From 6cf01f614f7b1be7e42c885b0566c9709f7803ef Mon Sep 17 00:00:00 2001
From: RogerWillis <roger.willis@r3cev.com>
Date: Fri, 26 Aug 2016 13:46:11 +0100
Subject: [PATCH] Added getFreeLocalPorts() for grabbing more than one port.
 Fixes bug in freeLocalHostAndPort() where the same port can be picked
 multiple times.

---
 .../com/r3corda/core/testing/CoreTestUtils.kt | 21 +++++++++++++++++++
 .../com/r3corda/core/testing/IRSDemoTest.kt   | 10 +++++----
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/core/src/main/kotlin/com/r3corda/core/testing/CoreTestUtils.kt b/core/src/main/kotlin/com/r3corda/core/testing/CoreTestUtils.kt
index 51a4d5afaa..91ea70255b 100644
--- a/core/src/main/kotlin/com/r3corda/core/testing/CoreTestUtils.kt
+++ b/core/src/main/kotlin/com/r3corda/core/testing/CoreTestUtils.kt
@@ -86,11 +86,32 @@ inline fun <R> rootCauseExceptions(body: () -> R): R {
     }
 }
 
+/**
+ * Returns a free port.
+ *
+ * Unsafe for getting multiple ports!
+ * Use [getFreeLocalPorts] for getting multiple ports.
+ */
 fun freeLocalHostAndPort(): HostAndPort {
     val freePort = ServerSocket(0).use { it.localPort }
     return HostAndPort.fromParts("localhost", freePort)
 }
 
+/**
+ * Creates a specified number of ports for use by the Node.
+ *
+ * Unlikely, but in the time between running this function and handing the ports
+ * to the Node, some other process else could allocate the returned ports.
+ */
+fun getFreeLocalPorts(hostName: String, numberToAlloc: Int): List<HostAndPort> {
+    // Create a bunch of sockets up front.
+    val sockets = Array(numberToAlloc) { ServerSocket(0) }
+    val result = sockets.map { HostAndPort.fromParts(hostName, it.localPort) }
+    // Close sockets only once we've grabbed all the ports we need.
+    sockets.forEach(ServerSocket::close)
+    return result
+}
+
 /**
  * Creates and tests a ledger built by the passed in dsl. The provided services can be customised, otherwise a default
  * of a freshly built [MockServices] is used.
diff --git a/src/integration-test/kotlin/com/r3corda/core/testing/IRSDemoTest.kt b/src/integration-test/kotlin/com/r3corda/core/testing/IRSDemoTest.kt
index 31cc7f9f22..9efbd15a56 100644
--- a/src/integration-test/kotlin/com/r3corda/core/testing/IRSDemoTest.kt
+++ b/src/integration-test/kotlin/com/r3corda/core/testing/IRSDemoTest.kt
@@ -9,9 +9,11 @@ import java.nio.file.Paths
 
 class IRSDemoTest {
     @Test fun `runs IRS demo`() {
-        val nodeAddrA = freeLocalHostAndPort()
-        val apiAddrA = freeLocalHostAndPort()
-        val apiAddrB = freeLocalHostAndPort()
+        val hostAndPorts = getFreeLocalPorts("localhost", 4)
+
+        val nodeAddrA = hostAndPorts[0]
+        val apiAddrA = hostAndPorts[1]
+        val apiAddrB = hostAndPorts[2]
 
         val baseDirectory = Paths.get("./build/integration-test/${TestTimestamp.timestamp}/irs-demo")
         var procA: Process? = null
@@ -29,7 +31,7 @@ class IRSDemoTest {
             procB = startNode(
                     baseDirectory = baseDirectory,
                     nodeType = "NodeB",
-                    nodeAddr = freeLocalHostAndPort(),
+                    nodeAddr = hostAndPorts[3],
                     networkMapAddr = nodeAddrA,
                     apiAddr = apiAddrB
             )