Fix Dockerfile

Fix (and simplify) the ASP.NET Core dockerfile.

Author: martincostello

examples/net8.0/aspnetcore/Dockerfile

@@ -1,25 +1,19 @@
-#See https://aka.ms/customizecontainer to learn how to customize your debug container and how Visual Studio uses this Dockerfile to build your images for faster debugging.
-
-FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
-WORKDIR /app
-EXPOSE 80
-
-FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
-
+FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:8.0 AS build
+ARG TARGETARCH
+ARG CONFIGURATION="Release"
 ARG DOTNET_PUBLISH_ARGS=""
 
-WORKDIR /src
-COPY ["examples/net8.0/aspnetcore/aspnetcore.csproj", "examples/net8.0/aspnetcore/"]
-RUN dotnet restore "examples/net8.0/aspnetcore/aspnetcore.csproj"
-COPY . .
-WORKDIR "/src/examples/net8.0/aspnetcore"
-RUN dotnet build "aspnetcore.csproj" -c Release -o /app/build
+COPY . /source
+WORKDIR /source
+
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 
-FROM build AS publish
-RUN dotnet publish "aspnetcore.csproj" -c Release -o /app/publish ${DOTNET_PUBLISH_ARGS}
+RUN --mount=type=cache,id=nuget,target=/root/.nuget/packages \
+    dotnet publish "examples/net8.0/aspnetcore/aspnetcore.csproj" --arch "${TARGETARCH}" --configuration "${CONFIGURATION}" --output /app "${DOTNET_PUBLISH_ARGS}"
 
-FROM base AS final
+FROM mcr.microsoft.com/dotnet/sdk:8.0 AS final
 WORKDIR /app
-COPY --from=publish /app/publish .
-RUN apt-get update && apt-get install -y curl
+EXPOSE 8080
+
+COPY --from=build /app .
 ENTRYPOINT ["dotnet", "aspnetcore.dll"]