Be more resilient when endpoints with the same id are discovered.

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

@@ -27,13 +27,20 @@ import reactor.core.publisher.Mono;
 import java.net.URI;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.List;
+import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Collectors;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.util.Assert;
 import org.springframework.web.reactive.function.client.ClientResponse;
 import org.springframework.web.util.UriComponentsBuilder;
 
+import static java.util.stream.Collectors.groupingBy;
+
 public class ProbeEndpointsStrategy implements EndpointDetectionStrategy {
+    private static final Logger log = LoggerFactory.getLogger(ProbeEndpointsStrategy.class);
     private final Collection<EndpointDefinition> endpoints;
     private final InstanceWebClient instanceWebClient;
 
@@ -49,7 +56,7 @@ public class ProbeEndpointsStrategy implements EndpointDetectionStrategy {
         return Flux.fromIterable(endpoints)
                    .flatMap(endpoint -> detectEndpoint(instance, endpoint))
                    .collectList()
-                   .flatMap(list -> list.isEmpty() ? Mono.empty() : Mono.just(Endpoints.of(list)));
+                   .flatMap(this::convert);
     }
 
     private Mono<Endpoint> detectEndpoint(Instance instance, EndpointDefinition endpoint) {
@@ -63,9 +70,29 @@ public class ProbeEndpointsStrategy implements EndpointDetectionStrategy {
 
     private Function<ClientResponse, Mono<Endpoint>> convert(EndpointDefinition endpoint, URI uri) {
         return response -> response.bodyToMono(Void.class)
-                                   .then(response.statusCode().is2xxSuccessful() ?
-                                       Mono.just(Endpoint.of(endpoint.getId(), uri.toString())) :
-                                       Mono.empty());
+                                   .then(response.statusCode()
+                                                 .is2xxSuccessful() ? Mono.just(Endpoint.of(endpoint.getId(),
+                                       uri.toString()
+                                   )) : Mono.empty());
+    }
+
+
+    private Mono<Endpoints> convert(List<Endpoint> endpoints) {
+        if (endpoints.isEmpty()) {
+            return Mono.empty();
+        }
+
+        Map<String, List<Endpoint>> endpointsById = endpoints.stream().collect(groupingBy(Endpoint::getId));
+        List<Endpoint> result = endpointsById.values().stream().map(endpointList -> {
+            if (endpointList.size() > 1) {
+                log.warn("Duplicate endpoints for id '{}' detected. Omitting: {}",
+                    endpointList.get(0).getId(),
+                    endpointList.subList(1, endpointList.size())
+                );
+            }
+            return endpointList.get(0);
+        }).collect(Collectors.toList());
+        return Mono.just(Endpoints.of(result));
     }
 
     @Data
@@ -79,7 +106,8 @@ public class ProbeEndpointsStrategy implements EndpointDetectionStrategy {
                 return new EndpointDefinition(idWithPath, idWithPath);
             } else {
                 return new EndpointDefinition(idWithPath.substring(0, idxDelimiter),
-                    idWithPath.substring(idxDelimiter + 1));
+                    idWithPath.substring(idxDelimiter + 1)
+                );
             }
         }
     }

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

@@ -63,12 +63,13 @@ public class ProbeEndpointsStrategyTest {
                                                           .managementUrl(wireMock.url("/mgmt"))
                                                           .build());
 
+        wireMock.stubFor(options(urlEqualTo("/mgmt/metrics")).willReturn(ok()));
         wireMock.stubFor(options(urlEqualTo("/mgmt/stats")).willReturn(ok()));
         wireMock.stubFor(options(urlEqualTo("/mgmt/info")).willReturn(ok()));
         wireMock.stubFor(options(urlEqualTo("/mgmt/non-exist")).willReturn(notFound()));
 
         ProbeEndpointsStrategy strategy = new ProbeEndpointsStrategy(instanceWebClient,
-            new String[]{"metrics:stats", "info", "non-exist"});
+            new String[]{"metrics:stats", "metrics", "info", "non-exist"});
 
         //when
         StepVerifier.create(strategy.detectEndpoints(instance))