I m not sure to have well understood what the mutate filter do and what it doesn't do.
After a lot of pain I've finaly imported CSV datas into elastic. Logstash was treating every single csv field as a string, obviously I was not using the mutate filter.
Then i deleted the index and retried using the mutate filter. With debug mode enabled i could see that logstash converts correctly the inputs, but on ES they're still got indexed as "string".
I know that we cannot change field type in ES, so if we need we muste reindex, but what i m talking about is a bit different I guess. Because launching logstash the index are not created, so in my mind, I m not creating a data conflict.
Do I have to firstly create and map the entire index, and pushing data through logstash only after mapping ? Cant't mutate filter be used as a kind of mapper since we are talking about a new index ?
Thank you very much