From 3ee803c2ba32702c3476b517f8df4c4aa5f578d4 Mon Sep 17 00:00:00 2001
From: Fabio Erculiani <lxnay@sabayon.org>
Date: Sun, 9 Sep 2012 18:04:52 +0200
Subject: [PATCH] [entropy.const] implement a debug watchdog thread dumper
 thread.

If ETP_DEBUG_WATCHDOG env variable is set, entropy.const will create
a timer thread that prints to stderr the full application thread dump.
This is quite useful in case of hard to reproduce deadlocks at the library
level.
---
 lib/entropy/const.py | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/lib/entropy/const.py b/lib/entropy/const.py
index c61df11b9..050bd2f9f 100644
--- a/lib/entropy/const.py
+++ b/lib/entropy/const.py
@@ -1676,3 +1676,34 @@ def const_get_cpus():
 
 # load config
 initconfig_entropy_constants(etpSys['rootdir'])
+
+# Debug Watchdog support. If enabled, a thread dump
+# will be pushed to stderr every ETP_DEBUG_WATCHDOG_INTERVAL
+# seconds (or 60 seconds if unset).
+_debug_watchdog = os.getenv("ETP_DEBUG_WATCHDOG")
+if _debug_watchdog is not None:
+    from threading import Timer
+    _default_debug_watchdog_interval = 60
+    _debug_watchdog_interval = os.getenv(
+        "ETP_DEBUG_WATCHDOG_INTERVAL",
+        _default_debug_watchdog_interval)
+    try:
+        _debug_watchdog_interval = int(_debug_watchdog_interval)
+    except (ValueError, TypeError):
+        _debug_watchdog_interval = _default_debug_watchdog_interval
+
+    const_debug_write(
+        __name__,
+        "DebugWatchdogTimer enabled, interval: %d" % (
+            _debug_watchdog_interval,))
+
+    def _dumper():
+        dump_signal(None, None)
+        _setup_timer()
+
+    def _setup_timer():
+        _timer = Timer(_debug_watchdog_interval, _dumper)
+        _timer.name = "DebugWatchdogTimer"
+        _timer.daemon = True
+        _timer.start()
+    _setup_timer()