Reduce image size

.github/workflows/workflow.yaml

@@ -2,7 +2,11 @@ name: Workflow
 on: push
 jobs:
   docker:
-    name: Docker
+    strategy:
+      matrix:
+        ghc:
+          - 9.0.2
+    name: Docker with GHC ${{ matrix.ghc }}
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -13,14 +17,19 @@ jobs:
         with:
           images: ghcr.io/${{ github.repository }}
           flavor: latest=false
-          tags: type=sha,format=long
+          tags: |
+            type=sha,format=long,prefix=${{ matrix.ghc }}-
+            type=raw,value=${{ matrix.ghc }},enable={{ is_default_branch }}
       - uses: docker/login-action@v2
         with:
           password: ${{ secrets.GITHUB_TOKEN }}
           registry: ghcr.io
           username: ${{ github.actor }}
       - uses: docker/build-push-action@v3
         with:
+          build-args: GHC_VERSION=${{ matrix.ghc }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
           labels: ${{ steps.meta.outputs.labels }}
           platforms: linux/amd64,linux/arm64
           push: true

Dockerfile

@@ -56,6 +56,7 @@ ARG GHC_VERSION=9.0.2
 RUN \
   set -o errexit -o xtrace; \
   ghcup install ghc "$GHC_VERSION" --set; \
+  ghcup gc --profiling-libs --share-dir; \
   ghc --version
 
 # Install Cabal.
@@ -80,6 +81,7 @@ ARG HLS_VERSION=1.7.0.0
 RUN \
   set -o errexit -o xtrace; \
   ghcup install hls "$HLS_VERSION" --set; \
+  ghcup gc --hls-no-ghc; \
   haskell-language-server-wrapper --version
 
 # Configure Cabal.

README.markdown

@@ -0,0 +1,9 @@
+# docker-haskell
+
+This Docker image provides a Haskell development environment with the following tools:
+
+- [GHCup](https://www.haskell.org/ghcup/)
+- [GHC](https://www.haskell.org/ghc/)
+- [Cabal](https://www.haskell.org/cabal/)
+- [Stack](https://docs.haskellstack.org/en/stable/README/)
+- [HLS](https://haskell-language-server.readthedocs.io/en/latest/)