nardo86/dotnet-ci repository overview

⁠dotnet-ci

Generic CI job image for .NET projects: the official .NET SDK 10 image plus what CI jobs usually need on top of it. Works with GitHub Actions (container:), Forgejo / Gitea runners and act.

linux/amd64 only. Rebuilt weekly and whenever mcr.microsoft.com/dotnet/sdk:10.0 changes.

⁠Contents

Runs as root, CMD ["bash"], no ENTRYPOINT, no HEALTHCHECK. Telemetry and the first-run banner of the .NET CLI are off (DOTNET_CLI_TELEMETRY_OPTOUT=1, DOTNET_NOLOGO=1).

Docker commands (Testcontainers, docker compose, docker buildx) use whatever daemon the runner provides: a Docker-in-Docker sidecar via DOCKER_HOST, or a mounted socket.

⁠Tags

For reproducible CI, pin the immutable tag together with its digest (nardo86/dotnet-ci:10.0.401-20261007@sha256:…); the digest of every build is printed in the summary of the workflow run.

OCI labels: org.opencontainers.image.version (SDK version), .source, .revision, .created, .base.name, .base.digest.

⁠Usage

jobs:
  build:
    runs-on: docker            # GitHub: ubuntu-latest
    container:
      image: nardo86/dotnet-ci:10.0
    steps:
      - uses: actions/checkout@v5
      - run: dotnet test

⁠Adding what you need

The image stays small on purpose. Three ways to complete it, from the quickest to the most reusable:

1. In the job, for occasional needs (you pay the install time on every run):

apt-get update && apt-get install -y --no-install-recommends zip postgresql-client

# another SDK next to the 10.0 one, e.g. for multi-targeting
dotnet-install.sh --channel 8.0 --install-dir /usr/share/dotnet
# only a runtime
dotnet-install.sh --channel 8.0 --runtime aspnetcore --install-dir /usr/share/dotnet

dotnet tool install -g dotnet-reportgenerator-globaltool && export PATH="$PATH:$HOME/.dotnet/tools"

2. A derived image, when the same additions are needed by every run:

FROM nardo86/dotnet-ci:10.0
RUN dotnet-install.sh --channel 8.0 --install-dir /usr/share/dotnet \
 && apt-get update && apt-get install -y --no-install-recommends zip \
 && rm -rf /var/lib/apt/lists/*

3. Browsers / Playwright: use the -playwright variant (see the tags table above); it adds more than 1 GB and most jobs don't need it.

⁠Build locally

docker build --pull --target generic -t dotnet-ci:local .
docker build --pull --target playwright -t dotnet-ci:local-playwright .

The build fails if any of the version checks at the end of the Dockerfile fails (SDK ≥ 10.0.401, Node 24.x, Docker CLI and plugins, Python, Git, jq).