Queue handlers for XMPP individual & firehose output now send their XML stanzas
to another output queue instead of connecting directly to the chat server. This
lets us have as many general processing threads as we need, while all actual
XMPP input and output go through a single daemon with a single connection open.
This avoids problems with multiple connected resources:
* multiple windows shown in some chat clients (psi, gajim, kopete)
* extra load on server
* incoming message delivery forwarding issues
Database changes:
* queue_item drops 'notice_id' in favor of a 'frame' blob.
This is based on Craig Andrews' work branch to generalize queues to take any
object, but conservatively leaving out the serialization for now.
Table updater (preserves any existing queued items) in db/rc3to09.sql
Code changes to watch out for:
* Queue handlers should now define a handle() method instead of handle_notice()
* QueueDaemon and XmppDaemon now share common i/o (IoMaster) and respawning
thread management (RespawningDaemon) infrastructure.
* The polling XmppConfirmManager has been dropped, as the message is queued
directly when saving IM settings.
* Enable $config['queue']['debug_memory'] to output current memory usage at
each run through the event loop to watch for memory leaks
To do:
* Adapt XMPP i/o to component connection mode for multi-site support.
* XMPP input can also be broken out to a queue, which would allow the actual
notice save etc to be handled by general queue threads.
* Make sure there are no problems with simply pushing serialized Notice objects
to queues.
* Find a way to improve interactive performance of the database-backed queue
handler; polling is pretty painful to XMPP.
* Possibly redo the way QueueHandlers are injected into a QueueManager. The
grouping used to split out the XMPP output queue is a bit awkward.
Key changes:
* Initialization code moved from common.php to StatusNet class;
can now switch configurations during runtime.
* As a consequence, configuration files must now be idempotent...
Be careful with constant, function or class definitions.
* Control structure for daemons/QueueManager/QueueHandler has been refactored;
the run loop is now managed by IoMaster run via scripts/queuedaemon.php
IoManager subclasses are woken to handle socket input or polling, and may
cover multiple sites.
* Plugins can implement notice queue handlers more easily by registering a
QueueHandler class; no more need to add a daemon.
The new QueueDaemon runs from scripts/queuedaemon.php:
* This replaces most of the old *handler.php scripts; they've been refactored
to the bare handler classes.
* Spawns multiple child processes to spread load; defaults to CPU count on
Linux and Mac OS X systems, or override with --threads=N
* When multithreaded, child processes are automatically respawned on failure.
* Threads gracefully shut down and restart when passing a soft memory limit
(defaults to 90% of memory_limit), limiting damage from memory leaks.
* Support for UDP-based monitoring: http://www.gitorious.org/snqmon
Rough control flow diagram:
QueueDaemon -> IoMaster -> IoManager
QueueManager [listen or poll] -> QueueHandler
XmppManager [ping & keepalive]
XmppConfirmManager [poll updates]
Todo:
* Respawning features not currently available running single-threaded.
* When running single-site, configuration changes aren't picked up.
* New sites or config changes affecting queue subscriptions are not yet
handled without a daemon restart.
* SNMP monitoring output to integrate with general tools (nagios, ganglia)
* Convert XMPP confirmation message sends to use stomp queue instead of polling
* Convert xmppdaemon.php to IoManager?
* Convert Twitter status, friends import polling daemons to IoManager
* Clean up some error reporting and failure modes
* May need to adjust queue priorities for best perf in backlog/flood cases
Detailed code history available in my daemon-work branch:
http://www.gitorious.org/~brion/statusnet/brion-fixes/commits/daemon-work
Consolidated several separate implementations of the same weighting algorithm into common_sql_weight() and fixed some bugs...
For MySQL, now using timestampdiff() instead of subtraction for the comparison, so we get sane results when the year doesn't match, and utc_timestamp() rather than now() so we don't get negative ages for recent items with local server timezone.
Unknown whether the same problems affect PostgreSQL, but note that it lacks the timestampdiff() SQL function.
Consolidated several separate implementations of the same weighting algorithm into common_sql_weight() and fixed some bugs...
For MySQL, now using timestampdiff() instead of subtraction for the comparison, so we get sane results when the year doesn't match, and utc_timestamp() rather than now() so we don't get negative ages for recent items with local server timezone.
Unknown whether the same problems affect PostgreSQL, but note that it lacks the timestampdiff() SQL function.
Allows storage of larger objects (over 1mb in size uncompressed), such as huge LDAP schemas.
Should also improve cache efficiency (allows more stuff to be stored in same memory) and reduce network latency (less data transfer)
Added EmailAuthenticationPlugin
Added ReverseUsernameAuthenticationPlugin
Changed the StartChangePassword and EndChangePassword events to take a user, instead of a nickname
User::allowed_nickname was declared non-static, but used as if it was static, so I made the declaration static
common_logged_in() returned bogus results because it checks against null specifically, but common_current_user() was sticking 'false' into $_cur because that's what User::staticGet() returned from a failed lookup. Now we skip over a failed lookup here, so we keep null and all is well.
