Count configured minimum and maximum numbers of instances

appengine/gce-backend/config.py

 # Copyright 2016 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 """Utilities for reading GCE Backend configuration."""
 
 import collections
 import logging
 
 from components import utils
@@ skipping 47 matching lines @@
         'template.cfg', configuration.template_config,
         config_pb2.InstanceTemplateConfig()
     )
     manager_cfg = _adds_cfg_to_message(
         'manager.cfg', configuration.manager_config,
         config_pb2.InstanceGroupManagerConfig()
     )
     return template_cfg, manager_cfg
 
 
+def count_instances():
+  """Counts the numbers of instances configured by each instance template.
+
+  Returns:
+    A dict mapping instance template name to a list of (min, max).
+  """
+  # Aggregate the numbers of instances configured in each instance group manager
+  # created for each instance template.
+  totals = collections.defaultdict(lambda: [0, 0])
+  _, manager_cfg = Configuration.load()
+  for manager in manager_cfg.managers:
+    totals[manager.template_base_name][0] += manager.minimum_size
+    totals[manager.template_base_name][1] += manager.maximum_size
+  return totals
+
+
 def update_template_configs():
   """Updates the local template configuration from the config service.
 
   Ensures that all config files are at the same path revision.
   """
   template_revision, template_config = config.get_self_config(
       TEMPLATES_CFG_FILENAME, config_pb2.InstanceTemplateConfig,
       store_last_good=True)
   manager_revision, manager_config = config.get_self_config(
       MANAGERS_CFG_FILENAME, config_pb2.InstanceGroupManagerConfig,
@@ skipping 116 matching lines @@
     if cfg.mp_server != current_config.instance_url:
       logging.info('Updating Machine Provider server to %s', cfg.mp_server)
       current_config.modify(instance_url=cfg.mp_server)
   return rev, cfg
 
 
 @utils.cache_with_expiration(60)
 def settings():
   """Loads settings from an NDB-based cache or a default one if not present."""
   return _get_settings()[1]