Changeset 1392

Timestamp:

02/22/07 16:32:40 (6 years ago)

Author:

mglb1

Message:

Use a lock so that we only have one thread executing the session maintenance
routine at a time. If a second thread tries to run at the same time, exit
immediately. The only scenario for this to happen is if the first thread has
blocked on IO and is waiting for it to complete. So there is no point starting
a second thread which is going to do the same thing...

File:

• ccsd/trunk/crcnetd/_utils/ccsd_session.py (modified) (3 diffs)

ccsd/trunk/crcnetd/_utils/ccsd_session.py

@@ -870 +870 @@
 def sessionMaintenance(*args, **kwargs):
     """Checks for expired sessions and removes them"""
-    start = time.time()
-    asession = getSessionE(ADMIN_SESSION_ID)
-    
-    # Loop through the list of sessions and remove expired ones
-    for sessionID,session in ccsd_session.sessions.items():
-        # Never expire the admin session
-        if sessionID==ADMIN_SESSION_ID: continue
-        if session.isExpired(): continue
-        # Not expired, update db expiry time if we're expiring "soon"
-        if session.lifetime() < MAINT_INTERVAL * 3:
-            sql = "UPDATE sessions SET expires=%s WHERE sid=%s"
-            res = asession.execute(sql, \
-                    (time.ctime(session.expires), session.session_id))
-
-    # Also delete expired login cookies
-    session = getSessionE(ADMIN_SESSION_ID)
-    sql = "DELETE FROM cookies WHERE expires<NOW()"
-    res = session.execute(sql, ())
-    log_debug("Session maintenance completed successfully in %.3f seconds" % \
-            (time.time()-start))
-    
+    global sessionLock
+
+    # Ensure that only one thread is executing session maintenance at once
+    if not sessionLock.acquire(False):
+        log_warn("A previous session maintenance task is still in progress!")
+        return
+    try:
+        ct = threading.currentThread()
+        ct.setName("sessionMaintenance")
+        start = time.time()
+        asession = getSessionE(ADMIN_SESSION_ID)
+        
+        # Loop through the list of sessions and remove expired ones
+        for sessionID,session in ccsd_session.sessions.items():
+            # Never expire the admin session
+            if sessionID==ADMIN_SESSION_ID: continue
+            if session.isExpired(): continue
+            # Not expired, update db expiry time if we're expiring "soon"
+            if session.lifetime() < MAINT_INTERVAL * 3:
+                sql = "UPDATE sessions SET expires=%s WHERE sid=%s"
+                res = asession.execute(sql, \
+                        (time.ctime(session.expires), session.session_id))
+
+        # Also delete expired login cookies
+        session = getSessionE(ADMIN_SESSION_ID)
+        sql = "DELETE FROM cookies WHERE expires<NOW()"
+        res = session.execute(sql, ())
+        log_debug("Session maintenance completed successfully in %.3f " \
+                "seconds" % (time.time()-start))
+    except:
+        log_error("Failed to complete session maintenace", sys.exc_info())
+    sessionLock.release()
+
 @catchEvent("shutdown")
 def shutdownSessions(*args, **kwargs):
@@ -1160 +1172 @@
 #####################################################################
 def initSessions():
+    global sessionLock
     try:
         # Get database connection parameters
@@ -1179 +1192 @@
         # Load any other saved sessions
         ccsd_session.sessions.update(loadSessions())
+        
+        # Initialise the lock
+        sessionLock = threading.RLock()
 
         log_info("Successfully loaded sessions")