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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.pulsar.metadata.api;
import com.fasterxml.jackson.core.type.TypeReference;
import com.google.common.annotations.Beta;
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.
*
* NOTE: This API is still evolving and will be refactored as needed until all the metadata usages are converted into
* using it.
*/
@Beta
public interface MetadataStore extends AutoCloseable {
Logger LOGGER = LoggerFactory.getLogger(MetadataStore.class);
/**
* Read the value of one key, identified by the path
*
* The async call will return a future that yields a {@link GetResult} that will contain the value and the
* associated {@link Stat} object.
*
* If the value is not found, the future will yield an empty {@link Optional}.
*
* @param path
* the path of the key to get from the store
* @return a future to track the async request
*/
CompletableFuture> get(String path);
/**
* Ensure that the next value read from the local client will be up-to-date with the latest version of the value
* as it can be seen by all the other clients.
* @param path
* @return a handle to the operation
*/
default CompletableFuture sync(String path) {
return CompletableFuture.completedFuture(null);
}
/**
* Return all the nodes (lexicographically sorted) that are children to the specific path.
*
* If the path itself does not exist, it will return an empty list.
*
* @param path
* the path of the key to get from the store
* @return a future to track the async request
*/
CompletableFuture> getChildren(String path);
/**
* Read whether a specific path exists.
*
* Note: In case of keys with multiple levels (eg: '/a/b/c'), checking the existence of a parent (eg. '/a') might
* not necessarily return true, unless the key had been explicitly created.
*
* @param path
* the path of the key to check on the store
* @return a future to track the async request
*/
CompletableFuture exists(String path);
/**
* Put a new value for a given key.
*
* The caller can specify an expected version to be atomically checked against the current version of the stored
* data.
*
* The future will return the {@link Stat} object associated with the newly inserted value.
*
*
* @param path
* the path of the key to delete from the store
* @param value
* the value to
* @param expectedVersion
* if present, the version will have to match with the currently stored value for the operation to
* succeed. Use -1 to enforce a non-existing value.
* @throws BadVersionException
* if the expected version doesn't match the actual version of the data
* @return a future to track the async request
*/
CompletableFuture put(String path, byte[] value, Optional expectedVersion);
/**
*
* @param path
* the path of the key to delete from the store
* @param expectedVersion
* if present, the version will have to match with the currently stored value for the operation to
* succeed
* @throws NotFoundException
* if the path is not found
* @throws BadVersionException
* if the expected version doesn't match the actual version of the data
* @return a future to track the async request
*/
CompletableFuture delete(String path, Optional expectedVersion);
default CompletableFuture deleteIfExists(String path, Optional 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.
*
* Note: the operation might not be carried in an atomic fashion. If the operation fails, the deletion of the
* tree might be only partial.
*
* @param path
* the path of the key to delete from the store
* @return a future to track the async request
*/
CompletableFuture deleteRecursive(String path);
/**
* Register a listener that will be called on changes in the underlying store.
*
* @param listener
* a consumer of notifications
*/
void registerListener(Consumer listener);
/**
* Create a metadata cache specialized for a specific class.
*
* @param
* @param clazz
* the class type to be used for serialization/deserialization
* @param cacheConfig
* the cache configuration to be used
* @return the metadata cache object
*/
MetadataCache getMetadataCache(Class clazz, MetadataCacheConfig cacheConfig);
/**
* Create a metadata cache specialized for a specific class.
*
* @param
* @param clazz
* the class type to be used for serialization/deserialization
* @return the metadata cache object
*/
default MetadataCache getMetadataCache(Class clazz) {
return getMetadataCache(clazz, getDefaultMetadataCacheConfig());
}
/**
* Create a metadata cache specialized for a specific class.
*
* @param
* @param typeRef
* the type ref description to be used for serialization/deserialization
* @param cacheConfig
* the cache configuration to be used
* @return the metadata cache object
*/
MetadataCache getMetadataCache(TypeReference typeRef, MetadataCacheConfig cacheConfig);
/**
* Create a metadata cache specialized for a specific class.
*
* @param
* @param typeRef
* the type ref description to be used for serialization/deserialization
* @return the metadata cache object
*/
default MetadataCache getMetadataCache(TypeReference typeRef) {
return getMetadataCache(typeRef, getDefaultMetadataCacheConfig());
}
/**
* Create a metadata cache that uses a particular serde object.
*
* @param
* @param serde
* the custom serialization/deserialization object
* @param cacheConfig
* the cache configuration to be used
* @return the metadata cache object
*/
MetadataCache getMetadataCache(MetadataSerde serde, MetadataCacheConfig cacheConfig);
/**
* Create a metadata cache that uses a particular serde object.
*
* @param
* @param serde
* the custom serialization/deserialization object
* @return the metadata cache object
*/
default MetadataCache getMetadataCache(MetadataSerde serde) {
return getMetadataCache(serde, getDefaultMetadataCacheConfig());
}
/**
* Returns the default metadata cache config.
*
* @return default metadata cache config
*/
default MetadataCacheConfig getDefaultMetadataCacheConfig() {
return MetadataCacheConfig.builder().build();
}
}