Logstash configuration file error(Answer not worki

Question

The only thing that is certain about [url][queryString] is that it begins with 404; or that the key is long.I need to remove such keys. If I use the ruby code below it gives cannot convert linked hashmap to string exception.

input {
    file {
        # Wildcards work, here :)
        path => ["C:\Users\ppurush\Desktop\test\*.log"]
        start_position => "beginning"
    }
}

filter {
    ruby {
        code=>
        "
        require json
        my_hash = JSON.parse([url][queryString])
        my_hash.delete_if { |key,value| key.to_s.match(/^404;/) }
        "
    }
}

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

Answer 1

You get a ruby exception because your ruby code is invalid. Try this instead:

filter {
    ruby {
        init => "require 'json'"
        code => "
            my_hash = JSON.parse( event['url']['queryString'] )
            my_hash.delete_if { |key,value| key.to_s.match(/^404;/) }
        "
    }
}

This works if your event has a 'url' => 'queryString' field which contains valid json. You might already have some kind of filter to achieve this (e.g. grok). You might also consider using logstash's built-in json filter and maybe drop to delete certain events.

---

EDIT:

Suppose your input is plain json (I had to tidy this up):

{"id":"val1","host":"val2","app":"val3","@timestamp":"2015-08-04T19:00:03.642932‌​2Z","@timestampEnd":"2015-08-04T19:00:03.6429322Z","vid":"val4","vidNew":"val5","se‌​ssionId":"val6","url":{"rawUrl":"val7","path":"val8","queryString":{"404;dfdgfdgf‌​ghfhjghhhhhhhhhhhhh":""}},"net":{"method":"GET","status":"200","size":"0","timeTa‌​kenMillis":"0"},"context":{"SearchType":""}}

You can use codec => "json" in your file input.

input {
    file {
        path => ["C:\Users\ppurush\Desktop\test\*.log"]
        start_position => "beginning"
        codec => "json"
    }
}

You will get a field:

"url" => {
         "rawUrl" => "val7",
           "path" => "val8",
    "queryString" => {
        "404;dfdgfdgf‌​ghfhjghhhhhhhhhhhhh" => ""
    }
}

So 404;dfdgfdgf‌​ghfhjghhhhhhhhhhhhh is a variable, too. To check for it and delete the event you could do something like this:

if [url][queryString][404;dfdgfdgf‌​ghfhjghhhhhhhhhhhhh] {
        drop {}
    }