Make the number of green threads configurable

The patch makes the number of green threads configurable by creating a
global eventlet GreenPool, and providing the function utils.spawn_n as a
proxy to create threads using the pool. The total number of threads
available in the pool is configurable through the new max_threads config
option.

Change-Id: Id62ca6a2fc342de0514c6a88af8bebbe94d86dbc
Closes-Bug: #1419736

example.conf

@@ -52,6 +52,9 @@
 # Path to SSL key (string value)
 #ssl_key_path =
 
+# The green thread pool size. (integer value)
+#max_concurrency = 1000
+
 
 [firewall]
 

ironic_inspector/conf.py

@@ -178,6 +178,9 @@ SERVICE_OPTS = [
     cfg.StrOpt('ssl_key_path',
                default='',
                help='Path to SSL key'),
+    cfg.IntOpt('max_concurrency',
+               default=1000,
+               help='The green thread pool size.')
 ]
 
 

ironic_inspector/introspect.py

@@ -16,7 +16,6 @@
 import logging
 import string
 
-import eventlet
 from ironicclient import exceptions
 from oslo_config import cfg
 
@@ -109,7 +108,7 @@ def introspect(uuid, new_ipmi_credentials=None):
             LOG.exception(msg)
             cached_node.finished(error=msg)
 
-    eventlet.greenthread.spawn_n(_handle_exceptions)
+    utils.spawn_n(_handle_exceptions)
 
 
 def _background_introspect(ironic, cached_node):

ironic_inspector/main.py

@@ -160,11 +160,11 @@ def init():
     if CONF.firewall.manage_firewall:
         firewall.init()
         period = CONF.firewall.firewall_update_period
-        eventlet.greenthread.spawn_n(periodic_update, period)
+        utils.spawn_n(periodic_update, period)
 
     if CONF.timeout > 0:
         period = CONF.clean_up_period
-        eventlet.greenthread.spawn_n(periodic_clean_up, period)
+        utils.spawn_n(periodic_clean_up, period)
     else:
         LOG.warning(_LW('Timeout is disabled in configuration'))
 

ironic_inspector/process.py

@@ -156,14 +156,14 @@ def _process_node(ironic, node, node_info, cached_node):
     if cached_node.options.get('new_ipmi_credentials'):
         new_username, new_password = (
             cached_node.options.get('new_ipmi_credentials'))
-        eventlet.greenthread.spawn_n(_finish_set_ipmi_credentials,
+        utils.spawn_n(_finish_set_ipmi_credentials,
                       ironic, node, cached_node, node_info,
                       new_username, new_password)
         return {'ipmi_setup_credentials': True,
                 'ipmi_username': new_username,
                 'ipmi_password': new_password}
     else:
-        eventlet.greenthread.spawn_n(_finish, ironic, cached_node)
+        utils.spawn_n(_finish, ironic, cached_node)
         return {}
 
 

ironic_inspector/test/test_introspect.py

@@ -48,7 +48,7 @@ class BaseTest(test_base.NodeTest):
 
 
 @mock.patch.object(eventlet.greenthread, 'sleep', lambda _: None)
-@mock.patch.object(eventlet.greenthread, 'spawn_n',
+@mock.patch.object(utils, 'spawn_n',
                    lambda f, *a, **kw: f(*a, **kw) and None)
 @mock.patch.object(firewall, 'update_filters', autospec=True)
 @mock.patch.object(node_cache, 'add_node', autospec=True)
@@ -244,7 +244,7 @@ class TestIntrospect(BaseTest):
         self.assertFalse(add_mock.called)
 
 
-@mock.patch.object(eventlet.greenthread, 'spawn_n',
+@mock.patch.object(utils, 'spawn_n',
                    lambda f, *a, **kw: f(*a, **kw) and None)
 @mock.patch.object(firewall, 'update_filters', autospec=True)
 @mock.patch.object(node_cache, 'add_node', autospec=True)

ironic_inspector/test/test_main.py

@@ -181,7 +181,7 @@ class TestPlugins(unittest.TestCase):
                       plugins_base.processing_hooks_manager())
 
 
-@mock.patch.object(eventlet.greenthread, 'spawn_n')
+@mock.patch.object(utils, 'spawn_n')
 @mock.patch.object(firewall, 'init')
 @mock.patch.object(utils, 'add_auth_middleware')
 @mock.patch.object(utils, 'get_client')

ironic_inspector/test/test_process.py

@@ -305,7 +305,7 @@ class TestProcess(BaseTest):
         self.assertFalse(pop_mock.return_value.finished.called)
 
 
-@mock.patch.object(eventlet.greenthread, 'spawn_n',
+@mock.patch.object(utils, 'spawn_n',
                    lambda f, *a: f(*a) and None)
 @mock.patch.object(eventlet.greenthread, 'sleep', lambda _: None)
 @mock.patch.object(example_plugin.ExampleProcessingHook, 'before_update')

ironic_inspector/test/test_utils.py

@@ -16,12 +16,16 @@ import unittest
 import eventlet
 from ironicclient import exceptions
 from keystonemiddleware import auth_token
-import mock
 from oslo_config import cfg
 
 from ironic_inspector.test import base
 from ironic_inspector import utils
 
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
 CONF = cfg.CONF
 
 
@@ -124,3 +128,24 @@ class TestCapabilities(unittest.TestCase):
         output = utils.dict_to_capabilities(capabilities_dict)
         self.assertIn('cat:meow', output)
         self.assertIn('dog:wuff', output)
+
+
+class TestSpawnN(unittest.TestCase):
+
+    def setUp(self):
+        super(TestSpawnN, self).setUp()
+        utils.GREEN_POOL = None
+
+    @mock.patch('eventlet.greenpool.GreenPool', autospec=True)
+    def test_spawn_n(self, mock_green_pool):
+        greenpool = mock_green_pool.return_value
+        func = lambda x: x
+
+        utils.spawn_n(func, "hello")
+        self.assertEqual(greenpool, utils.GREEN_POOL)
+        greenpool.spawn_n.assert_called_with(func, "hello")
+
+        utils.spawn_n(func, "goodbye")
+        greenpool.spawn_n.assert_called_with(func, "goodbye")
+
+        mock_green_pool.assert_called_once_with(CONF.max_concurrency)

ironic_inspector/utils.py

@@ -34,6 +34,8 @@ LOG = logging.getLogger('ironic_inspector.utils')
 RETRY_COUNT = 12
 RETRY_DELAY = 5
 
+GREEN_POOL = None
+
 
 class Error(Exception):
     """Inspector exception."""
@@ -44,6 +46,13 @@ class Error(Exception):
         self.http_code = code
 
 
+def spawn_n(*args, **kwargs):
+    global GREEN_POOL
+    if not GREEN_POOL:
+        GREEN_POOL = eventlet.greenpool.GreenPool(CONF.max_concurrency)
+    return GREEN_POOL.spawn_n(*args, **kwargs)
+
+
 def get_client():  # pragma: no cover
     """Get Ironic client instance."""
     args = dict({'os_password': CONF.ironic.os_password,