org.jclouds.byon.functions.NodesFromYamlStream.java Source code

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Here is the source code for org.jclouds.byon.functions.NodesFromYamlStream.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.jclouds.byon.functions;

import static com.google.common.base.Preconditions.checkState;

import java.io.InputStream;
import java.util.List;
import java.util.Map;

import javax.inject.Singleton;

import org.jclouds.byon.Node;
import org.jclouds.byon.domain.YamlNode;
import org.yaml.snakeyaml.Loader;
import org.yaml.snakeyaml.TypeDescription;
import org.yaml.snakeyaml.Yaml;
import org.yaml.snakeyaml.constructor.Constructor;

import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.Iterables;
import com.google.common.collect.Maps;

/**
 * Parses the following syntax.
 * 
 * <pre>
 * nodes:
 *     - id: cluster-1:
 *       name: cluster-1
 *       description: xyz
 *       hostname: cluster-1.mydomain.com
 *       location_id: virginia
 *       os_arch: x86
 *       os_family: linux
 *       os_description: redhat
 *       os_version: 5.3
 *       group: hadoop
 *       tags:
 *           - vanilla
 *       username: kelvin
 *       credential: password_or_rsa
 *         or
 *       credential_url: password_or_rsa_file ex. resource:///id_rsa will get the classpath /id_rsa; file://path/to/id_rsa
 *       sudo_password: password
 * </pre>
 * 
 * @author Kelvin Kakugawa
 * @author Adrian Cole
 */
@Singleton
public class NodesFromYamlStream implements Function<InputStream, LoadingCache<String, Node>> {

    /**
     * Type-safe config class for YAML
     * 
     */
    public static class Config {
        public List<YamlNode> nodes;
    }

    @Override
    public LoadingCache<String, Node> apply(InputStream source) {

        Constructor constructor = new Constructor(Config.class);

        TypeDescription nodeDesc = new TypeDescription(YamlNode.class);
        nodeDesc.putListPropertyType("tags", String.class);
        constructor.addTypeDescription(nodeDesc);

        TypeDescription configDesc = new TypeDescription(Config.class);
        configDesc.putListPropertyType("nodes", YamlNode.class);
        constructor.addTypeDescription(configDesc);
        // note that snakeyaml also throws nosuchmethod error when you use the
        // non-deprecated
        // constructor
        Yaml yaml = new Yaml(new Loader(constructor));
        Config config = (Config) yaml.load(source);
        checkState(config != null, "missing config: class");
        checkState(config.nodes != null, "missing nodes: collection");

        Map<String, Node> backingMap = Maps.uniqueIndex(Iterables.transform(config.nodes, YamlNode.toNode),
                new Function<Node, String>() {
                    public String apply(Node node) {
                        return node.getId();
                    }
                });
        LoadingCache<String, Node> cache = CacheBuilder.newBuilder()
                .build(CacheLoader.from(Functions.forMap(backingMap)));
        for (String node : backingMap.keySet())
            cache.getUnchecked(node);
        return cache;
    }
}