How to run Sequelize migrations inside Docker - mysql

Question

I'm trying to docerize my NodeJS API together with a MySQL image. Before the initial run, I want to run Sequelize migrations and seeds to have the tables up and ready to be served.
Here's my docker-compose.yaml:
version: '3.8'
services:
mysqldb:
image: mysql
restart: unless-stopped
environment:
MYSQL_ROOT_USER: myuser
MYSQL_ROOT_PASSWORD: mypassword
MYSQL_DATABASE: mydb
ports:
- '3306:3306'
networks:
- app-connect
volumes:
- db-config:/etc/mysql
- db-data:/var/lib/mysql
- ./db/backup/files/:/data_backup/data
app:
build:
context: .
dockerfile: ./Dockerfile
image: node-mysql-app
depends_on:
- mysqldb
ports:
- '3030:3030'
networks:
- app-connect
stdin_open: true
tty: true
volumes:
db-config:
db-data:
networks:
app-connect:
driver: bridge
Here's my app's Dockerfile:
FROM node:lts-alpine
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3030
ENV PORT 3030
ENV NODE_ENV docker
RUN npm run db:migrate:up
RUN npm run db:seeds:up
CMD [ "npm", "start" ]
And here's my default.db.json that the Sequelize migration uses (shortened):
{
"development": {
},
"production": {
},
"docker": {
"username": "myuser",
"password": "mypassword",
"database": "mydb",
"host": "mysqldb",
"port": "3306",
"dialect": "mysql"
}
}
Upon running compose up the DB installs well, the image deploys, but when it reaches the RUN npm run db:migrate:up (which translates into npx sequelize-cli db:migrate) I get the error:
npx: installed 81 in 13.108s
Sequelize CLI [Node: 14.17.0, CLI: 6.2.0, ORM: 6.6.2]
Loaded configuration file "default.db.json".
Using environment "docker".
ERROR: getaddrinfo EAI_AGAIN mysqldb
npm ERR! code ELIFECYCLE
npm ERR! errno 1
If I change the "host" in the default.db.json to "127.0.0.1", I get ERROR: connect ECONNREFUSED 127.0.0.1:3306 in place of the ERROR: getaddrinfo EAI_AGAIN mysqldb.
What am i doing wrong, and what host should I specify so the app can see the MySQL container? Should I remove the network? Should I change ports? (I tried combinations of both to no avail, so far).

Answer 1

I solved my issue by using Docker Compose Wait. Essentially, it adds a wait loop that samples the DB container, and only when it's up, runs migrations and seeds the DB.
My next problem was: those seeds ran every time the container was run - I solved that by instead running a script that runs the seeds, and touchs a semaphore file. If the file exists already, it skips the seeds.

Answer 2

The following configuration worked for me, I am adding the .env, sequelize configuration along with mysql database and docker. And finally don't forget to run docker-compose up --build cheers 🎁 🎁 🎁
.env
DB_NAME="testdb"
DB_USER="root"
DB_PASS="root"
DB_HOST="mysql"
.sequelizerc now we can use config.js rather than config.json for sequelize
const path = require('path');
module.exports = {
'config': path.resolve('config', 'config.js')
}
config.js
require("dotenv").config();
module.exports = {
development: {
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME,
host: process.env.DB_HOST,
dialect: "mysql"
},
test: {
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME,
host: process.env.DB_HOST,
dialect: "mysql"
},
production: {
username: process.env.DB_USER,
password: process.env.DB_PASS,
database: process.env.DB_NAME,
host: process.env.DB_HOST,
dialect: "mysql"
}
}
database-connection with sequelize
import Sequelize from 'sequelize';
import dbConfig from './config/config';
const conf = dbConfig.development;
const sequelize = new Sequelize(
conf.database,
conf.username,
conf.password,
{
host: conf.host,
dialect: "mysql",
operatorsAliases: 0,
logging: 0
}
);
sequelize.sync();
(async () => {
try {
await sequelize.authenticate();
console.log("Database connection setup successfully!");
} catch (error) {
console.log("Unable to connect to the database", error);
}
})();
export default sequelize;
global.sequelize = sequelize;
docker-compose.yaml
version: "3.8"
networks:
proxy:
name: proxy
services:
mysql:
image: mysql
networks:
- proxy
ports:
- 3306:3306
environment:
- MYSQL_ROOT_PASSWORD=root
- MYSQL_DATABASE=testdb
healthcheck:
test: "mysql -uroot -p$$MYSQL_ROOT_PASSWORD -e 'SHOW databases'"
interval: 10s
retries: 3
api:
build: ./node-backend
networks:
- proxy
ports:
- 3000:3000
depends_on:
mysql:
condition: service_healthy
Dockerfile
FROM node:16
WORKDIR /api
COPY . /api
RUN npm i
EXPOSE 3000
RUN chmod +x startup.sh
RUN npm i -g sequelize-cli
RUN npm i -g nodemon
ENTRYPOINT [ "./startup.sh" ]
startup.sh
#!/bin/bash
npm run migrate-db
npm run start

Answer 3

I found a really clean solution wanted to share it. First of all I used docker-compose, so if you are using only docker, it might not help.
First thig first, I created a docker file which looks like that.I am using typescript, so if you are using js, you don't need to download typescript and build it!
FROM node:current-alpine
WORKDIR /app
COPY . ./
COPY .env.development ./.env
RUN npm install
RUN npm install -g typescript
RUN npm install -g sequelize-cli
RUN npm install -g nodemon
RUN npm run build
RUN rm -f .npmrc
RUN cp -R res/ dist/
RUN chmod 755 docker/entrypoint.sh
EXPOSE 8000
EXPOSE 3000
EXPOSE 9229
CMD ["sh", "-c","--","echo 'started';while true; do sleep 1000; done"]
Till here it is standart. In order to do things in right order, I need a docker compose and entrypoint file. Entrypoint file is a file, that runs when your containers start. Here is docker-compose file.
version: '3'
services:
app:
build:
context: ..
dockerfile: docker/Dockerfile.development
entrypoint: docker/development-entrypoint.sh
ports:
- 3000:3000
env_file:
- ../.env.development
depends_on:
- postgres
postgres:
image: postgres:alpine
environment:
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=test
volumes:
- ./docker_postgres_init.sql:/docker-entrypoint-initdb.d/docker_postgres_init.sql
As you can see, I am using postgresql for db. My docker file, docker-compose and also entrypoint files are in a folder called docker, thats why the paths starts wtih docker, change it according to your file structure. Last and the best part is the entrypoint file. It is really simple.
#!/bin/sh
echo "Starting get ready!!!"
sequelize db:migrate
nodemon ./dist/index.js
Ofcourse change the path of the index.js file according to your settings.
Hope it helps!