package com.example.howtodoinjava.elkexamplespringboot;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Date;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpMethod;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class ElkExampleSpringBootApplication {

	public static void main(String[] args) {
		SpringApplication.run(ElkExampleSpringBootApplication.class, args);
	}
}

@RestController
class ELKController {
	private static final Logger LOG = Logger.getLogger(ELKController.class.getName());

	@Autowired
	RestTemplate restTemplete;

	@Bean
	RestTemplate restTemplate() {
		return new RestTemplate();
	}

	@RequestMapping(value = "/elkdemo")
	public String helloWorld() {
		String response = "Hello user ! " + new Date();
		LOG.log(Level.INFO, "/elkdemo - > " + response);

		return response;
	}

	@RequestMapping(value = "/elk")
	public String helloWorld1() {

		String response = restTemplete.exchange("http://localhost:8080/elkdemo", HttpMethod.GET, null, new ParameterizedTypeReference() {
		}).getBody();
		LOG.log(Level.INFO, "/elk - > " + response);

		try {
			String exceptionrsp = restTemplete.exchange("http://localhost:8080/exception", HttpMethod.GET, null, new ParameterizedTypeReference() {
			}).getBody();
			LOG.log(Level.INFO, "/elk trying to print exception - > " + exceptionrsp);
			response = response + " === " + exceptionrsp;
		} catch (Exception e) {
			// exception should not reach here. Really bad practice :)
		}

		return response;
	}

	@RequestMapping(value = "/exception")
	public String exception() {
		String rsp = "";
		try {
			int i = 1 / 0;
			// should get exception
		} catch (Exception e) {
			e.printStackTrace();
			LOG.error(e);

			StringWriter sw = new StringWriter();
			PrintWriter pw = new PrintWriter(sw);
			e.printStackTrace(pw);
			String sStackTrace = sw.toString(); // stack trace as a string
			LOG.error("Exception As String :: - > "+sStackTrace);

			rsp = sStackTrace;
		}

		return rsp;
	}
}

logging.file=elk-example.log
spring.application.name = elk-example

input {
  file {
    type => "java"
    path => "F:/Study/eclipse_workspace_mars/elk-example-spring-boot/elk-example.log"
    codec => multiline {
      pattern => "^%{YEAR}-%{MONTHNUM}-%{MONTHDAY} %{TIME}.*"
      negate => "true"
      what => "previous"
    }
  }
}

filter {
  #If log line contains tab character followed by 'at' then we will tag that entry as stacktrace
  if [message] =~ "\tat" {
    grok {
      match => ["message", "^(\tat)"]
      add_tag => ["stacktrace"]
    }
  }

 grok {
    match => [ "message", 
               "(?<timestamp>%{YEAR}-%{MONTHNUM}-%{MONTHDAY} %{TIME})  %{LOGLEVEL:level} %{NUMBER:pid} --- \[(?<thread>[A-Za-z0-9-]+)\] [A-Za-z0-9.]*\.(?<class>[A-Za-z0-9#_]+)\s*:\s+(?<logmessage>.*)",
               "message",
               "(?<timestamp>%{YEAR}-%{MONTHNUM}-%{MONTHDAY} %{TIME})  %{LOGLEVEL:level} %{NUMBER:pid} --- .+? :\s+(?<logmessage>.*)"
             ]
  }

  date {
    match => [ "timestamp" , "yyyy-MM-dd HH:mm:ss.SSS" ]
  }
}

output {

  stdout {
    codec => rubydebug
  }

  # Sending properly parsed log events to elasticsearch
  elasticsearch {
    hosts => ["localhost:9200"]
  }
}