By "Everything" in my post, I mean all of our own applications. Some services allow you to format logs to json like nginx using log_format[1]. For others, you may find app-specific configuration or plugins for log formatting or simply use plain grep / kibana text search.

I imagine in those cases something like logstash may help, but I don't really know as I tend to avoid logstash.

1: https://stackoverflow.com/a/42564710/14651