Unexpected behaviour for exec input plugin

[Marco_Strambelli]

• Plugin version: v3.3.1

  input {

  exec {
    command => " curl -s -I <url>"
    interval => 30
    tags => ["solr"]
  }
  

  }

  filter {

  grok { match => { "curl -s -I %{HOSTNAME:instance} " } }
  

  }

  output {

  stdout {
    codec => rubydebug
  }
  

  }