Micrometer - Prometheus Gauge displays NaN

Question

I am trying to generate Prometheus metrics with using Micrometer.io with Spring Boot 2.0.0.RELEASE.

When I am trying to expose the size of a List as Gauge, it ke

Answer 1

my example for gauge using

private final AtomicLong countTryUsers = new AtomicLong(0);
Metrics.gauge("app.countTry", countTryUsers);

public void updateCountTryUsers(Long countTryUsersDb){
   countTryUsers.set(countTryUsersDb);
}

so I register app.countTry just once, and then just update AtomicLong countTryUsers over custom method updateCountTryUsers()