SQLAlchemy-based stack and is under active development in parallel with the move to Google Analytics 4. For the current production code, see the main branch.

article-rec-db

Database models and migrations for the Local News Lab's article recommendation system.

Usage

A note before continuing: A lot of the commands you'll see below are wrapped inside Poe tasks defined in pyproject.toml. Poe is installed as a dev-dependency; run poe --help to get a list of tasks and their descriptions. It's entirely possible to run commands without using Poe, but if you decide to use Poe, make sure to read through the tasks to understand what they do.

As a package

We use SQLModel, a layer on top of SQLAlchemy with Pydantic, to define our tables. This is useful because we can import this package to interact with the tables AND have Pydantic objects in Python that correspond to a row in the table.

To install the package from PyPi, run: pip install article-rec-db. Check existing versions here.

Initialize a new cluster

If you want to initialize a fresh database cluster, pass in the env vars to connect to the cluster and run init_db. If the target cluster has IP restrictions, make sure your IP address is a valid access point.

An example run with fake credentials (from the root dir of this project with the virtual env activated): HOST=fakehost USER=fakeuser PASSWORD=fakepw DB_NAME=postgres python db_init_steps/_0_init_db.py

(If you run into a ModuleNotFoundError, try including PYTHONPATH=$(pwd) before the python command. This applies to any other commands that uses python.)

This should run the most up-to-date SQLModel definitions of the tables, which means you are safe to then run any additional changes in role, access, and policy changes. So you can run the rest of the steps in db_init_steps, one after the other in ascending numerical order.

No PORT is passed because the default port is 5432, the standard for Postgres.

Migrations

So you made some changes to what tables there are, what columns there are, indices, etc. and you'd like to update the databases. This is what alembic is for!

To generate a new revision after you've updated the models:

1. Run this from the root of the project: DB_CONNECTION_STRING='postgresql://user:password@host:port/db_name' alembic revision --autogenerate -m "message". (There's a Poe task for this: run poe rmtdiff -d db_name -m "message")
2. Check the /alembic/versions/ directory for the new revision and verify that it does what you want it to
3. Run this from the root of the project: DB_CONNECTION_STRING='postgresql://user:password@host:port/db_name' alembic upgrade head
4. Note that you only need to generate the revision file (step 1) once because we want the same content in each environment's database, but you do need to run the upgrade head command once for each database (change the DB_NAME to the desired target). (There's a Poe task for this: run poe rmtupgrade -d db_name)

If you decide to do Step 1 or 4 with Poe, make sure to include the DB_CREDENTIALS_SSM_PARAM env var set to the name of the AWS SSM parameter that stores the credentials for the database, either inline or in a top-level .env file. Make sure the AWS CLI and jq command-line package are installed.

To make new users, grant privileges, etc., follow the patterns used in db_init_stages along with the helpers under article_rec_db.

1. Create a new file under db*init_stages that does what you want and is prefixed with \_X*, where X is the next number (it has no function, it's just nice to keep track of the step order).
2. Run the file. You can run it like so: HOST=fakehost USER=fakeuser PASSWORD=fakepw DB_NAME=postgres python article_rec_db/db_init_stages/_X_fake_file.py
3. I'd recommend that you then connect to the cluster and verify your changes took place.

Note that you must provide valid host, user, password, and database name environment variables for it to work. The PORT env var has a default value of 5432, so it is omitted here. The only other env var you might need (if you are creating new roles/users that have credentials) is the ENABLE_SSM env var. By default it is FALSE but if you set it to TRUE then it will make sure to upload any new credentials to the SSM parameter store.

Development

This project uses Poetry to manage dependencies. It also helps with pinning dependency and python versions. We also use pre-commit with hooks for isort, black, and flake8 for consistent code style and readability. Note that this means code that doesn't meet the rules will fail to commit until it is fixed.

We use mypy for static type checking. This can be run manually, and the CI runs it on PRs to the main branch. We also use pytest to run our tests. This can be run manually and the CI runs it on PRs to the main branch.

Setup

1. Install Poetry.
2. Run poetry install --no-root
3. Run source $(poetry env list --full-path)/bin/activate && pre-commit install && deactivate to set up pre-commit

You're all set up! Your local environment should include all dependencies, including dev dependencies like black. This is done with Poetry via the poetry.lock file.

Run Code Format and Linting

To manually run isort, black, and flake8 all in one go, simply run poe format or pre-commit run --all-files. Explore the pre-commit docs (linked above) to see more options.

Run Static Type Checking

To manually run mypy, simply run mypy from the root directory of the project. It will use the default configuration specified in pyproject.toml.

Update Dependencies

To update dependencies in your local environment, make changes to the pyproject.toml file then run poetry update from the root directory of the project.

Run Tests

To manually run rests, you need to have a Postgres instance running locally on port 5432. One way to do this is to run a Docker container, then run the tests while it is active.

1. (If you don't already have the image locally) Run docker pull postgres
2. Run docker run --rm --name postgres -e POSTGRES_PASSWORD=postgres -e POSTGRES_HOST_AUTH_METHOD=trust -p 127.0.0.1:5432:5432/tcp postgres
3. Run DB_NAME=postgres pytest tests from the root directory of the project. Explore the pytest docs (linked above) to see more options.

Steps 2 and 3 can be combined into one Poe task: poe test, which also stops the container after the tests are done, even if tests fail. In addition, you can also run poe lclstart to just start the container, and poe lclstop to stop it whenever you're done. poe lclconnect will connect you to the container via psql so you can poke around.

Note that if you decide to run the Postgres container with different credentials (a different password, port, etc.) or via a different method, you will likely need to update the test file to point to the correct Postgres instance.

Additionally, if you want to re-run the tests, you want to make sure you start over from a fresh Postgres instance. If you run Postgres via Docker, you can simply ctrl-C to stop the image and start a new one.