[chore] enhance Docker build workflow with cache and disk space optimi…

.github/workflows/build-images.yml

@@ -8,8 +8,6 @@ on:
 
 env:
   REGISTRY: ghcr.io
-  PROVER_IMAGE_NAME: ${{ github.repository }}
-  STREAMR_IMAGE_NAME: ${{ github.repository }}/streamr-client
 
 jobs:
   build-and-push-images:
@@ -24,6 +22,24 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v5
 
+      - name: Normalize image names
+        run: |
+          echo "PROVER_IMAGE_NAME=${GITHUB_REPOSITORY,,}" >> $GITHUB_ENV
+          echo "STREAMR_IMAGE_NAME=${GITHUB_REPOSITORY,,}/streamr-client" >> $GITHUB_ENV
+
+      # Free up ~15-30 GB by removing unused pre-installed tools/packages
+      - name: Free disk space
+        uses: jlumbroso/free-disk-space@main 
+        with:
+          tool-cache: true
+          android: true
+          dotnet: true
+          haskell: true
+          large-packages: true
+          docker-images: true
+          swap-storage: true
+
+      # Multi-platform setup
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
         with:
@@ -32,6 +48,7 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      # Login only on push
       - name: Log in to GitHub Container Registry
         if: github.event_name != 'pull_request'
         uses: docker/login-action@v3
@@ -40,50 +57,56 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      # Build and push Prover image (energy-tracker)
+      # Prover image (energy-tracker)
       - name: Extract metadata for Prover image
         id: meta-prover
         uses: docker/metadata-action@v5
         with:
           images: ${{ env.REGISTRY }}/${{ env.PROVER_IMAGE_NAME }}
 
       - name: Build and push Prover image
+        id: docker_build_prover
         uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64,linux/arm64
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta-prover.outputs.tags }}
           labels: ${{ steps.meta-prover.outputs.labels }}
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.PROVER_IMAGE_NAME }}:buildcache
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.PROVER_IMAGE_NAME }}:buildcache,mode=max
 
       - name: Generate attestation for Prover image
         if: github.event_name != 'pull_request'
         uses: actions/attest-build-provenance@v3
         with:
           subject-name: ${{ env.REGISTRY }}/${{ env.PROVER_IMAGE_NAME }}
-          subject-digest: ${{ steps.build-and-push-prover.outputs.digest }}
+          subject-digest: ${{ steps.docker_build_prover.outputs.digest }}
           push-to-registry: true
 
-      # Build and push Streamr client image
+      # Streamr client image
       - name: Extract metadata for Streamr client image
         id: meta-streamr
         uses: docker/metadata-action@v5
         with:
           images: ${{ env.REGISTRY }}/${{ env.STREAMR_IMAGE_NAME }}
 
       - name: Build and push Streamr client image
+        id: docker_build_streamr
         uses: docker/build-push-action@v6
         with:
           context: ./streamr-client
           platforms: linux/amd64,linux/arm64
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta-streamr.outputs.tags }}
           labels: ${{ steps.meta-streamr.outputs.labels }}
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.STREAMR_IMAGE_NAME }}:buildcache
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.STREAMR_IMAGE_NAME }}:buildcache,mode=max
 
       - name: Generate attestation for Streamr client image
         if: github.event_name != 'pull_request'
         uses: actions/attest-build-provenance@v3
         with:
           subject-name: ${{ env.REGISTRY }}/${{ env.STREAMR_IMAGE_NAME }}
-          subject-digest: ${{ steps.build-and-push-streamr.outputs.digest }}
-          push-to-registry: true
+          subject-digest: ${{ steps.docker_build_streamr.outputs.digest }}
+          push-to-registry: true