Fix AMI callback queue desynchronization causing dialer lockup under high call volume

[psycho84tr]

Summary

Under high outbound call volume, the dialer can lock up completely due to a race condition in AMI (Asterisk Manager Interface) callback queue processing. This affects production systems running predictive/progressive dialer campaigns and requires a manual restart to recover.

Root Cause

Three related issues in AMIClientConn.class.php:

1. wait_response() infinite loop — When an AMI response is lost or delayed, the synchronous wait loop blocks indefinitely, freezing the entire dialer event loop.

2. Orphan responses break the event chain — AMI responses arriving without a matching callback in _queue_requests cause process_event() to return FALSE, halting event processing.

3. Unsent request queue mismatch — When a queued request hasn't been sent yet but a response arrives for a different request, the handler assignment fails silently.

Additionally, AMIEventProcess.class.php crashes with a PHP Fatal Error (Call to a member function asyncOriginate() on a non-object) when _ejecutarOriginate() is called before the AMI connection is established after a process restart.

Changes

AMIClientConn.class.php:

• Add 30-second timeout to wait_response() to prevent indefinite blocking
• Handle orphan responses gracefully (log warning, return TRUE to continue processing)
• Handle unsent-request/response mismatch by sending the next queued request and continuing

AMIEventProcess.class.php:

• Add NULL check for $this->_ami in _ejecutarOriginate() before calling marcarLlamada()

Symptoms (before fix)

• Dialer freezes completely during high-volume campaigns
• Agents get logged out from their sessions
• No new calls are placed
• Web interface becomes unresponsive
• Only a full dialer restart recovers the system
• Log shows: segundo Response sobreescribe primer Response and se pierde respuesta porque no hay callback encolado

Testing

• Tested on a production Issabel 4 system with ~13 agents running predictive outbound campaigns
• Confirmed the dialer survives high call volume without freezing after the fix
• Warning messages appear in the log but the system continues operating normally

Made with Cursor