co.cask.cdap.internal.app.runtime.artifact.SystemArtifactLoader.java Source code

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Here is the source code for co.cask.cdap.internal.app.runtime.artifact.SystemArtifactLoader.java

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/*
 * Copyright  2015 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.internal.app.runtime.artifact;

import co.cask.cdap.common.service.RetryOnStartFailureService;
import co.cask.cdap.common.service.RetryStrategies;
import co.cask.cdap.proto.security.Principal;
import co.cask.cdap.security.spi.authentication.SecurityRequestContext;
import com.google.common.base.Supplier;
import com.google.common.util.concurrent.AbstractService;
import com.google.common.util.concurrent.Service;
import com.google.inject.Inject;

import java.util.concurrent.TimeUnit;

/**
 * Thread that scans the local filesystem for system artifacts and adds them to the artifact repository if they
 * are not already there.
 */
public final class SystemArtifactLoader extends AbstractService {
    private final Service serviceDelegate;

    @Inject
    SystemArtifactLoader(final ArtifactRepository artifactRepository) {
        this.serviceDelegate = new RetryOnStartFailureService(new Supplier<Service>() {
            @Override
            public Service get() {
                return new AbstractService() {
                    @Override
                    protected void doStart() {
                        String oldUserId = SecurityRequestContext.getUserId();
                        try {
                            SecurityRequestContext.setUserId(Principal.SYSTEM.getName());
                            artifactRepository.addSystemArtifacts();
                            // if there is no exception, all good, continue on
                            notifyStarted();
                        } catch (Exception e) {
                            // transient error, fail it and retry
                            notifyFailed(e);
                        } finally {
                            SecurityRequestContext.setUserId(oldUserId);
                        }
                    }

                    @Override
                    protected void doStop() {
                        notifyStopped();
                    }
                };
            }
        }, RetryStrategies.exponentialDelay(200, 5000, TimeUnit.MILLISECONDS));
    }

    @Override
    protected void doStart() {
        serviceDelegate.start();
        notifyStarted();
    }

    @Override
    protected void doStop() {
        serviceDelegate.stop();
        notifyStopped();
    }
}