[fix][broker] fix null lookup result when brokers are starting

pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java

@@ -979,6 +979,9 @@ public void start() throws PulsarServerException {
                 this.webSocketService.setLocalCluster(clusterData);
             }
 
+            // Initialize namespace service, after service url assigned. Should init zk and refresh self owner info.
+            this.nsService.initialize();
+
             // Start the leader election service
             startLeaderElectionService();
 
@@ -990,9 +993,6 @@ public void start() throws PulsarServerException {
             // (namespace service depends on load manager)
             this.startLoadManagementService();
 
-            // Initialize namespace service, after service url assigned. Should init zk and refresh self owner info.
-            this.nsService.initialize();
-
             // Start topic level policies service
             this.topicPoliciesService = initTopicPoliciesService();
             this.topicPoliciesService.start(this);

pulsar-broker/src/main/java/org/apache/pulsar/broker/lookup/TopicLookupBase.java

@@ -318,6 +318,7 @@ public static CompletableFuture<ByteBuf> lookupTopicAsync(PulsarService pulsarSe
                             }
 
                             LookupData lookupData = lookupResult.get().getLookupData();
+                            printWarnLogIfLookupResUnexpected(topicName, lookupData, options, pulsarService);
                             if (lookupResult.get().isRedirect()) {
                                 boolean newAuthoritative = lookupResult.get().isAuthoritativeRedirect();
                                 lookupfuture.complete(
@@ -342,6 +343,24 @@ public static CompletableFuture<ByteBuf> lookupTopicAsync(PulsarService pulsarSe
         return lookupfuture;
     }
 
+    /**
+     * Check if a internal client will get a null lookup result.
+     */
+    private static void printWarnLogIfLookupResUnexpected(TopicName topic, LookupData lookupData, LookupOptions options,
+                                                          PulsarService pulsar) {
+        if (!pulsar.getBrokerService().isSystemTopic(topic)) {
+            return;
+        }
+        boolean tlsEnabled = pulsar.getConfig().isBrokerClientTlsEnabled();
+        if (!tlsEnabled && StringUtils.isBlank(lookupData.getBrokerUrl())) {
+            log.warn("[{}] Unexpected lookup result: brokerUrl is required when TLS isn't enabled. options: {},"
+                + " result {}", topic, options, lookupData);
+        } else if (tlsEnabled && StringUtils.isBlank(lookupData.getBrokerUrlTls())) {
+            log.warn("[{}] Unexpected lookup result: brokerUrlTls is required when TLS is enabled. options: {},"
+                    + " result {}", topic, options, lookupData);
+        }
+    }
+
     private static void handleLookupError(CompletableFuture<ByteBuf> lookupFuture, String topicName, String clientAppId,
                                    long requestId, Throwable ex){
         Throwable unwrapEx = FutureUtil.unwrapCompletionException(ex);

pulsar-broker/src/main/java/org/apache/pulsar/broker/namespace/OwnershipCache.java

@@ -72,7 +72,7 @@ public class OwnershipCache {
     /**
      * The NamespaceEphemeralData objects that can be associated with the current owner, when the broker is disabled.
      */
-    private final NamespaceEphemeralData selfOwnerInfoDisabled;
+    private NamespaceEphemeralData selfOwnerInfoDisabled;
 
     private final LockManager<NamespaceEphemeralData> lockManager;
 
@@ -119,6 +119,9 @@ public OwnershipCache(PulsarService pulsar, NamespaceService namespaceService) {
         this.pulsar = pulsar;
         this.ownerBrokerUrl = pulsar.getBrokerServiceUrl();
         this.ownerBrokerUrlTls = pulsar.getBrokerServiceUrlTls();
+        // At this moment, the variables "webServiceAddress" and "webServiceAddressTls" and so on have not been
+        // initialized, so we will get an empty "selfOwnerInfo" and an empty "selfOwnerInfoDisabled" here.
+        // But do not worry, these two fields will be set by the method "refreshSelfOwnerInfo" soon.
         this.selfOwnerInfo = new NamespaceEphemeralData(ownerBrokerUrl, ownerBrokerUrlTls,
                 pulsar.getWebServiceAddress(), pulsar.getWebServiceAddressTls(),
                 false, pulsar.getAdvertisedListeners());
@@ -351,6 +354,9 @@ public synchronized boolean refreshSelfOwnerInfo() {
         this.selfOwnerInfo = new NamespaceEphemeralData(pulsar.getBrokerServiceUrl(),
                 pulsar.getBrokerServiceUrlTls(), pulsar.getWebServiceAddress(),
                 pulsar.getWebServiceAddressTls(), false, pulsar.getAdvertisedListeners());
+        this.selfOwnerInfoDisabled = new NamespaceEphemeralData(pulsar.getBrokerServiceUrl(),
+                pulsar.getBrokerServiceUrlTls(), pulsar.getWebServiceAddress(),
+                pulsar.getWebServiceAddressTls(), true, pulsar.getAdvertisedListeners());
         return selfOwnerInfo.getNativeUrl() != null || selfOwnerInfo.getNativeUrlTls() != null;
     }
 }