Microprofile – Metric API: How Create a Metric Programatically

The Microprofile Metric API is a great way to extend a Microservice with custom metrics. There are a lot of examples how you can add different metrics by annotations.

@Counted(name = "my_coutner", absolute = true, 
         tags={"category=ABC"}) 
public void countMeA() { 
...
}

@Counted(name = "my_coutner", absolute = true, 
         tags={"category=DEF"}) 
public void countMeB() { 
...
}

In this example I use tags to specify variants of the same metric name. With MP Metrics 2.0, tags are used in combination with the metric’s name to create the identity of the metric. So by using different tags for the same metric name will result in an individual metric output for each identity.

But in case you want to create a custom metric with custom tags you can not use annotations. This is typically the case if the tags are computed by application data at runtime. The following example shows how you can create a metric with tags programatically:

...    
  @Inject
  @RegistryType(type=MetricRegistry.Type.APPLICATION)
  MetricRegistry metricRegistry;
...   
   Metadata m = Metadata.builder()
   .withName("my_metric")
   .withDescription("my description")
   .withType(MetricType.COUNTER)
   .build();
 Tag[] tags = {new Tag("type","ABC")};
    Counter counter = metricRegistry.counter(m, tags);
    counter.inc();
...