ranger-plugin/service/src/main/java/org/apache/hawq/ranger/authorization/Utils.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.hawq.ranger.authorization;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;


/**
 * Utility class for reading values from the environment with falling back to reading them from the property file.
 */
public abstract class Utils {

    public static final String HAWQ = "hawq";
    public static final String APPID = "rps";
    public static final String UNKNOWN = "unknown";
    public static final String INSTANCE_PROPERTY_KEY_ENV = "ranger.hawq.instance";
    public static final String INSTANCE_PROPERTY_KEY_FILE = "RANGER_HAWQ_INSTANCE";
    public static final String VERSION_PROPERTY_KEY_ENV = "version";
    public static final String VERSION_PROPERTY_KEY_FILE = "RPS_VERSION";
    public static final String RANGER_SERVICE_PROPERTY_FILE = "rps.properties";

    //kerberos support property
    public static enum AuthMethod { SIMPLE, KERBEROS }
    public static final String AUTH_KEY_ENV = "auth";
    public static final String AUTH_KEY_FILE = "RPS_AUTH";
    public static final String PRINCIPAL_KEY_ENV = "principal";
    public static final String PRINCIPAL_KEY_FILE = "RPS_PRINCIPAL";
    public static final String KEYTAB_KEY_ENV = "keytab";
    public static final String KEYTAB_KEY_FILE = "RPS_KEYTAB";


    private static final Log LOG = LogFactory.getLog(Utils.class);
    private static final Properties properties = readPropertiesFromFile();

    /**
     * Retrieves the instance name from the environment variable with the key ranger.hawq.instance
     * or from the rps.properties file with the key RANGER_HAWQ_INSTANCE
     *
     * If none exist, hawq is used as the default
     *
     * @return instance name
     */
    public static String getInstanceName() {
        return System.getProperty(INSTANCE_PROPERTY_KEY_ENV, properties.getProperty(INSTANCE_PROPERTY_KEY_FILE, HAWQ));
    }

    /**
     * Retrieves the version from the environment variable with the key version
     * or from the rps.properties file with the key RPS_VERSION
     *
     * If none exist, unknown is used as the default
     *
     * @return version of the service
     */
    public static String getVersion() {
        return System.getProperty(VERSION_PROPERTY_KEY_ENV, properties.getProperty(VERSION_PROPERTY_KEY_FILE, UNKNOWN));
    }

    /**
     * Retrieves the authentication
     * @return kerberos or simple[default]
     */
    public static AuthMethod getAuth() {
        String auth = System.getProperty(AUTH_KEY_ENV, properties.getProperty(AUTH_KEY_FILE, "simple"));
        if (auth.toLowerCase().equals("kerberos"))
            return AuthMethod.KERBEROS;
        else
            return AuthMethod.SIMPLE;
    }

    /**
     * Retrieves the kerberos client principal
     * @return principal name or ""[default]
     */
    public static String getPrincipal() {
        return System.getProperty(PRINCIPAL_KEY_ENV, properties.getProperty(PRINCIPAL_KEY_FILE, ""));
    }

    /**
     * Retrieves the kerberos keytab file path
     * @return keytab file path or ""[default]
     */
    public static String getKeytab() {
        return System.getProperty(KEYTAB_KEY_ENV, properties.getProperty(KEYTAB_KEY_FILE, ""));
    }

    /**
     * Reads properties from the property file.
     * @return properties read from the file
     */
    private static Properties readPropertiesFromFile() {
        Properties prop = new Properties();
        InputStream inputStream = Utils.class.getClassLoader().getResourceAsStream(RANGER_SERVICE_PROPERTY_FILE);
        try {
            prop.load(inputStream);
        } catch (IOException e) {
            LOG.error("Failed to read from: " + RANGER_SERVICE_PROPERTY_FILE);
        }
        return prop;
    }
}