# HELP process_threads The number of process threads
# TYPE process_threads gauge
process_threads 486.0

# HELP process_memory_threads_bytes  
# TYPE process_memory_threads_bytes gauge
process_memory_threads_bytes 486.0

package com.redhat.examples.hellospringboot;

/* annotations: http://zetcode.com/springboot/bean/ */
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

import io.micrometer.core.instrument.Gauge;
import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.binder.MeterBinder;
import io.github.mweirauch.micrometer.jvm.extras.*;

@SpringBootApplication
public class HelloSpringbootApplication {

        /* With Spring */
        @Bean
        public MeterBinder processMemoryMetrics() {
                return new ProcessMemoryMetrics();
        }

        @Bean
        public MeterBinder processThreadMetrics() {
                return new ProcessThreadMetrics();
        }

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

}

# curl http://localhost:8080/actuator/prometheus -sq | grep ^process
process_files_open_files 63.0
process_uptime_seconds 15.319
process_memory_rss_bytes -1.0
process_cpu_usage 0.0011735164450160725
process_files_max_files 10240.0
process_start_time_seconds 1.583642854501E9
process_memory_threads_bytes -1.0
process_threads -1.0
process_memory_vss_bytes -1.0
process_memory_swap_bytes -1.0

@Configuration
@RequiredArgsConstructor
public class MicrometerConfiguration {
    private final MeterRegistry registry;
    @PostConstruct
    public void postConstruct() {
        new ProcessMemoryMetrics().bindTo(registry);
    }
}