I need to parse this log message format

[A_B]

@Tanya_Sharma

I just started working on this so i haven't had any idea about the logs or how to parse them.
Can you please tell me how do filter the logs that's already in JSON format because i used type => json in my input block of logstash.conf.

<{
            "repo" => "feature/3.0.2_DeviceServices",
           "build" => 2,
   "short_message" => "BUILD_FINISHED",
        "duration" => 829193,
        "@version" => "1",
         "message" => [
       [    0] "Branch indexing",
       [    ].................../>

This is the format in which the logs appear.

That does not look like the source is in JSON. Logstash does not convert log formats into JSON by using type => json it is just told to expect JOSN on the input so it knows how to tokenise/parse it correctly. Are you feeding Logstash JSON or the original format you posted (which is)?

< [2019-03-04T12:29:49,990][INFO ][logstash.agent ] Successfully started Logstash API endpoint {:port=>9600} />