如何在Docker Compose中为.NET C#控制台应用传递命令行参数？

问题现象 #

运行.NET C#控制台应用时，日志抛出参数为空的异常：

2025-01-15 13:07:47 System.ArgumentException: Required input args was empty. (Parameter 'args')
2025-01-15 13:07:47 at Ardalis.GuardClauses.GuardClauseExtensions.NullOrEmpty[T](IGuardClause guardClause, IEnumerable`1 input, String parameterName, String message, Func`1 exceptionCreator)
2025-01-15 13:07:47 at Personnel.Infrastructure.Migrator.Program.Main(String[] args) in C:\Users\user\RiderProjects\staffpro.learn.redkozubov\src\Services\Personnel\Infrastructure\Personnel.Infrastructure.Migrator\Program.cs:line 21

相关配置代码 #

Docker Compose配置 #

personnel_migrator:
    container_name: personnel_migrator
    build:
        context: .
        dockerfile: src/Services/Personnel/Infrastructure/Personnel.Infrastructure.Migrator/Dockerfile
    depends_on:
        - personnel_db
    networks:
        - personnel_db
    ports:
        - "5001:5001"
    environment:
        - CONNECTION_STRING=${CONNECTION_STRING}
    command: dotnet Personnel.Infrastructure.Migrator.dll --${CONNECTION_STRING}

.env文件内容 #

CONNECTION_STRING="ConnectionString"

Program.cs核心代码 #

private static readonly Migrator Migrator = new();
internal static void Main(string[] args)
{
    try
    {
        Guard.Against.NullOrEmpty(args);
        Migrator.Migrate(args);
    }
    catch (Exception exception)
    {
        Console.WriteLine(exception);
        throw;
    }
}

Dockerfile代码 #

FROM mcr.microsoft.com/dotnet/runtime:8.0 AS base
USER $APP_UID
WORKDIR /app

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
ARG BUILD_CONFIGURATION=Release
WORKDIR /src
COPY ["src/Services/Personnel/Infrastructure/Personnel.Infrastructure.Migrator/Personnel.Infrastructure.Migrator.csproj", "src/Services/Personnel/Infrastructure/Personnel.Infrastructure.Migrator/"]
COPY ["src/Services/Personnel/Infrastructure/Personnel.Infrastructure.Data/Personnel.Infrastructure.Data.csproj", "src/Services/Personnel/Infrastructure/Personnel.Infrastructure.Data/"]
COPY ["src/Services/Personnel/Domain/Personnel.Domain/Personnel.Domain.csproj", "src/Services/Personnel/Domain/Personnel.Domain/"]
RUN dotnet restore "src/Services/Personnel/Infrastructure/Personnel.Infrastructure.Migrator/Personnel.Infrastructure.Migrator.csproj"
COPY . .
WORKDIR "/src/src/Services/Personnel/Infrastructure/Personnel.Infrastructure.Migrator"
RUN dotnet build "Personnel.Infrastructure.Migrator.csproj" -c $BUILD_CONFIGURATION -o /app/build

FROM build AS publish
ARG BUILD_CONFIGURATION=Release
RUN dotnet publish "Personnel.Infrastructure.Migrator.csproj" -c $BUILD_CONFIGURATION -o /app/publish /p:UseAppHost=false

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .

解决方案 #

1. 修正Docker Compose的command参数格式 #

当前command配置存在两个问题：字符串形式传递命令时shell可能错误解析变量，以及不必要的--前缀（若应用未要求）。改为数组形式传递，避免解析异常：

command: ["dotnet", "Personnel.Infrastructure.Migrator.dll", "${CONNECTION_STRING}"]

如果应用期望参数带命名前缀（如--connection-string xxx），则调整为：

command: ["dotnet", "Personnel.Infrastructure.Migrator.dll", "--connection-string", "${CONNECTION_STRING}"]

2. 修正.env文件的变量格式 #

.env中变量值的引号会被当作参数的一部分传递，导致应用无法正确识别，直接去掉引号：

CONNECTION_STRING=ConnectionString

3. 可选：通过Dockerfile设置ENTRYPOINT简化配置 #

在Dockerfile的final阶段添加ENTRYPOINT，固定启动命令，后续Docker Compose只需传递参数：

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "Personnel.Infrastructure.Migrator.dll"]

此时Docker Compose的command可简化为：

command: ["${CONNECTION_STRING}"]

若需带命名前缀则改为：

command: ["--connection-string", "${CONNECTION_STRING}"]

4. 验证参数传递（可选） #

在Program.cs的Main方法开头添加日志，确认参数是否正常接收：

Console.WriteLine($"Received args: {string.Join(", ", args)}");

内容的提问来源于stack exchange，提问作者LemonPotion