Collect gsutil process count in devserver

One major cause of devserver overload is too many downloading attempts from
gsutil. That leads to disk io and CPU load issue. This change collects the
gsutil process count in check_health, so caller can use that data to pick
a healthy devserver.

BUG=None
TEST=run devserver, curl http://localhost:8080/check_health

Change-Id: Ib4980164bc23e5d6af12a5c75a53745c8a659311
Reviewed-on: https://chromium-review.googlesource.com/348710
Commit-Ready: Dan Shi <dshi@google.com>
Tested-by: Dan Shi <dshi@google.com>
Reviewed-by: Dan Shi <dshi@google.com>
1 file changed