fix(terraform): duplicate caches created (#596)

.github/workflows/terraform.yml

@@ -110,14 +110,11 @@ jobs:
         shell: bash
         working-directory: ${{ inputs.working_directory }}
 
-    env:
-      # Enable Terraform plugin cache.
-      # https://developer.hashicorp.com/terraform/cli/config/config-file#provider-plugin-cache
-      TF_PLUGIN_CACHE_DIR: ${{ github.workspace }}/${{ inputs.working_directory }}/.terraform.d/plugin-cache
-
     outputs:
       upload-outcome: ${{ steps.upload.outcome }}
       artifact-id: ${{ steps.upload.outputs.artifact-id }}
+      plugin-cache-dir: ${{ steps.mkdir.outputs.plugin-cache-dir }}
+      cache-primary-key: ${{ steps.cache-restore.outputs.cache-primary-key }}
 
     steps:
       - name: Checkout
@@ -135,13 +132,18 @@ jobs:
           # The wrapper must be disabled to prevent this.
 
       - name: Create Terraform plugin cache
-        run: mkdir --parents "$TF_PLUGIN_CACHE_DIR"
+        id: mkdir
+        run: |
+          plugin_cache_dir="$HOME/.terraform.d/plugin-cache"
+          mkdir --parents "$plugin_cache_dir"
+          echo "plugin-cache-dir=$plugin_cache_dir" >> "$GITHUB_OUTPUT"
 
-      - name: Cache Terraform plugins
-        uses: actions/cache@6849a6489940f00c2f30c0fb92c6274307ccb58a
+      - name: Restore cache
+        id: cache-restore
+        uses: actions/cache/restore@6849a6489940f00c2f30c0fb92c6274307ccb58a
         with:
-          path: ${{ env.TF_PLUGIN_CACHE_DIR }}
-          key: terraform-${{ hashFiles(format('{0}/.terraform.lock.hcl', inputs.working_directory)) }}
+          path: ${{ steps.mkdir.outputs.plugin-cache-dir }}
+          key: ${{ runner.os }}-terraform-${{ hashFiles(format('{0}/.terraform.lock.hcl', inputs.working_directory)) }}
           # The dependency lock file tracks provider dependencies for the Terraform configuration in the working directory.
           # Calculate a hash for the dependency lock file and use this hash to identify the plugin cache for the Terraform configuration.
           # https://developer.hashicorp.com/terraform/language/files/dependency-lock
@@ -163,6 +165,9 @@ jobs:
         id: init
         env:
           TFBACKEND_CONFIG: ${{ inputs.backend_config }}
+          # Enable Terraform plugin cache.
+          # https://developer.hashicorp.com/terraform/cli/config/config-file#provider-plugin-cache
+          TF_PLUGIN_CACHE_DIR: ${{ steps.mkdir.outputs.plugin-cache-dir }}
         run: |
           optional_args=()
           if [[ -n "$TFBACKEND_CONFIG" ]]; then
@@ -251,6 +256,13 @@ jobs:
           # Ref: https://docs.github.com/en/actions/learn-github-actions/usage-limits-billing-and-administration#usage-limits
           retention-days: 35
 
+      - name: Save cache
+        if: steps.cache-restore.outputs.cache-hit != 'true'
+        uses: actions/cache/save@6849a6489940f00c2f30c0fb92c6274307ccb58a
+        with:
+          path: ${{ steps.mkdir.outputs.plugin-cache-dir }}
+          key: ${{ steps.cache-restore.outputs.cache-primary-key }}
+
   terraform-apply:
     name: Terraform Apply
     needs: terraform-plan
@@ -288,6 +300,12 @@ jobs:
           gpg -d --batch --passphrase "$ENCRYPTION_PASSWORD" "$tarball" | tar -xv
           rm "$tarball"
 
+      - name: Restore cache
+        uses: actions/cache/restore@6849a6489940f00c2f30c0fb92c6274307ccb58a
+        with:
+          path: ${{ needs.terraform-plan.outputs.plugin-cache-dir }}
+          key: ${{ needs.terraform-plan.outputs.cache-primary-key }}
+
       - name: Terraform Apply
         run: terraform apply -auto-approve -input=false "$TFPLAN_FILE"