swarming: Back off requests on poll failure.

appengine/swarming/swarming_bot/bot_code/bot_main.py

Index: appengine/swarming/swarming_bot/bot_code/bot_main.py
diff --git a/appengine/swarming/swarming_bot/bot_code/bot_main.py b/appengine/swarming/swarming_bot/bot_code/bot_main.py
index b50d7ebbd95b2e19b6e0bbb20978d656c5b360c6..378fd973f01ef26c18407bc168644aad98d1cac3 100644
--- a/appengine/swarming/swarming_bot/bot_code/bot_main.py
+++ b/appengine/swarming/swarming_bot/bot_code/bot_main.py
@@ -518,6 +518,8 @@ def poll_server(botobj, quit_bit):
   resp = botobj.remote.url_read_json(
       '/swarming/api/v1/bot/poll', data=botobj._attributes)
   if not resp:
+    # Back off on failure.
+    time.sleep(min(1, max(60, botobj.state.get('sleep_streak', 10) * 2)))

[Vadim Sh., 2016/07/26 17:56:13]

this will always be time.sleep(1)

[M-A Ruel, 2016/07/28 15:26:04]

Apologies for making you go through this. Fixed.

     return False
   logging.debug('Server response:\n%s', resp)