How to Dockerize a Go API with a Database

Create a Dockerfile to build the Go binary and a docker-compose.yml to orchestrate the API and database containers.

FROM golang:1.23-alpine AS builder
WORKDIR /app
COPY . .
RUN go build -o main .

FROM alpine:latest
WORKDIR /app
COPY --from=builder /app/main .
EXPOSE 8080
CMD ["./main"]

version: '3.8'
services:
  api:
    build: .
    ports:
      - "8080:8080"
    depends_on:
      - db
    environment:
      - DATABASE_URL=postgres://user:pass@db:5432/mydb
  db:
    image: postgres:16
    environment:
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=pass
      - POSTGRES_DB=mydb

Run docker-compose up --build to start both services.

Dockerizing a Go API with a Database packages your Go code into a lightweight container and connects it to a database container. It ensures your application runs the same way on any machine without needing to install Go or PostgreSQL manually. Think of it as shipping your app and its database in two sealed boxes that automatically talk to each other when you start them.