How to access external database from Node container? - mysql

Question

I have a nextjs app which is supposed to connect to an external MySQL database (not one from the same docker network). When running the app locally, it works correctly when connecting to DB, but when running it in a Docker container it keeps on trying to connect to 127.0.0.1, even though the environment variables are configured correctly in the container
Error: Error: connect ECONNREFUSED 127.0.0.1:3306
nextjs_1 | at connect (/opt/app/node_modules/serverless-mysql/index.js:80:15)
Dockerfile config:
FROM node:alpine
RUN mkdir -p /opt/app
RUN apk add --no-cache libc6-compat
ENV NODE_ENV production
ENV PORT 3000
EXPOSE 3000
WORKDIR /opt/app
COPY package.json /opt/app
COPY package-lock.json /opt/app
RUN npm install --no-optional
COPY . /opt/app
RUN npm run build
RUN npx next telemetry disable
RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001
USER nextjs
CMD [ "npm", "start" ]
Connection code:
const mysql = require('serverless-mysql')
const db = mysql({
config: {
host: process.env.MYSQL_HOST,
database: process.env.MYSQL_DATABASE,
user: process.env.MYSQL_USER,
password: process.env.MYSQL_PASSWORD,
},
})
exports.query = async (query) => {
try {
const results = await db.query(query)
await db.end()
return results
} catch (error) {
return { error }
}
}
Any ideas?