Provide an API to register callback on app shutdown (#2402)

Provide an API to register callback on app shutdown.

node/src/integration-test/kotlin/net/corda/node/NodePerformanceTests.kt

@@ -31,13 +31,6 @@ import java.util.*
 import java.util.concurrent.TimeUnit
 import kotlin.streams.toList
 
-
-private fun checkQuasarAgent() {
-    if (!(ManagementFactory.getRuntimeMXBean().inputArguments.any { it.contains("quasar") })) {
-        throw IllegalStateException("No quasar agent")
-    }
-}
-
 @Ignore("Run these locally")
 class NodePerformanceTests {
     @StartableByRPC
@@ -52,11 +45,6 @@ class NodePerformanceTests {
             val averageMs: Double
     )
 
-    @Before
-    fun before() {
-        checkQuasarAgent()
-    }
-
     @Test
     fun `empty flow per second`() {
         driver(startNodesInProcess = true) {

node/src/integration-test/kotlin/net/corda/node/NodeUnloadHandlerTests.kt

@@ -0,0 +1,48 @@
+package net.corda.node
+
+import net.corda.core.node.ServiceHub
+import net.corda.core.node.services.CordaService
+import net.corda.core.serialization.SingletonSerializeAsToken
+import net.corda.core.utilities.contextLogger
+import net.corda.core.utilities.getOrThrow
+import net.corda.testing.DUMMY_BANK_A_NAME
+import net.corda.testing.driver.driver
+import org.junit.Assert
+import org.junit.Test
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+
+class NodeUnloadHandlerTests {
+
+    companion object {
+        val latch = CountDownLatch(1)
+    }
+
+    @Test
+    fun `should be able to register run on stop lambda`() {
+        driver(startNodesInProcess = true, extraCordappPackagesToScan = listOf("net.corda.node"), isDebug = true) {
+            startNode(providedName = DUMMY_BANK_A_NAME).getOrThrow()
+            // just want to fall off the end of this for the mo...
+        }
+        Assert.assertTrue("Timed out waiting for AbstractNode to invoke the test service shutdown callback",latch.await(30, TimeUnit.SECONDS))
+    }
+
+    @CordaService
+    class RunOnStopTestService(serviceHub: ServiceHub) : SingletonSerializeAsToken() {
+
+        companion object {
+            private val log = contextLogger()
+        }
+
+        init {
+            serviceHub.registerUnloadHandler(this::shutdown)
+        }
+
+        fun shutdown() {
+            log.info("shutting down")
+            latch.countDown()
+        }
+
+    }
+
+}

node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt

@@ -804,6 +804,11 @@ abstract class AbstractNode(val configuration: NodeConfiguration,
         }
 
         override fun jdbcSession(): Connection = database.createSession()
+
+        // allows services to register handlers to be informed when the node stop method is called
+        override fun registerUnloadHandler(handler: () -> Unit) {
+            runOnStop += handler
+        }
     }
 }