feat(importer): instrument REST API importing (#2753)

Currently the REST API is entirely silent about what records it is
processing. This commit addresses that and makes the instrumentation
more in line with the Git and GCS sources, for easier debugging.

docker/importer/importer.py

@@ -711,6 +711,7 @@ def _process_updates_rest(self, source_repo: osv.SourceRepository):
         request.text, source_repo.extension, strict=self._strict_validation)
 
     vulns_last_modified = last_update_date
+    logging.info('%d records to consider', len(vulns))
     # Create tasks for changed files.
     for vuln in vulns:
       import_failure_logs = []
@@ -730,6 +731,8 @@ def _process_updates_rest(self, source_repo: osv.SourceRepository):
         _ = osv.parse_vulnerability_from_dict(single_vuln.json(),
                                               source_repo.key_path,
                                               self._strict_validation)
+        logging.info('Requesting analysis of REST record: %s',
+                     vuln.id + source_repo.extension)
         self._request_analysis_external(
             source_repo, osv.sha256_bytes(single_vuln.text.encode()),
             vuln.id + source_repo.extension)