Dockerize a Platformatic App

This guide explains how to create a new Platformatic DB app, which connects to a PostgreSQL database.

We will then create a docker-compose.yml file that will run both services in separate containers

Generate a Platformatic DB App

Run this command in your terminal to start the Platformatic creator wizard:

npm

npm create platformatic@latest

yarn

yarn create platformatic

pnpm

pnpm create platformatic@latest

This interactive command-line tool will ask you some questions about how you'd like to set up your new Platformatic project. For this guide, select these options:

- What kind of project do you want to create?   => Application
- Where would you like to create your project?  => quick-start
- Which kind of project do you want to create?  => DB
- What is the name of the service?              => (generated-randomly), e.g. legal-soup
- What is the connection string?                => sqlite://./db.sqlite
- Do you want to create default migrations?     => Yes
- Do you want to create another service?        => No
- Do you want to use TypeScript?                => No
- What port do you want to use?                 => 3042
- Do you want to init the git repository?       => No

Once the wizard is complete, you'll have a Platformatic app project in the folder quick-start, with example migration files, plugin script, routes, and tests inside your service directory under services/

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Make sure you run the npm/yarn/pnpm command install command manually if you don't ask the wizard to do it for you.

Create Docker image for the Platformatic DB App

In this step you are going to create some files into the root project directory

• .dockerignore - This file tells Docker to ignore some files when copying the directory into the image filesystem

node_modules
.env*

• start.sh - This is our entrypoint. We will run migrations then start platformatic

#!/bin/sh

echo "Running migrations..." && \
npx platformatic db migrations apply && \
echo "Starting Platformatic App..." && \
npm start

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Make sure you make this file executable with the command chmod +x start.sh

• Dockerfile - This is the file Docker uses to create the image

FROM node:18-alpine
WORKDIR /usr/src/app
COPY . .
RUN npm install
COPY . .
EXPOSE 3042
CMD [ "./start.sh" ]

At this point you can build your Docker image with the command

$ docker build -t platformatic-app .

Create Docker Compose config file

docker-compose.yml is the configuration file for docker-compose which will spin up containers for both PostgresSQL and our Platformatic App

version: "3.3"
services:
  postgresql:
    ports:
      - "5433:5432"
    image: "postgres:15-alpine"
    environment:
      - POSTGRES_PASSWORD=postgres
  platformatic:
    ports:
      - "3042:3042"
    image: 'platformatic-app:latest'
    depends_on:
      - postgresql
    links:
      - postgresql
    environment:
      PLT_SERVER_HOSTNAME: ${PLT_SERVER_HOSTNAME}
      PORT: ${PORT}
      PLT_SERVER_LOGGER_LEVEL: ${PLT_SERVER_LOGGER_LEVEL}
      DATABASE_URL: postgres://postgres:postgres@postgresql:5432/postgres

A couple of things to notice:

• The Platformatic app is started only once the database container is up and running (depends_on).
• The Platformatic app is linked with postgresql service. Meaning that inside its container ping postgresql will be resolved with the internal ip of the database container.
• The environment is taken directly from the .env file created by the wizard

You can now run your containers with

$ docker-compose up # (-d if you want to send them in the background)

Everything should start smoothly, and you can access your app pointing your browser to http://0.0.0.0:3042

To stop the app you can either press CTRL-C if you are running them in the foreground, or, if you used the -d flag, run

$ docker-compose down