org.apache.zeppelin.helium.HeliumOnlineRegistry.java Source code

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Here is the source code for org.apache.zeppelin.helium.HeliumOnlineRegistry.java

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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.zeppelin.helium;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import org.apache.commons.io.FileUtils;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.zeppelin.util.Util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;
import java.net.URL;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

/**
 * This registry reads helium package json data
 * from specified url.
 *
 * File should be look like
 * [
 *    "packageName": {
 *       "0.0.1": json serialized HeliumPackage class,
 *       "0.0.2": json serialized HeliumPackage class,
 *       ...
 *    },
 *    ...
 * ]
 */
public class HeliumOnlineRegistry extends HeliumRegistry {
    Logger logger = LoggerFactory.getLogger(HeliumOnlineRegistry.class);
    private final Gson gson;
    private final File registryCacheFile;

    public HeliumOnlineRegistry(String name, String uri, File registryCacheDir) {
        super(name, uri);
        registryCacheDir.mkdirs();
        this.registryCacheFile = new File(registryCacheDir, name);
        gson = new Gson();
    }

    @Override
    public synchronized List<HeliumPackage> getAll() throws IOException {
        HttpClient client = HttpClientBuilder.create().setUserAgent("ApacheZeppelin/" + Util.getVersion()).build();
        HttpGet get = new HttpGet(uri());
        HttpResponse response;

        try {
            response = client.execute(get);
        } catch (Exception e) {
            logger.error(e.getMessage());
            return readFromCache();
        }

        if (response.getStatusLine().getStatusCode() != 200) {
            // try read from cache
            logger.error(uri() + " returned " + response.getStatusLine().toString());
            return readFromCache();
        } else {
            List<HeliumPackage> packageList = new LinkedList<>();

            BufferedReader reader;
            reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

            List<Map<String, Map<String, HeliumPackage>>> packages = gson.fromJson(reader,
                    new TypeToken<List<Map<String, Map<String, HeliumPackage>>>>() {
                    }.getType());
            reader.close();

            for (Map<String, Map<String, HeliumPackage>> pkg : packages) {
                for (Map<String, HeliumPackage> versions : pkg.values()) {
                    packageList.addAll(versions.values());
                }
            }

            writeToCache(packageList);
            return packageList;
        }
    }

    private List<HeliumPackage> readFromCache() {
        synchronized (registryCacheFile) {
            if (registryCacheFile.isFile()) {
                try {
                    return gson.fromJson(new FileReader(registryCacheFile), new TypeToken<List<HeliumPackage>>() {
                    }.getType());
                } catch (FileNotFoundException e) {
                    logger.error(e.getMessage(), e);
                    return new LinkedList<>();
                }
            } else {
                return new LinkedList<>();
            }
        }
    }

    private void writeToCache(List<HeliumPackage> pkg) throws IOException {
        synchronized (registryCacheFile) {
            if (registryCacheFile.exists()) {
                registryCacheFile.delete();
            }
            String jsonToCache = gson.toJson(pkg);
            FileUtils.writeStringToFile(registryCacheFile, jsonToCache);
        }
    }
}