ZSWatch: Optimize to keep container small to work with Github hosted runners.

Create a zswatch-ci Docker image that is optimized for CI usage on Github hosted runners.
Based on the same base image as the zephyr ci-base image, but with only the necessary
toolchains and dependencies installed to keep the image size small.

Author: jakkra

.github/workflows/ci.yml

@@ -1,16 +1,10 @@
-name: CI
+name: Upstream CI (disabled in fork)
 
 on:
-  push:
-    branches:
-    - main
-    - v*-branch
-    tags:
-    - v*
-  pull_request:
-    branches:
-    - main
-    - v*-branch
+  # Disabled in this fork to avoid relying on Zephyr's
+  # self-hosted runners and DockerHub credentials.
+  # Kept only for reference and manual runs.
+  workflow_dispatch:
 
 permissions:
   packages: write

.github/workflows/zswatch-ci-image.yml

@@ -0,0 +1,56 @@
+name: Build and publish ZSWatch CI image
+
+on:
+  push:
+    branches:
+      - main
+      - zswatch_*
+    paths:
+      - Dockerfile.base
+      - Dockerfile.ci
+      - .github/workflows/zswatch-ci-image.yml
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  build-and-push-ci:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push base image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: ./Dockerfile.base
+          push: true
+          tags: |
+            ghcr.io/zswatch/ci-base:${{ github.ref_name }}
+            ghcr.io/zswatch/ci-base:latest
+
+      - name: Build and push CI image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: ./Dockerfile.zswatch-ci
+          push: true
+          tags: |
+            ghcr.io/zswatch/zswatch-ci:latest
+            ghcr.io/zswatch/zswatch-ci:${{ github.ref_name }}
+          build-args: |
+            BASE_IMAGE=ghcr.io/zswatch/ci-base:${{ github.ref_name }}

Dockerfile.zswatch-ci

@@ -0,0 +1,54 @@
+# ZSWatch CI Image
+# Based on ci-base, with only the extra bits needed for ZSWatch builds.
+
+ARG BASE_IMAGE
+FROM ${BASE_IMAGE:-ghcr.io/zswatch/ci-base:latest}
+
+ARG USERNAME=user
+ARG WGET_ARGS="-q --show-progress --progress=bar:force:noscroll"
+ARG UBUNTU_MIRROR_ARCHIVE=archive.ubuntu.com/ubuntu
+ARG UBUNTU_MIRROR_SECURITY=security.ubuntu.com/ubuntu
+ARG UBUNTU_MIRROR_PORTS=ports.ubuntu.com/ubuntu-ports
+
+ARG ZSDK_VERSION=0.17.4
+ENV ZSDK_VERSION=$ZSDK_VERSION
+
+# Install minimal extra APT packages required for ZSWatch CI
+RUN <<EOF
+	apt-get update -y
+	apt-get install --no-install-recommends -y \
+		clang-format
+
+	# Clean up local repository
+	apt-get clean -y
+	rm -rf /var/lib/apt/lists/*
+EOF
+
+# Install Zephyr SDK
+RUN <<EOF
+	mkdir -p /opt/toolchains
+	cd /opt/toolchains
+	wget ${WGET_ARGS} https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v${ZSDK_VERSION}/zephyr-sdk-${ZSDK_VERSION}_linux-${HOSTTYPE}.tar.xz
+	tar xf zephyr-sdk-${ZSDK_VERSION}_linux-${HOSTTYPE}.tar.xz
+	zephyr-sdk-${ZSDK_VERSION}/setup.sh -t all -h -c
+	rm zephyr-sdk-${ZSDK_VERSION}_linux-${HOSTTYPE}.tar.xz
+EOF
+
+# Run the Zephyr SDK setup script as 'user' in order to ensure that the
+# `Zephyr-sdk` CMake package is located in the package registry under the
+# user's home directory.
+USER $USERNAME
+
+RUN <<EOF
+	sudo -E -- bash -c '
+	/opt/toolchains/zephyr-sdk-${ZSDK_VERSION}/setup.sh -c &&
+	chown -R $USERNAME:$USERNAME /home/$USERNAME/.cmake
+	'
+EOF
+
+USER root
+
+# Set build environment variables
+ENV ZEPHYR_TOOLCHAIN_VARIANT=zephyr
+ENV PKG_CONFIG_PATH=/usr/lib/i386-linux-gnu/pkgconfig
+ENV OVMF_FD_PATH=/usr/share/ovmf/OVMF.fd

README.md

@@ -7,6 +7,21 @@ This repository contains the Dockerfiles for the following images:
 - **Developer Image (_zephyr-build_):** includes additional tools that can be useful for Zephyr
   development.
 
+## ZSWatch CI usage
+
+For the ZSWatch project, a trimmed CI image is built from `Dockerfile.zswatch-ci` and published to GitHub Container Registry using the workflow `.github/workflows/zswatch-ci-image.yml` in this repository.
+
+- Updating the CI image:
+  - Edit `Dockerfile.base` and/or `Dockerfile.zswatch-ci`.
+  - Push to a branch matching `zswatch_*` (or `main`).
+  - The `Build and publish ZSWatch CI image` workflow builds `ci-base` and `zswatch-ci` and pushes them to `ghcr.io/<namespace>/ci-base:<tag>` and `ghcr.io/<namespace>/zswatch-ci:<tag>`.
+- Using the image in ZSWatch:
+  - In the `ZSWatch` repo, set the job container to the published image, for example:
+    ```yaml
+    container: ghcr.io/<namespace>/zswatch-ci:<tag>
+    ```
+  - The `build.yml` workflow in `ZSWatch` can then reuse this image without rebuilding toolchains on every run.
+
 ## Developer Docker Image
 
 ### Overview