Improve debugging of thread and other leaks

- Add basethread.BaseThread that all threads outside of test suites should use
- Add a signal handler to mitmproxy, mitmdump and mitmweb that dumps resource
information to screen when SIGUSR1 is received.
- Improve thread naming throughout to make thread dumps understandable

3 files changed, 86 insertions, 17 deletions

diff --git a/netlib/basethread.py b/netlib/basethread.py
new file mode 100644
index 00000000..7963eb7e
--- /dev/null
+++ b/netlib/basethread.py
@@ -0,0 +1,14 @@
+import time
+import threading
+
+
+class BaseThread(threading.Thread):
+    def __init__(self, name, *args, **kwargs):
+        super(BaseThread, self).__init__(name=name, *args, **kwargs)
+        self._thread_started = time.time()
+
+    def _threadinfo(self):
+        return "%s - age: %is" % (
+            self.name,
+            int(time.time() - self._thread_started)
+        )
diff --git a/netlib/debug.py b/netlib/debug.py
index bf446eb0..b48cb122 100644
--- a/netlib/debug.py
+++ b/netlib/debug.py
@@ -1,29 +1,76 @@
+from __future__ import (absolute_import, print_function, division)
+
+import sys
+import threading
+import signal
 import platform
+
+import psutil
+
 from netlib import version
 
-"""
-    Some utilities to help with debugging.
-"""
 
 def sysinfo():
     data = [
-        "Mitmproxy verison: %s"%version.VERSION,
-        "Python version: %s"%platform.python_version(),
-        "Platform: %s"%platform.platform(),
+        "Mitmproxy verison: %s" % version.VERSION,
+        "Python version: %s" % platform.python_version(),
+        "Platform: %s" % platform.platform(),
     ]
     d = platform.linux_distribution()
-    t = "Linux distro: %s %s %s"%d
-    if d[0]: # pragma: no-cover
+    t = "Linux distro: %s %s %s" % d
+    if d[0]:  # pragma: no-cover
         data.append(t)
 
     d = platform.mac_ver()
-    t = "Mac version: %s %s %s"%d
-    if d[0]: # pragma: no-cover
+    t = "Mac version: %s %s %s" % d
+    if d[0]:  # pragma: no-cover
         data.append(t)
 
     d = platform.win32_ver()
-    t = "Windows version: %s %s %s %s"%d
-    if d[0]: # pragma: no-cover
+    t = "Windows version: %s %s %s %s" % d
+    if d[0]:  # pragma: no-cover
         data.append(t)
 
     return "\n".join(data)
+
+
+def dump_info(sig, frm, file=sys.stdout):  # pragma: no cover
+    p = psutil.Process()
+
+    print("****************************************************", file=file)
+    print("Summary", file=file)
+    print("=======", file=file)
+    print("num threads: ", p.num_threads(), file=file)
+    print("num fds: ", p.num_fds(), file=file)
+    print("memory: ", p.memory_info(), file=file)
+
+    print(file=file)
+    print("Threads", file=file)
+    print("=======", file=file)
+    bthreads = []
+    for i in threading.enumerate():
+        if hasattr(i, "_threadinfo"):
+            bthreads.append(i)
+        else:
+            print(i.name, file=file)
+    bthreads.sort(key=lambda x: x._thread_started)
+    for i in bthreads:
+        print(i._threadinfo(), file=file)
+
+    print(file=file)
+    print("Files", file=file)
+    print("=====", file=file)
+    for i in p.open_files():
+        print(i, file=file)
+
+    print(file=file)
+    print("Connections", file=file)
+    print("===========", file=file)
+    for i in p.connections():
+        print(i, file=file)
+
+    print("****************************************************", file=file)
+
+
+def register_info_dumper():  # pragma: no cover
+    signal.signal(signal.SIGUSR1, dump_info)
diff --git a/netlib/tcp.py b/netlib/tcp.py
index 0eec326b..acd67cad 100644
--- a/netlib/tcp.py
+++ b/netlib/tcp.py
@@ -17,7 +17,11 @@ import six
 import OpenSSL
 from OpenSSL import SSL
 
-from netlib import certutils, version_check, basetypes, exceptions
+from netlib import certutils
+from netlib import version_check
+from netlib import basetypes
+from netlib import exceptions
+from netlib import basethread
 
 # This is a rather hackish way to make sure that
 # the latest version of pyOpenSSL is actually installed.
@@ -900,12 +904,16 @@ class TCPServer(object):
                         raise
                 if self.socket in r:
                     connection, client_address = self.socket.accept()
-                    t = threading.Thread(
+                    t = basethread.BaseThread(
+                        "TCPConnectionHandler (%s: %s:%s -> %s:%s)" % (
+                            self.__class__.__name__,
+                            client_address[0],
+                            client_address[1],
+                            self.address.host,
+                            self.address.port
+                        ),
                         target=self.connection_thread,
                         args=(connection, client_address),
-                        name="ConnectionThread (%s:%s -> %s:%s)" %
-                             (client_address[0], client_address[1],
-                              self.address.host, self.address.port)
                     )
                     t.setDaemon(1)
                     try: