Sync eventlet_backdoor from oslo.

Change-Id: I2b0021e0612226e71700d74c865a84a5b6d8e735
Signed-off-by: Matthew Treinish <treinish@linux.vnet.ibm.com>

nova/openstack/common/eventlet_backdoor.py

@@ -0,0 +1,80 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright (c) 2012 Openstack, LLC.
+# Administrator of the National Aeronautics and Space Administration.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import gc
+import pprint
+import sys
+import traceback
+
+import eventlet
+import eventlet.backdoor
+import greenlet
+
+from nova.openstack.common import cfg
+
+eventlet_backdoor_opts = [
+    cfg.IntOpt('backdoor_port',
+               default=None,
+               help='port for eventlet backdoor to listen')
+]
+
+CONF = cfg.CONF
+CONF.register_opts(eventlet_backdoor_opts)
+
+
+def _dont_use_this():
+    print "Don't use this, just disconnect instead"
+
+
+def _find_objects(t):
+    return filter(lambda o: isinstance(o, t), gc.get_objects())
+
+
+def _print_greenthreads():
+    for i, gt in enumerate(find_objects(greenlet.greenlet)):
+        print i, gt
+        traceback.print_stack(gt.gr_frame)
+        print
+
+
+def initialize_if_enabled():
+    backdoor_locals = {
+        'exit': _dont_use_this,      # So we don't exit the entire process
+        'quit': _dont_use_this,      # So we don't exit the entire process
+        'fo': _find_objects,
+        'pgt': _print_greenthreads,
+    }
+
+    if CONF.backdoor_port is None:
+        return None
+
+    # NOTE(johannes): The standard sys.displayhook will print the value of
+    # the last expression and set it to __builtin__._, which overwrites
+    # the __builtin__._ that gettext sets. Let's switch to using pprint
+    # since it won't interact poorly with gettext, and it's easier to
+    # read the output too.
+    def displayhook(val):
+        if val is not None:
+            pprint.pprint(val)
+    sys.displayhook = displayhook
+
+    sock = eventlet.listen(('localhost', CONF.backdoor_port))
+    port = sock.getsockname()[1]
+    eventlet.spawn_n(eventlet.backdoor.backdoor_server, sock,
+                     locals=backdoor_locals)
+    return port

openstack-common.conf

@@ -1,7 +1,7 @@
 [DEFAULT]
 
 # The list of modules to copy from openstack-common
-modules=cfg,context,excutils,fileutils,gettextutils,importutils,iniparser,jsonutils,local,lockutils,log,network_utils,notifier,plugin,policy,setup,timeutils,rpc,uuidutils
+modules=cfg,context,excutils,eventlet_backdoor,fileutils,gettextutils,importutils,iniparser,jsonutils,local,lockutils,log,network_utils,notifier,plugin,policy,setup,timeutils,rpc,uuidutils
 
 # The base module to hold the copy of openstack.common
 base=nova