001/*
002 * CDDL HEADER START
003 *
004 * The contents of this file are subject to the terms of the
005 * Common Development and Distribution License, Version 1.0 only
006 * (the "License").  You may not use this file except in compliance
007 * with the License.
008 *
009 * You can obtain a copy of the license at
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012 * See the License for the specific language governing permissions
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015 * When distributing Covered Code, include this CDDL HEADER in each
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022 * CDDL HEADER END
023 *
024 *
025 *      Copyright 2011-2018 Ping Identity Corporation
026 */
027package com.unboundid.directory.sdk.sync.api;
028
029
030import java.io.Serializable;
031import java.util.Collections;
032import java.util.Iterator;
033import java.util.LinkedList;
034import java.util.List;
035import java.util.Map;
036import java.util.concurrent.BlockingQueue;
037import java.util.concurrent.atomic.AtomicLong;
038
039import com.unboundid.directory.sdk.common.internal.Configurable;
040import com.unboundid.directory.sdk.common.internal.ExampleUsageProvider;
041import com.unboundid.directory.sdk.common.internal.UnboundIDExtension;
042import com.unboundid.directory.sdk.sync.config.SyncSourceConfig;
043import com.unboundid.directory.sdk.sync.internal.SynchronizationServerExtension;
044import com.unboundid.directory.sdk.sync.types.EndpointException;
045import com.unboundid.directory.sdk.sync.types.SetStartpointOptions;
046import com.unboundid.directory.sdk.sync.types.SyncOperation;
047import com.unboundid.directory.sdk.sync.types.SyncServerContext;
048import com.unboundid.directory.sdk.sync.types.ChangeRecord;
049import com.unboundid.ldap.sdk.Entry;
050import com.unboundid.util.Extensible;
051import com.unboundid.util.args.ArgumentException;
052import com.unboundid.util.args.ArgumentParser;
053
054
055
056/**
057 * This class defines an API that must be implemented by extensions in order to
058 * synchronize data from a generic (non-LDAP and non-JDBC) endpoint. Since the
059 * UnboundID Synchronization Server is LDAP-centric, this API allows you to take
060 * generic content and convert it into LDAP entries which can then be processed
061 * by the Synchronization Server. The lifecycle of a sync operation is as
062 * follows:
063 * <ol>
064 * <li>Detect change at the synchronization source</li>
065 * <li>Fetch full source entry</li>
066 * <li>Perform any mappings and compute the equivalent destination entry</li>
067 * <li>Fetch full destination entry</li>
068 * <li>Diff the computed destination entry and actual (fetched) destination
069 * entry</li>
070 * <li>Apply the minimal set of changes at the destination to bring it in sync
071 * </li>
072 * </ol>
073 * This implies that the
074 * {@link #fetchEntry(SyncOperation)} method will be called once for every
075 * change that is returned by
076 * {@link #getNextBatchOfChanges(int, AtomicLong)}.
077 * <p>
078 * This is a generic interface and there is no protocol-specific connection
079 * management provided. It is expected that implementers will provide their own
080 * libraries for talking to the source endpoint and handle the connection
081 * lifecycle in the {@link #initializeSyncSource(SyncServerContext,
082 * SyncSourceConfig, ArgumentParser)} and {@link #finalizeSyncSource()}
083 * methods of this extension.
084 * <p>
085 * During realtime synchronization (i.e. when a Sync Pipe is running), there is
086 * a sliding window of changes being processed, and this API provides a
087 * distinction between some different points along that window:
088 * <ul>
089 *   <li><b>Old changes</b>: These are changes that the Sync Server has
090 *       processed and acknowledged back to the Sync Source. The Sync Source is
091 *       under no obligation to re-detect these changes.</li>
092 *   <li><b>Startpoint</b>: This marks where the Sync Source will start
093 *       detecting changes if it is restarted.</li>
094 *   <li><b>Detected but unacknowledged</b>: These changes have been returned by
095 *       <code>getNextBatchOfChanges()</code> but not completely processed and
096 *       acknowledged back to the Sync Source.</li>
097 *   <li><b>Undetected changes</b>: The next call to
098 *       <code>getNextBatchOfChanges()</code> should return the first changes
099 *       that have not been detected.  This should be somewhere at or ahead of
100 *       the startpoint.</li>
101 * </ul>
102 * <p>
103 * Several of these methods throw {@link EndpointException}, which should be
104 * used in the case of any connection or endpoint error. For other types of
105 * errors, runtime exceptions may be used (IllegalStateException,
106 * NullPointerException, etc.). The Synchronization Server will automatically
107 * retry operations that fail, up to a configurable amount of attempts. The
108 * EndpointException class allows you to specify a retry policy as well.
109 * <BR>
110 * <H2>Configuring Sync Sources</H2>
111 * In order to configure a Sync Source based on this API and written in Java,
112 * use a command like:
113 * <PRE>
114 *      dsconfig create-sync-source \
115 *           --source-name "<I>{source-name}</I>" \
116 *           --type third-party \
117 *           --set "extension-class:<I>{class-name}</I>" \
118 *           --set "extension-argument:<I>{name=value}</I>"
119 * </PRE>
120 * where "<I>{source-name}</I>" is the name to use for the Sync Source
121 * instance, "<I>{class-name}</I>" is the fully-qualified
122 * name of the Java class written using this API, and "<I>{name=value}</I>"
123 * represents name-value pairs for any arguments to provide to the sync
124 * source.  If multiple arguments should be provided to the sync source,
125 * then the "<CODE>--set extension-argument:<I>{name=value}</I></CODE>" option
126 * should be provided multiple times.
127 */
128@Extensible()
129@SynchronizationServerExtension(appliesToLocalContent=false,
130                                appliesToSynchronizedContent=true)
131public abstract class SyncSource implements UnboundIDExtension,
132                                            Configurable,
133                                            ExampleUsageProvider
134{
135  /**
136   * Creates a new instance of this Sync Source.  All sync
137   * source implementations must include a default constructor, but any
138   * initialization should generally be done in the
139   * {@link #initializeSyncSource} method.
140   */
141  public SyncSource()
142  {
143    // No implementation is required.
144  }
145
146
147
148  /**
149   * {@inheritDoc}
150   */
151  public abstract String getExtensionName();
152
153
154
155  /**
156   * {@inheritDoc}
157   */
158  public abstract String[] getExtensionDescription();
159
160
161
162  /**
163   * {@inheritDoc}
164   */
165  public Map<List<String>,String> getExamplesArgumentSets()
166  {
167    return Collections.emptyMap();
168  }
169
170
171
172  /**
173   * {@inheritDoc}
174   */
175  public void defineConfigArguments(final ArgumentParser parser)
176         throws ArgumentException
177  {
178    // No arguments will be allowed by default.
179  }
180
181
182
183  /**
184   * This hook is called when a Sync Pipe first starts up, when the
185   * <i>resync</i> process first starts up, or when the set-startpoint
186   * subcommand is called from the <i>realtime-sync</i> command line tool.
187   * Any initialization of this sync source should be performed here. This
188   * method should generally store the {@link SyncServerContext} in a class
189   * member so that it can be used elsewhere in the implementation.
190   * <p>
191   * The default implementation is empty.
192   *
193   * @param  serverContext  A handle to the server context for the server in
194   *                        which this extension is running.
195   * @param  config         The general configuration for this sync source.
196   * @param  parser         The argument parser which has been initialized from
197   *                        the configuration for this sync source.
198   */
199  public void initializeSyncSource(final SyncServerContext serverContext,
200                                   final SyncSourceConfig config,
201                                   final ArgumentParser parser)
202  {
203    // No initialization will be performed by default.
204  }
205
206
207
208  /**
209   * This hook is called when a Sync Pipe shuts down, when the <i>resync</i>
210   * process shuts down, or when the set-startpoint subcommand (from the
211   * <i>realtime-sync</i> command line tool) is finished. Any clean up of this
212   * sync source should be performed here.
213   * <p>
214   * The default implementation is empty.
215   */
216  public void finalizeSyncSource()
217  {
218    //No implementation required by default.
219  }
220
221
222
223  /**
224   * Return the URL or path identifying the source endpoint
225   * from which this extension is transmitting data. This is used for logging
226   * purposes only, so it could just be a server name or hostname and port, etc.
227   *
228   * @return the path to the source endpoint (should not return {@code null})
229   */
230  public abstract String getCurrentEndpointURL();
231
232
233
234  /**
235   * This method should effectively set the starting point for synchronization
236   * to the place specified by the <code>options</code> parameter. This should
237   * cause all changes previous to the specified start point to be disregarded
238   * and only changes after that point to be returned by
239   * {@link #getNextBatchOfChanges(int, AtomicLong)}.
240   * <p>
241   * There are several different startpoint types (see
242   * {@link SetStartpointOptions}), and this implementation is not required to
243   * support them all. If the specified startpoint type is unsupported, this
244   * method should throw an {@link UnsupportedOperationException}.
245   * <p>
246   * <b>IMPORTANT</b>: The <code>RESUME_AT_SERIALIZABLE</code> startpoint type
247   * must be supported by your implementation, because this is used when a Sync
248   * Pipe first starts up. The {@link Serializable} in this case is the same
249   * type that is returned by {@link #getStartpoint()}; the Sync Server persists
250   * it and passes it back in on a restart.
251   * <p>
252   * This method can be called from two different contexts:
253   * <ul>
254   * <li>When the 'set-startpoint' subcommand of the realtime-sync CLI is used
255   * (the Sync Pipe is required to be stopped in this context)</li>
256   * <li>Immediately after a Sync Pipe starts up and a connection is first
257   *     established to the source server (e.g. before the first call to
258   * {@link #getNextBatchOfChanges(int, AtomicLong)})</li>
259   * </ul>
260   *
261   * @param options
262   *          an object which indicates where exactly to start synchronizing
263   *          (e.g. the end of the changelog, specific change number, a certain
264   *          time ago, etc)
265   * @throws EndpointException
266   *           if there is any error while setting the start point
267   */
268  public abstract void setStartpoint(final SetStartpointOptions options)
269                                        throws EndpointException;
270
271
272
273  /**
274   * Gets the current value of the startpoint for change detection. This is the
275   * "bookmark" which indicates which changes have already been processed and
276   * which have not. In most cases, a change number is used to detect changes
277   * and is managed by the Synchronization Server, in which case this
278   * implementation needs only to return the latest acknowledged
279   * change number. In other cases, the return value may correspond to a
280   * different value, such as the SYS_CHANGE_VERSION in Microsoft SQL Server.
281   * In any case, this method should return the value that is updated by
282   * {@link #acknowledgeCompletedOps(LinkedList)}.
283   * <p>
284   * This method is called periodically and the return value is saved in the
285   * persistent state for the Sync Pipe that uses this extension as its Sync
286   * Source.
287   * <p>
288   * <b>IMPORTANT</b>: The internal value for the startpoint should only be
289   * updated after a sync operation is acknowledged back to this script (via
290   * {@link #acknowledgeCompletedOps(LinkedList)}).
291   * Otherwise it will be possible for changes to be missed when the
292   * Synchronization Server is restarted or a connection error occurs.
293   * @return a value to store in the persistent state for the Sync Pipe. This is
294   *         usually a change number, but if a changelog table is not used to
295   *         detect changes, this value should represent some other token to
296   *         pass into {@link #setStartpoint(SetStartpointOptions)}
297   *         when the sync pipe starts up.
298   */
299  public abstract Serializable getStartpoint();
300
301
302
303  /**
304   * Return the next batch of change records from the source. Change records
305   * are usually just hints that a change happened; they do not include
306   * the full contents of the target entry. In an effort to never synchronize
307   * stale data, the Synchronization Server will go back and fetch the full
308   * target entry for each change record.
309   * <p>
310   * On the first invocation, this should return changes starting from the
311   * startpoint that was set by
312   * {@link #setStartpoint(SetStartpointOptions)}. This method is also
313   * responsible for updating the internal state such that subsequent
314   * invocations do not return duplicate changes.
315   * <p>
316   * The resulting list should be limited by <code>maxChanges</code>. The
317   * <code>numStillPending</code> reference should be set to the estimated
318   * number of changes that haven't yet been retrieved from the source endpoint
319   * when this method returns, or zero if all the current changes have been
320   * retrieved.
321   * <p>
322   * <b>IMPORTANT</b>: While this method needs to keep track of which changes
323   * have already been returned so that it does not return them again, it should
324   * <b>NOT</b> modify the official startpoint. The internal value for the
325   * startpoint should only be updated after a sync operation is acknowledged
326   * back to this script (via
327   * {@link #acknowledgeCompletedOps(LinkedList)}).
328   * Otherwise it will be possible for changes to be missed when the
329   * Synchronization Server is restarted or a connection error occurs. The
330   * startpoint should not change as a result of this method.
331   * <p>
332   * This method <b>does not need to be thread-safe</b>. It will be invoked
333   * repeatedly by a single thread, based on the polling interval set in the
334   * Sync Pipe configuration.
335   *
336   * @param maxChanges
337   *          the maximum number of changes to retrieve
338   * @param numStillPending
339   *          this should be set to the number of unretrieved changes that
340   *          are still pending after this batch has been retrieved. This will
341   *          be passed in
342   *          as zero, and may be left that way if the actual value cannot be
343   *          determined.
344   * @return a list of {@link ChangeRecord} instances, each
345   *         corresponding to a single change at the source endpoint.
346   *         If there are no new changes to return, this method should return
347   *         an empty list.
348   * @throws EndpointException
349   *           if there is any error while retrieving the next batch of changes
350   */
351  public abstract List<ChangeRecord> getNextBatchOfChanges(
352                                              final int maxChanges,
353                                              final AtomicLong numStillPending)
354                                                      throws EndpointException;
355
356
357
358  /**
359   * Return a full source entry (in LDAP form) from the source, corresponding
360   * to the {@link ChangeRecord} that is passed in through the
361   * {@link SyncOperation}. This method should perform any queries necessary to
362   * gather the latest values for all the attributes to be synchronized.
363   * <p>
364   * This method <b>must be thread safe</b>, as it will be called repeatedly and
365   * concurrently by each of the Sync Pipe worker threads as they process
366   * entries.
367   * <p>
368   * If the original ChangeRecord has the full entry already set on it (which
369   * can be done using <code>ChangeRecord.Builder#fullEntry(Entry)</code>,
370   * then this method will not get called, and the Sync Server will
371   * automatically use the full entry from the ChangeRecord. In this case, the
372   * implementation can always return {@code null}.
373   *
374   * @param operation
375   *          the SyncOperation which identifies the source "entry" to
376   *          fetch. The ChangeRecord can be obtained by calling
377   *          <code>operation.getChangeRecord()</code>.
378   *          These ChangeRecords are generated by
379   *        {@link #getNextBatchOfChanges(int, AtomicLong)}
380   *          or by
381   *        {@link #listAllEntries(BlockingQueue)}.
382   *
383   * @return a full LDAP Entry, or null if no such entry exists.
384   * @throws EndpointException
385   *           if there is an error fetching the entry
386   */
387  public abstract Entry fetchEntry(final SyncOperation operation)
388                                      throws EndpointException;
389
390
391
392  /**
393   * Provides a way for the Synchronization Server to acknowledge back to the
394   * script which sync operations it has processed. This method should update
395   * the official startpoint which was set by
396   * {@link #setStartpoint(SetStartpointOptions)} and is
397   * returned by {@link #getStartpoint()}.
398   * <p>
399   * <b>IMPORTANT</b>: The internal value for the startpoint should only be
400   * updated after a sync operation is acknowledged back to this extension (via
401   * this method). Otherwise it will be possible for changes to be missed when
402   * the Synchronization Server is restarted or a connection error occurs.
403   *
404   * @param completedOps
405   *          a list of {@link SyncOperation}s that have finished processing.
406   *          The records are listed in the order they were first detected.
407   * @throws EndpointException
408   *           if there is an error acknowledging the changes back to the
409   *           database
410   */
411  public abstract void acknowledgeCompletedOps(
412                                   final LinkedList<SyncOperation> completedOps)
413                                      throws EndpointException;
414
415
416
417  /**
418   * Gets a list of all the entries in the source endpoint. This is used by the
419   * 'resync' command line tool. The default implementation throws a
420   * {@link UnsupportedOperationException}; subclasses should override if the
421   * resync functionality is needed.
422   * <p>
423   * The <code>outputQueue</code> should contain {@link ChangeRecord} objects
424   * with the <code>ChangeType</code> set to <code>null</code> to indicate that
425   * these are resync operations.  {@code ChangeRecords} should be added to
426   * the queue using the blocking {@code put()} method.
427   * <p>
428   * This method should not return until all the entries at the source
429   * have been added to the output queue. Separate threads will concurrently
430   * drain entries from the queue and process them. The queue typically should
431   * not contain full entries, but rather ChangeRecord objects which identify
432   * the full source entries. These objects are then individually passed in to
433   * {@link #fetchEntry(SyncOperation)}. Therefore, it is important to make sure
434   * that the ChangeRecord instances contain enough identifiable information
435   * (e.g. primary keys) for each entry so that the entry can be found again.
436   * <p>
437   * The lifecycle of resync is similar to that of real-time sync, with a few
438   * differences:
439   * <ol>
440   * <li>Stream out a list of identifiers for the entries in the source
441   *     endpoint, using a ChangeRecord as the identifier</li>
442   * <li>Fetch full source entry for a ChangeRecord</li>
443   * <li>Perform any mappings and compute the equivalent destination entry</li>
444   * <li>Fetch full destination entry</li>
445   * <li>Diff the computed destination entry and actual destination entry</li>
446   * <li>Apply the minimal set of changes at the destination to bring it in sync
447   * </li>
448   * </ol>
449   * <p>
450   * Alternatively, the full entry can be set on the ChangeRecord within this
451   * method, which will cause the "fetch full entry" step to be skipped. In this
452   * case the Sync Server will just use the entry specified on the ChangeRecord.
453   * <p>
454   * If the total set of entries is very large, it is fine to split up the work
455   * into multiple network queries within this method. The queue will not grow
456   * out of control because it blocks when it becomes full. The queue capacity
457   * is fixed at 1000.
458   * <p>
459   * @param outputQueue
460   *          a queue of ChangeRecord objects which will be individually
461   *          fetched via {@link #fetchEntry(SyncOperation)}.
462   *          {@code ChangeRecords} should be added to the queue using the
463   *          blocking {@code put()} method.
464   * @throws EndpointException
465   *           if there is an error retrieving the list of entries to resync
466   */
467  public void listAllEntries(final BlockingQueue<ChangeRecord> outputQueue)
468                                throws EndpointException
469  {
470    throw new UnsupportedOperationException(
471            "The listAllEntries(BlockingQueue) " +
472            "method must be implemented in the '" +
473            getExtensionName() + "' extension (Java class " +
474            getClass().getName() + ").");
475  }
476
477
478
479  /**
480   * Gets a list of all the entries in the source from a given file input.
481   * This is used by the 'resync' command line tool. The default implementation
482   * throws a {@link UnsupportedOperationException}; subclasses should override
483   * if the resync functionality is needed for specific records, which
484   * can be specified in the input file.
485   * <p>
486   * The format for the <code>inputLines</code> (e.g. the content of the file)
487   * is user-defined; it may be key/value pairs, primary keys, or full SQL
488   * statements, for example. The use of this method is triggered via the
489   * <i>--sourceInputFile</i> argument on the resync CLI. The
490   * <code>outputQueue</code> should contain {@link ChangeRecord}
491   * objects with the <code>ChangeType</code> set to <code>null</code> to
492   * indicate that these are resync operations.
493   * <p>
494   * This method should not return until all the entries specified by the input
495   * file have been added to the output queue. Separate threads will
496   * concurrently drain entries from the queue and process them. The queue
497   * typically should not contain full entries, but rather ChangeRecord
498   * objects which identify the full source entries. These objects are then
499   * individually passed in to {@link #fetchEntry(SyncOperation)}. Therefore,
500   * it is important to make sure that the ChangeRecord instances
501   * contain enough identifiable information (e.g. primary keys) for each entry
502   * so that the entry can be found again.
503   * <p>
504   * The lifecycle of resync is similar to that of real-time sync, with a few
505   * differences:
506   * <ol>
507   * <li>Stream out a list of identifiers for entries in the source endpoint,
508   *     using the given input file as the basis for which entries to resync
509   * </li>
510   * <li>Fetch full source entry for an identifier</li>
511   * <li>Perform any mappings and compute the equivalent destination entry</li>
512   * <li>Fetch full destination entry</li>
513   * <li>Diff the computed destination entry and actual destination entry</li>
514   * <li>Apply the minimal set of changes at the destination to bring it in sync
515   * </li>
516   * </ol>
517   * <p>
518   * Alternatively, the full entry can be set on the ChangeRecord within this
519   * method, which will cause the "fetch full entry" step to be skipped. In this
520   * case the Sync Server will just use the entry specified on the ChangeRecord.
521   * <p>
522   * If the total set of entries is very large, it is fine to split up the work
523   * into multiple network queries within this method. The queue will not grow
524   * out of control because it blocks when it becomes full. The queue capacity
525   * is fixed at 1000.
526   * <p>
527   * @param inputLines
528   *          an Iterator containing the lines from the specified input file to
529   *          resync (this is specified on the CLI for the resync command).
530   *          These lines can be any format, for example a set of primary keys,
531   *          a set of WHERE clauses, a set of full SQL queries, etc.
532   * @param outputQueue
533   *          a queue of ChangeRecord objects which will be individually
534   *          fetched via {@link #fetchEntry(SyncOperation)}.
535   *          {@code ChangeRecords} should be added to the queue using the
536   *          blocking {@code put()} method.
537   * @throws EndpointException
538   *           if there is an error retrieving the list of entries to resync
539   */
540  public void listAllEntries(final Iterator<String> inputLines,
541                             final BlockingQueue<ChangeRecord> outputQueue)
542                                    throws EndpointException
543  {
544    throw new UnsupportedOperationException(
545            "The listAllEntries(Iterator,BlockingQueue) " +
546            "method must be implemented in the '" +
547            getExtensionName() + "' extension (Java class " +
548            getClass().getName() + ").");
549  }
550}