Timezones Docs Misleading

[yaauie]

The timezone documentation1 says that the timezone is optional and has no default. Both of these statements are misleading.

It is true that the filter runs without specifying the timezone option. What happens in that circumstance is that the date provided is altered as if the timezone of the OS where logstash is running has been specified.

So the default is determined by the OS running logstash. And unless that happens to be the timezone of the data then the timezone parameter is not optional.

I imagine this is what the "platform default" is supposed to communicate in these sentences: "This is useful in case the time zone cannot be extracted from the value, and is not the platform default. If this is not specified the platform default will be used." I don't think that I'm the only one who would not have guessed that "platform default" meant the OS setting. I imagined that "platform" meant logstash 6.X.X and that default was in the settings file, or failing that UTC.

-- https://discuss.elastic.co/t/date-filter-plugin-timezone-documentation-misleading/126299