[improve][broker]Ensure namespace deletion doesn't fail

pulsar-broker-common/src/main/java/org/apache/pulsar/broker/resources/BaseResources.java

@@ -197,22 +197,21 @@ protected CompletableFuture<Void> deleteAsync(String path) {
     }
 
     protected CompletableFuture<Void> deleteIfExistsAsync(String path) {
-        return cache.exists(path).thenCompose(exists -> {
-            if (!exists) {
-                return CompletableFuture.completedFuture(null);
+        log.info("Deleting path: {}", path);
+        CompletableFuture<Void> future = new CompletableFuture<>();
+        cache.delete(path).whenComplete((ignore, ex) -> {
+            if (ex != null && ex.getCause() instanceof MetadataStoreException.NotFoundException) {
+                log.info("Path {} did not exist in metadata store", path);
+                future.complete(null);
+            } else if (ex != null) {
+                log.info("Cannot path from metadata store: {}", path, ex);
+                future.completeExceptionally(ex);
+            } else {
+                log.info("Deleted path from metadata store: {}", path);
+                future.complete(null);
             }
-            CompletableFuture<Void> future = new CompletableFuture<>();
-            cache.delete(path).whenComplete((ignore, ex) -> {
-                if (ex != null && ex.getCause() instanceof MetadataStoreException.NotFoundException) {
-                    future.complete(null);
-                } else if (ex != null) {
-                    future.completeExceptionally(ex);
-                } else {
-                    future.complete(null);
-                }
-            });
-            return future;
         });
+        return future;
     }
 
     protected boolean exists(String path) throws MetadataStoreException {

pulsar-broker-common/src/main/java/org/apache/pulsar/broker/resources/LocalPoliciesResources.java

@@ -79,7 +79,7 @@ public void deleteLocalPolicies(NamespaceName ns) throws MetadataStoreException
     }
 
     public CompletableFuture<Void> deleteLocalPoliciesAsync(NamespaceName ns) {
-        return deleteAsync(joinPath(LOCAL_POLICIES_ROOT, ns.toString()));
+        return deleteIfExistsAsync(joinPath(LOCAL_POLICIES_ROOT, ns.toString()));
     }
 
     public CompletableFuture<Void> deleteLocalPoliciesTenantAsync(String tenant) {

pulsar-broker-common/src/main/java/org/apache/pulsar/broker/resources/NamespaceResources.java

@@ -115,7 +115,7 @@ public void deletePolicies(NamespaceName ns) throws MetadataStoreException{
     }
 
     public CompletableFuture<Void> deletePoliciesAsync(NamespaceName ns){
-        return deleteAsync(joinPath(BASE_POLICIES_PATH, ns.toString()));
+        return deleteIfExistsAsync(joinPath(BASE_POLICIES_PATH, ns.toString()));
     }
 
     public Optional<Policies> getPolicies(NamespaceName ns) throws MetadataStoreException{
@@ -155,10 +155,18 @@ public static boolean pathIsNamespaceLocalPolicies(String path) {
                 && path.substring(LOCAL_POLICIES_ROOT.length() + 1).contains("/");
     }
 
-    // clear resource of `/namespace/{namespaceName}` for zk-node
+    /**
+     * Clear resource of `/namespace/{namespaceName}` for zk-node.
+     * @param ns the namespace name
+     * @return a handle to the results of the operation
+     * */
+    //
     public CompletableFuture<Void> deleteNamespaceAsync(NamespaceName ns) {
         final String namespacePath = joinPath(NAMESPACE_BASE_PATH, ns.toString());
-        return deleteIfExistsAsync(namespacePath);
+        // please beware that this will delete all the children of the namespace
+        // including the ownership nodes (ephemeral nodes)
+        // see ServiceUnitUtils.path(ns) for the ownership node path
+        return getStore().deleteRecursive(namespacePath);
     }
 
     // clear resource of `/namespace/{tenant}` for zk-node
@@ -303,11 +311,14 @@ public CompletableFuture<Void> deletePartitionedTopicAsync(TopicName tn) {
 
         public CompletableFuture<Void> clearPartitionedTopicMetadataAsync(NamespaceName namespaceName) {
             final String globalPartitionedPath = joinPath(PARTITIONED_TOPIC_PATH, namespaceName.toString());
+            log.info("Clearing partitioned topic metadata for namespace {}, path is {}",
+                    namespaceName, globalPartitionedPath);
             return getStore().deleteRecursive(globalPartitionedPath);
         }
 
         public CompletableFuture<Void> clearPartitionedTopicTenantAsync(String tenant) {
             final String partitionedTopicPath = joinPath(PARTITIONED_TOPIC_PATH, tenant);
+            log.info("Clearing partitioned topic metadata for tenant {}, path is {}", tenant, partitionedTopicPath);
             return deleteIfExistsAsync(partitionedTopicPath);
         }
 

pulsar-broker-common/src/main/java/org/apache/pulsar/broker/resources/TopicResources.java

@@ -75,11 +75,6 @@ public CompletableFuture<List<String>> getExistingPartitions(NamespaceName ns, T
         );
     }
 
-    public CompletableFuture<Void> deletePersistentTopicAsync(TopicName topic) {
-        String path = MANAGED_LEDGER_PATH + "/" + topic.getPersistenceNamingEncoding();
-        return store.delete(path, Optional.of(-1L));
-    }
-
     public CompletableFuture<Void> createPersistentTopicAsync(TopicName topic) {
         String path = MANAGED_LEDGER_PATH + "/" + topic.getPersistenceNamingEncoding();
         return store.put(path, new byte[0], Optional.of(-1L))
@@ -93,38 +88,20 @@ public CompletableFuture<Boolean> persistentTopicExists(TopicName topic) {
 
     public CompletableFuture<Void> clearNamespacePersistence(NamespaceName ns) {
         String path = MANAGED_LEDGER_PATH + "/" + ns;
-        return store.exists(path)
-                .thenCompose(exists -> {
-                    if (exists) {
-                        return store.delete(path, Optional.empty());
-                    } else {
-                        return CompletableFuture.completedFuture(null);
-                    }
-                });
+        log.info("Clearing namespace persistence for namespace: {}, path {}", ns, path);
+        return store.deleteIfExists(path, Optional.empty());
     }
 
     public CompletableFuture<Void> clearDomainPersistence(NamespaceName ns) {
         String path = MANAGED_LEDGER_PATH + "/" + ns + "/persistent";
-        return store.exists(path)
-                .thenCompose(exists -> {
-                    if (exists) {
-                        return store.delete(path, Optional.empty());
-                    } else {
-                        return CompletableFuture.completedFuture(null);
-                    }
-                });
+        log.info("Clearing domain persistence for namespace: {}, path {}", ns, path);
+        return store.deleteIfExists(path, Optional.empty());
     }
 
     public CompletableFuture<Void> clearTenantPersistence(String tenant) {
         String path = MANAGED_LEDGER_PATH + "/" + tenant;
-        return store.exists(path)
-                .thenCompose(exists -> {
-                    if (exists) {
-                        return store.deleteRecursive(path);
-                    } else {
-                        return CompletableFuture.completedFuture(null);
-                    }
-                });
+        log.info("Clearing tenant persistence for tenant: {}, path {}", tenant, path);
+        return store.deleteIfExists(path, Optional.empty());
     }
 
     void handleNotification(Notification notification) {

pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/NamespacesBase.java

@@ -309,8 +309,14 @@ private void internalRetryableDeleteNamespaceAsync0(boolean force, int retryTime
                                                     clientAppId(), ex);
                                             return FutureUtil.failedFuture(ex);
                                         }
+                                        log.info("[{}] Deleting namespace bundle {}/{}", clientAppId(),
+                                                namespaceName, bundle.getBundleRange());
                                         return admin.namespaces().deleteNamespaceBundleAsync(namespaceName.toString(),
                                                 bundle.getBundleRange(), force);
+                                    } else {
+                                        log.warn("[{}] Skipping deleting namespace bundle {}/{} "
+                                                        + "as it's not owned by any broker",
+                                                clientAppId(), namespaceName, bundle.getBundleRange());
                                     }
                                     return CompletableFuture.completedFuture(null);
                                 })
@@ -321,16 +327,20 @@ private void internalRetryableDeleteNamespaceAsync0(boolean force, int retryTime
                         final Throwable rc = FutureUtil.unwrapCompletionException(error);
                         if (rc instanceof MetadataStoreException) {
                             if (rc.getCause() != null && rc.getCause() instanceof KeeperException.NotEmptyException) {
+                                KeeperException.NotEmptyException ne =
+                                        (KeeperException.NotEmptyException) rc.getCause();
                                 log.info("[{}] There are in-flight topics created during the namespace deletion, "
-                                        + "retry to delete the namespace again.", namespaceName);
+                                        + "retry to delete the namespace again. (path {} is not empty on metadata)",
+                                        namespaceName, ne.getPath());
                                 final int next = retryTimes - 1;
                                 if (next > 0) {
                                     // async recursive
                                     internalRetryableDeleteNamespaceAsync0(force, next, callback);
                                 } else {
                                     callback.completeExceptionally(
                                             new RestException(Status.CONFLICT, "The broker still have in-flight topics"
-                                                    + " created during namespace deletion, please try again."));
+                                                    + " created during namespace deletion (path " + ne.getPath() + ") "
+                                                    + "is not empty on metadata store, please try again."));
                                     // drop out recursive
                                 }
                                 return;
@@ -476,6 +486,8 @@ protected CompletableFuture<Void> internalClearZkSources() {
     @SuppressWarnings("deprecation")
     protected CompletableFuture<Void> internalDeleteNamespaceBundleAsync(String bundleRange, boolean authoritative,
                                                                          boolean force) {
+        log.info("[{}] Deleting namespace bundle {}/{} authoritative:{} force:{}",
+                clientAppId(), namespaceName, bundleRange, authoritative, force);
         return validateNamespaceOperationAsync(namespaceName, NamespaceOperation.DELETE_BUNDLE)
                 .thenCompose(__ -> validatePoliciesReadOnlyAccessAsync())
                 .thenCompose(__ -> {

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/SystemTopicBasedTopicPoliciesService.java

@@ -543,7 +543,8 @@ private void readMorePoliciesAsync(SystemTopicClient.Reader<PulsarEvent> reader)
                     } else {
                         Throwable cause = FutureUtil.unwrapCompletionException(ex);
                         if (cause instanceof PulsarClientException.AlreadyClosedException) {
-                            log.warn("Read more topic policies exception, close the read now!", ex);
+                            log.info("Closing the topic policies reader for {}",
+                                    reader.getSystemTopic().getTopicName());
                             cleanCacheAndCloseReader(
                                     reader.getSystemTopic().getTopicName().getNamespaceObject(), false);
                         } else {

pulsar-metadata/src/main/java/org/apache/pulsar/metadata/api/MetadataStore.java

@@ -23,9 +23,12 @@
 import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
 import java.util.function.Consumer;
 import org.apache.pulsar.metadata.api.MetadataStoreException.BadVersionException;
 import org.apache.pulsar.metadata.api.MetadataStoreException.NotFoundException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Metadata store client interface.
@@ -36,6 +39,8 @@
 @Beta
 public interface MetadataStore extends AutoCloseable {
 
+    Logger LOGGER = LoggerFactory.getLogger(MetadataStore.class);
+
     /**
      * Read the value of one key, identified by the path
      *
@@ -121,6 +126,23 @@ default CompletableFuture<Void> sync(String path) {
      */
     CompletableFuture<Void> delete(String path, Optional<Long> expectedVersion);
 
+    default CompletableFuture<Void> deleteIfExists(String path, Optional<Long> expectedVersion) {
+        return delete(path, expectedVersion)
+                .exceptionally(e -> {
+                    if (e.getCause() instanceof NotFoundException) {
+                        LOGGER.info("Path {} not found while deleting (this is not a problem)", path);
+                        return null;
+                    } else {
+                        if (expectedVersion.isEmpty()) {
+                            LOGGER.info("Failed to delete path {}", path, e);
+                        } else {
+                            LOGGER.info("Failed to delete path {} with expected version {}", path, expectedVersion, e);
+                        }
+                        throw new CompletionException(e);
+                    }
+                });
+    }
+
     /**
      * Delete a key-value pair and all the children nodes.
      *

pulsar-metadata/src/main/java/org/apache/pulsar/metadata/impl/AbstractMetadataStore.java

@@ -360,6 +360,7 @@ public void accept(Notification n) {
 
     @Override
     public final CompletableFuture<Void> delete(String path, Optional<Long> expectedVersion) {
+        log.info("Deleting path: {} (v. {})", path, expectedVersion);
         if (isClosed()) {
             return FutureUtil.failedFuture(
                     new MetadataStoreException.AlreadyClosedException());
@@ -405,11 +406,13 @@ private CompletableFuture<Void> deleteInternal(String path, Optional<Long> expec
             }
 
             metadataCaches.forEach(c -> c.invalidate(path));
+            log.info("Deleted path: {} (v. {})", path, expectedVersion);
         });
     }
 
     @Override
     public CompletableFuture<Void> deleteRecursive(String path) {
+        log.info("Deleting recursively path: {}", path);
         if (isClosed()) {
             return FutureUtil.failedFuture(
                     new MetadataStoreException.AlreadyClosedException());
@@ -419,13 +422,9 @@ public CompletableFuture<Void> deleteRecursive(String path) {
                         children.stream()
                                 .map(child -> deleteRecursive(path + "/" + child))
                                 .collect(Collectors.toList())))
-                .thenCompose(__ -> exists(path))
-                .thenCompose(exists -> {
-                    if (exists) {
-                        return delete(path, Optional.empty());
-                    } else {
-                        return CompletableFuture.completedFuture(null);
-                    }
+                .thenCompose(__ -> {
+                    log.info("After deleting all children, now deleting path: {}", path);
+                    return deleteIfExists(path, Optional.empty());
                 });
     }