Why though? Even if your own app logs JSON, everything around it (the DB, the log collector, the metrics collector, the kernel, the LDAP server) most likely logs plain text, so you need to know regexes anyway.
Oh that’s the other part. With the structured logging framework that I’m most familiar with - Serilog - if you send it to an output source like Mongo or ElasticSearch it logs documents. So you can query your logs. With Serilog you can tell it to always add certain attributes and you can tell it to add attributes with a certain context - like everything in a “using” block.
As far as the logs that you don’t control, if they are in some sort of standardized format even if it is just a line of text, you can use logstash to create a structure around it.
Of course with ElasticSearch, you have a powerful reporting app in Kibana. If you are on AWS you can send logs to CloudWatch and use the alerting, metric framework that’s built in.
