fix(ci): add restore/save cache for onchain

.github/workflows/ci.yml

@@ -16,6 +16,9 @@ jobs:
       id-token: write
       contents: read
     runs-on: [ self-hosted, Linux ]
+    env:
+      # Modify this value to "invalidate" the cabal cache.
+      CABAL_CACHE_VERSION: "2024-11-14"
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -25,29 +28,59 @@ jobs:
       - name: Add signing key for nix
         run: echo "${{ secrets.NIX_SIGNING_KEY }}" > "${{ runner.temp }}/nix-key"
 
-      #      - name: Cache cabal directories
-      #        uses: actions/cache@v4
-      #        with:
-      #          path: |
-      #            ~/.local/state/cabal/store
-      #            ~/.cabal/store
-      #            onchain/dist-newstyle
-      #          key: ${{ runner.os }}-${{ hashFiles('**/*.cabal', '**/cabal.project') }}
-      #          restore-keys: ${{ runner.os }}-
+      - name: Record dependencies to be used as cache keys
+        id: record-deps
+        run: |
+          nix develop && cd onchain
+          cabal build all --enable-tests --dry-run --minimize-conflict-set
+          cat dist-newstyle/cache/plan.json \
+          | jq '.["install-plan"][].id' \
+          | sort \
+          | uniq \
+          | tee dependencies.txt
+
+      - name: Restore cache
+        uses: actions/cache/restore@v4
+        id: restore-cabal-cache
+        with:
+          path: |
+            ~/.local/state/cabal/store
+            ~/.cabal/store
+            onchain/dist-newstyle
+
+          key: ${{ runner.os }}-${{ env.CABAL_CACHE_VERSION }}-${{ hashFiles('dependencies.txt') }}-${{ hashFiles('cabal.project*') }}
+
+          restore-keys: |
+            ${{ runner.os }}-${{ env.CABAL_CACHE_VERSION }}-${{ hashFiles('dependencies.txt') }}
+            ${{ runner.os }}-${{ env.CABAL_CACHE_VERSION }}-
+
+      - name: Build dependencies
+        id: build-dependencies
+        run: cabal build all --only-dependencies
+
+      - name: Save cache
+        uses: actions/cache/save@v4
+        id: save-cabal-cache
+        if: steps.build-dependencies.outcome == 'success' && steps.restore-cabal-cache.outputs.cache-hit != 'true'
+        with:
+          path: |
+            ~/.local/state/cabal/store
+            ~/.cabal/store
+            onchain/dist-newstyle
+          key:  ${{ steps.restore-cabal-cache.outputs.cache-primary-key }}
 
       - name: Lint sources
         run: |
           nix flake check
 
       - name: Build onchain
         run: |
-          cd onchain
-          nix develop --command "make"
+          make
 
-      - name: Build offchain
-        run: |
-          cd offchain
-          nix develop --command "make"
+      # - name: Build offchain
+      #   run: |
+      #     cd offchain
+      #     nix develop --command "make"
 
       - name: Acquire AWS credentials
         uses: aws-actions/configure-aws-credentials@v4