[FLINK-32392][ci] Invalidate Maven repo cache on Azure every year to …

…reduce its disk usage

azure-pipelines.yml

@@ -52,6 +52,7 @@ variables:
   E2E_CACHE_FOLDER: $(Pipeline.Workspace)/e2e_cache
   E2E_TARBALL_CACHE: $(Pipeline.Workspace)/e2e_artifact_cache
   MAVEN_ARGS: '-Dmaven.repo.local=$(MAVEN_CACHE_FOLDER)'
+  PIPELINE_START_YEAR: $[format('{0:yyyy}', pipeline.startTime)]
   CACHE_KEY: maven | $(Agent.OS) | **/pom.xml, !**/target/**
   CACHE_FALLBACK_KEY: maven | $(Agent.OS)
   DOCKER_IMAGES_CACHE_KEY: docker-images-cache | $(Agent.OS) | **/cache_docker_images.sh | flink-test-utils-parent/**/DockerImageVersions.java

tools/azure-pipelines/build-apache-repo.yml

@@ -46,6 +46,7 @@ variables:
   E2E_CACHE_FOLDER: $(Pipeline.Workspace)/e2e_cache
   E2E_TARBALL_CACHE: $(Pipeline.Workspace)/e2e_artifact_cache
   MAVEN_ARGS: '-Dmaven.repo.local=$(MAVEN_CACHE_FOLDER)'
+  PIPELINE_START_YEAR: $[format('{0:yyyy}', pipeline.startTime)]
   CACHE_KEY: maven | $(Agent.OS) | **/pom.xml, !**/target/**
   CACHE_FALLBACK_KEY: maven | $(Agent.OS)
   DOCKER_IMAGES_CACHE_KEY: docker-images-cache | $(Agent.OS) | **/cache_docker_images.sh | flink-test-utils-parent/**/DockerImageVersions.java

tools/azure-pipelines/build-nightly-dist.yml

@@ -27,8 +27,8 @@ jobs:
       - task: Cache@2
         displayName: Cache Maven local repo
         inputs:
-          key: $(CACHE_KEY)
-          restoreKeys: $(CACHE_FALLBACK_KEY)
+          key: $(PIPELINE_START_YEAR) | $(CACHE_KEY)
+          restoreKeys: $(PIPELINE_START_YEAR) | $(CACHE_FALLBACK_KEY)
           path: $(MAVEN_CACHE_FOLDER)
         continueOnError: true
       - script: |
@@ -79,8 +79,8 @@ jobs:
       - task: Cache@2
         displayName: Cache Maven local repo
         inputs:
-          key: $(CACHE_KEY)
-          restoreKeys: $(CACHE_FALLBACK_KEY)
+          key: $(PIPELINE_START_YEAR) | $(CACHE_KEY)
+          restoreKeys: $(PIPELINE_START_YEAR) | $(CACHE_FALLBACK_KEY)
           path: $(MAVEN_CACHE_FOLDER)
         continueOnError: true
       - script: |

tools/azure-pipelines/e2e-template.yml

@@ -58,8 +58,8 @@ jobs:
       displayName: Create cache directories
     - task: Cache@2
       inputs:
-        key: $(CACHE_KEY)
-        restoreKeys: $(CACHE_FALLBACK_KEY)
+        key: $(PIPELINE_START_YEAR) | $(CACHE_KEY)
+        restoreKeys: $(PIPELINE_START_YEAR) | $(CACHE_FALLBACK_KEY)
         path: $(MAVEN_CACHE_FOLDER)
       displayName: Cache Maven local repo
       continueOnError: true

tools/azure-pipelines/jobs-template.yml

@@ -49,11 +49,14 @@ jobs:
   # as a key for the build cache (CACHE_KEY). If we have a cache miss on the hash
   # (usually because a pom file has changed), we'll fall back to a key without
   # the pom files (CACHE_FALLBACK_KEY).
+  # Note that we use the year number that the pipeline run starts in the cache key,
+  # which means the cache is invalidated per year, in order to avoid the size of
+  # cached .m2 directory growing indefinitely.
   # Offical documentation of the Cache task: https://docs.microsoft.com/en-us/azure/devops/pipelines/caching/?view=azure-devops
   - task: Cache@2
     inputs:
-      key: $(CACHE_KEY)
-      restoreKeys: $(CACHE_FALLBACK_KEY)
+      key: $(PIPELINE_START_YEAR) | $(CACHE_KEY)
+      restoreKeys: $(PIPELINE_START_YEAR) | $(CACHE_FALLBACK_KEY)
       path: $(MAVEN_CACHE_FOLDER)
     continueOnError: true # continue the build even if the cache fails.
     # do not use cache on the "Default" queue
@@ -118,8 +121,8 @@ jobs:
 
   - task: Cache@2
     inputs:
-      key: $(CACHE_KEY)
-      restoreKeys: $(CACHE_FALLBACK_KEY)
+      key: $(PIPELINE_START_YEAR) | $(CACHE_KEY)
+      restoreKeys: $(PIPELINE_START_YEAR) | $(CACHE_FALLBACK_KEY)
       path: $(MAVEN_CACHE_FOLDER)
     continueOnError: true # continue the build even if the cache fails.
     condition: not(eq('${{parameters.test_pool_definition.name}}', 'Default'))