com.streamsets.datacollector.security.LoginUgiProviderFactory.java Source code

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Here is the source code for com.streamsets.datacollector.security.LoginUgiProviderFactory.java

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/**
 * Copyright 2016 StreamSets Inc.
 *
 * Licensed under 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 com.streamsets.datacollector.security;

import com.streamsets.pipeline.api.impl.Utils;
import org.apache.hadoop.security.UserGroupInformation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.security.auth.Subject;
import java.io.IOException;
import java.util.ServiceLoader;

public abstract class LoginUgiProviderFactory {

    private static final Logger LOG = LoggerFactory.getLogger(LoginUgiProviderFactory.class);

    private static LoginUgiProviderFactory loginUgiProviderFactory;

    public abstract LoginUgiProvider createLoginUgiProvider();

    private static ServiceLoader<LoginUgiProviderFactory> loginUgiProviderFactoryServiceLoader = ServiceLoader
            .load(LoginUgiProviderFactory.class);

    static {
        int serviceCount = 0;
        for (LoginUgiProviderFactory bean : loginUgiProviderFactoryServiceLoader) {
            loginUgiProviderFactory = bean;
            serviceCount++;
        }

        if (loginUgiProviderFactory == null) {
            LOG.warn(
                    "Could not find implementation of LoginUgiProviderFactory. Using default implementation meant for Apache Hadoop.");
            loginUgiProviderFactory = getDefaultLoginUgiProviderFactory();
        } else if (serviceCount != 1) {
            throw new RuntimeException(
                    Utils.format("Unexpected number of LoginUgiProviderFactory : {} instead of 1", serviceCount));
        }
    }

    public static LoginUgiProvider getLoginUgiProvider() {
        return loginUgiProviderFactory.createLoginUgiProvider();
    }

    private static LoginUgiProviderFactory getDefaultLoginUgiProviderFactory() {
        return new LoginUgiProviderFactory() {
            @Override
            public LoginUgiProvider createLoginUgiProvider() {
                return new LoginUgiProvider() {
                    @Override
                    public UserGroupInformation getLoginUgi(Subject subject) throws IOException {
                        UserGroupInformation loginUgi;
                        if (UserGroupInformation.isSecurityEnabled()) {
                            loginUgi = UserGroupInformation.getUGIFromSubject(subject);
                        } else {
                            UserGroupInformation.loginUserFromSubject(subject);
                            loginUgi = UserGroupInformation.getLoginUser();
                        }
                        return loginUgi;
                    }
                };
            }
        };
    }
}