[IMP] cron: the maximum number of cron threads is configurable.

bzr revid: vmt@openerp.com-20110808135453-qdlhkyupb6803jln

openerp/conf/__init__.py

@@ -32,4 +32,10 @@ of paths.
 
 import deprecation
 
+# Maximum number of threads processing concurrently cron jobs.
+# Access to this variable must be thread-safe; they have to be done
+# through the functions in openerp.cron.
+max_cron_threads = 4 # Actually the default value here is meaningless,
+                     # look at tools.config for the default value.
+
 # vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4:

openerp/cron.py

@@ -64,10 +64,8 @@ _wakeup_by_db = {}
 # while spawning a few threads.
 _wakeups_lock = threading.RLock()
 
-# Maximum number of threads allowed to process cron jobs concurrently.
-_thread_count = 2 # TODO make it configurable
-
-# A (non re-entrant) lock to protect the above _thread_count variable.
+# A (non re-entrant) lock to protect the openerp.conf.max_cron_threads
+# variable.
 _thread_count_lock = threading.Lock()
 
 _logger = logging.getLogger('cron')
@@ -75,21 +73,19 @@ _logger = logging.getLogger('cron')
 
 def get_thread_count():
     """ Return the number of available threads. """
-    return _thread_count
+    return openerp.conf.max_cron_threads
 
 
 def inc_thread_count():
     """ Increment by the number of available threads. """
-    global _thread_count
     with _thread_count_lock:
-        _thread_count += 1
+        openerp.conf.max_cron_threads += 1
 
 
 def dec_thread_count():
     """ Decrement by the number of available threads. """
-    global _thread_count
     with _thread_count_lock:
-        _thread_count -= 1
+        openerp.conf.max_cron_threads -= 1
 
 
 def cancel(db_name):

openerp/tools/config.py

@@ -24,6 +24,7 @@ import optparse
 import os
 import sys
 import openerp
+import openerp.conf
 import openerp.loglevels as loglevels
 import logging
 import openerp.release as release
@@ -250,6 +251,9 @@ class configmanager(object):
                               "osv_memory tables. This is a decimal value expressed in hours, "
                               "and the default is 1 hour.",
                          type="float")
+        group.add_option("--max-cron-threads", dest="max_cron_threads", my_default=4,
+                         help="Maximum number of threads processing concurrently cron jobs.",
+                         type="int")
         parser.add_option_group(group)
 
         # Copy all optparse options (i.e. MyOption) into self.options.
@@ -335,7 +339,7 @@ class configmanager(object):
             'stop_after_init', 'logrotate', 'without_demo', 'netrpc', 'xmlrpc', 'syslog',
             'list_db', 'xmlrpcs',
             'test_file', 'test_disable', 'test_commit', 'test_report_directory',
-            'osv_memory_count_limit', 'osv_memory_age_limit',
+            'osv_memory_count_limit', 'osv_memory_age_limit', 'max_cron_threads',
         ]
 
         for arg in keys:
@@ -417,6 +421,8 @@ class configmanager(object):
         if opt.save:
             self.save()
 
+        openerp.conf.max_cron_threads = self.options['max_cron_threads']
+
     def _generate_pgpassfile(self):
         """
         Generate the pgpass file with the parameters from the command line (db_host, db_user,