Extracts a Client ID from an APIAuditEntry's HTTP request path.

def _ExtractClientIdFromPath(entry, event):
  """Extracts a Client ID from an APIAuditEntry's HTTP request path."""
  match = re.match(r".*(C\.[0-9a-fA-F]{16}).*", entry.http_request_path)
  if match:
    event.client = match.group(1)