Filter empty line with just \r in it

Elastic Stack Logstash
2

Try if [Message] == "\\r"

irb(main):012:0> unescaped = "\r"
=> "\r"
irb(main):013:0> escaped = "\\r"
=> "\\r"
irb(main):014:0> puts unescaped

=> nil
irb(main):015:0> puts escaped
\r
=> nil
irb(main):016:0> escaped=="\r"
=> false
irb(main):017:0> escaped=="\\r"
=> true
irb(main):018:0>