corrected syntax

Config:

input {
  file {
    path => "c:\logstash\main.log "
    start_position => "beginning"
    type => "main_log"
  }
}

filter {
  if [type] == "main_log" {
    grok {
      patterns_dir => "c:\logstash\patterns"
      match => [ "message", "%{TIMESTAMP_ISO8601:logtimestamp}" ]
    }
    date {
      match => [ "logtimestamp", "ISO8601" ]
      #target => "@timestamp"
    }
  }
  else {
    mutate { { replace => { type => "RANDOM" } } }
  }
}

output {
  elasticsearch {
    host => localhost
  }
  stdout { codec => rubydebug }
}