nestjs-drizzle

A basic NestJS setup using drizzle and PostgreSQL with migrations included.

Getting started

1. Run pnpm install (or use whatever your preferred package manager today is)
2. Copy .env.example to .env, no changes needed if you run the database via the included docker-compose file
3. Run docker-compose up -d to start the database in the background
4. Run pnpm start:dev to start the server in dev mode
5. Use the included Insomnia workspace to try out the API (GET /messages and POST /messages)

How it works

This setup is purely a NestJS-style wrapper around drizzle.

Inside of the DatabaseService the getDB() function sets up the database connection using the Postgres.js client and passes it to drizzle. It's also possible to use other clients or databases, see the drizzle docs for what's supported.

In order to be able to easily get access to your database you can use the @InjectDatabase() decorator to inject the database into your services. The DatabaseModule is global which means you can simply use the decorator everywhere we you can inject dependencies without worrying about module/service imports. As the return type of the decorator you can either use PostgresJsDatabase or PostgresJsDatabase<typeof schema>. The latter allows you to use the Relational queries extension of drizzle with your typed schema, see the docs for more on that.

Migrations will be run on startup before the Nest app starts. Depending on your setup you can also remove the logic from the main.ts and run migrations within your CI/CD pipeline using drizzle-kit for example.

Migrations

Migrations are stored in database/migrations. They are run automatically on startup before the Nest app starts.

You can generate a new migration using pnpm run db:generate which will use drizzle-kit under the hood.

If you're still developing and sync your schema to your local database you can use pnpm run db:push to sync your schema without involving migrations.

Pitfalls

In case you're just copy pasting some parts of the code here, there are a few things that need to be considered.

Error: TypeError: (0 , postgres_1.default) is not a function

Set esModuleInterop to true in your tsconfig.json, see docs.

Can't find the meta/_journal.json file

By default the src/ directory is the main folder from where the project is being built. This means the dist/ and src/ folders should have the same structure. Because we add the drizzle.config.ts config to our root it now may shifts the src/ folder to dist/src/ when building the project as it considers the drizzle.config.ts file as part of the source code. Basically instead of dist/database/migrations/... you now end up with dist/src/database/migrations/....

This can be fixed by adding the drizzle.config.ts to the exclude array of your tsconfig which is being used for building, usually tsconfig.build.json.

The database/migrations folder is not showing up in the dist output

By default NestJs only copies all files which have been compiled and ignores all other files. Because the migrations are stored as *.sql and drizzle metadata as *.json files they won't be copied to the dist/ folder.

This can be fixed by adding the path for the migrations folder as an asset to the nest-cli.json file. Assets are just non-code files that should be copied to the dist/ folder, more here.

By adding the following to the nest-cli.json all migration related files will be copied and also trigger a reload on changes if you're using the dev server:

{
  // other stuff...
  "compilerOptions": {
    "assets": [
      {
        "include": "**/database/migrations/**/*.{json,sql}",
        "watchAssets": true
      }
    ]
  }
}