This code is intended to provide the absolute bare minimum you need to get started with a database-backed Go project. With this code you can write and run unit tests that hit a real Postgres database (see main_test.go), with a development loop that is less than 1s long.
It also allows you to cleanly define migrations in a migrations/ folder so that you can document your database schema changes over time.
To get started, you can simply add tests to the main_test.go file, modify the schema by editing the files in the migrations/ folder, or take a look at the docker-compose.yml to understand how the go binary talks to the database. You can also check out the Dockerfile to see how the go_test service is set up (and note how it's super fast because it doesn't copy any data into the image).
$ docker-compose run --rm go_test
Make sure your $GOPATH is set. This will spin up a test postgres service called "postgres_test" defined in docker-compose.yml and a "go_test" service, also defined there, which will run all of your tests that require database access.
Before running the tests, it reads environment variables from test.env, which contains the database config parameters.
It then connects to the database and applies the migrations specified in the migrations/ folder (it uses golang-migrate to apply the migrations with an "up" suffix from that folder).
After the test is complete, it undoes the migrations by applying the "down"-suffixed files in the migrations/ folder.
$ docker-compose down
This step is optional since the --rm parameter above will automatically remove the go_test service once it finishes running the tests.
However, there is a bug with --rm, which causes it to leave dependent services running even after the main service is complete. This means that your "postgres_test" service will stay up until you run this command. See this issue for details on that. Were it not for this issue, you wouldn't need to run this command.