can't connect db in container (node 16)

Discussed in https://github.com/prisma/prisma/discussions/14970

<div type='discussions-op-text'>

^{Originally posted by Atsuyoshi-Funahashi August 24, 2022} Hi. I am currently creating an application in Next.js and using mysql for the DB. I am building the environment with docker. Originally I was using node version 17.6.0 and it was working fine.

Problem

I have lowered my node version to 16.13.0 in order to install NextAuth. After that, when I launch the container with docker compose up --build, the following error occurs during migration.

# error
Error: P1001: Can't reach database server at `mysql`:`3306`
Please make sure your database server is running at `mysql`:`3306`

Since this did not occur when node version was 17, I would like to know how to solve this problem.

Version

node  16.13.0
prisma 4.2.1
mysql 5.7

reproduction method

1  create next app
2 install and init prisma
3 Copy-paste the file below.
4 docker compose up --build

File

Dockerfile, docker-compose.yml, run.sh, and .env are as follows

## Dockerfile
FROM node:16.13.0

RUN mkdir /test
WORKDIR /test
COPY . /test
RUN yarn add create-next-app
COPY run.sh /usr/bin/run
RUN chmod +x /usr/bin/run
EXPOSE 3000

CMD ["run"]

## docker-compose.yml
version: '3'
services:
  db:
    image: mysql:5
    platform: linux/x86_64
    container_name: mysql
    ports:
      - '3306:3306'
    environment:
      - MYSQL_ALLOW_EMPTY_PASSWORD=yes
    volumes:
      - ./tmp/db:/var/lib/mysql
  app:
    build: .
    volumes:
      - .:/test
    ports:
      - '3000:3000'
    restart: always
    depends_on:
      - db

This is schema.prisma.

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "mysql"
  url      = env("DATABASE_URL")
}

model users {
  id               Int       @id @default(autoincrement())
  email            String    @unique
 # other value
}

This is seed.ts.

import { PrismaClient } from '@prisma/client';
const prisma = new PrismaClient();
async function main() {
    await prisma.users.createMany({
        data: [
            {
                email: '[e-mail]',
            },
            {
                email: '[e-mail]',
            },
        ],
    });
}

main()
    .then(async () => {
        await prisma.$disconnect();
    })
    .catch(async e => {
        console.error(e);
        await prisma.$disconnect();
        process.exit(1);
    });

This is run.sh. Please set under the project root.

# run.sh
#!/bin/sh

bash -c "sleep 30 && yarn -s run prisma migrate dev --name init && yarn install && yarn dev "

This is .env

# .env
MYSQL_HOST = 'mysql'
MYSQL_DATABASE = 'database_name'
# MYSQL_USER = 'root'
MYSQL_ROOT_PASSWORD = ''
DATABASE_URL="mysql://root:@mysql:3306/database_name"

```</div>

[goda-kazuki]

I don’t know if this is related, but I added connect_timeout and now I can connect stably.

DATABASE_URL="mysql://docker:docker@db:3306/docker?connect_timeout=30"

[Suniron]

I don’t know if this is related, but I added connect_timeout and now I can connect stably.

DATABASE_URL="mysql://docker:docker@db:3306/docker?connect_timeout=30"

What is the equivalent in PostgreSQL?