Add the ability to send SIGPROF to an edx-platform process to obtain a memory dump

cms/wsgi.py

@@ -6,8 +6,10 @@ defuse_xml_libs()
 import contracts
 contracts.disable_all()
 
-import os
+import openedx.core.operations
+openedx.core.operations.install_memory_dumper()
 
+import os
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "cms.envs.aws")
 
 import cms.startup as startup

lms/wsgi.py

@@ -6,8 +6,10 @@ defuse_xml_libs()
 import contracts
 contracts.disable_all()
 
-import os
+import openedx.core.operations
+openedx.core.operations.install_memory_dumper()
 
+import os
 os.environ.setdefault("DJANGO_SETTINGS_MODULE", "lms.envs.aws")
 
 import lms.startup as startup

openedx/core/operations.py

+import os
+import signal
+import tempfile
+
+from datetime import datetime
+from meliae import scanner
+
+
+def dump_memory(signum, frame):
+    """Dump memory stats for the current process to a temp directory. Uses the meliae output format."""
+    scanner.dump_all_objects('{}/meliae.{}.{}.dump'.format(tempfile.gettempdir(), datetime.now().isoformat(), os.getpid()))
+
+def install_memory_dumper(dump_signal=signal.SIGPROF):
+    """
+    Install a signal handler on `signal` to dump memory stats for the current process.
+    """
+    signal.signal(dump_signal, dump_memory)

requirements/edx/base.txt

@@ -50,6 +50,9 @@ lazy==1.1
 lxml==3.3.6
 mako==0.9.1
 Markdown==2.2.1
+--allow-external meliae
+--allow-unverified meliae
+meliae==0.4.0
 mongoengine==0.7.10
 networkx==1.7
 nltk==2.0.4

requirements/edx/pre.txt

@@ -10,3 +10,6 @@ numpy==1.6.2
 
 # Needed to make sure that options in base.txt are allowed
 pip==6.0.7
+
+# Needed for meliae
+Cython==0.21.2