Add RemindingNotifier

spring-boot-admin-docs/src/main/asciidoc/index.adoc

@@ -103,7 +103,7 @@ Also have a look at the http://projects.spring.io/spring-cloud/spring-cloud.html
 <dependency>
     <groupId>org.springframework.cloud</groupId>
     <artifactId>spring-cloud-starter-eureka</artifactId>
-    <version>1.0.4.RELEASE</version>
+    <version>1.0.6.RELEASE</version>
 </dependency>
 ----
 
@@ -228,7 +228,7 @@ spring.boot.admin.password
 | `${spring.application.name}` if set, `"spring-boot-application"` otherwise.
 
 | spring.boot.admin.client.prefer-ip
-| Use the ip-address rather then the hostname in the guessed urls. If `server.address` / `management.address` is set they get used otherwise the IP address returned from `InetAddress.getLocalHost()` gets used.
+| Use the ip-address rather then the hostname in the guessed urls. If `server.address` / `management.address` is set, it get used. Otherwise the IP address returned from `InetAddress.getLocalHost()` gets used.
 | `false`
 |===
 
@@ -332,8 +332,10 @@ public class SpringBootAdminApplication {
 | `"spring-boot-admin-event-store"`
 |===
 
+=== Notifications ===
+
 [[mail-notifications]]
-=== Mail notifications ===
+==== Mail notifications ====
 
 Configure a `JavaMailSender` using `spring-boot-starter-mail` and set a recipient.
 
@@ -385,9 +387,8 @@ spring.boot.admin.notify.mail.to=admin@example.com
 | `+++"#{application.name} (#{application.id})\nstatus changed from #{from.status} to #{to.status}\n\n#{application.healthUrl}"+++`
 |===
 
-
 [[pagerduty-notifications]]
-=== Pagerduty notifications ===
+==== Pagerduty notifications ====
 To enable pagerduty notifications you just have to add a generic service to your pagerduty-account and set `spring.boot.admin.notify.pagerduty.service-key` to the service-key you received.
 
 .Pagerduty notifications configuration options
@@ -423,6 +424,36 @@ To enable pagerduty notifications you just have to add a generic service to your
 |
 |===
 
+[reminder-notifactaions]
+==== Reminder notifications ====
+To get reminders for down/offline applications you can add a `RemindingNotifier` to your `ApplicationContext`. The `RemindingNotifier` uses another `Notifier` as delegate to send the reminders.
+
+.How to configure reminders
+[source,java]
+----
+@Configuration
+public class ReminderConfiguration {
+    @Autowired
+    private Notifier notifier;
+
+    @Bean
+    @Primary
+    public RemindingNotifier remindingNotifier() {
+        RemindingNotifier remindingNotifier = new RemindingNotifier(notifier);
+        remindingNotifier.setReminderPeriod(TimeUnit.MINUTES.toMillis(5)); // <1>
+        return remindingNotifier;
+    }
+
+    @Scheduled(fixedRate = 6000L) // <2>
+    public void remind() {
+        remindingNotifier().sendReminders();
+    }
+}
+----
+<1> The reminders will be sent every 5 minutes.
+<2> Schedules sending of due reminders every 60 seconds.
+
+
 [[faqs]]
 == FAQs ==
 [qanda]

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/config/AdminServerImportSelector.java

@@ -28,12 +28,11 @@ public class AdminServerImportSelector implements DeferredImportSelector {
 
 	@Override
 	public String[] selectImports(AnnotationMetadata importingClassMetadata) {
-		return new String[] { MailNotifierConfiguration.class.getCanonicalName(),
+		return new String[] { NotifierConfiguration.class.getCanonicalName(),
 				HazelcastStoreConfiguration.class.getCanonicalName(),
 				AdminServerWebConfiguration.class.getCanonicalName(),
 				DiscoveryClientConfiguration.class.getCanonicalName(),
-				RevereseZuulProxyConfiguration.class.getCanonicalName(),
-				PagerdutyNotifierConfiguration.class.getCanonicalName() };
+				RevereseZuulProxyConfiguration.class.getCanonicalName() };
 	}
 
 }

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/config/MailNotifierConfiguration.java → spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/config/NotifierConfiguration.java

 /*
- * Copyright 2014 the original author or authors.
+ * Copyright 2013-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@ package de.codecentric.boot.admin.config;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
+import org.springframework.boot.autoconfigure.AutoConfigureBefore;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -27,12 +28,31 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.mail.MailSender;
 
 import de.codecentric.boot.admin.notify.MailNotifier;
+import de.codecentric.boot.admin.notify.Notifier;
+import de.codecentric.boot.admin.notify.NotifierListener;
+import de.codecentric.boot.admin.notify.PagerdutyNotifier;
 
 @Configuration
-@ConditionalOnBean(MailSender.class)
-@AutoConfigureAfter({ MailSenderAutoConfiguration.class })
-public class MailNotifierConfiguration {
+public class NotifierConfiguration {
 
+	@Configuration
+	@ConditionalOnBean(Notifier.class)
+	public static class NotifierListenerConfiguration {
+		@Autowired
+		public Notifier notifier;
+
+		@Bean
+		@ConditionalOnMissingBean
+		public NotifierListener notifierListener() {
+			return new NotifierListener(notifier);
+		}
+	}
+
+	@Configuration
+	@ConditionalOnBean(MailSender.class)
+	@AutoConfigureAfter({ MailSenderAutoConfiguration.class })
+	@AutoConfigureBefore({ NotifierListenerConfiguration.class })
+	public static class MailNotifierConfiguration {
 		@Autowired
 		private MailSender mailSender;
 
@@ -43,4 +63,18 @@ public class MailNotifierConfiguration {
 		public MailNotifier mailNotifier() {
 			return new MailNotifier(mailSender);
 		}
+	}
+
+	@Configuration
+	@ConditionalOnProperty(prefix = "spring.boot.admin.notify.pagerduty", name = "service-key")
+	@AutoConfigureBefore({ NotifierListenerConfiguration.class })
+	public static class PagerdutyNotifierConfiguration {
+		@Bean
+		@ConditionalOnMissingBean
+		@ConditionalOnProperty(prefix = "spring.boot.admin.notify.pagerduty", name = "enabled", matchIfMissing = true)
+		@ConfigurationProperties("spring.boot.admin.notify.pagerduty")
+		public PagerdutyNotifier pagerdutyNotifier() {
+			return new PagerdutyNotifier();
+		}
+	}
 }

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/config/PagerdutyNotifierConfiguration.java

-/*
- * Copyright 2014 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package de.codecentric.boot.admin.config;
-
-import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
-import org.springframework.boot.context.properties.ConfigurationProperties;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-
-import de.codecentric.boot.admin.notify.PagerdutyNotifier;
-
-@Configuration
-@ConditionalOnProperty("spring.boot.admin.notify.pagerduty.service-key")
-public class PagerdutyNotifierConfiguration {
-
-	@Bean
-	@ConditionalOnMissingBean
-	@ConditionalOnProperty(prefix = "spring.boot.admin.notify.pagerduty", name = "enabled", matchIfMissing = true)
-	@ConfigurationProperties("spring.boot.admin.notify.pagerduty")
-	public PagerdutyNotifier pagerdutyNotifier() {
-		return new PagerdutyNotifier();
-	}
-}
\ No newline at end of file

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/notify/AbstractNotifier.java → spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/notify/AbstractStatusChangeNotifier.java

+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package de.codecentric.boot.admin.notify;
 
 import java.util.Arrays;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.springframework.context.event.EventListener;
 
+import de.codecentric.boot.admin.event.ClientApplicationEvent;
 import de.codecentric.boot.admin.event.ClientApplicationStatusChangedEvent;
 
-public abstract class AbstractNotifier {
+/**
+ * Abstract Notifier for status change which allows filtering of certain status changes.
+ *
+ * @author Johannes Edmeier
+ */
+public abstract class AbstractStatusChangeNotifier implements Notifier {
 
 	/**
 	 * List of changes to ignore. Must be in Format OLD:NEW, for any status use * as wildcard, e.g.
@@ -21,13 +41,17 @@ public abstract class AbstractNotifier {
 	 */
 	private boolean enabled = true;
 
-	@EventListener
-	public void onClientApplicationStatusChanged(ClientApplicationStatusChangedEvent event) {
-		if (enabled && shouldNotify(event.getFrom().getStatus(), event.getTo().getStatus())) {
+	@Override
+	public void notify(ClientApplicationEvent event) {
+		if (event instanceof ClientApplicationStatusChangedEvent) {
+			ClientApplicationStatusChangedEvent statusChange = (ClientApplicationStatusChangedEvent) event;
+			if (enabled && shouldNotify(statusChange.getFrom().getStatus(),
+					statusChange.getTo().getStatus())) {
 				try {
-				notify(event);
+					doNotify(statusChange);
 				} catch (Exception ex) {
-				getLogger().error("Couldn't notify for status change {} ", event, ex);
+					getLogger().error("Couldn't notify for status change {} ", statusChange, ex);
+				}
 			}
 		}
 	}
@@ -38,7 +62,7 @@ public abstract class AbstractNotifier {
 				&& Arrays.binarySearch(ignoreChanges, (from + ":*")) < 0;
 	}
 
-	protected abstract void notify(ClientApplicationStatusChangedEvent event) throws Exception;
+	protected abstract void doNotify(ClientApplicationStatusChangedEvent event) throws Exception;
 
 	private Logger getLogger() {
 		return LoggerFactory.getLogger(this.getClass());

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/notify/MailNotifier.java

@@ -27,7 +27,12 @@ import org.springframework.mail.SimpleMailMessage;
 
 import de.codecentric.boot.admin.event.ClientApplicationStatusChangedEvent;
 
-public class MailNotifier extends AbstractNotifier {
+/**
+ * Notifier sending emails.
+ *
+ * @author Johannes Edmeier
+ */
+public class MailNotifier extends AbstractStatusChangeNotifier {
 	private final static String DEFAULT_SUBJECT = "#{application.name} (#{application.id}) is #{to.status}";
 	private final static String DEFAULT_TEXT = "#{application.name} (#{application.id})\nstatus changed from #{from.status} to #{to.status}\n\n#{application.healthUrl}";
 
@@ -66,7 +71,7 @@ public class MailNotifier extends AbstractNotifier {
 	}
 
 	@Override
-	protected void notify(ClientApplicationStatusChangedEvent event) {
+	protected void doNotify(ClientApplicationStatusChangedEvent event) {
 		EvaluationContext context = new StandardEvaluationContext(event);
 
 		SimpleMailMessage message = new SimpleMailMessage();

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/notify/Notifier.java

+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.codecentric.boot.admin.notify;
+
+import de.codecentric.boot.admin.event.ClientApplicationEvent;
+
+/**
+ * Interface for components which emits notifications upon status changes in clients
+ *
+ * @author Johannes Edmeier
+ */
+public interface Notifier {
+
+	void notify(ClientApplicationEvent event);
+
+}
\ No newline at end of file

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/notify/NotifierListener.java

+package de.codecentric.boot.admin.notify;
+
+import org.springframework.context.event.EventListener;
+
+import de.codecentric.boot.admin.event.ClientApplicationEvent;
+
+public class NotifierListener {
+	private final Notifier notifier;
+
+	public NotifierListener(Notifier notifier) {
+		this.notifier = notifier;
+	}
+
+	@EventListener
+	public void onClientApplicationEvent(ClientApplicationEvent event) {
+		notifier.notify(event);
+	}
+}

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/notify/PagerdutyNotifier.java

@@ -27,7 +27,12 @@ import org.springframework.web.client.RestTemplate;
 
 import de.codecentric.boot.admin.event.ClientApplicationStatusChangedEvent;
 
-public class PagerdutyNotifier extends AbstractNotifier {
+/**
+ * Notifier submitting events to Pagerduty.
+ *
+ * @author Johannes Edmeier
+ */
+public class PagerdutyNotifier extends AbstractStatusChangeNotifier {
 	public static final URI DEFAULT_URI = URI
 			.create("https://events.pagerduty.com/generic/2010-04-15/create_event.json");
 
@@ -67,7 +72,7 @@ public class PagerdutyNotifier extends AbstractNotifier {
 	}
 
 	@Override
-	protected void notify(ClientApplicationStatusChangedEvent event) throws Exception {
+	protected void doNotify(ClientApplicationStatusChangedEvent event) throws Exception {
 		restTemplate.postForEntity(url, createPagerdutyEvent(event), Void.class);
 	}
 

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/notify/RemindingNotifier.java

+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.codecentric.boot.admin.notify;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.TimeUnit;
+
+import de.codecentric.boot.admin.event.ClientApplicationDeregisteredEvent;
+import de.codecentric.boot.admin.event.ClientApplicationEvent;
+import de.codecentric.boot.admin.event.ClientApplicationStatusChangedEvent;
+
+/**
+ * Notifier that reminds certain statuses to send reminder notification using a delegate.
+ *
+ * @author Johannes Edmeier
+ */
+public class RemindingNotifier implements Notifier {
+	private final ConcurrentHashMap<String, Reminder> reminders = new ConcurrentHashMap<String, Reminder>();
+	private long reminderPeriod = TimeUnit.MINUTES.toMillis(10L);
+	private String[] reminderStatuses = { "DOWN", "OFFLINE" };
+	private final Notifier delegate;
+
+	public RemindingNotifier(Notifier delegate) {
+		this.delegate = delegate;
+	}
+
+	@Override
+	public void notify(ClientApplicationEvent event) {
+		delegate.notify(event);
+		if (shouldEndReminder(event)) {
+			reminders.remove(event.getApplication().getId());
+		} else if (shouldStartReminder(event)) {
+			reminders.putIfAbsent(event.getApplication().getId(), new Reminder(event));
+		}
+	}
+
+	public void sendReminders() {
+		long now = System.currentTimeMillis();
+		for (Reminder reminder : new ArrayList<Reminder>(reminders.values())) {
+			if (now - reminder.getLastNotification() > reminderPeriod) {
+				reminder.setLastNotification(now);
+				delegate.notify(reminder.getEvent());
+			}
+		}
+	}
+
+	protected boolean shouldStartReminder(ClientApplicationEvent event) {
+		if (event instanceof ClientApplicationStatusChangedEvent) {
+			return Arrays.binarySearch(reminderStatuses,
+					event.getApplication().getStatusInfo().getStatus()) >= 0;
+		}
+		return false;
+	}
+
+	protected boolean shouldEndReminder(ClientApplicationEvent event) {
+		if (event instanceof ClientApplicationDeregisteredEvent) {
+			return true;
+		}
+		if (event instanceof ClientApplicationStatusChangedEvent) {
+			return Arrays.binarySearch(reminderStatuses,
+					event.getApplication().getStatusInfo().getStatus()) < 0;
+		}
+		return false;
+	}
+
+	public void setReminderPeriod(long reminderPeriod) {
+		this.reminderPeriod = reminderPeriod;
+	}
+
+	public void setReminderStatuses(String[] reminderStatuses) {
+		String[] copy = Arrays.copyOf(reminderStatuses, reminderStatuses.length);
+		Arrays.sort(copy);
+		this.reminderStatuses = copy;
+	}
+
+	private static class Reminder {
+		private final ClientApplicationEvent event;
+		private long lastNotification;
+
+		public Reminder(ClientApplicationEvent event) {
+			this.event = event;
+			this.lastNotification = event.getTimestamp();
+		}
+
+		public void setLastNotification(long lastNotification) {
+			this.lastNotification = lastNotification;
+		}
+
+		public long getLastNotification() {
+			return lastNotification;
+		}
+
+		public ClientApplicationEvent getEvent() {
+			return event;
+		}
+	}
+}

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/config/AdminServerWebConfigurationTest.java

@@ -150,8 +150,7 @@ public class AdminServerWebConfigurationTest {
 		applicationContext.register(ServerPropertiesAutoConfiguration.class);
 		applicationContext.register(MailSenderAutoConfiguration.class);
 		applicationContext.register(HazelcastAutoConfiguration.class);
-		applicationContext.register(MailNotifierConfiguration.class);
-		applicationContext.register(PagerdutyNotifierConfiguration.class);
+		applicationContext.register(NotifierConfiguration.class);
 		applicationContext.register(HazelcastStoreConfiguration.class);
 		applicationContext.register(DiscoveryClientConfiguration.class);
 		applicationContext.register(AdminServerWebConfiguration.class);

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/notify/MailNotifierTest.java

@@ -47,7 +47,7 @@ public class MailNotifierTest {
 
 	@Test
 	public void test_onApplicationEvent() {
-		notifier.onClientApplicationStatusChanged(new ClientApplicationStatusChangedEvent(
+		notifier.notify(new ClientApplicationStatusChangedEvent(
 				Application.create("App").withId("-id-").withHealthUrl("http://health").build(),
 				StatusInfo.ofDown(), StatusInfo.ofUp()));
 
@@ -66,7 +66,7 @@ public class MailNotifierTest {
 	@Test
 	public void test_onApplicationEvent_disbaled() {
 		notifier.setEnabled(false);
-		notifier.onClientApplicationStatusChanged(new ClientApplicationStatusChangedEvent(
+		notifier.notify(new ClientApplicationStatusChangedEvent(
 				Application.create("App").withId("-id-").withHealthUrl("http://health").build(),
 				StatusInfo.ofDown(), StatusInfo.ofUp()));
 
@@ -75,7 +75,7 @@ public class MailNotifierTest {
 
 	@Test
 	public void test_onApplicationEvent_noSend() {
-		notifier.onClientApplicationStatusChanged(new ClientApplicationStatusChangedEvent(
+		notifier.notify(new ClientApplicationStatusChangedEvent(
 				Application.create("App").withId("-id-").withHealthUrl("http://health").build(),
 				StatusInfo.ofUnknown(), StatusInfo.ofUp()));
 
@@ -85,7 +85,7 @@ public class MailNotifierTest {
 	@Test
 	public void test_onApplicationEvent_noSend_wildcard() {
 		notifier.setIgnoreChanges(new String[] { "*:UP" });
-		notifier.onClientApplicationStatusChanged(new ClientApplicationStatusChangedEvent(
+		notifier.notify(new ClientApplicationStatusChangedEvent(
 				Application.create("App").withId("-id-").withHealthUrl("http://health").build(),
 				StatusInfo.ofOffline(), StatusInfo.ofUp()));
 
@@ -94,13 +94,13 @@ public class MailNotifierTest {
 
 	@Test
 	public void test_onApplicationEvent_throw_doesnt_propagate() {
-		AbstractNotifier notifier = new AbstractNotifier() {
+		Notifier notifier = new AbstractStatusChangeNotifier() {
 			@Override
-			protected void notify(ClientApplicationStatusChangedEvent event) throws Exception {
+			protected void doNotify(ClientApplicationStatusChangedEvent event) throws Exception {
 				throw new RuntimeException();
 			}
 		};
-		notifier.onClientApplicationStatusChanged(new ClientApplicationStatusChangedEvent(
+		notifier.notify(new ClientApplicationStatusChangedEvent(
 				Application.create("App").withId("-id-").withHealthUrl("http://health").build(),
 				StatusInfo.ofOffline(), StatusInfo.ofUp()));
 	}

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/notify/PagerdutyNotifierTest.java

@@ -52,7 +52,7 @@ public class PagerdutyNotifierTest {
 		StatusInfo infoDown = StatusInfo.ofDown();
 		StatusInfo infoUp = StatusInfo.ofUp();
 
-		notifier.onClientApplicationStatusChanged(new ClientApplicationStatusChangedEvent(
+		notifier.notify(new ClientApplicationStatusChangedEvent(
 				Application.create("App").withId("-id-").withHealthUrl("http://health").build(),
 				infoDown, infoUp));
 
@@ -75,7 +75,7 @@ public class PagerdutyNotifierTest {
 		StatusInfo infoDown = StatusInfo.ofDown();
 		StatusInfo infoUp = StatusInfo.ofUp();
 
-		notifier.onClientApplicationStatusChanged(new ClientApplicationStatusChangedEvent(
+		notifier.notify(new ClientApplicationStatusChangedEvent(
 				Application.create("App").withId("-id-").withHealthUrl("http://health").build(),
 				infoUp, infoDown));
 

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/notify/RemindingNotifierTest.java

+package de.codecentric.boot.admin.notify;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Test;
+
+import de.codecentric.boot.admin.event.ClientApplicationEvent;
+import de.codecentric.boot.admin.event.ClientApplicationStatusChangedEvent;
+import de.codecentric.boot.admin.model.Application;
+import de.codecentric.boot.admin.model.StatusInfo;
+
+public class RemindingNotifierTest {
+
+	private static final ClientApplicationEvent APP_DOWN = new ClientApplicationStatusChangedEvent(
+			Application.create("App").withId("id-1").withHealthUrl("http://health")
+					.withStatusInfo(StatusInfo.ofDown()).build(),
+			StatusInfo.ofUp(), StatusInfo.ofDown());
+
+	private static final ClientApplicationEvent APP_UP = new ClientApplicationStatusChangedEvent(
+			Application.create("App").withId("id-1").withHealthUrl("http://health")
+					.withStatusInfo(StatusInfo.ofUp()).build(),
+			StatusInfo.ofDown(), StatusInfo.ofUp());
+
+	private static final ClientApplicationEvent OTHER_APP_UP = new ClientApplicationStatusChangedEvent(
+			Application.create("App").withId("id-2").withHealthUrl("http://health")
+					.withStatusInfo(StatusInfo.ofUp()).build(),
+			StatusInfo.ofDown(), StatusInfo.ofUp());
+
+	@Test
+	public void test_remind() throws Exception {
+		TestNotifier notifier = new TestNotifier();
+		RemindingNotifier reminder = new RemindingNotifier(notifier);
+		reminder.setReminderPeriod(-1000L);
+
+		reminder.notify(APP_DOWN);
+		reminder.notify(OTHER_APP_UP);
+		reminder.sendReminders();
+		reminder.sendReminders();
+
+		assertThat(notifier.getEvents(),
+				is(Arrays.asList(APP_DOWN, OTHER_APP_UP, APP_DOWN, APP_DOWN)));
+
+	}
+
+	@Test
+	public void test_no_remind_after_up() throws Exception {
+		TestNotifier notifier = new TestNotifier();
+		RemindingNotifier reminder = new RemindingNotifier(notifier);
+		reminder.setReminderPeriod(0L);
+
+		reminder.notify(APP_DOWN);
+		reminder.notify(APP_UP);
+		reminder.sendReminders();
+
+		assertThat(notifier.getEvents(), is(Arrays.asList(APP_DOWN, APP_UP)));
+	}
+
+	@Test
+	public void test_no_remind_before_end() throws Exception {
+		TestNotifier notifier = new TestNotifier();
+		RemindingNotifier reminder = new RemindingNotifier(notifier);
+		reminder.setReminderPeriod(Long.MAX_VALUE);
+
+		reminder.notify(APP_DOWN);
+		reminder.sendReminders();
+
+		assertThat(notifier.getEvents(), is(Arrays.asList(APP_DOWN)));
+	}
+
+	private static class TestNotifier implements Notifier {
+		private List<ClientApplicationEvent> events = new ArrayList<ClientApplicationEvent>();
+
+		@Override
+		public void notify(ClientApplicationEvent event) {
+			this.events.add(event);
+		}
+
+		public List<ClientApplicationEvent> getEvents() {
+			return events;
+		}
+	}
+}