Add CI script for deleting old cache entries

This script finds hub cache entries that have a last access time older than 30 days
and will delete them from the cache. This way, if a model is not used by the CI
anymore it does not eat up disk space needlessly.

.github/workflows/tests.yml

@@ -96,6 +96,9 @@ jobs:
           [ -f "$(which shasum)" ] && SHASUM=shasum
           find "${{ env.HF_HOME }}/hub" -type f -exec "$SHASUM" {} \; > cache_content_after
           diff -udp cache_content_initial cache_content_after || true
+      - name: Delete old model cache entries
+        run: |
+          python scripts/ci_clean_cache.py -d
       - name: Update model cache
         uses: actions/cache/save@v4
         # Only let one runner (preferably the one that covers most tests) update the model cache

scripts/ci_clean_cache.py

@@ -0,0 +1,61 @@
+"""
+Utility to clean cache files that exceed a specific time in days according to their
+last access time recorded in the cache.
+
+Exit code:
+- 1 if no candidates are found
+- 0 if candidates are found
+
+Deletion can be enabled by passing `-d` parameter, otherwise it will only list the candidates.
+"""
+import sys
+import argparse
+from huggingface_hub import scan_cache_dir
+from datetime import datetime as dt
+
+
+def find_old_revisions(scan_results, max_age_days=30):
+    """Find commit hashes of objects in the cache. These objects need a last access time that
+    is above the passed `max_age_days` parameter. Returns an empty list if no objects are found.
+    Time measurement is based of the current time and the recorded last access tiem in the cache.
+    """
+    now = dt.now()
+    revisions = [(i.revisions, i.last_accessed) for i in scan_results.repos]
+    revisions_ages = [(rev, (now - dt.fromtimestamp(ts_access)).days) for rev, ts_access in revisions]
+    delete_candidates = [rev for rev, age in revisions_ages if age > max_age_days]
+    hashes = [n.commit_hash for rev in delete_candidates for n in rev]
+
+    return hashes
+
+
+def delete_old_revisions(scan_results, delete_candidates, do_delete=False):
+    delete_operation = scan_results.delete_revisions(*delete_candidates)
+    print(f'Would free {delete_operation.expected_freed_size_str}')
+    print(f'Candidates: {delete_candidates}')
+
+    if do_delete:
+        print("Deleting now.")
+        delete_operation.execute()
+    else:
+        print("Not deleting, pass the -d flag.")
+
+
+if __name__ == "__main__":
+    from argparse import ArgumentParser
+
+    parser = ArgumentParser()
+    parser.add_argument('-a', '--max-age', type=int, default=30, help="Max. age in days items in the cache may have.")
+    parser.add_argument('-d', '--delete', action='store_true', help=(
+        "Delete mode; Really delete items if there are candidates. Exit code = 0 when we found something to delete, 1 "
+        "otherwise."
+    ))
+    args = parser.parse_args()
+
+    scan_results = scan_cache_dir()
+
+    delete_candidates = find_old_revisions(scan_results, args.max_age)
+    if not delete_candidates:
+        print('No delete candidates found, not deleting anything.')
+        sys.exit(1)
+
+    delete_old_revisions(scan_results, delete_candidates, do_delete=args.delete)