Catch errors in CompositeNotifier and resume with next

fixes codecentric#940

Author: joshiste

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

@@ -20,6 +20,8 @@
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.util.Assert;
 
 /**
@@ -28,6 +30,7 @@
  * @author Sebastian Meiser
  */
 public class CompositeNotifier implements Notifier {
+ private static final Logger log = LoggerFactory.getLogger(CompositeNotifier.class);
  private final Iterable<Notifier> delegates;
 
  public CompositeNotifier(Iterable<Notifier> delegates) {
@@ -37,6 +40,9 @@ public CompositeNotifier(Iterable<Notifier> delegates) {
 
  @Override
  public Mono<Void> notify(InstanceEvent event) {
- return Flux.fromIterable(delegates).flatMap(d -> d.notify(event)).then();
+ return Flux.fromIterable(delegates).flatMap(d -> d.notify(event).onErrorResume(error -> {
+ log.warn("Unexpected exception while triggering notifications. Notification might not be sent.", error);
+ return Mono.empty();
+ })).then();
  }
 }

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

@@ -20,6 +20,7 @@
 import de.codecentric.boot.admin.server.domain.events.InstanceStatusChangedEvent;
 import de.codecentric.boot.admin.server.domain.values.InstanceId;
 import de.codecentric.boot.admin.server.domain.values.StatusInfo;
+import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
 import java.util.Arrays;
@@ -28,16 +29,18 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class CompositeNotifierTest {
- private static final InstanceEvent APP_DOWN = new InstanceStatusChangedEvent(InstanceId.of("-"), 0L,
- StatusInfo.ofDown());
+ private static final InstanceEvent APP_DOWN = new InstanceStatusChangedEvent(InstanceId.of("-"),
+ 0L,
+ StatusInfo.ofDown()
+ );
 
  @Test(expected = IllegalArgumentException.class)
- public void test_ctor_assert() {
+ public void should_throw_for_invariants() {
  new CompositeNotifier(null);
  }
 
  @Test
- public void test_all_notifiers_get_notified() {
+ public void should_trigger_all_notifiers() {
  TestNotifier notifier1 = new TestNotifier();
  TestNotifier notifier2 = new TestNotifier();
  CompositeNotifier compositeNotifier = new CompositeNotifier(Arrays.asList(notifier1, notifier2));
@@ -47,4 +50,15 @@ public void test_all_notifiers_get_notified() {
  assertThat(notifier1.getEvents()).containsOnly(APP_DOWN);
  assertThat(notifier2.getEvents()).containsOnly(APP_DOWN);
  }
+
+ @Test
+ public void should_continue_on_exception() {
+ Notifier notifier1 = ev -> Mono.error(new IllegalStateException("Test"));
+ TestNotifier notifier2 = new TestNotifier();
+ CompositeNotifier compositeNotifier = new CompositeNotifier(Arrays.asList(notifier1, notifier2));
+
+ StepVerifier.create(compositeNotifier.notify(APP_DOWN)).verifyComplete();
+
+ assertThat(notifier2.getEvents()).containsOnly(APP_DOWN);
+ }
 }