gobblin.config.store.deploy.ClasspathConfigSource.java Source code

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Here is the source code for gobblin.config.store.deploy.ClasspathConfigSource.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 gobblin.config.store.deploy;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import java.util.Set;
import java.util.regex.Pattern;

import org.apache.commons.lang.StringUtils;
import org.reflections.Reflections;
import org.reflections.scanners.ResourcesScanner;
import org.reflections.util.ClasspathHelper;
import org.reflections.util.ConfigurationBuilder;
import org.reflections.util.FilterBuilder;

import com.google.common.base.Optional;
import com.google.common.base.Strings;
import com.google.common.collect.Sets;

/**
 * A {@link DeployableConfigSource} that reads configs to be deployed from classpath.
 * Caller can set {@link #CONFIG_STORE_CLASSPATH_RESOURCE_NAME_KEY} to the name of classpath resource under which deployable configs are available.
 * If the property is not set the {@link #DEFAULT_CONFIG_STORE_CLASSPATH_RESOURCE_NAME} is used to search the classpath for deployable configs
 * <p>
 * It finds the config files in classpath under the
 * <code>classpathRootName</code> directory. Every config file found will be deployed to the <code>storeUri</code> with
 * a new <code>version</code>.
 * </p>
 */
public class ClasspathConfigSource implements DeployableConfigSource {

    private final String classpathRootName;
    private static final String DEFAULT_CONFIG_STORE_CLASSPATH_RESOURCE_NAME = "_CONFIG_STORE";
    public static final String CONFIG_STORE_CLASSPATH_RESOURCE_NAME_KEY = "gobblin.config.management.store.deploy.classpathresource";

    /**
     * A {@link DeployableConfigSource} that reads configs to be deployed from classpath.
     * Caller can set {@link #CONFIG_STORE_CLASSPATH_RESOURCE_NAME_KEY} to the name of classpath resource under which deployable configs are available.
     * If the property is not set the {@link #DEFAULT_CONFIG_STORE_CLASSPATH_RESOURCE_NAME} is used to search the classpath for deployable configs
     * <p>
     * It finds the config files in classpath under the
     * <code>classpathRootName</code> directory. Every config file found will be deployed to the <code>storeUri</code> with
     * a new <code>version</code>.
     * </p>
     */
    public ClasspathConfigSource(Properties props) {
        this.classpathRootName = props.getProperty(CONFIG_STORE_CLASSPATH_RESOURCE_NAME_KEY,
                DEFAULT_CONFIG_STORE_CLASSPATH_RESOURCE_NAME);
    }

    /**
     * Scan the classpath for {@link #classpathRootName} and return all resources under it.
     * {@inheritDoc}
     * @see gobblin.config.store.deploy.DeployableConfigSource#getDeployableConfigPaths()
     */
    private Set<String> getDeployableConfigPaths() {

        ConfigurationBuilder cb = new ConfigurationBuilder().setUrls(ClasspathHelper.forClassLoader())
                .setScanners(new ResourcesScanner())
                .filterInputsBy(new FilterBuilder().include(String.format(".*%s.*", this.classpathRootName)));

        Reflections reflections = new Reflections(cb);
        Pattern pattern = Pattern.compile(".*");

        return reflections.getResources(pattern);
    }

    /**
     * Open an {@link InputStream} for <code>resourcePath</code> in classpath
     * {@inheritDoc}
     * @see gobblin.config.store.deploy.DeployableConfigSource#getConfigStream(java.lang.String)
     */
    private static InputStream getConfigStream(String configPath) {
        return ClasspathConfigSource.class.getClassLoader().getResourceAsStream(configPath);
    }

    /**
     * Scan the classpath for {@link #classpathRootName} and opens an {@link InputStream} each resource under it.
     * {@inheritDoc}
     * @see gobblin.config.store.deploy.DeployableConfigSource#getConfigStreams()
     */
    @Override
    public Set<ConfigStream> getConfigStreams() throws IOException {
        Set<ConfigStream> configStreams = Sets.newHashSet();
        for (String configPath : getDeployableConfigPaths()) {
            configStreams.add(new ConfigStream(Optional.of(getConfigStream(configPath)),
                    StringUtils.substringAfter(Strings.nullToEmpty(configPath), this.classpathRootName + "/")));
        }
        return configStreams;
    }
}