Fluentd Regexp - how to extract time

[karspartha]

I have log lines of the format -

2022-06-06 16:43:46.930 [MyQuartzScheduler_Worker-1] DEBUG ...

I am trying to write a parse tag inside source and using regex.. I am able to extract everything but the timestamp field is coming to my output (mongdb) as String. There is some documentation on how to use 'Types'. I did that. But, I am running into multiple technical issues. While there is some documentation, there is no example on how to specify Time parameters - time_type and time_format

This is what I have

	<parse>
		@type regexp
		expression /(?<logTime>\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{3}).*\[message:user=(?<username>[^ ]*);ipaddress=(?<ip>[^ ]*);TxID=(?<txID>[^ ]*?);/
		types logTime:time:string:%Y-%m-%d %H:%M:%S.%L
	</parse>

The regex works clean. I am not able to get logTime as a time field. Either the field is null in the output (db) or fluentd throws an exception. If I dont specify 'types' i am able to get it as a String. Any help (on how to specify time_type and time_format) would be appreciated. Thanks in advance.