This is a basic database-backed GraphQL server implementation to demonstrate the concepts.
You need to have a database running to run this app. Run the included script to start a database in a docker container:
$ ./db_create.sh
That creates a persistent PostgreSQL container with an exposed port,
credentials, and database name that match the values that the app expects as
configured in .env.
If you want the database to go away you will need to stop, and remove it:
$ docker stop graphql_server_demo_db
$ docker rm graphql_server_demo_db
Because the container is persistent, if it is stopped and not removed, or you reboot or something you can get the database back with intact data by starting it again.
$ docker start graphql_server_demo_db
The app will not compile until migrations are applied. To do that you need to
install sqlx-cli.
$ cargo install sqlx-cli
$ sqlx migrate run
Run with:
$ cargo run
Environment variables, such as the web app port and log levels, are read from
.env.
You can open https://localhost:8000/ in a web browser to load the interactive GraphQL playground. This lets you see the API schema, and run queries and mutations, and so forth.
You can send GraphQL API requests to the same address.
If you want to make changes to the database schema the proper way to do that is
to write a migration. First make sure that you have slqx-cli installed:
$ cargo install sqlx-cli
To create a migration run:
$ sqlx migrate add -r <name for your migration>
Add some create table or alter table or what-have-you SQL statements to the
generated migration file. The app will automatically apply the migration the
next time you start it.
If you see this error from the Rust compiler:
error: error communicating with database: Connection refused (os error 111)
That means that you don't have the database running. See the "Prerequisites - database" section above.
Sqlx provides some really nifty macros that query the database on-the-fly to type-check database queries in Rust code. But that means that you need to have a running database to build the program. It is possible to dump database metadata into a JSON file that the macro will read instead of connecting to the database. That would be convenient for someone checking out the project for the first time - but it also adds a required step of updating that JSON file whenever the database schema changes. See https://github.com/launchbadge/sqlx/blob/master/sqlx-cli/README.md#enable-building-in-offline-mode-with-query