Best way to parse json input?

Elastic Stack Logstash
5

Based on https://gist.github.com/shurane/60eee09eeee15a50f289, I changed my config to:

input{
  exec{
    command => "cat file.json"
    codec => json_lines
    interval => 60
  }
}
output{
  stdout{codec => ruby_debug}
}

...with this result:

A plugin had an unrecoverable error. Will restart this plugin.
Plugin: <LogStash::Inputs::Exec command=>...
Error: string not matched {:level=>:error}
{
  "message" => "}{\r",
  "tags" => ...
}

Am I correct in thinking the json_lines codec looks for \n and is failing when it comes to a \r?