exceptionfactory commented on a change in pull request #5254: URL: https://github.com/apache/nifi/pull/5254#discussion_r686148027
########## File path: nifi-stateless/nifi-stateless-bundle/nifi-stateless-engine/src/main/java/org/apache/nifi/stateless/repository/StatelessFileSystemRepository.java ########## @@ -0,0 +1,361 @@ +/* + * 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.nifi.stateless.repository; + +import org.apache.nifi.controller.repository.ContentRepository; +import org.apache.nifi.controller.repository.claim.ContentClaim; +import org.apache.nifi.controller.repository.claim.ResourceClaim; +import org.apache.nifi.controller.repository.claim.ResourceClaimManager; +import org.apache.nifi.controller.repository.claim.StandardContentClaim; +import org.apache.nifi.controller.repository.claim.StandardResourceClaim; +import org.apache.nifi.controller.repository.io.LimitedInputStream; +import org.apache.nifi.stream.io.StreamUtils; +import org.apache.nifi.stream.io.SynchronizedByteCountingOutputStream; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.ByteArrayInputStream; +import java.io.File; +import java.io.FileInputStream; +import java.io.FileOutputStream; +import java.io.FilterOutputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.OutputStream; +import java.nio.file.Files; +import java.nio.file.OpenOption; +import java.nio.file.Path; +import java.nio.file.StandardOpenOption; +import java.util.Collection; +import java.util.Collections; +import java.util.Set; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentMap; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.atomic.AtomicLong; + +public class StatelessFileSystemRepository implements ContentRepository { + private static final Logger logger = LoggerFactory.getLogger(StatelessFileSystemRepository.class); + + private static final String CONTAINER = "stateless"; + private static final String SECTION = "stateless"; + + private final File directory; + private final ConcurrentMap<ResourceClaim, SynchronizedByteCountingOutputStream> writableStreamMap = new ConcurrentHashMap<>(); + private final AtomicLong resourceClaimIndex = new AtomicLong(0L); + private final BlockingQueue<ResourceClaim> writableClaimQueue = new LinkedBlockingQueue<>(); + private ResourceClaimManager resourceClaimManager; + + public StatelessFileSystemRepository(final File directory) { + this.directory = directory; + } + + @Override + public void initialize(final ResourceClaimManager claimManager) throws IOException { + this.resourceClaimManager = claimManager; + if (!directory.exists() && !directory.mkdirs()) { + throw new IOException("Cannot initialize Content Repository because " + directory.getAbsolutePath() + " does not exist and cannot be created"); + } + + // Check if there are any existing files and if so, purges them. + final File[] existingFiles = directory.listFiles(file -> file.getName().matches("\\d+\\.nifi\\.bin")); + if (existingFiles == null) { + throw new IOException("Cannot initialize Content Repository because failed to list contents of directory " + directory.getAbsolutePath()); + } + + for (final File existingFile : existingFiles) { + logger.info("Found existing file from previous run {}. Removing file.", existingFile.getName()); + final boolean deleted = existingFile.delete(); + + if (!deleted) { + logger.warn("Failed to remove existing file from previous run {}", existingFile); + } + } + } + + @Override + public void shutdown() { + purge(); + } + + @Override + public Set<String> getContainerNames() { + return Collections.singleton(CONTAINER); + } + + @Override + public long getContainerCapacity(final String containerName) { + return 0; + } + + @Override + public long getContainerUsableSpace(final String containerName) { + return 0; + } + + @Override + public String getContainerFileStoreName(final String containerName) { + return "container"; + } + + @Override + public ContentClaim create(final boolean lossTolerant) throws IOException { + ResourceClaim resourceClaim = writableClaimQueue.poll(); + long offset; + + if (resourceClaim == null) { + resourceClaim = new StandardResourceClaim(resourceClaimManager, CONTAINER, SECTION, String.valueOf(resourceClaimIndex.getAndIncrement()), false); + offset = 0L; + + final File resourceClaimFile = getFile(resourceClaim); + final OutputStream fos = new FileOutputStream(resourceClaimFile); + final SynchronizedByteCountingOutputStream contentOutputStream = new SynchronizedByteCountingOutputStream(fos); + writableStreamMap.put(resourceClaim, contentOutputStream); + } else { + final SynchronizedByteCountingOutputStream contentOutputStream = writableStreamMap.get(resourceClaim); + offset = contentOutputStream.getBytesWritten(); + } + + final ContentClaim contentClaim = new StandardContentClaim(resourceClaim, offset); + resourceClaimManager.incrementClaimantCount(contentClaim.getResourceClaim()); + return contentClaim; + } + + @Override + public int incrementClaimaintCount(final ContentClaim claim) { + if (claim == null) { + return 0; + } + + return resourceClaimManager.incrementClaimantCount(claim.getResourceClaim()); + } + + @Override + public int getClaimantCount(final ContentClaim claim) { + if (claim == null) { + return 0; + } + + return resourceClaimManager.getClaimantCount(claim.getResourceClaim()); + } + + @Override + public int decrementClaimantCount(final ContentClaim claim) { + if (claim == null) { + return 0; + } + + return resourceClaimManager.decrementClaimantCount(claim.getResourceClaim()); + } + + @Override + public boolean remove(final ContentClaim claim) { + return true; + } + + @Override + public ContentClaim clone(final ContentClaim original, final boolean lossTolerant) throws IOException { + final ContentClaim clone = create(lossTolerant); + try (final InputStream in = read(original); + final OutputStream out = write(clone)) { + StreamUtils.copy(in, out); + } + + return clone; + } + + @Override + public long merge(final Collection<ContentClaim> claims, final ContentClaim destination, final byte[] header, final byte[] footer, final byte[] demarcator) { + throw new UnsupportedOperationException("This never gets used"); + } + + @Override + public long importFrom(final Path content, final ContentClaim claim) throws IOException { + try (final InputStream in = Files.newInputStream(content, StandardOpenOption.READ)) { + return importFrom(in, claim); + } + } + + @Override + public long importFrom(final InputStream content, final ContentClaim claim) throws IOException { + try (final OutputStream out = write(claim)) { + return StreamUtils.copy(content, out); + } + } + + @Override + public long exportTo(final ContentClaim claim, final Path destination, final boolean append) throws IOException { + final OpenOption[] openOptions = append ? new StandardOpenOption[] {StandardOpenOption.CREATE, StandardOpenOption.APPEND} : + new StandardOpenOption[] {StandardOpenOption.CREATE}; + + try (final OutputStream out = Files.newOutputStream(destination, openOptions)) { + return exportTo(claim, out); + } + } + + @Override + public long exportTo(final ContentClaim claim, final Path destination, final boolean append, final long offset, final long length) throws IOException { + final OpenOption[] openOptions = append ? new StandardOpenOption[] {StandardOpenOption.CREATE, StandardOpenOption.APPEND} : + new StandardOpenOption[] {StandardOpenOption.CREATE}; + + try (final OutputStream out = Files.newOutputStream(destination, openOptions)) { + return exportTo(claim, out, offset, length); + } + } + + @Override + public long exportTo(final ContentClaim claim, final OutputStream destination) throws IOException { + try (final InputStream in = read(claim)) { + return StreamUtils.copy(in, destination); + } + } + + @Override + public long exportTo(final ContentClaim claim, final OutputStream destination, final long offset, final long length) throws IOException { + try (final InputStream in = read(claim)) { + StreamUtils.skip(in, offset); + StreamUtils.copy(in, destination, length); + } + + return length; + } + + @Override + public long size(final ContentClaim claim) { + return claim.getLength(); + } + + @Override + public InputStream read(final ContentClaim claim) throws IOException { + if (claim == null) { + return new ByteArrayInputStream(new byte[0]); + } + + final InputStream resourceClaimIn = read(claim.getResourceClaim()); + StreamUtils.skip(resourceClaimIn, claim.getOffset()); + + final InputStream limitedIn = new LimitedInputStream(resourceClaimIn, claim.getLength()); + return limitedIn; + } + + @Override + public InputStream read(final ResourceClaim claim) throws IOException { + validateResourceClaim(claim); + final File file = getFile(claim); + return new FileInputStream(file); + } + + private File getFile(final ResourceClaim claim) { + return new File(directory, claim.getId() + ".nifi.bin"); Review comment: That seems reasonable, thanks for making the update to declare the regular expression pattern as a static member. -- This is an automated message from the Apache Git Service. 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