Merge pull request #15 from lsst-sqre/u/ajt/freespace

Add flag to free up space on the GHA Runner

Author: athornton

.github/workflows/build.yaml

@@ -22,7 +22,7 @@ on:
         default: "."
         type: string
       cache:
-        description: "Whether to use GitHub cache for images.  If they are very large, you might not want to."
+        description: "Whether to use GitHub cache for images.  Since the caches are not keyed by platform, they do not work well anyway (hence the default)."
         required: false
         default: false
         type: boolean
@@ -49,6 +49,11 @@ on:
         required: false
         type: number
         default: 1
+      free-space:
+        description: "Free space on GitHub runner."
+        required: false
+        type: boolean
+        default: false
     outputs:
       tag:
         description: "The tag that was used for the built image"
@@ -118,6 +123,24 @@ jobs:
           - arch: "arm64"
             runs_on: "ubuntu-24.04-arm"
     steps:
+      - name: Free space
+        if: ${{ inputs.free-space }}
+        shell: bash
+        run: |
+          set -euo pipefail
+          echo "Free disk space (start)"
+          df -ah
+          echo "Removing .NET"
+          sudo rm -rf /usr/share/dotnet
+          echo "Removing Android SDK"
+          sudo rm -rf /usr/local/lib/android
+          echo "Removing Haskell"
+          sudo rm -rf /opt/ghc
+          echo "Removing CodeQL"
+          sudo rm -rf /opt/hostedtoolcache/CodeQL
+          echo "Free disk space (end)"
+          df -ah
+
       - name: Checkout source
         uses: actions/checkout@v5
         with:

README.md

@@ -113,13 +113,17 @@ RUN --mount=type=secret,id=NPM_TOKEN \
   If `true`, the action uses the built-in GitHub Actions cache to to store Docker build layers between runs.
   However, this cache appears to have a race condition when used across multiple architectures so that only one architecture is effectively cached.
   Disabling caching altogether at least avoids the time cost of uploading and downloading the cache.
-  If the image being built is very large, `false` might be preferable, as the total cache size is 10GB as of October 2025.
 
 - `push` (boolean, optional) a flag to enable pushing to artifact registries (based on the `image` input) .
   Default is `true`.
   If `false`, the action skips the image push, but still builds the image with [`docker build`](https://docs.docker.com/engine/reference/commandline/build/).
   In that case the action does not perform the manifest reassembly across platforms.
 
+- `free-space` (boolean, optional) a flag to remove the .NET, Android SDK, Haskell, and CodeQL directories.
+  If your builds are running out of space, try this.
+  Default is `false`.
+  This saves 18GB on amd64 (only 3GB on arm64).
+
 - `target` (string, optional) the name of a build stage in the Dockerfile to target for the image. This allows multiple images built from a single Dockerfile, e.g., "runtime-A" and "runtime-B".
 
 - `fetch-depth` (number, optional) the git checkout fetch-depth. Set to 0 for complete history, which some builds require.