add wildfly session metrics + tests

Author: SylvainJuge

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/target_systems/WildflyIntegrationTest.java

@@ -100,6 +100,35 @@ protected JmxScraperContainer customizeScraperContainer(
   @Override
   protected void verifyMetrics() {
     waitAndAssertMetrics(
+        metric ->
+            assertSumWithAttributes(
+                metric,
+                "wildfly.session.count",
+                "The number of sessions created.",
+                "{session}",
+                attrs -> attrs.containsOnly(entry("deployment", "testapp.war"))),
+        metric ->
+            assertSumWithAttributes(
+                metric,
+                "wildfly.session.active",
+                "The number of currently active sessions.",
+                "{session}",
+                /* isMonotonic= */ false,
+                attrs -> attrs.containsOnly(entry("deployment", "testapp.war"))),
+        metric ->
+            assertSumWithAttributes(
+                metric,
+                "wildfly.session.expired",
+                "The number of sessions that have expired.",
+                "{session}",
+                attrs -> attrs.containsOnly(entry("deployment", "testapp.war"))),
+        metric ->
+            assertSumWithAttributes(
+                metric,
+                "wildfly.session.rejected",
+                "The number of sessions that have been rejected.",
+                "{session}",
+                attrs -> attrs.containsOnly(entry("deployment", "testapp.war"))),
         metric ->
             assertSumWithAttributes(
                 metric,

jmx-scraper/src/main/resources/wildfly.yaml

@@ -1,6 +1,28 @@
 ---
 
 rules:
+  - bean: jboss.as:deployment=*,subsystem=undertow
+    metricAttribute:
+      deployment: param(deployment)
+    prefix: wildfly.session.
+    unit: "{session}"
+    mapping:
+      sessionsCreated:
+        metric: count
+        type: counter
+        desc: The number of sessions created.
+      activeSessions:
+        metric: active
+        type: updowncounter
+        desc: The number of currently active sessions.
+      expiredSessions:
+        metric: expired
+        type: counter
+        desc: The number of sessions that have expired.
+      rejectedSessions:
+        metric: rejected
+        type: counter
+        desc: The number of sessions that have been rejected.
 
   - bean: jboss.as:subsystem=undertow,server=*,http-listener=*
     metricAttribute: