How to dynamically define file filter pattern for Spring Integration SFTP Inbound Adapter?

Question

I need to dynamically pull specific files from different directories from different sftp servers to a local server directory of a spring boot application.

I store the paths and a file pattern in a postgres database. I got everything working but i don't know how to dynamically define a file filter pattern depending on the remote directory for spring integration sftp inbound adapter so that not all xml files in that specific directory are pulled.

I use a RotatingServerAdvice and a DelegatingSessionFactory for accessing dynamic directories and servers.

For the dynamic file pattern filter I tried for instance to use the

.filterFunction(f -> do_some_filtering_based_on_filename(f)

I wanted to read the remote directory of that file but f is from the type ChannelSftp.LsEntry and doesn't have a field with the remote directory. Otherwise I would have loaded the config data from the database, searched for the path and applied the file pattern.

Is there a better way for my scenario?

SFTP example:

127.0.0.1:22

directory: root/partner1

... test_p1_2343545.xml

... test_p1_453453.xml

... don_t_pull_this_file_453453.xml

127.0.0.2:22

directory: root/partner2

... companyname_2343545.xml

... companyname_453453.xml

... don_t_pull_this_file_3434.xml

Database configuration example:

| URL       | PATH      | FILE_PATTERN      |
|-----------|-----------|-------------------|
| 127.0.0.1 | /partner1 | test_p1_*.xml     |
| 127.0.0.2 | /partner2 | companyname_*.xml |

Adapter Class of my spring boot application with working code but pulling all xml files because of .patternFilter("*.xml"):

import com.jcraft.jsch.ChannelSftp;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.channel.NullChannel;
import org.springframework.integration.dsl.IntegrationFlow;
import org.springframework.integration.dsl.IntegrationFlows;
import org.springframework.integration.dsl.Pollers;
import org.springframework.integration.dsl.SourcePollingChannelAdapterSpec;
import org.springframework.integration.expression.FunctionExpression;
import org.springframework.integration.file.remote.aop.RotatingServerAdvice;
import org.springframework.integration.file.remote.session.DelegatingSessionFactory;
import org.springframework.integration.file.remote.session.SessionFactory;
import org.springframework.integration.scheduling.PollerMetadata;
import org.springframework.integration.sftp.dsl.Sftp;
import org.springframework.integration.sftp.dsl.SftpInboundChannelAdapterSpec;
import org.springframework.integration.sftp.session.DefaultSftpSessionFactory;
import org.springframework.messaging.MessageChannel;
import org.springframework.stereotype.Component;

import java.io.File;
import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Consumer;

/**
 * flow.
 */
@Configuration
@Component
public class SFTIntegration {

  public static final String TIMEZONE_UTC = "UTC";
  public static final String TIMESTAMP_FORMAT_OF_FILES = "yyyyMMddHHmmssSSS";
  public static final String TEMPORARY_FILE_SUFFIX = ".part";
  public static final int POLLER_FIXED_PERIOD_DELAY = 5000;
  public static final int MAX_MESSAGES_PER_POLL = 100;

  private static final Logger LOG = LoggerFactory.getLogger(SFTIntegration.class);
  private static final String CHANNEL_INTERMEDIATE_STAGE = "intermediateChannel";

  /** database access repository */
  private final PartnerConfigRepo partnerConfigRepo;

  @Value("${app.tmp-dir}")
  private String localTemporaryPath;

  public SFTIntegration(final PartnerConfigRepo partnerConfigRepo) {
    this.partnerConfigRepo = partnerConfigRepo;
  }

  /**
   * The default poller with 5s, 100 messages, RotatingServerAdvice and transaction.
   *
   * @return default poller.
   */
  @Bean(name = PollerMetadata.DEFAULT_POLLER)
  public PollerMetadata poller() {
    return Pollers
        .fixedDelay(POLLER_FIXED_PERIOD_DELAY)
        .advice(advice())
        .maxMessagesPerPoll(MAX_MESSAGES_PER_POLL)
        .transactional()
        .get();
  }

  /**
   * The direct channel for the flow.
   *
   * @return MessageChannel
   */
  @Bean
  public MessageChannel stockIntermediateChannel() {
    return new DirectChannel();
  }

  /**
   * Get the files from a remote directory. Add a timestamp to the filename
   * and write them to a local temporary folder.
   *
   * @return IntegrationFlow
   */
  @Bean
  public IntegrationFlow stockInboundFlowFromSFTPServer() {
    // Source definition
    final SftpInboundChannelAdapterSpec sourceSpec = Sftp.inboundAdapter(delegatingSFtpSessionFactory())

        .preserveTimestamp(true)
        .patternFilter("*.xml")
        //.filterFunction(f -> do_some_filtering_based_on_filename(f, delegatingSFtpSessionFactory().getSession()))
        //.filter(new ModifiedFilter())
        //.filterExpression("#remoteDirectory")
        .deleteRemoteFiles(true)
        .maxFetchSize(MAX_MESSAGES_PER_POLL)
        .remoteDirectory("/")
        .localDirectory(new File(localTemporaryPath))
        .temporaryFileSuffix(TEMPORARY_FILE_SUFFIX)
        .localFilenameExpression(new FunctionExpression<String>(s -> {
          final int fileTypeSepPos = s.lastIndexOf('.');
          return
              DateTimeFormatter
                  .ofPattern(TIMESTAMP_FORMAT_OF_FILES)
                  .withZone(ZoneId.of(TIMEZONE_UTC))
                  .format(Instant.now())
                  + "_"
                  + s.substring(0, fileTypeSepPos)
                  + s.substring(fileTypeSepPos);
        }));

    // Poller definition
    final Consumer<SourcePollingChannelAdapterSpec> stockInboundPoller = endpointConfigurer -> endpointConfigurer
        .id("stockInboundPoller")
        .autoStartup(true)
        .poller(poller());

    return IntegrationFlows
        .from(sourceSpec, stockInboundPoller)
        .transform(File.class, p -> {
          // log step
          LOG.info("flow=stockInboundFlowFromAFT, message=incoming file: " + p);
          return p;
        })
        .channel(CHANNEL_INTERMEDIATE_STAGE)
        .get();
  }

  @Bean
  public IntegrationFlow stockIntermediateStageChannel() {
    return IntegrationFlows
        .from(CHANNEL_INTERMEDIATE_STAGE)
        .transform(p -> {
          //log step
          LOG.info("flow=stockIntermediateStageChannel, message=rename file: " + p);
          return p;
        })
        //TODO
        .channel(new NullChannel())
        .get();
  }

  public DefaultSftpSessionFactory createNewSftpSessionFactory(final PartnerConfigEntity pc) {
    final DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory(
        false);
    factory.setHost(pc.getServerIp());
    factory.setPort(pc.getPort());
    factory.setUser(pc.getUsername());
    factory.setPassword(pc.getPassword());
    factory.setAllowUnknownKeys(true);
    return factory;
  }

  @Bean
  public DelegatingSessionFactory<ChannelSftp.LsEntry> delegatingSFtpSessionFactory() {
    final List<PartnerConfigEntity> partnerConnections = partnerConfigRepo
        .findByTypeAndActiveIsTrue(PartnerConfigType.STOCK);

    if (partnerConnections.isEmpty()) {
      return null;
    }

    final Map<Object, SessionFactory<ChannelSftp.LsEntry>> factories = new LinkedHashMap<>(10);

    for (PartnerConfigEntity pc : partnerConnections) {
      // create a factory for every key containing server type, url and port
      if (factories.get(pc.getKey()) == null) {
        factories.put(pc.getKey(), createNewSftpSessionFactory(pc));
      }
    }

    // use the first SF as the default
    return new DelegatingSessionFactory<>(factories, factories.values().iterator().next());
  }

  @Bean
  public RotatingServerAdvice advice() {
    final List<PartnerConfigEntity> partnerConnections = partnerConfigRepo.findByTypeAndActiveIsTrue("A_TYPE");

    final List<RotatingServerAdvice.KeyDirectory> keyDirectories = new ArrayList<>();
    for (PartnerConfigEntity pc : partnerConnections) {
      keyDirectories
          .add(new RotatingServerAdvice.KeyDirectory(pc.getKey(), pc.getServerPath()));
    }

    return new RotatingServerAdvice(delegatingSFtpSessionFactory(), keyDirectories, true);
  }

  //  private Boolean do_some_filtering_based_on_filename(final ChannelSftp.LsEntry f,
  //      final Session<ChannelSftp.LsEntry> session) {
  //    Object instance = session.getClientInstance();
  //    System.out.println(f);
  //    return true;
  //  }

  //
  //  private class ModifiedFilter<F> extends AbstractFileListFilter<F> {
  //    private final Logger log = LoggerFactory.getLogger(ModifiedFilter.class);
  //
  //    @Override public boolean accept(final F file) {
  //      log.info(file.toString());
  //      return false;
  //    }
  //  }
}

Answer 1

I suggest you to implement a custom variant of the SftpSimplePatternFileListFilter logic and have there a setter for changing pattern at runtime.

Then you go to the RotatingServerAdvice and inject there a custom RotationPolicy, let's say as a copy of the StandardRotationPolicy with an injected your custom FileListFilter and then in the configureSource() after:

((AbstractInboundFileSynchronizingMessageSource<?>) source).getSynchronizer()
                    .setRemoteDirectory(this.current.getDirectory());

You perform a DB query to get a pattern by that this.current.getDirectory() and set it into your FileListFilter.

The same filter has to be used in the Sftp.inboundAdapter() mentioned in your code instead of that .patternFilter("*.xml").

I think we need to make all the properties in the StandardRotationPolicy as protected or with the getters to let access from the inheritors. Feel free to raise a JIRA on the matter: https://jira.spring.io/browse/INT!

Hope this helps somehow.

Answer 2

Here is my source code for the solution provided by Artem Bilan. If anybody wants to see it.

I copied the spring integration classes and adapted them like Artem Bilan suggested it.

@Artem Bilan Thank you very much!

The Abstract Filter:

/**
 * based on {@link org.springframework.integration.file.filters.AbstractSimplePatternFileListFilter}
 *
 * @param <F>
 */
public abstract class MyAbstractSimplePatternFileListFilter<F> extends AbstractDirectoryAwareFileListFilter<F> {

  private final AntPathMatcher matcher = new AntPathMatcher();

  private String path;

  public MyAbstractSimplePatternFileListFilter(final String path) {
    this.path = path;
  }

  /**
   * Accepts the given file if its name matches the pattern.
   */
  @Override
  public final boolean accept(final F file) {
    return alwaysAccept(file) || (file != null && this.matcher.match(this.path, this.getFilename(file)));
  }

  /**
   * Subclasses must implement this method to extract the file's name.
   *
   * @param file The file.
   * @return The file name.
   */
  protected abstract String getFilename(F file);

  /**
   * Get directory path at runtime.
   *
   * @return directory path
   */
  public String getPath() {
    return path;
  }

  /**
   * Set directory path at runtime.
   *
   * @param path the directory path
   */
  public void setPath(final String path) {
    this.path = path;
  }
}

The Filter implementation using the setter from abstract filter class before:

import com.jcraft.jsch.ChannelSftp.LsEntry;
import org.springframework.integration.file.filters.AbstractSimplePatternFileListFilter;

/**
 * Implementation of {@link AbstractSimplePatternFileListFilter} for SFTP with logic for changing the file pattern at runtime.
 */
public class MySftpPatternFileListFilter extends MyAbstractSimplePatternFileListFilter<LsEntry> {

  public MySftpPatternFileListFilter(final String pattern) {
    super(pattern);
  }

  @Override
  protected String getFilename(final LsEntry entry) {
    return (entry != null) ? entry.getFilename() : null;
  }

  @Override
  protected boolean isDirectory(final LsEntry file) {
    return file.getAttrs().isDir();
  }

  /**
   * Sets the file pattern for the file filter
   *
   * @param pattern a file pattern like "*.xml"
   */
  public void setPattern(final String pattern) {
    setPath(pattern);
  }

}

The Rotation Policy with the added filter and repository

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.integration.core.MessageSource;
import org.springframework.integration.file.remote.AbstractRemoteFileStreamingMessageSource;
import org.springframework.integration.file.remote.aop.RotatingServerAdvice;
import org.springframework.integration.file.remote.session.DelegatingSessionFactory;
import org.springframework.integration.file.remote.synchronizer.AbstractInboundFileSynchronizingMessageSource;
import org.springframework.util.Assert;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * Adapted version of {@link RotatingServerAdvice.RotationPolicy} with own FileListFilter {@link MySftpPatternFileListFilter} and
 * database access for configuration.
 * <p>
 * Standard rotation policy; iterates over key/directory pairs; when the end
 * is reached, starts again at the beginning. If the fair option is true
 * the rotation occurs on every poll, regardless of result. Otherwise rotation
 * occurs when the current pair returns no message.
 */
public class MyStandardRotationPolicy implements RotatingServerAdvice.RotationPolicy {

  protected final Log logger = LogFactory.getLog(getClass());

  private final DelegatingSessionFactory<?> factory;

  private final List<RotatingServerAdvice.KeyDirectory> keyDirectories = new ArrayList<>();

  private final boolean fair;
  private final MySftpPatternFileListFilter fileListFilter;
  private final PartnerConfigRepo partnerConfigRepo;
  private volatile Iterator<RotatingServerAdvice.KeyDirectory> iterator;
  private volatile RotatingServerAdvice.KeyDirectory current;
  private volatile boolean initialized;

  public MyStandardRotationPolicy(final DelegatingSessionFactory<?> factory,
      final List<RotatingServerAdvice.KeyDirectory> keyDirectories,
      final boolean fair,
      final MySftpPatternFileListFilter fileListFilter,
      final PartnerConfigRepo partnerConfigRepo) {

    Assert.notNull(factory, "factory cannot be null");
    Assert.notNull(keyDirectories, "keyDirectories cannot be null");
    Assert.isTrue(keyDirectories.size() > 0, "At least one KeyDirectory is required");
    this.factory = factory;
    this.keyDirectories.addAll(keyDirectories);
    this.fair = fair;
    this.iterator = this.keyDirectories.iterator();
    this.fileListFilter = fileListFilter;
    this.partnerConfigRepo = partnerConfigRepo;
  }

  protected Iterator<RotatingServerAdvice.KeyDirectory> getIterator() {
    return this.iterator;
  }

  protected void setIterator(final Iterator<RotatingServerAdvice.KeyDirectory> iterator) {
    this.iterator = iterator;
  }

  protected boolean isInitialized() {
    return this.initialized;
  }

  protected void setInitialized(final boolean initialized) {
    this.initialized = initialized;
  }

  protected DelegatingSessionFactory<?> getFactory() {
    return this.factory;
  }

  protected List<RotatingServerAdvice.KeyDirectory> getKeyDirectories() {
    return this.keyDirectories;
  }

  protected boolean isFair() {
    return this.fair;
  }

  @Override
  public void beforeReceive(final MessageSource<?> source) {
    if (this.fair || !this.initialized) {
      configureSource(source);
      this.initialized = true;
    }
    if (this.logger.isTraceEnabled()) {
      this.logger.trace("Next poll is for " + this.current);
    }
    this.factory.setThreadKey(this.current.getKey());
  }

  @Override
  public void afterReceive(final boolean messageReceived, final MessageSource<?> source) {
    if (this.logger.isTraceEnabled()) {
      this.logger.trace("Poll produced "
          + (messageReceived ? "a" : "no")
          + " message");
    }
    this.factory.clearThreadKey();
    if (!this.fair && !messageReceived) {
      configureSource(source);
    }
  }

  protected void configureSource(final MessageSource<?> source) {
    Assert.isTrue(source instanceof AbstractInboundFileSynchronizingMessageSource
            || source instanceof AbstractRemoteFileStreamingMessageSource,
        "source must be an AbstractInboundFileSynchronizingMessageSource or a "
            + "AbstractRemoteFileStreamingMessageSource");
    if (!this.iterator.hasNext()) {
      this.iterator = this.keyDirectories.iterator();
    }
    this.current = this.iterator.next();

    fileListFilter.setPattern(getPatternFromDataBase(this.current.getDirectory()));

    if (source instanceof AbstractRemoteFileStreamingMessageSource) {
      ((AbstractRemoteFileStreamingMessageSource<?>) source).setRemoteDirectory(this.current.getDirectory());
    } else {
      ((AbstractInboundFileSynchronizingMessageSource<?>) source).getSynchronizer()
          .setRemoteDirectory(this.current.getDirectory());

    }
  }

  private String getPatternFromDataBase(final String directory) {
    //String Pattern;
    final List<PartnerConfigEntity> allStock = partnerConfigRepo.findByTypeAndActiveIsTrue(PartnerConfigType.STOCK);
    for (final PartnerConfigEntity s : allStock) {
      if (s.getServerPath().equals(directory)) {
        return s.getFileNamePattern();
      }
    }
    //TODO throw exception
    return "*.xml";
  }

}

Flow class with new getFilter() method, changed SftpInboundChannelAdapterSpec with .filter(getFilter()) and changed advice() method.

/**
 * flow.
 */
@Configuration
@Component
public class SFTIntegration {

  public static final String TIMEZONE_UTC = "UTC";
  public static final String TIMESTAMP_FORMAT_OF_FILES = "yyyyMMddHHmmssSSS";
  public static final String TEMPORARY_FILE_SUFFIX = ".part";
  public static final int POLLER_FIXED_PERIOD_DELAY = 5000;
  public static final int MAX_MESSAGES_PER_POLL = 100;
  private static final Logger LOG = LoggerFactory.getLogger(SFTIntegration.class);
  private static final String CHANNEL_INTERMEDIATE_STAGE = "stockIntermediateChannel";

  /**
   * database access repository
   */
  private final PartnerConfigRepo partnerConfigRepo;

  @Value("${app.tmp-dir}")
  private String localTemporaryPath;

  public SFTIntegration(final PartnerConfigRepo partnerConfigRepo) {
    this.partnerConfigRepo = partnerConfigRepo;
  }

  @Bean
  MySftpPatternFileListFilter getFilter() {
    //initial pattern
    return new MySftpPatternFileListFilter("*.xml");
  }

  /**
   * The default poller with 5s, 100 messages, RotatingServerAdvice and transaction.
   *
   * @return default poller.
   */
  @Bean(name = PollerMetadata.DEFAULT_POLLER)
  public PollerMetadata poller() {
    return Pollers
        .fixedDelay(POLLER_FIXED_PERIOD_DELAY)
        .advice(advice())
        .maxMessagesPerPoll(MAX_MESSAGES_PER_POLL)
        .transactional()
        .get();
  }

  /**
   * The direct channel for the flow.
   *
   * @return MessageChannel
   */
  @Bean
  public MessageChannel stockIntermediateChannel() {
    return new DirectChannel();
  }

  /**
   * Get the files from a remote directory. Add a timestamp to the filename (milliseconds since midnight January 1st 1970, UTC)
   * and write them to a local temporary folder. Get the files from the local temporary folder.
   *
   * @return IntegrationFlow
   */
  @Bean
  public IntegrationFlow stockInboundFlowFromSFTPServer() {
    // Source definition
    final SftpInboundChannelAdapterSpec sourceSpec = Sftp.inboundAdapter(delegatingSFtpSessionFactory())

        .preserveTimestamp(true)
        .filter(getFilter())
        .deleteRemoteFiles(true)
        .maxFetchSize(MAX_MESSAGES_PER_POLL)
        .remoteDirectory("/")
        .localDirectory(new File(localTemporaryPath))
        .temporaryFileSuffix(TEMPORARY_FILE_SUFFIX)
        .localFilenameExpression(new FunctionExpression<String>(s -> {
          final int fileTypeSepPos = s.lastIndexOf('.');
          // use Instant.now().toEpochMilli() for utc time in milliseconds
          return
              DateTimeFormatter
                  .ofPattern(TIMESTAMP_FORMAT_OF_FILES)
                  .withZone(ZoneId.of(TIMEZONE_UTC))
                  .format(Instant.now())
                  + "_"
                  + (new SecureRandom()).nextInt(99999)
                  + "_"
                  + s.substring(0, fileTypeSepPos)
                  + s.substring(fileTypeSepPos);
        }));

    // Poller definition
    final Consumer<SourcePollingChannelAdapterSpec> stockInboundPoller = endpointConfigurer -> endpointConfigurer
        .id("stockInboundPoller")
        .autoStartup(true)
        .poller(poller());

    return IntegrationFlows
        .from(sourceSpec, stockInboundPoller)
        .transform(File.class, p -> {
          // log step
          LOG.info("flow=stockInboundFlowFromAFT, message=incoming file: " + p);
          return p;
        })
        .channel(CHANNEL_INTERMEDIATE_STAGE)
        .get();
  }

  @Bean
  public IntegrationFlow stockIntermediateStageChannel() {
    return IntegrationFlows
        .from(CHANNEL_INTERMEDIATE_STAGE)
        .transform(p -> {
          //log step
          LOG.info("flow=stockIntermediateStageChannel, message=rename file: " + p);
          return p;
        })
        //TODO
        .channel(new NullChannel())
        .get();
  }

  public DefaultSftpSessionFactory createNewSftpSessionFactory(final PartnerConfigEntity pc) {
    final DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory(
        false); //TODO set true but use caching session https://docs.spring.io/spring-integration/reference/html/sftp.html
    factory.setHost(pc.getServerIp());
    factory.setPort(pc.getPort());
    factory.setUser(pc.getUsername());
    factory.setPassword(pc.getPassword());
    factory.setAllowUnknownKeys(true);
    return factory;
  }

  @Bean
  public DelegatingSessionFactory<ChannelSftp.LsEntry> delegatingSFtpSessionFactory() {
    final List<PartnerConfigEntity> partnerConnections = partnerConfigRepo
        .findByTypeAndActiveIsTrue(PartnerConfigType.STOCK);

    if (partnerConnections.isEmpty()) {
      return null;
    }

    final Map<Object, SessionFactory<ChannelSftp.LsEntry>> factories = new LinkedHashMap<>(10);

    for (final PartnerConfigEntity pc : partnerConnections) {
      // create a factory for every key containing PartnerConfigEntity.getKey() attributes (server type, url and port)
      if (factories.get(pc.getKey()) == null) {
        factories.put(pc.getKey(), createNewSftpSessionFactory(pc));
      }
    }

    // use the first SF as the default
    return new DelegatingSessionFactory<>(factories, factories.values().iterator().next());
  }

  @Bean
  public RotatingServerAdvice advice() {
    final List<PartnerConfigEntity> partnerConnections = partnerConfigRepo
        .findByTypeAndActiveIsTrue(PartnerConfigType.STOCK);
    LOG.debug("Found " + partnerConnections.size() + " server entries for type stock.");

    final List<RotatingServerAdvice.KeyDirectory> keyDirectories = new ArrayList<>();
    for (final PartnerConfigEntity pc : partnerConnections) {
      keyDirectories
          .add(new RotatingServerAdvice.KeyDirectory(pc.getKey(), pc.getServerPath()));
    }
    final RotatingServerAdvice rot = new RotatingServerAdvice(
        new MyStandardRotationPolicy(delegatingSFtpSessionFactory(), keyDirectories, true,
            getFilter(), partnerConfigRepo));
    return rot;
  }

}