Add metrics for active connections count

* Fix and refactor gauges tests in MicrometerMetricsTests
  as they were not executing
* Fix client disconnection handler in NettyTcpServer
* Add metrics gauge and counters required to measure active connections

Change-Id: I5620d398525c6859679cd5a49dc55a9fefd8b592
Signed-off-by: Jakub Dudycz <jakub.dudycz@nokia.com>
Issue-ID: DCAEGEN2-1041

3 files changed, 129 insertions, 36 deletions

diff --git a/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/metrics/MicrometerMetrics.kt b/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/metrics/MicrometerMetrics.kt
index d35e17d6..288145aa 100644
--- a/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/metrics/MicrometerMetrics.kt
+++ b/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/metrics/MicrometerMetrics.kt
@@ -50,10 +50,13 @@ class MicrometerMetrics internal constructor(
     private val receivedMsgCount = registry.counter(name(MESSAGES, RECEIVED, COUNT))
     private val receivedMsgBytes = registry.counter(name(MESSAGES, RECEIVED, BYTES))
 
+    private val connectionsTotalCount = registry.counter(name(CONNECTIONS, TOTAL, COUNT))
+    private val disconnectionsCount = registry.counter(name(DISCONNECTIONS, COUNT))
+
     private val processingTime = registry.timer(name(MESSAGES, PROCESSING, TIME))
     private val totalLatency = registry.timer(name(MESSAGES, LATENCY, TIME))
 
-    private val sentCountTotal = registry.counter(name(MESSAGES, SENT, COUNT))
+    private val sentCount = registry.counter(name(MESSAGES, SENT, COUNT))
     private val sentToTopicCount = { topic: String ->
         registry.counter(name(MESSAGES, SENT, TOPIC, COUNT), TOPIC, topic)
     }.memoize<String, Counter>()
@@ -70,8 +73,13 @@ class MicrometerMetrics internal constructor(
 
     init {
         registry.gauge(name(MESSAGES, PROCESSING, COUNT), this) {
-            (receivedMsgCount.count() - sentCountTotal.count()).coerceAtLeast(0.0)
+            (receivedMsgCount.count() - sentCount.count()).coerceAtLeast(0.0)
+        }
+
+        registry.gauge(name(CONNECTIONS, ACTIVE, COUNT), this) {
+            (connectionsTotalCount.count() - disconnectionsCount.count()).coerceAtLeast(0.0)
         }
+
         ClassLoaderMetrics().bindTo(registry)
         JvmMemoryMetrics().bindTo(registry)
         JvmGcMetrics().bindTo(registry)
@@ -79,7 +87,6 @@ class MicrometerMetrics internal constructor(
         JvmThreadMetrics().bindTo(registry)
     }
 
-
     val metricsProvider = MicrometerPrometheusMetricsProvider(registry)
 
     override fun notifyBytesReceived(size: Int) {
@@ -93,7 +100,7 @@ class MicrometerMetrics internal constructor(
 
     override fun notifyMessageSent(msg: RoutedMessage) {
         val now = Instant.now()
-        sentCountTotal.increment()
+        sentCount.increment()
         sentToTopicCount(msg.topic).increment()
 
         processingTime.record(Duration.between(msg.message.wtpFrame.receivedAt, now))
@@ -110,11 +117,22 @@ class MicrometerMetrics internal constructor(
         clientsRejectedCauseCount(cause.tag).increment()
     }
 
+    override fun notifyClientConnected() {
+        connectionsTotalCount.increment()
+    }
+
+    override fun notifyClientDisconnected() {
+        disconnectionsCount.increment()
+    }
+
     companion object {
         val INSTANCE = MicrometerMetrics()
         internal const val PREFIX = "hvves"
         internal const val MESSAGES = "messages"
         internal const val RECEIVED = "received"
+        internal const val DISCONNECTIONS = "disconnections"
+        internal const val CONNECTIONS = "connections"
+        internal const val ACTIVE = "active"
         internal const val BYTES = "bytes"
         internal const val COUNT = "count"
         internal const val DATA = "data"
@@ -125,6 +143,7 @@ class MicrometerMetrics internal constructor(
         internal const val REJECTED = "rejected"
         internal const val TOPIC = "topic"
         internal const val DROPPED = "dropped"
+        internal const val TOTAL = "total"
         internal const val TIME = "time"
         internal const val LATENCY = "latency"
         internal fun name(vararg name: String) = "$PREFIX.${name.joinToString(".")}"
diff --git a/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/servers/VesServer.kt b/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/servers/VesServer.kt
index b35dc53d..f9be546a 100644
--- a/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/servers/VesServer.kt
+++ b/sources/hv-collector-main/src/main/kotlin/org/onap/dcae/collectors/veshv/main/servers/VesServer.kt
@@ -44,7 +44,7 @@ object VesServer : ServerStarter() {
                 config.maximumPayloadSizeBytes
         ).createVesHvCollectorProvider()
 
-        return ServerFactory.createNettyTcpServer(config, collectorProvider)
+        return ServerFactory.createNettyTcpServer(config, collectorProvider, MicrometerMetrics.INSTANCE)
     }
 
     override fun serverStartedMessage(handle: ServerHandle) =
diff --git a/sources/hv-collector-main/src/test/kotlin/org/onap/dcae/collectors/veshv/main/MicrometerMetricsTest.kt b/sources/hv-collector-main/src/test/kotlin/org/onap/dcae/collectors/veshv/main/MicrometerMetricsTest.kt
index 71fc8f7f..24355d5d 100644
--- a/sources/hv-collector-main/src/test/kotlin/org/onap/dcae/collectors/veshv/main/MicrometerMetricsTest.kt
+++ b/sources/hv-collector-main/src/test/kotlin/org/onap/dcae/collectors/veshv/main/MicrometerMetricsTest.kt
@@ -22,7 +22,6 @@ package org.onap.dcae.collectors.veshv.main
 import arrow.core.Try
 import io.micrometer.core.instrument.Counter
 import io.micrometer.core.instrument.Gauge
-import io.micrometer.core.instrument.Meter
 import io.micrometer.core.instrument.Timer
 import io.micrometer.core.instrument.search.RequiredSearch
 import io.micrometer.prometheus.PrometheusConfig
@@ -35,10 +34,10 @@ import org.jetbrains.spek.api.dsl.it
 import org.jetbrains.spek.api.dsl.on
 import org.onap.dcae.collectors.veshv.main.metrics.MicrometerMetrics
 import org.onap.dcae.collectors.veshv.main.metrics.MicrometerMetrics.Companion.PREFIX
-import org.onap.dcae.collectors.veshv.model.ClientRejectionCause.INVALID_WIRE_FRAME_MARKER
-import org.onap.dcae.collectors.veshv.model.ClientRejectionCause.PAYLOAD_SIZE_EXCEEDED_IN_MESSAGE
 import org.onap.dcae.collectors.veshv.model.MessageDropCause.INVALID_MESSAGE
 import org.onap.dcae.collectors.veshv.model.MessageDropCause.ROUTE_NOT_FOUND
+import org.onap.dcae.collectors.veshv.model.ClientRejectionCause.INVALID_WIRE_FRAME_MARKER
+import org.onap.dcae.collectors.veshv.model.ClientRejectionCause.PAYLOAD_SIZE_EXCEEDED_IN_MESSAGE
 import org.onap.dcae.collectors.veshv.model.RoutedMessage
 import org.onap.dcae.collectors.veshv.model.VesMessage
 import org.onap.dcae.collectors.veshv.tests.utils.emptyWireProtocolFrame
@@ -46,6 +45,8 @@ import org.onap.dcae.collectors.veshv.tests.utils.vesEvent
 import org.onap.dcae.collectors.veshv.tests.utils.wireProtocolFrame
 import org.onap.dcae.collectors.veshv.tests.utils.wireProtocolFrameWithPayloadSize
 import java.time.Instant
+import io.micrometer.core.instrument.Meter
+
 import java.time.temporal.Temporal
 import java.util.concurrent.TimeUnit
 import kotlin.reflect.KClass
@@ -56,7 +57,6 @@ import kotlin.reflect.KClass
  */
 object MicrometerMetricsTest : Spek({
     val doublePrecision = Percentage.withPercentage(0.5)
-    val alwaysChangedMeters = setOf("$PREFIX.messages.processing.time", "$PREFIX.messages.latency.time")
     lateinit var registry: PrometheusMeterRegistry
     lateinit var cut: MicrometerMetrics
 
@@ -87,6 +87,7 @@ object MicrometerMetricsTest : Spek({
     fun <T> verifyCounter(name: String, verifier: (Counter) -> T) =
             verifyCounter(registrySearch(name), verifier)
 
+
     fun verifyCountersAndTimersAreUnchangedBut(vararg changedMeters: String) {
         fun <T : Meter> verifyAllMetersAreUnchangedBut(
                 clazz: KClass<T>,
@@ -98,7 +99,9 @@ object MicrometerMetricsTest : Spek({
                     .map { it as T }
                     .filterNot { it.id.name in changedCounters }
                     .forEach {
-                        assertThat(valueOf(it)).describedAs(it.id.toString()).isCloseTo(0.0, doublePrecision)
+                        assertThat(valueOf(it))
+                                .describedAs(it.id.toString())
+                                .isCloseTo(0.0, doublePrecision)
                     }
         }
 
@@ -108,8 +111,8 @@ object MicrometerMetricsTest : Spek({
         }
     }
 
-    describe("notifyBytesReceived") {
 
+    describe("notifyBytesReceived") {
         on("$PREFIX.data.received.bytes counter") {
             val counterName = "$PREFIX.data.received.bytes"
 
@@ -187,6 +190,7 @@ object MicrometerMetricsTest : Spek({
 
         on("$PREFIX.messages.sent.topic.count counter") {
             val counterName = "$PREFIX.messages.sent.topic.count"
+
             it("should handle counters for different topics") {
                 cut.notifyMessageSent(routedMessage(topicName1))
                 cut.notifyMessageSent(routedMessage(topicName2))
@@ -242,13 +246,12 @@ object MicrometerMetricsTest : Spek({
                         "$PREFIX.messages.processing.time")
             }
         }
-
     }
 
     describe("notifyMessageDropped") {
-
         on("$PREFIX.messages.dropped.count counter") {
             val counterName = "$PREFIX.messages.dropped.count"
+
             it("should increment counter") {
                 cut.notifyMessageDropped(ROUTE_NOT_FOUND)
                 cut.notifyMessageDropped(INVALID_MESSAGE)
@@ -262,6 +265,7 @@ object MicrometerMetricsTest : Spek({
 
         on("$PREFIX.messages.dropped.cause.count counter") {
             val counterName = "$PREFIX.messages.dropped.cause.count"
+
             it("should handle counters for different drop reasons") {
                 cut.notifyMessageDropped(ROUTE_NOT_FOUND)
                 cut.notifyMessageDropped(INVALID_MESSAGE)
@@ -278,36 +282,38 @@ object MicrometerMetricsTest : Spek({
         }
     }
 
-    describe("processing gauge") {
-        it("should show difference between sent and received messages") {
+    describe("notifyClientConnected") {
+        on("$PREFIX.connections.total.count counter") {
+            val counterName = "$PREFIX.connections.total.count"
 
-            on("positive difference") {
-                cut.notifyMessageReceived(wireProtocolFrameWithPayloadSize(128))
-                cut.notifyMessageReceived(wireProtocolFrameWithPayloadSize(256))
-                cut.notifyMessageReceived(wireProtocolFrameWithPayloadSize(256))
-                cut.notifyMessageSent(routedMessage("perf3gpp"))
-                verifyGauge("messages.processing.count") {
-                    assertThat(it.value()).isCloseTo(2.0, doublePrecision)
-                }
-            }
+            it("should increment counter") {
+                cut.notifyClientConnected()
+                cut.notifyClientConnected()
 
-            on("zero difference") {
-                cut.notifyMessageReceived(emptyWireProtocolFrame())
-                cut.notifyMessageSent(routedMessage("perf3gpp"))
-                verifyGauge("messages.processing.count") {
-                    assertThat(it.value()).isCloseTo(0.0, doublePrecision)
+                verifyCounter(counterName) {
+                    assertThat(it.count()).isCloseTo(2.0, doublePrecision)
                 }
+                verifyCountersAndTimersAreUnchangedBut(counterName)
             }
+        }
 
-            on("negative difference") {
-                cut.notifyMessageReceived(wireProtocolFrameWithPayloadSize(128))
-                cut.notifyMessageSent(routedMessage("fault"))
-                cut.notifyMessageSent(routedMessage("perf3gpp"))
-                verifyGauge("messages.processing.count") {
-                    assertThat(it.value()).isCloseTo(0.0, doublePrecision)
+    }
+
+    describe("notifyClientDisconnected") {
+        on("$PREFIX.disconnections.count counter") {
+            val counterName = "$PREFIX.disconnections.count"
+
+            it("should increment counter") {
+                cut.notifyClientDisconnected()
+                cut.notifyClientDisconnected()
+
+                verifyCounter(counterName) {
+                    assertThat(it.count()).isCloseTo(2.0, doublePrecision)
                 }
+                verifyCountersAndTimersAreUnchangedBut(counterName)
             }
         }
+
     }
 
     describe("notifyClientRejected") {
@@ -342,6 +348,74 @@ object MicrometerMetricsTest : Spek({
             }
         }
     }
+
+    describe("$PREFIX.messages.processing.count gauge") {
+        val gaugeName = "$PREFIX.messages.processing.count"
+
+        on("message traffic") {
+            it("should calculate positive difference between sent and received messages") {
+                cut.notifyMessageReceived(wireProtocolFrameWithPayloadSize(128))
+                cut.notifyMessageReceived(wireProtocolFrameWithPayloadSize(256))
+                cut.notifyMessageReceived(wireProtocolFrameWithPayloadSize(256))
+                cut.notifyMessageSent(routedMessage("perf3gpp"))
+
+                verifyGauge(gaugeName) {
+                    assertThat(it.value()).isCloseTo(2.0, doublePrecision)
+                }
+            }
+
+            it("should calculate no difference between sent and received messages") {
+                cut.notifyMessageSent(routedMessage("perf3gpp"))
+                cut.notifyMessageSent(routedMessage("fault"))
+
+                verifyGauge(gaugeName) {
+                    assertThat(it.value()).isCloseTo(0.0, doublePrecision)
+                }
+            }
+
+            it("should calculate negative difference between sent and received messages") {
+                cut.notifyMessageSent(routedMessage("fault"))
+
+                verifyGauge(gaugeName) {
+                    assertThat(it.value()).isCloseTo(0.0, doublePrecision)
+                }
+            }
+        }
+    }
+
+    describe("$PREFIX.connections.active.count gauge") {
+        val gaugeName = "$PREFIX.connections.active.count"
+
+        on("connection traffic") {
+            it("should calculate positive difference between connected and disconnected clients") {
+                cut.notifyClientConnected()
+                cut.notifyClientConnected()
+                cut.notifyClientConnected()
+                cut.notifyClientDisconnected()
+
+                verifyGauge(gaugeName) {
+                    assertThat(it.value()).isCloseTo(2.0, doublePrecision)
+                }
+            }
+
+            it("should calculate no difference between connected and disconnected clients") {
+                cut.notifyClientDisconnected()
+                cut.notifyClientDisconnected()
+
+                verifyGauge(gaugeName) {
+                    assertThat(it.value()).isCloseTo(0.0, doublePrecision)
+                }
+            }
+
+            it("should calculate negative difference between connected and disconnected clients") {
+                cut.notifyClientDisconnected()
+
+                verifyGauge(gaugeName) {
+                    assertThat(it.value()).isCloseTo(0.0, doublePrecision)
+                }
+            }
+        }
+    }
 })
 
 fun routedMessage(topic: String, partition: Int = 0) =
@@ -364,4 +438,4 @@ fun routedMessageSentAt(topic: String, sentAt: Instant, partition: Int = 0) =
         }.let { evt ->
             RoutedMessage(topic, partition,
                     VesMessage(evt.commonEventHeader, wireProtocolFrame(evt)))
-        }
+        }
\ No newline at end of file