swarming: Add server-side implementation for supplemental bot_config

appengine/swarming/handlers_bot_test.py

Index: appengine/swarming/handlers_bot_test.py
diff --git a/appengine/swarming/handlers_bot_test.py b/appengine/swarming/handlers_bot_test.py
index 4912a9bf62a1c69c2c2c9cca7b02a09eb2d535a5..f2ddc483cf433b54b7e98a0bf4d601a377ccc197 100755
--- a/appengine/swarming/handlers_bot_test.py
+++ b/appengine/swarming/handlers_bot_test.py
@@ -434,7 +434,8 @@ class BotApiTest(test_env_handlers.AppTestBase):
         require_service_account=None,
         ip_whitelist=None,
         owners=None,
-        dimensions={u'pool': [u'server-side']})
+        dimensions={u'pool': [u'server-side']},
+        bot_config_script='')
     self.mock(bot_auth, 'validate_bot_id_and_fetch_config',
               lambda *args, **kwargs: cfg)
 
@@ -461,6 +462,41 @@ class BotApiTest(test_env_handlers.AppTestBase):
         },
     }], actions)
 
+  def test_poll_missing_extra_bot_config(self):
+    cfg = bot_groups_config.BotGroupConfig(
+        version='default',
+        require_luci_machine_token=False,
+        require_service_account=None,
+        ip_whitelist=None,
+        owners=None,
+        dimensions={},
+        bot_config_script='foo.py')
+    self.mock(bot_auth, 'validate_bot_id_and_fetch_config',
+              lambda *args, **kwargs: cfg)
+    self.do_handshake(status=503)
+
+  def test_poll_extra_bot_config(self):
+    cfg = bot_groups_config.BotGroupConfig(
+        version='default',
+        require_luci_machine_token=False,
+        require_service_account=None,
+        ip_whitelist=None,
+        owners=None,
+        dimensions={},
+        bot_config_script='foo.py')
+    self.mock(bot_auth, 'validate_bot_id_and_fetch_config',
+              lambda *args, **kwargs: cfg)
+    # Inject the script.
+    def get_self_config(name, store_last_good):
+      self.assertEqual(True, store_last_good)
+      if name == 'scripts/bot_config.py':
+        return None, None
+      self.assertEqual('scripts/foo.py', name)
+      return '1', 'import sys; sys.exit(1)'
+    self.mock(handlers_bot.config.config, 'get_self_config', get_self_config)
+    params = self.do_handshake()
+    self.assertEqual(u'import sys; sys.exit(1)', params['bot_config'])
+
   def test_complete_task_isolated(self):
     # Successfully poll a task.
     self.mock(random, 'getrandbits', lambda _: 0x88)