Return null on missing version

spring-boot-admin-samples/spring-boot-admin-sample/src/main/resources/application.yml

@@ -11,10 +11,10 @@ management:
   endpoints:
     web:
       base-path: "/actuator"
+      expose: "*"
   jolokia:
     enabled: true
 
-
 spring:
   application:
     name: "@pom.artifactId@"
@@ -26,26 +26,6 @@ spring:
     active:
       - insecure
 
-endpoints:
-  health:
-    enabled: true
-  metrics:
-    enabled: true
-  logfile:
-    enabled: true
-  loggers:
-    enabled: true
-  trace:
-    enabled: true
-  auditevents:
-    enabled: true
-  heapdump:
-    enabled: true
-  threaddump:
-    enabled: true
-  env:
-    enabled: true
-
 ---
 spring:
   profiles: insecure

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/domain/values/Info.java

@@ -57,7 +57,7 @@ public class Info implements Serializable {
         if (version instanceof String) {
             return (String) version;
         }
-        return "";
+        return null;
     }
 
     @JsonAnyGetter

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/domain/values/Registration.java

@@ -16,6 +16,8 @@
 
 package de.codecentric.boot.admin.server.domain.values;
 
+import lombok.ToString;
+
 import java.io.IOException;
 import java.io.Serializable;
 import java.net.URI;
@@ -44,6 +46,7 @@ import com.fasterxml.jackson.databind.ser.std.StdSerializer;
  */
 @lombok.Data
 @JsonDeserialize(using = Registration.Deserializer.class)
+@ToString(exclude = "metadata")
 public class Registration implements Serializable {
     private final String name;
     private final String managementUrl;

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/services/InstanceRegistry.java

@@ -53,7 +53,7 @@ public class InstanceRegistry {
                 instance = Instance.create(key);
             }
             return Mono.just(instance.register(registration));
-        }).then(Mono.just(id));
+        }).map(Instance::getId);
     }
 
     /**

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/web/ApplicationsController.java

@@ -50,12 +50,11 @@ import static java.util.stream.Collectors.toMap;
 @ResponseBody
 public class ApplicationsController {
     private static final Logger log = LoggerFactory.getLogger(ApplicationsController.class);
+    private static final ServerSentEvent<?> PING = ServerSentEvent.builder().comment("ping").build();
+    private static final Flux<ServerSentEvent<?>> PING_FLUX = Flux.interval(Duration.ZERO, Duration.ofSeconds(10L))
+                                                                  .map(tick -> PING);
     private final InstanceRegistry registry;
     private final InstanceEventPublisher eventPublisher;
-    private static final ServerSentEvent<Application> PING = ServerSentEvent.<Application>builder().comment("ping")
-                                                                                                   .build();
-    private static final Flux<ServerSentEvent<Application>> PING_FLUX = Flux.interval(Duration.ZERO,
-            Duration.ofSeconds(10L)).map(tick -> PING);
 
     public ApplicationsController(InstanceRegistry registry, InstanceEventPublisher eventPublisher) {
         this.registry = registry;
@@ -77,7 +76,7 @@ public class ApplicationsController {
                    .map(this::getApplicationForInstance)
                    .flatMap(group -> toApplication(group.getT1(), group.getT2()))
                    .map(application -> ServerSentEvent.builder(application).build())
-                   .mergeWith(PING_FLUX);
+                   .mergeWith(ping());
     }
 
     @DeleteMapping(path = "/applications/{name}")
@@ -152,6 +151,11 @@ public class ApplicationsController {
                              .orElse(Tuples.of(StatusInfo.STATUS_UNKNOWN, -1L));
     }
 
+    @SuppressWarnings("unchecked")
+    private static <T> Flux<ServerSentEvent<T>> ping() {
+        return (Flux<ServerSentEvent<T>>) (Flux) PING_FLUX;
+    }
+
     @lombok.Data
     public static class Application {
         private final String name;

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/web/InstancesController.java

@@ -66,13 +66,12 @@ import static org.springframework.web.reactive.function.client.WebClient.Request
 @ResponseBody
 public class InstancesController {
     private static final Logger LOGGER = LoggerFactory.getLogger(InstancesController.class);
-    private static final ServerSentEvent<InstanceEvent> PING = ServerSentEvent.<InstanceEvent>builder().comment("ping")
-                                                                                                       .build();
+    private static final ServerSentEvent<?> PING = ServerSentEvent.builder().comment("ping").build();
+    private static final Flux<ServerSentEvent<?>> PING_FLUX = Flux.interval(Duration.ZERO, Duration.ofSeconds(10L))
+                                                                  .map(tick -> (ServerSentEvent<?>) PING);
     private final InstanceRegistry registry;
     private final InstanceEventStore eventStore;
     private final InstanceWebClient instanceWebClient;
-    private static final Flux<ServerSentEvent<InstanceEvent>> PING_FLUX = Flux.interval(Duration.ZERO,
-            Duration.ofSeconds(10L)).map(tick -> PING);
 
     public InstancesController(InstanceRegistry registry,
                                InstanceEventStore eventStore,
@@ -151,7 +150,16 @@ public class InstancesController {
 
     @GetMapping(path = "/instances/events", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
     public Flux<ServerSentEvent<InstanceEvent>> eventStream() {
-        return Flux.from(eventStore).map(event -> ServerSentEvent.builder(event).build()).mergeWith(PING_FLUX);
+        return Flux.from(eventStore).map(event -> ServerSentEvent.builder(event).build()).mergeWith(ping());
+    }
+
+    @GetMapping(path = "/instances/{id}", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
+    public Flux<ServerSentEvent<Instance>> instanceStream(@PathVariable String id) {
+        return Flux.from(eventStore)
+                   .filter(event -> event.getInstance().equals(InstanceId.of(id)))
+                   .flatMap(event -> registry.getInstance(event.getInstance()))
+                   .map(event -> ServerSentEvent.builder(event).build())
+                   .mergeWith(ping());
     }
 
     private static final String[] HOP_BY_HOP_HEADERS = new String[]{"Connection", "Keep-Alive", "Proxy-Authenticate",
@@ -204,4 +212,10 @@ public class InstancesController {
                 return false;
         }
     }
+
+    @SuppressWarnings("unchecked")
+    private static <T> Flux<ServerSentEvent<T>> ping() {
+        return (Flux<ServerSentEvent<T>>) (Flux) PING_FLUX;
+    }
+
 }

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/server/domain/values/InfoTest.java

@@ -35,7 +35,7 @@ public class InfoTest {
 
     @Test
     public void should_return_version() {
-        assertThat(Info.empty().getVersion()).isEqualTo("");
+        assertThat(Info.empty().getVersion()).isNull();
         assertThat(Info.from(singletonMap("version", "1.0.0")).getVersion()).isEqualTo("1.0.0");
         assertThat(Info.from(singletonMap("build", singletonMap("version", "1.0.0"))).getVersion()).isEqualTo("1.0.0");