[WFLY-11578] Distinguish WildFly metrics types

* In microprofile-metrics-smallrye extension, when attributes that
  corresponds to metrics are collected, check whether the attribute
  access has the COUNTER_METRIC flag to register it in Prometheus
  collector as a counter. Otherwise, the metric is registered as a
  gauge.
* Append _total to the Prometheus name for counters.

JIRA: https://issues.jboss.org/browse/WFLY-11578

docs/src/main/asciidoc/_admin-guide/subsystem-configuration/MicroProfile_Metrics.adoc

@@ -91,12 +91,18 @@ The [helloworld-rs quickstart](https://github.com/wildfly/quickstart/tree/master
 that can be deployed in WildFly.
 A corresponding metric will be exposed for it with the name and labels:
 
-* `wildfly_undertow_request_count{deployment="helloworld-rs.war",servlet="org.jboss.as.quickstarts.rshelloworld.JAXActivator",subdeployment="helloworld-rs.war"}`
+* `wildfly_undertow_request_count_total{deployment="helloworld-rs.war",servlet="org.jboss.as.quickstarts.rshelloworld.JAXActivator",subdeployment="helloworld-rs.war"}`
 
+[NOTE]
+Some subsystems (such as `undertow` or `messaing-activemq`) do not enable their statistics by default
+as they have an impact on performance and memory usage. These subsystems provides a `statistics-enabled` attribute that must
+be set to `true` to enable them.
+For convenience, WildFly standalone configuration provides expression to enable the statistics by setting a
+System property `-Dwildfly.statistics-enabled=true` to enable statistics on the subsystems provided by the configuration.
 
 == Component Reference
 
-The Eclipse MicroProfile Health is implemented by the SmallRye Health project.
+The Eclipse MicroProfile Metrics is implemented by the SmallRye Metrics project.
 
 ****
 

microprofile/metrics-smallrye/src/main/java/org/wildfly/extension/microprofile/metrics/MetricCollector.java

@@ -25,8 +25,9 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import io.prometheus.client.Collector;
+import io.prometheus.client.Collector.MetricFamilySamples;
 import io.prometheus.client.CollectorRegistry;
+import io.prometheus.client.CounterMetricFamily;
 import io.prometheus.client.GaugeMetricFamily;
 import org.jboss.as.controller.LocalModelControllerClient;
 import org.jboss.as.controller.PathAddress;
@@ -101,10 +102,16 @@ private void collectResourceMetrics0(final Resource current,
             }
             PathAddress resourceAddress = resourceAddressResolver.apply(address);
             MeasurementUnit unit = attributeAccess.getAttributeDefinition().getMeasurementUnit();
-            MetricMetadata metricMetadata = new MetricMetadata(attributeName, resourceAddress, unit, globalPrefix);
+            boolean counter = attributeAccess.getFlags().contains(AttributeAccess.Flag.COUNTER_METRIC);
+            MetricMetadata metricMetadata = new MetricMetadata(attributeName, resourceAddress, unit, globalPrefix, counter);
             String attributeDescription = resourceDescription.get(ATTRIBUTES, attributeName, DESCRIPTION).asStringOrNull();
-            GaugeMetricFamily gaugeMetricFamily = new GaugeMetricFamily(metricMetadata.metricName, attributeDescription, metricMetadata.labelNames);
-            Supplier<Optional<Collector.MetricFamilySamples.Sample>> sampleSupplier = () -> {
+            final MetricFamilySamples metricFamilySamples;
+            if (counter) {
+                metricFamilySamples = new CounterMetricFamily(metricMetadata.metricName, attributeDescription, metricMetadata.labelNames);
+            } else {
+                metricFamilySamples = new GaugeMetricFamily(metricMetadata.metricName, attributeDescription, metricMetadata.labelNames);
+            }
+            Supplier<Optional<MetricFamilySamples.Sample>> sampleSupplier = () -> {
                 final ModelNode readAttributeOp = new ModelNode();
                 readAttributeOp.get(OP).set(READ_ATTRIBUTE_OPERATION);
                 readAttributeOp.get(OP_ADDR).set(resourceAddress.toModelNode());
@@ -120,14 +127,14 @@ private void collectResourceMetrics0(final Resource current,
                     try {
                         double initialValue = result.asDouble();
                         double scaledValue = UnitConverter.scaleToBase(initialValue, unit);
-                        return Optional.of(new Collector.MetricFamilySamples.Sample(metricMetadata.metricName, metricMetadata.labelNames, metricMetadata.labelValues, scaledValue));
+                        return Optional.of(new MetricFamilySamples.Sample(metricMetadata.metricName, metricMetadata.labelNames, metricMetadata.labelValues, scaledValue));
                     } catch (Exception e) {
                         throw LOGGER.unableToConvertAttribute(attributeName, address, e);
                     }
                 }
                 return Optional.empty();
             };
-            prometheusCollector.addMetricFamilySampleSupplier(gaugeMetricFamily, sampleSupplier);
+            prometheusCollector.addMetricFamilySampleSupplier(metricFamilySamples, sampleSupplier);
             registration.addUnregistrationTask(() -> prometheusCollector.removeMetricFamilySampleSupplier(metricMetadata.metricName, sampleSupplier));
         }
 
@@ -179,10 +186,16 @@ private void collectMetricFamilies(ImmutableManagementResourceRegistration manag
                 DescriptionProvider modelDescription = managementResourceRegistration.getModelDescription(address);
                 resourceDescription = modelDescription.getModelDescription(Locale.getDefault());
             }
-            MetricMetadata metricMetadata = new MetricMetadata(attributeName, address, attributeAccess.getAttributeDefinition().getMeasurementUnit(), globalPrefix);
+            boolean counter = attributeAccess.getFlags().contains(AttributeAccess.Flag.COUNTER_METRIC);
+            MetricMetadata metricMetadata = new MetricMetadata(attributeName, address, attributeAccess.getAttributeDefinition().getMeasurementUnit(), globalPrefix, counter);
             String attributeDescription = resourceDescription.get(ATTRIBUTES, attributeName, DESCRIPTION).asStringOrNull();
-            GaugeMetricFamily gaugeMetricFamily = new GaugeMetricFamily(metricMetadata.metricName, attributeDescription, metricMetadata.labelNames);
-            collector.addMetricFamilySamples(gaugeMetricFamily);
+            final MetricFamilySamples metricFamilySamples;
+            if (counter) {
+                metricFamilySamples = new CounterMetricFamily(metricMetadata.metricName, attributeDescription, metricMetadata.labelNames);
+            } else {
+                metricFamilySamples = new GaugeMetricFamily(metricMetadata.metricName, attributeDescription, metricMetadata.labelNames);
+            }
+            collector.addMetricFamilySamples(metricFamilySamples);
         }
 
         for (PathElement childAddress : managementResourceRegistration.getChildAddresses(address)) {
@@ -237,7 +250,7 @@ private static class MetricMetadata {
         private final List<String> labelNames;
         private final List<String> labelValues;
 
-        MetricMetadata(String attributeName, PathAddress address, MeasurementUnit unit, String globalPrefix) {
+        MetricMetadata(String attributeName, PathAddress address, MeasurementUnit unit, String globalPrefix, boolean counter) {
             String metricPrefix = "";
             labelNames = new ArrayList<>();
             labelValues = new ArrayList<>();
@@ -249,7 +262,7 @@ private static class MetricMetadata {
                     metricPrefix += value + "_";
                     continue;
                 }
-                labelNames.add(getPrometheusMetricName(key, null));
+                labelNames.add(getPrometheusMetricName(key, null, false));
                 labelValues.add(value);
             }
             // if the resource address defines a deployment (without subdeployment),
@@ -260,13 +273,14 @@ private static class MetricMetadata {
             if (globalPrefix != null && !globalPrefix.isEmpty()) {
                 metricPrefix = globalPrefix + "_" + metricPrefix;
             }
-            metricName = getPrometheusMetricName(metricPrefix + attributeName, unit);
+            metricName = getPrometheusMetricName(metricPrefix + attributeName, unit, counter);
         }
 
-        private static String getPrometheusMetricName(String name, MeasurementUnit unit) {
-            String out = (name + unitSuffix(unit)).replaceAll("[^\\w]+","_");
-            out = decamelize(out);
-            return out;
+        private static String getPrometheusMetricName(String name, MeasurementUnit unit, boolean counter) {
+            String prometheusName = name + unitSuffix(unit) + (counter ? "_total" : "");
+            prometheusName =prometheusName.replaceAll("[^\\w]+","_");
+            prometheusName = decamelize(prometheusName);
+            return prometheusName;
         }
 
 

microprofile/metrics-smallrye/src/main/java/org/wildfly/extension/microprofile/metrics/PrometheusCollector.java

@@ -10,7 +10,6 @@
 
 import io.prometheus.client.Collector;
 import io.prometheus.client.Collector.MetricFamilySamples.Sample;
-import io.prometheus.client.GaugeMetricFamily;
 
 public class PrometheusCollector extends Collector implements Collector.Describable {
 
@@ -26,7 +25,7 @@ public void addMetricFamilySamples(MetricFamilySamples mfs) {
         }
     }
 
-    void addMetricFamilySampleSupplier(GaugeMetricFamily mfs, Supplier<Optional<Sample>> sampleSupplier) {
+    void addMetricFamilySampleSupplier(MetricFamilySamples mfs, Supplier<Optional<Sample>> sampleSupplier) {
         if (!metricNames.containsKey(mfs.name)) {
             addMetricFamilySamples(mfs);
         }

testsuite/integration/basic/src/test/java/org/wildfly/test/integration/microprofile/metrics/application/MicroProfileMetricsApplicationTestCase.java

@@ -199,7 +199,7 @@ private static String performCall(URL url) throws Exception {
     }
 
     private void checkRequestCount(int expectedCount, boolean deploymentMetricMustExist) throws IOException {
-        String prometheusMetricName = "wildfly_undertow_request_count";
+        String prometheusMetricName = "wildfly_undertow_request_count_total";
 
         String metrics = getPrometheusMetrics(managementClient, "", true);
         for (String line : metrics.split("\\R")) {