Splitting Logs in Different ElasticSearch Document using Logstash - elasticsearch

Question

Hi StackOverflow community
I am working on implementing ELK for one of my project. I have a continuous stream of logs getting generated in the format. By continuous stream I mean that logs are getting generated in the following format(Date in starting of each log)
03 Apr 2017 05:54:30,416 [INFO] Log text
I want to parse these logs and convert to a structured document using Logstash and then put in ElasticSearch. Logs are going to ElasticSearch but they are in a block(i.e. for one request, all logs generated are part of one elasticsearch document) and every log is not creating a new document.
My logstash's input configuration is like following:
input {
file {
path => "/Users/abc/logfile.txt"
start_position => "beginning"
codec => multiline {
             pattern => "^([0-9]{2} [A-Za-z]{3} [0-9]{4} [0-9:]{8},[0-9]+)"
             negate => true
             what => previous
         }
}
}
Is there some issue with this configuration? The regex pattern added in multiline codec is tested using regex tester and it correctly identifies Date in the starting of log.