Utils.java

/**
 * Copyright 2015, Yahoo Inc.
 * Licensed under the terms of the Apache License 2.0. Please see LICENSE file in the project root for terms.
 */
package benchmark.common;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;

import org.yaml.snakeyaml.Yaml;
import org.yaml.snakeyaml.constructor.SafeConstructor;

public class Utils {
    private static final Logger LOG = LoggerFactory.getLogger(Utils.class);

    public static Map findAndReadConfigFile(String name, boolean mustExist) {
        InputStream in = null;
        boolean confFileEmpty = false;
        try {
            in = getConfigFileInputStream(name);
            if (null != in) {
                Yaml yaml = new Yaml(new SafeConstructor());
                Map ret = (Map) yaml.load(new InputStreamReader(in));
                if (null != ret) {
                    return new HashMap(ret);
                } else {
                    confFileEmpty = true;
                }
            }

            if (mustExist) {
                if(confFileEmpty)
                    throw new RuntimeException("Config file " + name + " doesn't have any valid storm configs");
                else
                    throw new RuntimeException("Could not find config file on classpath " + name);
            } else {
                return new HashMap();
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if (null != in) {
                try {
                    in.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }

    private static InputStream getConfigFileInputStream(String configFilePath)
            throws IOException {
        if (null == configFilePath) {
            throw new IOException(
                    "Could not find config file, name not specified");
        }

        HashSet<URL> resources = new HashSet<URL>(findResources(configFilePath));
        if (resources.isEmpty()) {
            File configFile = new File(configFilePath);
            if (configFile.exists()) {
                return new FileInputStream(configFile);
            }
        } else if (resources.size() > 1) {
            throw new IOException(
                    "Found multiple " + configFilePath
                            + " resources. You're probably bundling the Storm jars with your topology jar. "
                            + resources);
        } else {
            LOG.debug("Using "+configFilePath+" from resources");
            URL resource = resources.iterator().next();
            return resource.openStream();
        }
        return null;
    }

    public static List<URL> findResources(String name) {
        try {
            Enumeration<URL> resources = Thread.currentThread().getContextClassLoader().getResources(name);
            List<URL> ret = new ArrayList<URL>();
            while(resources.hasMoreElements()) {
                ret.add(resources.nextElement());
            }
            return ret;
        } catch(IOException e) {
            throw new RuntimeException(e);
        }
    }
}