dotnet-package-cache-gen

Tiny tool to generate cache files for Docker-powered .NET SDK projects.

This toos helps you to setup a docker-based builds for .NET Core projects with proper Docker image caching.

When to use it

This tool would be pretty handy if:

• your project is built via Docker
• and your project contains more than one .csproj file
• and (optionally) your project uses more than one target framework

If you don't build your project via Docker or you have only one .csproj file, you won't need dotnet-package-cache-gen.

How to use it

1. Add the following lines to your build script:

   docker run --rm -v $(pwd):/source ghcr.io/itglobal/dotnet-package-cache-gen:latest > ./build/package-cache.xml

   This command will generate Nuget package cache file from projects in current directory and write it into ./build/package-cache.xml file.

   It's important to run this command before running "docker build", otherwise your build will probably fail.

   ./build/package-cache.xml file should be gitignored but not dockerignored.

   If you need to get detailed output, add a -v or --verbose flag to the docker run command:

   docker run --rm -v $(pwd):/source ghcr.io/itglobal/dotnet-package-cache-gen:latest -v > ./build/package-cache.xml

2. Add the following lines to your Dockerfile:

   FROM your-base-image
   
   # Copy cache file and run "dotnet restore" against it
   COPY ./build/package-cache.xml /build-tmp/
   RUN dotnet restore -v q /build-tmp/package-cache.xml /nologo /nowarn:msb4011 && rm -rf /build-tmp
   
   # Everything above this line will be cached
   # Docker will not re-run "dotnet restore" command unless list of referenced nuget packages,
   # their versions or target frameworks is changed
   
   # Rest of your dockerfile...
   COPY . /src
   RUN dotnet publish

How it works

dotnet-package-cache-gen scans specified directory recursively for *.csproj files, skipping any bin and obj subdirectories.

Every found project file is analyzed. Analyzer is able to process the following parts of project file:

• <TargetFramework> element

• <TargetFrameworks> element

• <RuntimeIdentifier> element

• <RuntimeIdentifiers> element

• <Import> element

• <Sdk> element

• <PackageReference> element within a plain <ItemGroup>

• <PackageReference> element within a <ItemGroup> with condition. The following conditions are supported:

  • Condition="'$(TargetFramework)' == 'TARGET_FRAMEWORK'" - specifies <ItemGroup> which is applicable only to TARGET_FRAMEWORK.
  • Condition="'$(TargetFramework)' == 'TARGET_FRAMEWORK_1' Or '$(TargetFramework)' == 'TARGET_FRAMEWORK_2'" - specifies <ItemGroup> which is applicable only to TARGET_FRAMEWORK_1 or TARGET_FRAMEWORK_2.

Example:

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <!-- Project target frameworks -->
        <TargetFrameworks>net40;net45;netstandard2.0</TargetFrameworks>
    </PropertyGroup>

    <!-- This packages are references when building for any target framework -->
    <ItemGroup>
        <PackageReference Include="Nuget.Package.Id.1" Version="1.0.0" />
    </ItemGroup>

    <!-- This packages are references when building for .NET Framework 4.0 -->
    <ItemGroup Condition="'$(TargetFramework)' == 'net40'">
        <PackageReference Include="Nuget.Package.Id.2" Version="1.0.0" />
    </ItemGroup>

    <!-- This packages are references when building for .NET Framework 4.5 -->
    <ItemGroup Condition="'$(TargetFramework)' == 'net45'">
        <PackageReference Include="Nuget.Package.Id.3" Version="1.0.0" />
    </ItemGroup>

    <!-- This packages are references when building for .NET Standard 2.0 -->
    <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
        <PackageReference Include="Nuget.Package.Id.4" Version="1.0.0" />
    </ItemGroup>

    <!-- This packages are references when building for .NET Framework 4.0 or .NET Framework 4.5 -->
    <ItemGroup Condition="'$(TargetFramework)' == 'net40' Or '$(TargetFramework)' == 'net45'">
        <PackageReference Include="Nuget.Package.Id.3" Version="1.0.0" />
    </ItemGroup>
</Project>

License

MIT