Add use of structured arguments

[Jordan-Negreiros]

Hello, It would be very interesting to use the kv method to add new fields to the logs as in the example below:

code:

import static net.logstash.logback.argument.StructuredArguments.kv;

String orderId = "123";
String status = "NEW";
log.info("Order saved", kv("orderId", orderId), kv("status", status)); 

result:

{
    "@timestamp": "2019-04-17T18:29:14.079+02:00",
    "@version": "1",
    "message": "Order saved",
    "logger_name": "MyApplication",
    "thread_name": "main",
    "level": "INFO",
    "level_value": 20000,
    "orderId": "123",
    "status": "NEW"
}

[osiegmar]

Thanks for bringing this up! As this library has no dependencies to logstash, support for their kv is not possible. But with 82b080f I added support for key value pairs of SLF4J 2.0.0:

org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger("my logger");

String orderId = "123";
String status = "NEW";

log.atInfo().setMessage("Order saved")
    .addKeyValue("orderId", orderId)
    .addKeyValue("status", status)
    .log();

This will be part of version 5.0.0 of this library.