Fix: no status update when recieving response with no body but compatible content-type

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

@@ -31,6 +31,7 @@ import java.util.logging.Level;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.web.reactive.function.client.ClientResponse;
 
@@ -78,29 +79,32 @@ public class StatusUpdater {
     }
 
     protected Mono<StatusInfo> convertStatusInfo(ClientResponse response) {
-        if (response.headers()
-                    .contentType()
-                    .map(mt -> mt.isCompatibleWith(MediaType.APPLICATION_JSON) ||
-                               mt.isCompatibleWith(ACTUATOR_V2_MEDIATYPE))
-                    .orElse(false)) {
+        Boolean hasCompatibleContentType = response.headers()
+                                                   .contentType()
+                                                   .map(mt -> mt.isCompatibleWith(MediaType.APPLICATION_JSON) ||
+                                                              mt.isCompatibleWith(ACTUATOR_V2_MEDIATYPE))
+                                                   .orElse(false);
+
+        StatusInfo statusInfoFromStatus = this.getStatusInfoFromStatus(response.statusCode(), emptyMap());
+        if (hasCompatibleContentType) {
             return response.bodyToMono(RESPONSE_TYPE).map(body -> {
                 if (body.get("status") instanceof String) {
                     return StatusInfo.from(body);
                 }
-                return getStatusInfoFromStatus(response, body);
-            });
+                return getStatusInfoFromStatus(response.statusCode(), body);
+            }).defaultIfEmpty(statusInfoFromStatus);
         }
-        return response.bodyToMono(Void.class).then(Mono.just(this.getStatusInfoFromStatus(response, emptyMap())));
+        return response.bodyToMono(Void.class).then(Mono.just(statusInfoFromStatus));
     }
 
     @SuppressWarnings("unchecked")
-    protected StatusInfo getStatusInfoFromStatus(ClientResponse response, Map<String, ?> body) {
-        if (response.statusCode().is2xxSuccessful()) {
+    protected StatusInfo getStatusInfoFromStatus(HttpStatus httpStatus, Map<String, ?> body) {
+        if (httpStatus.is2xxSuccessful()) {
             return StatusInfo.ofUp();
         }
         Map<String, Object> details = new LinkedHashMap<>();
-        details.put("status", response.statusCode().value());
-        details.put("error", response.statusCode().getReasonPhrase());
+        details.put("status", httpStatus.value());
+        details.put("error", httpStatus.getReasonPhrase());
         if (body.get("details") instanceof Map) {
             details.putAll((Map<? extends String, ?>) body.get("details"));
         } else {

spring-boot-admin-server/src/test/java/de/codecentric/boot/admin/server/services/StatusUpdaterTest.java

@@ -73,7 +73,7 @@ public class StatusUpdaterTest {
     }
 
     @Test
-    public void test_update_statusChanged() {
+    public void should_change_status_to_down() {
         String body = "{ \"status\" : \"UP\", \"details\" : { \"foo\" : \"bar\" } }";
         wireMock.stubFor(get("/health").willReturn(
             okForContentType(ActuatorMediaType.V2_JSON, body).withHeader("Content-Length",
@@ -109,7 +109,7 @@ public class StatusUpdaterTest {
     }
 
     @Test
-    public void test_update_statusUnchanged() {
+    public void should_not_change_status() {
         String body = "{ \"status\" : \"UNKNOWN\" }";
         wireMock.stubFor(
             get("/health").willReturn(okJson(body).withHeader("Content-Type", Integer.toString(body.length()))));
@@ -124,7 +124,7 @@ public class StatusUpdaterTest {
     }
 
     @Test
-    public void test_update_up_noBody() {
+    public void should_change_status_to_up() {
         wireMock.stubFor(get("/health").willReturn(ok()));
 
         StepVerifier.create(eventStore)
@@ -140,7 +140,7 @@ public class StatusUpdaterTest {
     }
 
     @Test
-    public void test_update_down() {
+    public void should_change_status_to_down_with_details() {
         String body = "{ \"foo\" : \"bar\" }";
         wireMock.stubFor(get("/health").willReturn(
             status(503).withHeader("Content-Type", MediaType.APPLICATION_JSON_VALUE)
@@ -161,7 +161,7 @@ public class StatusUpdaterTest {
     }
 
     @Test
-    public void test_update_down_noBody() {
+    public void should_change_status_to_down_without_details_incompatible_content_type() {
         wireMock.stubFor(get("/health").willReturn(status(503)));
 
         StepVerifier.create(eventStore)
@@ -179,7 +179,26 @@ public class StatusUpdaterTest {
     }
 
     @Test
-    public void test_update_offline() {
+    public void should_change_status_to_down_without_details_no_body() {
+        wireMock.stubFor(
+            get("/health").willReturn(status(503).withHeader("Content-Type", MediaType.APPLICATION_JSON_VALUE)));
+
+        StepVerifier.create(eventStore)
+                    .expectSubscription()
+                    .then(() -> StepVerifier.create(updater.updateStatus(instance.getId())).verifyComplete())
+                    .assertNext(event -> assertThat(event).isInstanceOf(InstanceStatusChangedEvent.class))
+                    .thenCancel()
+                    .verify();
+
+        StepVerifier.create(repository.find(instance.getId())).assertNext(app -> {
+            assertThat(app.getStatusInfo().getStatus()).isEqualTo("DOWN");
+            assertThat(app.getStatusInfo().getDetails()).containsEntry("status", 503)
+                                                        .containsEntry("error", "Service Unavailable");
+        }).verifyComplete();
+    }
+
+    @Test
+    public void should_change_status_to_offline() {
         wireMock.stubFor(get("/health").willReturn(aResponse().withFault(Fault.CONNECTION_RESET_BY_PEER)));
 
         StepVerifier.create(eventStore)