Utility for listing the Bug IDs for a source in Datastore (#2212)

Helpful for large-scale data operations and comparing between staging
and production.

Borrowed heavily from reimport_gcs_record.py

tools/datafix/list_ids_for_source.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+"""Utility to list the Bug IDs for all of the PROCESSED Bugs in Cloud Datastore.
+
+Cloud Datastore lacks a CLI for issuing queries, and sometimes it's helpful to
+reason about all of the Bug IDs present for a given a source.
+"""
+
+from google.cloud import datastore
+from google.cloud.datastore.query import PropertyFilter
+
+import argparse
+
+MAX_BATCH_SIZE = 500
+
+
+def main() -> None:
+  parser = argparse.ArgumentParser(
+      description="Query the identifiers for the Bugs in Datastore "
+      "in a PROCESSED state for a given source")
+  parser.add_argument(
+      "--verbose",
+      action=argparse.BooleanOptionalAction,
+      dest="verbose",
+      default=False,
+      help="Be more verbose")
+  parser.add_argument(
+      "--project",
+      action="store",
+      dest="project",
+      default="oss-vdb-test",
+      help="GCP project to operate on")
+  parser.add_argument(
+      "--source_id",
+      action="store",
+      dest="source_id",
+      default="cve-osv",
+      help="the source_id to filter on")
+  args = parser.parse_args()
+
+  ds_client = datastore.Client(project=args.project)
+
+  query = ds_client.query(kind="Bug")
+  query.add_filter(filter=PropertyFilter("source", "=", args.source_id))
+  query.add_filter(filter=PropertyFilter("status", "=", 1))
+  print(f"Running query {query.filters} "
+        f"on {query.kind} (in {query.project})...")
+  result = list(query.fetch())
+  print(f"Retrieved {len(result)} bugs")
+
+  # Chunk the results to modify in acceptibly sized batches for the API.
+  for batch in range(0, len(result), MAX_BATCH_SIZE):
+    for bug in result[batch:batch + MAX_BATCH_SIZE]:
+      print(f"{bug['db_id']}")
+
+
+if __name__ == "__main__":
+  main()