Logstash config: check if boolean field exists

logstash

Solution

Kind of lame that it doesn't work right out of the box, but you can hack it like this -- add a string representation of the boolean, compare against the string, and then remove the added field:

filter {
   mutate {
     add_field => { "test" => "%{boolean}" }
   }
   if [test] == 'true' or [test] == 'false' {
     // field is present and set right
   } else {
     // field isn't present or set to something other than true/false
   }
   mutate {
     remove_field => [ "test" ]
   }
}

Problem

Using Logstash 1.4.2, I have a field `myfield` that is a boolean value in my JSON document. To check if it exists (don't care about the boolean value) I used: ``` if[myfield] { ...exists... } else { ...doesn't exist... } ``` The results from testing this conditional statement are: ``` [myfield] does not exist --> false [myfield] exists, is true --> true [myfield] exists, is false --> false //expected true because the field exists ``` It is checking the boolean value, not its existence. How can I check that a boolean field exists?

Original source

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