The gcloud log shows:

2018-01-25 00:58:54 default[20171121t145824]  WARNING:root:Invalid build_type None
2018-01-25 00:58:54 default[20171121t145824]  ERROR:root:Exception for getting CL status for change gerrit_host: "chromium-review.googlesource.com"
2018-01-25 00:58:54 default[20171121t145824]  change_number: 882162
2018-01-25 00:58:54 default[20171121t145824]  patch_number: 3
2018-01-25 00:58:54 default[20171121t145824]  : None has type NoneType, but expected one of: int, long

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/infra/cl_status_viewer/+/8f8fb2b2a07986c26a3d4f9198e1735635678e98

commit 8f8fb2b2a07986c26a3d4f9198e1735635678e98
Author: Ningning Xia <nxia@google.com>
Date: Thu Jan 25 02:39:51 2018

Set build_category to UNKNOWN for invalid build_type.

BUG= chromium:805743 
TEST=unit_tests

Change-Id: Ice721ba6e2676b895f91a7f07033fb9abff4d69d

[modify] https://crrev.com/8f8fb2b2a07986c26a3d4f9198e1735635678e98/cl_status_viewer_server/cl_status_server_unittest.py
[modify] https://crrev.com/8f8fb2b2a07986c26a3d4f9198e1735635678e98/cl_status_viewer_server/cl_status_server.py
[modify] https://crrev.com/8f8fb2b2a07986c26a3d4f9198e1735635678e98/cl_status_viewer_server/v1.py