Mac M1环境Docker构建.NET Core应用NuGet源加载失败求助

尝试为.NET Core 6应用创建Docker镜像时，执行RUN dotnet restore步骤报错：

Unable to load the service index for source https://api.nuget.org/v3/index.json

已完成以下排查操作：

• 在Visual Studio中执行nuget restore可正常完成
• 浏览器能正常访问https://api.nuget.org/v3/index.json
• 已将Docker配置中的DNS值修改为8.8.8.8
• Docker容器内可成功ping通google.com

怀疑问题与M1处理器或代理配置有关，但现有资料多针对Windows环境，寻求适配的解决方案。

附本地~/nuget/Nuget/Nuget.config文件内容：

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
  </packageSources>
</configuration>

Dockerfile内容：

FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
WORKDIR /app
EXPOSE 80

FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build
WORKDIR /src
COPY . .
RUN dotnet restore  "myapplication.Web/myapplication.Web.csproj"
COPY . .
WORKDIR "/src/myapplication.Web"
RUN dotnet build "myapplication.Web.csproj" -c Release -o /app/build

FROM build AS publish
WORKDIR "/src/myapplication.Web"
RUN dotnet publish "myapplication.Web.csproj" -c Release -o /app/publish /p:UseAppHost=false

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

1. 适配M1 ARM架构的镜像 #

M1为ARM64架构，默认的mcr.microsoft.com/dotnet/sdk:6.0是x86架构，依赖Rosetta转译可能引发网络异常。建议直接使用ARM64专属镜像：
修改Dockerfile中的基础镜像为ARM64版本：

FROM mcr.microsoft.com/dotnet/aspnet:6.0-alpine-arm64v8 AS base
FROM mcr.microsoft.com/dotnet/sdk:6.0-alpine-arm64v8 AS build

Alpine镜像体积更小，ARM64支持更完善，能减少架构兼容问题。

2. 处理代理环境变量干扰 #

即使容器ping连通正常，dotnet restore可能读取宿主代理配置，但Docker构建默认不会传递这些变量。

• 若使用代理，在dotnet restore前显式设置代理：

RUN export HTTP_PROXY=http://你的代理地址:端口 && export HTTPS_PROXY=http://你的代理地址:端口 && dotnet restore "myapplication.Web/myapplication.Web.csproj"

• 若无代理，清空代理变量避免残留配置影响：

RUN unset HTTP_PROXY HTTPS_PROXY && dotnet restore "myapplication.Web/myapplication.Web.csproj"

3. 优化Dockerfile构建缓存（同时避免文件干扰） #

当前Dockerfile先复制所有代码再执行restore，会导致代码变动时重复执行restore。调整顺序，先复制项目文件再restore：

FROM mcr.microsoft.com/dotnet/sdk:6.0-alpine-arm64v8 AS build
WORKDIR /src
# 仅复制项目文件，利用构建缓存
COPY "myapplication.Web/myapplication.Web.csproj" "myapplication.Web/"
RUN dotnet restore "myapplication.Web/myapplication.Web.csproj"
# 再复制全部代码
COPY . .
WORKDIR "/src/myapplication.Web"
RUN dotnet build "myapplication.Web.csproj" -c Release -o /app/build

4. 排查容器内HTTPS访问问题 #

若上述方法无效，可临时在Dockerfile中添加curl测试步骤，确认容器内能否正常访问nuget源：

FROM mcr.microsoft.com/dotnet/sdk:6.0-alpine-arm64v8 AS build
WORKDIR /src
# 测试nuget源的HTTPS连通性
RUN curl -v https://api.nuget.org/v3/index.json
# 安装证书（Alpine镜像可能缺少根证书）
RUN apk add --no-cache ca-certificates
# 执行restore
COPY "myapplication.Web/myapplication.Web.csproj" "myapplication.Web/"
RUN dotnet restore "myapplication.Web/myapplication.Web.csproj"

内容的提问来源于stack exchange，提问作者ebk