对于带有docker-compose的ASP.NET应用程序，我应该使用哪个数据库主机名？

Question

I am trying to set up an ASP.NET project (based on this tutorial) using Visual Studio for Mac, and need to run Docker containers for the web app and the SQL Server database.

Using the following docker-compose.yaml , both containers run successfully and I can load the web app landing page at http://localhost:5000 :

version: '3.4'

services:
  razorpagesmovie:
    image: ${DOCKER_REGISTRY-}razorpagesmovie
    build:
      context: .
      dockerfile: RazorPagesMovie/Dockerfile
    ports:
      - "5000:5000"
    depends_on:
      - mssql

  mssql:
    image: microsoft/mssql-server-linux
    ports:
      - "1433:1433"
    environment:
      SA_PASSWORD: "L0ngpassword"
      ACCEPT_EULA: "Y"

The connection string in appsettings.json is

Server=<host>,1433;Database=Movies;User=sa;Password=L0ngpassword;

However, I don't know what value to use for the hostname:

1. If I hardcode my machine's IP address, then both the web app AND dotnet ef database ... calls executed on my local shell can connect to the database - until my IP changes
2. If I use localhost then only dotnet ef database ... commands executed on my local shell can connect to the database
3. If I use mssql , then only the web app container can connect to the database

Is there a more robust approach than hardcoding my IP?

Answer 1

Assuming that your appsettings.json file has json key ConnectionString .

You can add an environment variable for connection string to that container. Use DB_IP or put service name mssql of the DB container.

version: '3.4'

services:
  razorpagesmovie:
    image: ${DOCKER_REGISTRY-}razorpagesmovie
    build:
      context: .
      dockerfile: RazorPagesMovie/Dockerfile
    ports:
      - "5000:5000"
    environment:
      - ConnectionString=${DB_IP:-Server=mssql;Database=Movies;User=sa;Password=L0ngpassword} 
    depends_on:
      - mssql

  mssql:
    image: microsoft/mssql-server-linux
    ports:
      - "1433:1433"
    environment:
      SA_PASSWORD: "L0ngpassword"
      ACCEPT_EULA: "Y"