If we fail to bind to port 2500 when starting an EmailServer try the next port up.

This change employs the same kind of logic that `HttpClientTest` uses to find an open port for it's server. This should prevent the rare build failures we have seen.

Original commit: elastic/x-pack-elasticsearch@f3b68adad5

src/test/java/org/elasticsearch/watcher/actions/email/service/AccountTests.java

@@ -5,10 +5,10 @@
  */
 package org.elasticsearch.watcher.actions.email.service;
 
-import org.elasticsearch.watcher.actions.email.service.support.EmailServer;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.test.ElasticsearchTestCase;
+import org.elasticsearch.watcher.actions.email.service.support.EmailServer;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -35,8 +35,7 @@ public class AccountTests extends ElasticsearchTestCase {
 
     @Before
     public void init() throws Exception {
-        server = new EmailServer("localhost", 2500, USERNAME, PASSWORD);
-        server.start();
+        server = EmailServer.localhost("2500-2600", USERNAME, PASSWORD, logger);
     }
 
     @After
@@ -155,7 +154,7 @@ public class AccountTests extends ElasticsearchTestCase {
     public void testSend() throws Exception {
         Account account = new Account(new Account.Config("default", ImmutableSettings.builder()
                 .put("smtp.host", "localhost")
-                .put("smtp.port", 2500)
+                .put("smtp.port", server.port())
                 .put("smtp.user", USERNAME)
                 .put("smtp.password", PASSWORD)
                 .build()), logger);
@@ -195,7 +194,7 @@ public class AccountTests extends ElasticsearchTestCase {
     public void testSend_CC_BCC() throws Exception {
         Account account = new Account(new Account.Config("default", ImmutableSettings.builder()
                 .put("smtp.host", "localhost")
-                .put("smtp.port", 2500)
+                .put("smtp.port", server.port())
                 .put("smtp.user", USERNAME)
                 .put("smtp.password", PASSWORD)
                 .build()), logger);
@@ -240,7 +239,7 @@ public class AccountTests extends ElasticsearchTestCase {
     public void testSend_Authentication() throws Exception {
         Account account = new Account(new Account.Config("default", ImmutableSettings.builder()
                 .put("smtp.host", "localhost")
-                .put("smtp.port", 2500)
+                .put("smtp.port", server.port())
                 .build()), logger);
 
         Email email = Email.builder()

src/test/java/org/elasticsearch/watcher/actions/email/service/support/EmailServer.java

@@ -5,6 +5,9 @@
  */
 package org.elasticsearch.watcher.actions.email.service.support;
 
+import org.elasticsearch.common.logging.ESLogger;
+import org.elasticsearch.common.transport.PortsRange;
+import org.elasticsearch.watcher.WatcherException;
 import org.subethamail.smtp.TooMuchDataException;
 import org.subethamail.smtp.auth.EasyAuthenticationHandlerFactory;
 import org.subethamail.smtp.auth.LoginFailedException;
@@ -18,9 +21,11 @@ import javax.mail.Session;
 import javax.mail.internet.MimeMessage;
 import java.io.IOException;
 import java.io.InputStream;
+import java.net.BindException;
 import java.util.List;
 import java.util.Properties;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.atomic.AtomicReference;
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
@@ -72,6 +77,13 @@ public class EmailServer {
         server.setPort(port);
     }
 
+    /**
+     * @return the port that the underlying server is listening on
+     */
+    public int port() {
+        return server.getPort();
+    }
+
     public void start() {
         server.start();
     }
@@ -86,6 +98,34 @@ public class EmailServer {
         return new Listener.Handle(listeners, listener);
     }
 
+    public static EmailServer localhost(String portRangeStr, final String username, final String password, final ESLogger logger) {
+        final AtomicReference<EmailServer> emailServer = new AtomicReference<>();
+        boolean bound = new PortsRange(portRangeStr).iterate(new PortsRange.PortCallback() {
+            @Override
+            public boolean onPortNumber(int port) {
+                try {
+                    EmailServer server = new EmailServer("localhost", port, username, password);
+                    server.start();
+                    emailServer.set(server);
+                    return true;
+                } catch (RuntimeException re) {
+                    if (re.getCause() instanceof BindException) {
+                        logger.warn("port [{}] was already in use trying next port", re, port);
+                        return false;
+                    } else {
+                        throw re;
+                    }
+                }
+            }
+        });
+        if (!bound || emailServer.get() == null) {
+            throw new WatcherException("could not bind to any of the port in [{}]" + portRangeStr);
+        }
+        return emailServer.get();
+    }
+
+
+
     public static interface Listener {
 
         void on(MimeMessage message) throws Exception;
@@ -106,5 +146,4 @@ public class EmailServer {
         }
 
     }
-
 }

src/test/java/org/elasticsearch/watcher/test/integration/EmailActionIntegrationTests.java

@@ -14,7 +14,6 @@ import org.elasticsearch.watcher.client.WatcherClient;
 import org.elasticsearch.watcher.test.AbstractWatcherIntegrationTests;
 import org.elasticsearch.watcher.trigger.schedule.IntervalSchedule;
 import org.junit.After;
-import org.junit.Before;
 import org.junit.Test;
 
 import javax.mail.internet.MimeMessage;
@@ -42,12 +41,6 @@ public class EmailActionIntegrationTests extends AbstractWatcherIntegrationTests
 
     private EmailServer server;
 
-    @Before
-    public void init() throws Exception {
-        server = new EmailServer("localhost", 2500, USERNAME, PASSWORD);
-        server.start();
-    }
-
     @After
     public void cleanup() throws Exception {
         server.stop();
@@ -55,12 +48,16 @@ public class EmailActionIntegrationTests extends AbstractWatcherIntegrationTests
 
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
+        if(server == null) {
+            //Need to construct the Email Server here as this happens before init()
+            server = EmailServer.localhost("2500-2600", USERNAME, PASSWORD, logger);
+        }
         return ImmutableSettings.builder()
                 .put(super.nodeSettings(nodeOrdinal))
                 .put("watcher.actions.email.service.account.test.smtp.auth", true)
                 .put("watcher.actions.email.service.account.test.smtp.user", USERNAME)
                 .put("watcher.actions.email.service.account.test.smtp.password", PASSWORD)
-                .put("watcher.actions.email.service.account.test.smtp.port", 2500)
+                .put("watcher.actions.email.service.account.test.smtp.port", server.port())
                 .put("watcher.actions.email.service.account.test.smtp.host", "localhost")
                 .build();
     }