How to use PostgreSQL in Docker with Docker Compose and Go

  • Go
  • Gabriele Romanato

In this article, we will explore how to configure PostgreSQL using Docker and Docker Compose and how to integrate it into a Go application. This approach is useful to simplify local development and application deployment.

Configuring Docker Compose

Let's create a docker-compose.yml file to configure PostgreSQL:

version: '3.8'
services:
  db:
    image: postgres:15
    container_name: postgres_container
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: mydb
    ports:
      - "5432:5432"
    volumes:
      - db_data:/var/lib/postgresql/data
volumes:
  db_data:

Starting PostgreSQL with Docker Compose

Run the following command to start the container:

docker compose up -d

Check that the container is running:

docker ps

Connecting to PostgreSQL in Go

Add the pq library to your Go project to connect to PostgreSQL:

go get github.com/lib/pq

Create a Go file, for example, main.go, with the following code:

package main

import (
  "database/sql"
  "fmt"
  _ "github.com/lib/pq"
)

func main() {
  connStr := "postgres://user:password@localhost:5432/mydb?sslmode=disable"
  db, err := sql.Open("postgres", connStr)
  if err != nil {
    panic(err)
  }
  defer db.Close()

  err = db.Ping()
  if err != nil {
    panic(err)
  }

  fmt.Println("Successfully connected to PostgreSQL!")
}

Testing the Application

Run the Go application to test the database connection:

go run main.go

If everything is configured correctly, you should see the message:

Successfully connected to PostgreSQL!

Conclusion

In this article, we configured PostgreSQL using Docker and Docker Compose, and we created a Go application to connect to the database. This workflow greatly simplifies database management in local development.

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