Why can't connect my .net core container to the SQL Server docker container?

Question

It fails to connect to the SQL Server container, even if the backend is running in local and the database in docker.

I tested with Azure SQL and everything worked perfectly.

Error(s):

1. After docker-compose up, and try to add element to the list:

2021-07-13 21:43:32.79 Logon       Login failed for user 'sa'. Reason: Failed to open the explicitly specified database 'AsdDB'. [CLIENT: XXX.168.XX.3]
backend    | fail: Microsoft.EntityFrameworkCore.Database.Connection[20004]
backend    |       An error occurred using the connection to database 'AsdDB' on server 'sqlserver'.
backend    | fail: Microsoft.EntityFrameworkCore.Query[10100]
backend    |       An exception occurred while iterating over the results of a query for context type 'Asd.Db.AppDbContext'.
backend    |       Microsoft.Data.SqlClient.SqlException (0x80131904): Cannot open database "AsdDB" requested by the login. The login failed.
backend    |       Login failed for user 'sa'.

2. dotnet ef update database

dotnet ef database update --project Asd.Api.csproj
Build started...
Build succeeded.

Microsoft.Data.SqlClient.SqlException (0x80131904): 建立与 SQL Server 的连接时发生与网络相关或特定于实例的错误。服务器未找到或无法访问。验证实例名称是否正确以及 SQL Server 是否配置为允许远程连接。（提供程序：命名管道提供程序，错误：40 - 无法打开与 SQL Server 的连接）

后端 Dockerfile：

FROM mcr.microsoft.com/dotnet/core/sdk:3.1-bionic AS build
WORKDIR /app



EXPOSE 80


COPY *.sln . 
COPY Asd.Api/*.*.csproj ./Asd.Api/
COPY Asd.Db/*.*.csproj ./Asd.Db/
    
RUN dotnet restore


COPY Asd.Api/. ./Asd.Api/
COPY Asd.Db/. ./Asd.Db/


WORKDIR /app/Asd.Api

RUN dotnet publish -c Release -o out



FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-bionic AS runtime
WORKDIR /app

COPY --from=build /app/Asd.Api/out ./
ENTRYPOINT ["dotnet", "Asd.Api.dll"]

Docker 组成：

version: "3.8"
services:
  backend:    
    container_name: backend
    build:      
      context: ./backend/
      dockerfile: Dockerfile
    depends_on:  
       - db      
    ports:
      - "5000:80"
  db:
    image: "mcr.microsoft.com/mssql/server:2017-latest"
    container_name: sqlserver
    hostname: sqlserver
    environment:
      SA_PASSWORD: "ASDFGHJ12345"
      ACCEPT_EULA: "Y"
    restart: unless-stopped    
    ports:
      - "1433:1433"

appsettings.json 中的连接字符串

"ConnectionStrings": {
    "DefaultConnection": "Server=sqlserver;Database=AsdDB;user id=sa;password=ASDFGHJ12345;"
},

Answer 1

在连接字符串中，必须向服务器传递以下值：

服务器= host.docker.internal ;数据库=AsdDB;用户id=sa;密码=ASDFGHJ12345%;

所以现在它可以工作了，花了两天时间搞乱它，但在我发布问题后，我找到了答案。