firehose-agent.json

{
   "cloudwatch.endpoint":"monitoring.us-east-1.amazonaws.com",
   "cloudwatch.emitMetrics":true,
   "firehose.endpoint":"firehose.us-east-1.amazonaws.com",
   "flows":[
      {
         "filePattern":"/var/log/nginx/access.log",
         "deliveryStream":"NAME_STREAM",
         "dataProcessingOptions":[
            {
               "initialPostion":"START_OF_FILE",
               "maxBufferAgeMillis":"2000",
               "optionName":"LOGTOJSON",
               "logFormat":"COMBINEDAPACHELOG",
               "matchPattern":"CUSTOM-REGEX",
               "customFieldNames": ["NAME-FIELD-1", "NAME-FIELD-2"]
           }
         ]
       }
   ]
}