ci: extract the pre-commit caching to a hidden job

.gitlab-ci.yml

@@ -25,6 +25,30 @@ workflow:
   variables:
     CI_GITIGNORE_DIR: ${CI_PROJECT_DIR}/.ci_dir
 
+.common_pre_commit:
+  extends: .ci_dir
+  variables:
+    APK_CACHE_DIR: ${CI_GITIGNORE_DIR}/apk-cache
+    PRE_COMMIT_HOME: ${CI_GITIGNORE_DIR}/pre-commit
+    CACHE_POLICY: pull
+  before_script:
+    - mkdir -p "${APK_CACHE_DIR}"
+    - apk update --cache-dir "${APK_CACHE_DIR}"
+    - apk add --cache-dir "${APK_CACHE_DIR}" git pre-commit
+  tags:
+    - alpine
+  cache:
+    - key: ${CI_COMMIT_REF_SLUG}
+      paths:
+        - ${APK_CACHE_DIR}
+      policy: ${CACHE_POLICY}
+    - key:
+        files:
+          - .pre-commit-config.yaml
+      paths:
+        - ${PRE_COMMIT_HOME}
+      policy: ${CACHE_POLICY}
+
 Check licenses:
   before_script:
     - python -m pip install --upgrade pip
@@ -41,32 +65,16 @@ Check licenses:
   interruptible: true
 
 Check style:
-  extends: .ci_dir
+  extends: .common_pre_commit
   variables:
-    APK_CACHE_DIR: ${CI_GITIGNORE_DIR}/apk-cache
-    PRE_COMMIT_HOME: ${CI_GITIGNORE_DIR}/pre-commit
-  before_script:
-    - mkdir -p "${APK_CACHE_DIR}"
-    - apk update --cache-dir "${APK_CACHE_DIR}"
-    - apk add --cache-dir "${APK_CACHE_DIR}" git pre-commit
+    CACHE_POLICY: pull-push
   script:
     - pre-commit run --show-diff-on-failure --color=always --all-files
-  tags:
-    - alpine
   rules:
     - if: $CI_PIPELINE_SOURCE == "web"
       when: manual
     - when: always
   interruptible: true
-  cache:
-    - key: ${CI_COMMIT_REF_SLUG}
-      paths:
-        - ${APK_CACHE_DIR}
-    - key:
-        files:
-          - .pre-commit-config.yaml
-      paths:
-        - ${PRE_COMMIT_HOME}
 
 include:
   - project: "anw_dienste/ci-templates"