Prometheus /metrics page wasn't updated after the Counter was called

Question

I have a Spring Bean where the Gauges are initilized like that:

   @PostConstruct
    public void initGauge() {
        paymentsTriedGauge = Gauge.build().name("payments_tried").help("How many payments was sent to PaymentServices to be created").register(registry.getPrometheusRegistry());
        paymentsCreated = Gauge.build().name("payments_created").help("How many payments sent to PaymentServices were created").register(registry.getPrometheusRegistry());
    }

where the registry is from

@Autowired
PrometheusMeterRegistry registry;

and then in one method I do:

paymentsTriedGauge.inc();

but later on Promtheus's /metrics page I got no update:

# HELP payments_tried How many payments was sent to PaymentServices to be created
# TYPE payments_tried gauge
payments_tried 0.0

Answer 1

Your usecase is using Prometheus gauges directly. Micrometer itself can be used with its own gauges. (Spring Boot is not required)

For example:

// maintain a reference to myGauge
AtomicInteger myGauge = registry.gauge("numberGauge", new AtomicInteger(0));

// ... elsewhere you can update the value it holds using the object reference
myGauge.set(27);
myGauge.set(11);

Notice the variable myGauge is actually an AtomicInteger and Micrometer is just reporting the value of that instance. AtomicInteger also has an increment() method you can use fine.