Allow event version to be non-consecutive

Because the eventstore may remove outdated events the versions can be non-consecutive

fixes #1149

Author: joshiste

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/domain/entities/Instance.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2018 the original author or authors.
+ * Copyright 2014-2019 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.
@@ -158,8 +158,7 @@ public Instance withStatusInfo(StatusInfo statusInfo) {
 
     public Instance withEndpoints(Endpoints endpoints) {
         Assert.notNull(endpoints, "'endpoints' must not be null");
-        Endpoints endpointsWithHealth = this.registration != null ? endpoints.withEndpoint(
-            Endpoint.HEALTH,
+        Endpoints endpointsWithHealth = this.registration != null ? endpoints.withEndpoint(Endpoint.HEALTH,
             this.registration.getHealthUrl()
         ) : endpoints;
         if (Objects.equals(this.endpoints, endpointsWithHealth)) {
@@ -189,8 +188,7 @@ Instance clearUnsavedEvents() {
             this.registration,
             this.registered,
             this.statusInfo,
-            this.statusTimestamp,
-            info,
+            this.statusTimestamp, this.info,
             this.endpoints,
             this.buildVersion,
             this.tags,
@@ -214,8 +212,8 @@ Instance apply(InstanceEvent event) {
     private Instance apply(InstanceEvent event, boolean isNewEvent) {
         Assert.notNull(event, "'event' must not be null");
         Assert.isTrue(this.id.equals(event.getInstance()), "'event' must refer the same instance");
-        Assert.isTrue(this.nextVersion() == event.getVersion(),
-            () -> "Event " + event.getVersion() + " doesn't match exptected version " + this.nextVersion()
+        Assert.isTrue(event.getVersion() >= this.nextVersion(),
+            () -> "Event " + event.getVersion() + " must be greater or equal to " + this.nextVersion()
         );
 
         List<InstanceEvent> unsavedEvents = appendToEvents(event, isNewEvent);

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/server/domain/entities/InstanceTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2018 the original author or authors.
+ * Copyright 2014-2019 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.
@@ -18,13 +18,16 @@
 
 import de.codecentric.boot.admin.server.domain.events.InstanceDeregisteredEvent;
 import de.codecentric.boot.admin.server.domain.events.InstanceEvent;
+import de.codecentric.boot.admin.server.domain.events.InstanceInfoChangedEvent;
 import de.codecentric.boot.admin.server.domain.values.BuildVersion;
 import de.codecentric.boot.admin.server.domain.values.Endpoints;
 import de.codecentric.boot.admin.server.domain.values.Info;
 import de.codecentric.boot.admin.server.domain.values.InstanceId;
 import de.codecentric.boot.admin.server.domain.values.Registration;
 import de.codecentric.boot.admin.server.domain.values.StatusInfo;
 
+import java.util.List;
+import java.util.stream.Collectors;
 import org.junit.Test;
 
 import static java.util.Collections.singletonMap;
@@ -145,8 +148,9 @@ public void should_throw_when_applied_wrong_event() {
         ))).isInstanceOf(IllegalArgumentException.class)
            .hasMessage("'event' must refer the same instance");
 
-        assertThatThrownBy(() -> instance.apply(new InstanceDeregisteredEvent(InstanceId.of("id"), 1L))).isInstanceOf(
-            IllegalArgumentException.class).hasMessage("Event 1 doesn't match exptected version 0");
+        assertThatThrownBy(() -> instance.apply(new InstanceDeregisteredEvent(InstanceId.of("id"), 1L))
+                                         .apply(new InstanceDeregisteredEvent(InstanceId.of("id"), 1L))).isInstanceOf(
+            IllegalArgumentException.class).hasMessage("Event 1 must be greater or equal to 2");
     }
 
     @Test
@@ -186,8 +190,7 @@ public void should_extract_tags() {
         assertThat(instance.getTags().getValues()).containsExactly(entry("environment", "test"), entry("region", "EU"));
 
         instance = instance.withInfo(Info.from(singletonMap("tags", singletonMap("region", "US-East"))));
-        assertThat(instance.getTags().getValues()).containsExactly(
-            entry("environment", "test"),
+        assertThat(instance.getTags().getValues()).containsExactly(entry("environment", "test"),
             entry("region", "US-East")
         );
 
@@ -197,4 +200,25 @@ public void should_extract_tags() {
         instance = instance.register(registration.toBuilder().clearMetadata().build());
         assertThat(instance.getTags().getValues()).isEmpty();
     }
+
+    @Test
+    public void shoud_rebuild_instance() {
+        Instance instance = Instance.create(InstanceId.of("id"))
+                                    .register(Registration.create("test", "http://test").build())
+                                    .withInfo(Info.from(singletonMap("info", "remove")))
+                                    .withInfo(Info.from(singletonMap("info", "test2")));
+
+        List<InstanceEvent> relevantEvents = instance.getUnsavedEvents()
+                                                     .stream()
+                                                     .filter(e -> !(e instanceof InstanceInfoChangedEvent &&
+                                                                    ((InstanceInfoChangedEvent) e).getInfo()
+                                                                                                  .getValues()
+                                                                                                  .get("info")
+                                                                                                  .equals("remove")))
+                                                     .collect(Collectors.toList());
+
+        Instance rebuilt = Instance.create(InstanceId.of("id")).apply(relevantEvents);
+
+        assertThat(rebuilt).isEqualTo(instance);
+    }
 }