dubbo-admin-server/src/main/java/org/apache/dubbo/admin/registry/metadata/impl/ZookeeperMetaDataCollector.java

/*
 * 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.dubbo.admin.registry.metadata.impl;

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.dubbo.admin.common.util.Constants;
import org.apache.dubbo.admin.registry.metadata.MetaDataCollector;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.metadata.identifier.MetadataIdentifier;

public class ZookeeperMetaDataCollector implements MetaDataCollector {

    private static final Logger logger = LoggerFactory.getLogger(ZookeeperMetaDataCollector.class);
    private CuratorFramework client;
    private URL url;
    private String root;
    private final static String DEFAULT_ROOT = "dubbo";

    @Override
    public void setUrl(URL url) {
        this.url = url;
    }

    @Override
    public URL getUrl() {
        return url;
    }

    @Override
    public void init() {
        String group = url.getParameter(Constants.GROUP_KEY, DEFAULT_ROOT);
        if (!group.startsWith(Constants.PATH_SEPARATOR)) {
            group = Constants.PATH_SEPARATOR + group;
        }
        root = group;
        client = CuratorFrameworkFactory.newClient(url.getAddress(), new ExponentialBackoffRetry(1000, 3));
        client.start();
    }


    @Override
    public String getProviderMetaData(MetadataIdentifier key) {
        return doGetMetadata(key);
    }

    @Override
    public String getConsumerMetaData(MetadataIdentifier key) {
        return doGetMetadata(key);
    }

    private String getNodePath(MetadataIdentifier metadataIdentifier) {
        return toRootDir() + metadataIdentifier.getUniqueKey(MetadataIdentifier.KeyTypeEnum.PATH);
    }

    private String toRootDir() {
        if (root.equals(Constants.PATH_SEPARATOR)) {
            return root;
        }
        return root + Constants.PATH_SEPARATOR;
    }

    private String doGetMetadata(MetadataIdentifier identifier) {
        //TODO error handing
        try {
            String path = getNodePath(identifier);
            if (client.checkExists().forPath(path) == null) {
                return null;
            }
            return new String(client.getData().forPath(path));
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        }
        return null;
    }
}