Could you tell me the monitoring system for a complex PHP project

I was always with her swamp: Zabbix able to execute WEB scripts of any complexity, you have to search the text, analyze the error code returned, etc. and react on the result in different ways.
Zabbix-agent on the server can execute any scripts, including making queries to the database and pass the result to the server, where you can configure the trigger events/thresholds values and receive notification by SMS/mail/jabber/beep/pigeons. On the page of the integrated report, you can display any graphics, state triggers, information specific audits in text/graphic form, etc.

Nagios — system monitoring and alerting, you can add your own plugins.

There is a PEAR library, Log. The program is overloading the standard error handling, error levels, support save error in database, sending in FireBug, soap, etc. is Very convenient.

Highly recommend pinba pinba.org/wiki/Main_Page

Take any system monitoring ( it so happened to me that I have an account in serverdensity.com but there are agents in python for the server easier ) and write to him agent for your project. To pull out a few queries and send them http corny IMHO

And there's a very cool library — Lagger. Very comfortable and flexibly nastraivaniya, catches all kinds of errors including fatal, sends emails/text messages writes to a log, supports FireBug for Firefox, native is also a very cool extension for Google Chrome.
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Highly recommend.