co.cask.cdap.common.guice.FileContextProvider.java Source code

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Here is the source code for co.cask.cdap.common.guice.FileContextProvider.java

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/*
 * Copyright  2016 Cask Data, Inc.
 *
 * Licensed 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 co.cask.cdap.common.guice;

import co.cask.cdap.common.conf.CConfiguration;
import co.cask.cdap.common.conf.Constants;
import com.google.common.base.Throwables;
import com.google.inject.Inject;
import com.google.inject.Provider;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileContext;
import org.apache.hadoop.security.UserGroupInformation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.PrivilegedAction;

/**
 * Guice module for {@link FileContext} created created with {@link UserGroupInformation} of
 * {@link Constants#CFG_HDFS_USER}
 */
public class FileContextProvider implements Provider<FileContext> {

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

    private final CConfiguration cConf;
    private final Configuration hConf;

    @Inject
    public FileContextProvider(CConfiguration cConf, Configuration hConf) {
        this.cConf = cConf;
        this.hConf = hConf;
    }

    @Override
    public FileContext get() {
        return createUGI().doAs(new PrivilegedAction<FileContext>() {
            @Override
            public FileContext run() {
                try {
                    return FileContext.getFileContext(hConf);
                } catch (Exception e) {
                    throw Throwables.propagate(e);
                }
            }
        });
    }

    private UserGroupInformation createUGI() {
        String hdfsUser = cConf.get(Constants.CFG_HDFS_USER);
        try {
            if (hdfsUser == null || UserGroupInformation.isSecurityEnabled()) {
                if (hdfsUser != null) {
                    LOG.debug("Ignoring configuration {}={}, running on secure Hadoop", Constants.CFG_HDFS_USER,
                            hdfsUser);
                }
                LOG.debug("Getting filesystem for current user");
                return UserGroupInformation.getCurrentUser();
            } else {
                LOG.debug("Getting filesystem for user {}", hdfsUser);
                return UserGroupInformation.createRemoteUser(hdfsUser);
            }
        } catch (Exception e) {
            throw Throwables.propagate(e);
        }
    }
}