连接数据库 - docker-compose up

Question

I'm trying to make one Docker Compose file to up an WEB (reactJS), API (.NET Core 2.1) and an SQL Server instance.

When I init the database and run .NET with dotnet cli, it works (using a connection string Server=localhost ). However what I've been googling is that localhost does not work on containers. And when using container I can't get my .NET Core to connect with my SQL Server.

Can anyone shed some light what am I doing wrong?

I have this repo: https://github.com/lucasgozzi/sagetest

And I'm currently using a branch names 'docker'. Here is my Docker files and composer in case you don't want to clone the repo.

Backend dockerfile:

FROM mcr.microsoft.com/dotnet/core/aspnet:2.1
WORKDIR /app
FROM mcr.microsoft.com/dotnet/core/sdk:2.1
WORKDIR /src
COPY . .
RUN dotnet restore "./Api/Api.csproj"
RUN dotnet build "Api/Api.csproj" -c Release -o /app/build
RUN dotnet publish "Api/Api.csproj" -c Release -o /app/publish
EXPOSE 5000
WORKDIR /app/publish
ENTRYPOINT ["dotnet", "Api.dll"]

Frontend dockerfile:

# base image
FROM node:12.2.0-alpine

# set working directory
WORKDIR /app
EXPOSE 3000

# add `/app/node_modules/.bin` to $PATH
ENV PATH /app/node_modules/.bin:$PATH

# install and cache app dependencies
COPY . .
RUN npm install --silent
RUN npm install react-scripts -g --silent

# start app
CMD ["npm", "start"]

Docker compose:

version: '3.1'

services:
  api:
    container_name: "teste-sage-api"
    image: 'teste-sage-api'
    build: 
      context: ./backend
      dockerfile: Dockerfile
    volumes:
      - ./backend:/var/www/backend
    ports:
      - "5000:5000"
    depends_on:
      - "database"
    networks:
      - sagetest-network
  web:
    container_name: "teste-sage-web"
    image: 'teste-sage-web'
    build: 
      context: ./frontend_react
      dockerfile: Dockerfile
    ports:
      - "3000:3000" 
    depends_on:
      - "api"
    networks:
      - sagetest-network
  database:
    container_name: "sql-server"
    image: "mcr.microsoft.com/mssql/server"
    environment:
      SA_PASSWORD: "Teste@123"
      ACCEPT_EULA: "Y"
    ports: 
      - "1433:1433"
    networks:
      - sagetest-network
networks:
  sagetest-network:
    driver: bridge 

Answer 1

You can access the database form your containers on the service name, in your case this will be database . But you need to make sure that the database container is up and running before trying to connect to it. depends_on is not enough for this case. you may need to implement a waitfor in your dotnet container. check this for more info https://docs.docker.com/compose/startup-order/