My worker scripts have really basic logging (as in, they echo when something happens, and I can see those in the supervisord logs). Which is kind of okay, but I wanted to at least add timestamps in to them, and maybe send emails when something REALLY bad happened. I'm a huge fan of Monolog so I grabbed that, but it wasn't immediately obvious which of the many and varied options I would need for this fairly simple addition. It turns out that the right thing to use is the ErrorLogHandler.
She includes a few lines of sample code that use the "ErrorLogger" to output the message. It includes the log level, a timestamp, the message itself and any additional contextual information you pass in.