As I have an interest in monitoring and logging,
I decided to read The Logstash Book by James Turnbull.
And it’s kind of a nice book, with examples and explanations about working with Logstash and ELK
stack. Also, it contains information about the ways to extend Logstash with plugins, even a few pages
about writing plugins on your own.
From the other side, the book is a bit too basic and a lot of it is primitive information about deploying Logstash and related stack.