Java tutorial
/* * dCache - http://www.dcache.org/ * * Copyright (C) 2016 Deutsches Elektronen-Synchrotron * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package diskCacheV111.srm.dcache; import com.google.common.base.Preconditions; import com.google.common.base.Throwables; import com.google.common.util.concurrent.Futures; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.Uninterruptibles; import org.apache.curator.framework.CuratorFramework; import org.apache.curator.framework.recipes.cache.ChildData; import org.springframework.beans.factory.annotation.Required; import org.springframework.dao.DataAccessException; import java.io.IOException; import java.io.Serializable; import java.net.URI; import java.util.List; import java.util.Optional; import java.util.concurrent.ExecutionException; import dmg.cells.nucleus.CellAddressCore; import dmg.cells.nucleus.CellIdentityAware; import dmg.cells.nucleus.CellMessageReceiver; import dmg.cells.nucleus.CellPath; import dmg.cells.nucleus.NoRouteToCellException; import dmg.cells.zookeeper.PathChildrenCache; import org.dcache.cells.CellStub; import org.dcache.cells.CuratorFrameworkAware; import org.dcache.srm.AbstractStorageElement; import org.dcache.srm.SRM; import org.dcache.srm.SRMException; import org.dcache.srm.SRMInternalErrorException; import org.dcache.srm.SRMInvalidPathException; import org.dcache.srm.SRMNonEmptyDirectoryException; import org.dcache.srm.SrmAbortTransfersRequest; import org.dcache.srm.SrmAbortTransfersResponse; import org.dcache.srm.SrmQueryPutRequest; import org.dcache.srm.SrmQueryPutResponse; import static java.nio.charset.StandardCharsets.US_ASCII; import static java.util.stream.Collectors.toList; /** * Subclass of the SRM main class implementing cross-cutting concerns in * clustered SrmManager deployments. */ public class DcacheSrm extends SRM implements CuratorFrameworkAware, CellIdentityAware, CellMessageReceiver { private PathChildrenCache backends; private CuratorFramework client; private CellStub srmManagerStub; private CellAddressCore address; public DcacheSrm(Configuration config, AbstractStorageElement storage) throws IOException, InterruptedException, DataAccessException { super(config, storage); } @Override public void start() throws Exception { backends = new PathChildrenCache(client, "/dcache/srm/backends", true); backends.start(); super.start(); } @Override public void stop() throws Exception { super.stop(); if (backends != null) { backends.close(); } } @Override public void setCellAddress(CellAddressCore address) { this.address = address; } @Override public void setCuratorFramework(CuratorFramework client) { this.client = client; } @Required public void setSrmManagerStub(CellStub srmManagerStub) { this.srmManagerStub = srmManagerStub; } @Override public boolean isFileBusy(URI surl) throws SRMException { return super.isFileBusy(surl) || findRemoteUpload(surl, false).isPresent(); } @Override public boolean hasMultipleUploads(URI surl) throws SRMException { Preconditions.checkState(super.isFileBusy(surl), "Must only be called while at least one local upload is active"); return super.hasMultipleUploads(surl) || findRemoteUpload(surl, false).isPresent(); } @Override public String getUploadFileId(URI surl) throws SRMException { String fileId = super.getUploadFileId(surl); if (fileId != null) { return fileId; } return findRemoteUpload(surl, false).map(SrmQueryPutResponse::getFileId).orElse(null); } @Override public boolean abortTransfers(URI surl, String reason) throws SRMException { boolean isUploadAborted = abortLocalTransfers(surl, reason); for (ListenableFuture<SrmAbortTransfersResponse> future : queryRemotes( new SrmAbortTransfersRequest(surl, reason), SrmAbortTransfersResponse.class)) { try { isUploadAborted |= Uninterruptibles.getUninterruptibly(future).isUploadAborted(); } catch (ExecutionException e) { Throwable cause = e.getCause(); if (!(cause instanceof NoRouteToCellException)) { Throwables.propagateIfPossible(cause, SRMException.class); throw new SRMInternalErrorException("Failed to abort transfers", cause); } } } return isUploadAborted; } @Override public void checkRemoveDirectory(URI surl) throws SRMException { super.checkRemoveDirectory(surl); Optional<SrmQueryPutResponse> request = findRemoteUpload(surl, true); if (request.isPresent()) { if (request.get().getSurl().equals(surl)) { throw new SRMInvalidPathException("Not a directory"); } else { throw new SRMNonEmptyDirectoryException("Directory is not empty"); } } } private boolean abortLocalTransfers(URI surl, String reason) throws SRMException { return super.abortTransfers(surl, reason); } private Optional<SrmQueryPutResponse> findRemoteUpload(URI surl, boolean isRecursive) throws SRMException { for (ListenableFuture<SrmQueryPutResponse> future : queryRemotes(new SrmQueryPutRequest(surl), SrmQueryPutResponse.class)) { try { SrmQueryPutResponse response = Uninterruptibles.getUninterruptibly(future); if (response.getSurl() != null && (isRecursive || response.getSurl().equals(surl))) { return Optional.of(response); } } catch (ExecutionException e) { Throwable cause = e.getCause(); if (!(cause instanceof NoRouteToCellException)) { Throwables.propagateIfPossible(cause, SRMException.class); throw new SRMInternalErrorException("Failed to abort transfers", cause); } } } return Optional.empty(); } private <T extends Serializable> List<ListenableFuture<T>> queryRemotes(Serializable request, Class<T> response) { return Futures.inCompletionOrder(backends.getCurrentData().stream().map(this::toCellAddress) .filter(adr -> !address.equals(adr)).map(CellPath::new) .map(path -> srmManagerStub.send(path, request, response)).collect(toList())); } private CellAddressCore toCellAddress(ChildData data) { return new CellAddressCore(new String(data.getData(), US_ASCII)); } public SrmQueryPutResponse messageArrived(SrmQueryPutRequest msg) { return getActivePutFileRequests(msg.getSurl()).min((a, b) -> a.getSurl().compareTo(b.getSurl())) .map(r -> new SrmQueryPutResponse(r.getSurl(), r.getId(), r.getFileId())) .orElseGet(SrmQueryPutResponse::new); } public SrmAbortTransfersResponse messageArrived(SrmAbortTransfersRequest msg) throws SRMException { return new SrmAbortTransfersResponse(msg.getSurl(), abortLocalTransfers(msg.getSurl(), msg.getReason())); } }