Elasticsearch not able to identify the time field defined in Fluentd

Hi Mark,
I was able to make it work thanks to the pointers that you had suggested. I did the format conversion to ISO8601 using the below snippet in the configuration file:

<filter *.**>
  @type record_transformer
  enable_ruby
  auto_typecast true
  <record>
    datetime_received ${require 'time'; Time.parse(record["logtime"].to_s + " +0530").iso8601.to_s}
  </record>
</filter>

Wanted to thank you for all the help you have extended. Appreciate it.

Regards,
Saurabh