Added an event to hook in thread pool monitoring.

CHANGES.txt

@@ -7,6 +7,7 @@ CHANGES
 -------------------
 
 - Added the thread stack trace to the log message.
+- Added an event to hook in monitoring of thread pool state.
 
 
 1.0.9 (2013-10-02)

src/cipher/longrequest/interfaces.py

@@ -104,3 +104,19 @@ def __init__(self, thread_id, duration, uri):
         self.thread_id = thread_id
         self.duration = duration
         self.uri = uri
+
+
+class ILongRequestTickEvent(zope.interface.Interface):
+    """An hook for additional processing of the thread pool
+
+    Can be used for things like monitoring the number of busy threads.
+    """
+
+    thread_pool = zope.interface.Attribute("Thread pool")
+
+
+class LongRequestTickEvent(object):
+    zope.interface.implements(ILongRequestTickEvent)
+
+    def __init__(self, thread_pool):
+        self.thread_pool = thread_pool

src/cipher/longrequest/longrequest.py

@@ -172,6 +172,7 @@ def doWork(self):
             if thread_id not in workingThreadIds:
                 del ZOPE_THREAD_REQUESTS[thread_id]
 
+        notify(interfaces.LongRequestTickEvent(THREADPOOL))
         workers = THREADPOOL.worker_tracker.items()
         for thread_id, (time_started, worker_environ) in workers:
             # make a duplicate of worker_environ ASAP