Suggest an open-source log analyser?

[Alec Taylor]

I use the Python logger class; with the example syntax of:
    Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')

Can of course easily use e.g.: a JSON syntax here instead.

Are there any open-source log viewers (e.g.: with a web-interface)
that you'd recommend; for drilling down into my logs?

Thanks for your suggestions,

Alec Taylor