Park API - Using PostgreSQL instead of SQLite

Server side Swift with Hummingbird

In the previous part of the article we built our first API server based on Swift using Hummingbird framework. That time we stored our data in SQLite database, which is perfect for rapid prototyping but for production we need something more robust.

Feather Database Component allows us to use PostgreSQL database as well. We need to make small modifications on our code.

Step 1. - Run PostgreSQL database as container

I prefer to use containers if I know that the development and the production environment most probably are different.

I have created this simple docker-compose.yml :

version: '3.7'

services:
  database:
    image: postgres:15-alpine
    restart: always
    env_file:
      - .env/development/database
    ports:
      - 5432:5432
    volumes:
      - db_data:/var/lib/postgresql/data
volumes:
  db_data:

The POSTGRES_USER, POSTGRES_PASSWORD, and POSTGRES_DB environment variables are moved to a separate file under .env/development folder.

The database file:

POSTGRES_USER = hummingbird
POSTGRES_PASSWORD = hummingbird_password
POSTGRES_DB = hb-parks

Run start the container:

docker-compose up

Step 2. - Add PostgreSQL database dependency to your Package.swift file

We need to replace the SQLite component: .product(name: "HummingbirdSQLiteDatabase", package: "hummingbird-db") to PostgreSQL.

 // Database dependencies
                .product(name: "HummingbirdDatabase", package: "hummingbird-db"),
                .product(name: "HummingbirdPostgresDatabase", package: "hummingbird-db"),

Step 3. - Configure PostgreSQL database in the DatabaseSetup.swift file

Creating and connecting to a PostgreSQL database needs more configuration than SQLite. So these changes need to be applied:

import Hummingbird
import HummingbirdPostgresDatabase

extension HBApplication {
    func setupDatabase() async throws {
        services.setUpPostgresDatabase(
            configuration: .init(
                host: "localhost",
                port: 5432,
                username: "hummingbird",
                password: "hummingbird_password",
                database: "hb-parks",
                tls: .disable
            ),
            eventLoopGroup: eventLoopGroup,
            logger: logger
        )

        try await db.execute(
            .init(unsafeSQL:
                                   """
                                   CREATE TABLE IF NOT EXISTS parks (
                                       "id" uuid PRIMARY KEY,
                                       "latitude" double precision NOT NULL,
                                       "longitude" double precision NOT NULL,
                                       "name" text NOT NULL
                                   );
                                   """
                 )
        )
    }
}

Obviously the .env/development/database file variables and setUpPostgresDatabase init values must be identical.

PostgreSQL database uses double precision instead of double as data type.

Step 4. - That's all. You can run your server.

Once the PostgreSQL database is running in a container and you start you server as:

swift run parkAPI

you are able to connect.

Tools - you can use to make your development process easier

Working with databases is not always easy, specially if you don't have client to test.

• For basic CRUD operations I use RaidAPI for Mac
• For checking SQLite database - Base 2
• For checking PostgreSQL - TablePlus