lnav Monolog format

monolog.json

{
  "monolog": {
    "title": "Monolog log file",
    "description": "Monolog log format",
    "url": "https://github.com/Seldaek/monolog",
    "regex": {
      "default": {
        "pattern": "\\[(?P<timestamp>.*)\\] (?P<logger>\\w+).(?P<level>\\w+): (?P<message>.+) (?P<context>[\\[\\{].*[\\]\\}]) (?P<extra>[\\[\\{].*[\\]\\}])$"
      }
    },
    "level-field" : "level",
    "body-field" : "message",
    "level": {
        "fatal": "EMERGENCY",
        "critical": "ALERT|CRITICAL",
        "error": "ERROR",
        "warning": "WARNING",
        "stats": "NOTICE",
        "info": "INFO",
        "debug": "DEBUG"
    },
    "value": {
        "logger": {
            "kind": "string",
            "identifier": true
        },
        "level": {
            "kind": "string",
            "identifier": true
        },
        "message": {
            "kind": "string"
        },
        "context": {
            "kind": "json"
        },
        "extra": {
            "kind": "json"
        }
    },
    "sample": [
      {
        "line": "[2015-08-10 15:05:12] event.DEBUG: Notified event \"kernel.terminate\" to listener \"Symfony\\Component\\HttpKernel\\EventListener\\ProfilerListener::onKernelTerminate\". [] []"
      }
    ]
  }
}

Expanded log level map (thanks @Everis) and correctly set the body-field so highlighting is applied to quoted strings, IPs, etc, in the message.

Still room for improvement, it doesn't handle the following log line due to the square brackets:
[2016-10-07 10:03:12] app.ERROR: Not set $foo['bar'] [] []

I suspect the fix is to anchor the regex to the end of the line and work backwards to find the two preceding fields, allowing the message capture group to pick up everything not assigned to another field.

Updated. Seems to work for my current logs.

Thanks @nickpeirson, works great!