Split cache step into two, hash composite requirements.txt (#422)

composite/action.yml

@@ -175,12 +175,13 @@ runs:
         esac
       shell: bash
 
-    - name: Cache PIP Packages
-      uses: actions/cache@v3
+    - name: Restore PIP packages cache
+      uses: actions/cache/restore@v3
+      id: cache
       continue-on-error: true
       with:
         path: ${{ steps.os.outputs.pip-cache }}
-        key: enricomi-publish-action-${{ runner.os }}-${{ runner.arch }}-pip-${{ steps.python.outputs.version }}-${{ hashFiles('**/requirements.txt', 'composite/action.yml') }}
+        key: enricomi-publish-action-${{ runner.os }}-${{ runner.arch }}-pip-${{ steps.python.outputs.version }}-f3f2c295046c91ed612b4efb6c9fb352
 
     - name: Install Python dependencies
       run: |
@@ -238,6 +239,14 @@ runs:
         LOG_LEVEL: ${{ inputs.log_level }}
       shell: bash
 
+    - name: Save PIP packages cache
+      uses: actions/cache/save@v3
+      if: ( success() || failure() ) && ! steps.cache.outputs.cache-hit
+      continue-on-error: true
+      with:
+        path: ${{ steps.os.outputs.pip-cache }}
+        key: ${{ steps.cache.outputs.cache-primary-key }}
+
 branding:
   icon: 'check-circle'
   color: 'green'

python/test/test_action_yml.py

@@ -1,4 +1,6 @@
+import hashlib
 import pathlib
+import sys
 import unittest
 
 import yaml
@@ -28,6 +30,17 @@ def test_composite_action(self):
         self.assertEqual(dockerfile_action_wo_runs, composite_action_wo_runs)
         self.assertIn(('using', 'composite'), composite_action.get('runs', {}).items())
 
+        # check cache key hash is up-to-date in composite action
+        # this md5 is linux-based (on Windows, git uses different newlines, which changes the hash)
+        if sys.platform != 'win32':
+            with open(project_root / 'python' / 'requirements.txt', mode='rb') as r:
+                expected_hash = hashlib.md5(r.read()).hexdigest()
+            cache_hash = next(step.get('with', {}).get('key', '').split('-')[-1]
+                              for step in composite_action.get('runs', {}).get('steps', [])
+                              if step.get('uses', '').startswith('actions/cache/restore@'))
+            self.assertEqual(expected_hash, cache_hash, msg='Changing python/requirements.txt requires '
+                                                            'to update the MD5 hash in composite/action.yaml')
+
     def test_composite_inputs(self):
         with open(project_root / 'composite/action.yml', encoding='utf-8') as r:
             action = yaml.safe_load(r)