Set root for json codec

[Nate_McCallum]

Using the json_codec on input I get all my fields parsed at the root level. I like to specify a name for the subfield for the items.
So right now with { "a" : "b", "c" : "d" } to get a = b and c = d. I'd like to get myname.a = b and myname.c = d.

I'm concerned about doing this in a ruby filter as I saw a post that the json_codec is much faster than a ruby filter.

Any thoughts?

[yaauie (Ry Biesemeyer)]

The JSON codec does not support this behaviour.

Your best bet is likely to use the JSON filter, which can take the value of a JSON string field, parse it, and place the result somewhere. Assuming you use your input's default codec and the raw contents are placed into message, this would do the trick:

filter {
  json {
    source => "message"
    target => "myname"
    remove_field => "message"
  }
}

The remove_field directive is optional and is only invoked on success.

[Nate_McCallum]

Thanks Ry, The problem I'm running into with that solution is the message maybe be an array of json objects. [{"a":"b"},{"a":"c"}]. In this case json_codec handles properly but json filter is unhappy as the entire array came in as a single message / document. Any ideas to handle the array format?

Again thank you for the quick response.

[Badger]

The json filter will handle an array provided that you use the target option.

[Nate_McCallum]

Thanks Badger. What I am seeing is this:

With this json filter:

json {

skip_on_invalid_json => true

source => "message"

target => "mytarget"

remove_field => [ "message"]

}

I get this as my document.

Am I implementing the filter incorrectly to get two documents?

[Badger]

If you want two documents then pass the array to a split filter.

[Nate_McCallum]

Thanks Badger. I ended up with this in my filter to get the desired result.

    json {
      skip_on_invalid_json => true
      source => "message"
      target => "myfield"
      remove_field => [ "message"]
    }

    # If the data is in an array then add a tag to allow for splitting each index into own event.
    ruby {
      code => "if event.get('myfield').is_a? Hash
                event.tag('ishash')
               end"
    }

    # if isHash is not set then go ahead and split without this check any fields that aren't arrays throw WARN.
    if "ishash" not in [tags] {
      split {
        field => "myfield"
      }
    }