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package org.dcache.resilience.handlers;
import com.google.common.collect.ImmutableList;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import diskCacheV111.util.CacheException;
import diskCacheV111.util.PnfsId;
import dmg.cells.nucleus.CellPath;
import org.dcache.alarms.AlarmMarkerFactory;
import org.dcache.alarms.PredefinedAlarm;
import org.dcache.cells.CellStub;
import org.dcache.pool.migration.PoolMigrationCopyFinishedMessage;
import org.dcache.pool.migration.PoolSelectionStrategy;
import org.dcache.pool.migration.Task;
import org.dcache.pool.migration.TaskParameters;
import org.dcache.pool.repository.ReplicaState;
import org.dcache.pool.repository.StickyRecord;
import org.dcache.resilience.data.FileOperation;
import org.dcache.resilience.data.FileOperationMap;
import org.dcache.resilience.data.FileUpdate;
import org.dcache.resilience.data.MessageType;
import org.dcache.resilience.data.PoolInfoMap;
import org.dcache.resilience.data.StorageUnitConstraints;
import org.dcache.resilience.db.NamespaceAccess;
import org.dcache.resilience.util.CacheExceptionUtils;
import org.dcache.resilience.util.DegenerateSelectionStrategy;
import org.dcache.resilience.util.ExceptionMessage;
import org.dcache.resilience.util.LocationSelectionException;
import org.dcache.resilience.util.LocationSelector;
import org.dcache.resilience.util.RemoveLocationExtractor;
import org.dcache.resilience.util.ResilientFileTask;
import org.dcache.resilience.util.StaticSinglePoolList;
import org.dcache.vehicles.FileAttributes;
import org.dcache.vehicles.resilience.RemoveReplicaMessage;
//import org.dcache.resilience.util.InaccessibleFileHandler;
/**
* <p>Principal resilience logic component.</p>
*
* <p>Contains methods for registering a pnfsid for handling and
* for updating the number of times it should be processed (based
* on the arrival of update messages), for verifying if some
* action indeed needs to be taken, for launching a copy/migration
* task and for eliminating an excess copy.</p>
*
* <p>Class is not marked final for stubbing/mocking purposes.</p>
*/
public class FileOperationHandler {
private static final Logger LOGGER = LoggerFactory.getLogger(
FileOperationHandler.class);
private static final ImmutableList<StickyRecord> ONLINE_STICKY_RECORD
= ImmutableList.of(
new StickyRecord("system", StickyRecord.NON_EXPIRING));
private static final String INACCESSIBLE_FILE_MESSAGE
= "Resilient pool {} is inaccessible but it contains "
+ "one or more files with no currently readable locations. "
+ "Administrator intervention is required. Run the command "
+ "'inaccessible {}' to produce a list of orphaned pnfsids.";
/**
* <p>For communication with the {@link ResilientFileTask}.</p>
*/
public enum Type {
COPY,
REMOVE,
VOID
}
private final PoolSelectionStrategy taskSelectionStrategy
= new DegenerateSelectionStrategy();
private FileOperationMap fileOpMap;
private PoolInfoMap poolInfoMap;
private NamespaceAccess namespace;
private LocationSelector locationSelector;
private CellStub pinManager;
private CellStub pools;
private ExecutorService taskService;
private ScheduledExecutorService scheduledService;
private FileTaskCompletionHandler completionHandler;
public ExecutorService getTaskService() {
return taskService;
}
public ScheduledExecutorService getRemoveService() {
return scheduledService;
}
public void handleBrokenFileLocation(PnfsId pnfsId, String pool) {
try {
FileAttributes attributes
= FileUpdate.getAttributes(pnfsId, pool,
MessageType.CORRUPT_FILE,
namespace);
if (attributes == null || attributes.getLocations().size() < 2) {
/*
* This is the only copy, or it is not/no longer in the
* namespace. In either case, do nothing, but cancel
* any running operations for this pnfsid.
*/
fileOpMap.cancel(pnfsId, true);
return;
}
removeTarget(pnfsId, pool);
FileUpdate update = new FileUpdate(pnfsId, pool,
MessageType.CLEAR_CACHE_LOCATION, false);
/*
* Bypass the message guard check of CDC session.
*/
handleLocationUpdate(update);
} catch (CacheException e) {
LOGGER.error("Error during handling of broken file removal ({}, {}): {}",
pnfsId, pool, new ExceptionMessage(e));
}
}
/**
* <p>The entry method for a PnfsId operation from a location update, called
* in response to an incoming message.</p>
*
* <p>If the entry is already in the current map, its count is incremented.</p>
*
* <p>A check is then made to see if the source belongs to a resilient
* pool group. If not, the update is discarded.</p>
*
* <p>All attributes of the file that are necessary for resilience
* processing are then fetched. Thereafter a series of preliminary
* checks are run for other disqualifying conditions. If the pnfsId
* does qualify, an entry is added to the {@link FileOperationMap}.</p>
*
* @return true if a new operation is added to the map.
*/
public boolean handleLocationUpdate(FileUpdate data)
throws CacheException {
LOGGER.trace("handleLocationUpdate {}", data);
if (data.pool == null) {
LOGGER.debug("Update of {} with no location; file has likely "
+ "been deleted from namespace.",
data.pnfsId);
return false;
}
if (!data.verifyPoolGroup(poolInfoMap)) {
LOGGER.debug("Handle location update ({}, {}, {}; "
+ "pool is not a member "
+ "of a resilient group.",
data.pnfsId, data.pool, data.getGroup());
return false;
}
/*
* Prefetch all necessary file attributes, including current locations.
*/
if (!data.validateAttributes(namespace)) {
/*
* Could be the result of a delete from namespace triggering a
* clear cache location message.
*/
return false;
}
/*
* Determine if action needs to be taken (counts).
*/
if (!data.validateForAction(null, poolInfoMap, locationSelector)) {
return false;
}
LOGGER.trace("handleLocationUpdate, update to be registered: {}", data);
return fileOpMap.register(data);
}
/**
* <p>The entry method for a PnfsId operation from a pool scan task.</p>
*
* <p>If the entry is already in the current map, its count is incremented.</p>
*
* <p>All attributes of the file that are necessary for resilience
* processing are then fetched. Preliminary checks run for disqualifying
* conditions here include whether this is a storage unit modification,
* in which case the task is registered if the file has the storage unit
* in question. Otherwise, verification proceeds as in the
* {@link #handleLocationUpdate(FileUpdate)} method.</p>
*
* @return true if a new operation is added to the map.
*/
public boolean handleScannedLocation(FileUpdate data, Integer storageUnit)
throws CacheException {
LOGGER.trace("handleScannedLocation {}", data);
/*
* These must be true during a pool scan.
*/
data.verifyPoolGroup(poolInfoMap);
data.validateAttributes(namespace);
/*
* Determine if action needs to be taken.
*/
if (!data.validateForAction(storageUnit, poolInfoMap, locationSelector)) {
return false;
}
LOGGER.trace("handleLocationUpdate, update to be registered: {}", data);
return fileOpMap.register(data);
}
/**
* <p>Wraps the creation of a migration {@link Task}. The task is given
* a static single pool list and a degenerate selection strategy,
* since the target has already been selected by this handler.</p>
*/
public Task handleMakeOneCopy(FileAttributes attributes) {
PnfsId pnfsId = attributes.getPnfsId();
FileOperation operation = fileOpMap.getOperation(pnfsId);
/*
* Fire-and-forget best effort.
*/
operation.ensureSticky(poolInfoMap, pools);
LOGGER.trace("Configuring migration task for {}.", pnfsId);
StaticSinglePoolList list;
try {
list = new StaticSinglePoolList(poolInfoMap.getPoolManagerInfo(operation.getTarget()));
} catch (NoSuchElementException e) {
CacheException exception = CacheExceptionUtils.getCacheException(
CacheException.NO_POOL_CONFIGURED,
"Copy %s, could not get PoolManager info for %s: %s.",
pnfsId, poolInfoMap.getPool(operation.getTarget()),
e);
completionHandler.taskFailed(pnfsId, exception);
return null;
}
String source = poolInfoMap.getPool(operation.getSource());
TaskParameters taskParameters = new TaskParameters(
pools,
null, // PnfsManager cell stub not used
pinManager,
scheduledService,
taskSelectionStrategy,
list,
false, // eager; update should not happen
false, // isMetaOnly; just move the metadata
false, // compute checksum on update; should not happen
false, // force copy even if pool not readable
true, // maintain atime
1);
Task task = new Task(taskParameters, completionHandler, source, pnfsId,
ReplicaState.CACHED, ONLINE_STICKY_RECORD,
Collections.EMPTY_LIST, attributes,
attributes.getAccessTime());
LOGGER.trace("Created migration task for {}: {}.", pnfsId, task);
return task;
}
/**
* @param message returned by pool migration task, needs to be passed
* to the migration task.
*/
public void handleMigrationCopyFinished(
PoolMigrationCopyFinishedMessage message) {
LOGGER.trace("Migration copy finished {}", message);
try {
fileOpMap.updateOperation(message);
} catch (IllegalStateException e) {
/*
* We treat the missing entry benignly, as it is
* possible to have a race between removal from forced cancellation
* and the arrival of the message from the pool.
*/
LOGGER.trace("{}", new ExceptionMessage(e));
}
}
/**
* <p>Calls {@link #removeTarget(PnfsId, String)} and then reports
* success or failure to the completion handler.</p>
*/
public void handleRemoveOneCopy(FileAttributes attributes) {
PnfsId pnfsId = attributes.getPnfsId();
FileOperation operation = fileOpMap.getOperation(pnfsId);
try {
String target = poolInfoMap.getPool(operation.getTarget());
LOGGER.trace("handleRemoveOneCopy {}, removing {}.", pnfsId,
target);
removeTarget(pnfsId, target);
} catch (CacheException e) {
completionHandler.taskFailed(pnfsId, e);
}
completionHandler.taskCompleted(pnfsId);
}
/**
* <p>Called when a pnfsid has been selected from the operation map for
* possible processing. Refreshes locations from namespace, and checks
* which of those are currently readable. Sends an alarm if
* no operation can occur but should.</p>
*
* @return COPY, REMOVE, or VOID if no operation is necessary.
*/
public Type handleVerification(FileAttributes attributes) {
PnfsId pnfsId = attributes.getPnfsId();
FileOperation operation = fileOpMap.getOperation(pnfsId);
int gindex = operation.getPoolGroup();
/*
* Note that the location-dependent checks are run on this thread
* instead of being pre-checked by the FileOperationMap consumer thread
* because they require a call to the database.
*/
try {
namespace.refreshLocations(attributes);
} catch (CacheException e) {
CacheException exception = CacheExceptionUtils.getCacheException(
CacheException.DEFAULT_ERROR_CODE,
FileTaskCompletionHandler.VERIFY_FAILURE_MESSAGE,
pnfsId, null, e.getCause());
completionHandler.taskFailed(pnfsId, exception);
return Type.VOID;
}
Collection<String> locations
= poolInfoMap.getMemberLocations(gindex,
attributes.getLocations());
/*
* Once again, if all the locations are pools now missing
* from the group, this is a NOP.
*/
if (locations.isEmpty()) {
return Type.VOID;
}
LOGGER.trace("handleVerification {}, locations {}", pnfsId, locations);
/*
* If we have arrived here, we are expecting there to be an
* available source file. So we need the strictly readable
* locations, not just "countable" ones.
*/
Set<String> readableLocations
= poolInfoMap.getReadableLocations(locations);
LOGGER.trace("handleVerification, {}, readable locations {}", pnfsId,
readableLocations);
if (readableLocations.size() == 0
&& operation.getRetentionPolicy()
!= FileOperation.CUSTODIAL) {
Integer pindex = operation.getParent();
if (pindex == null) {
pindex = operation.getSource();
}
if (pindex != null) {
String pool = poolInfoMap.getPool(pindex);
/*
* Send alarm keyed to pool;
* this will increment the count on the alarm
*/
LOGGER.error(AlarmMarkerFactory.getMarker(PredefinedAlarm.INACCESSIBLE_FILE,
pool), INACCESSIBLE_FILE_MESSAGE, pool, pool);
}
String error = String.format(
"%s currently has no active locations.",
pnfsId);
CacheException exception
= CacheExceptionUtils.getCacheException(
CacheException.PANIC,
FileTaskCompletionHandler.VERIFY_FAILURE_MESSAGE,
pnfsId, error, null);
completionHandler.taskFailed(pnfsId, exception);
return Type.VOID;
}
if (shouldEvictALocation(operation, readableLocations)) {
return Type.REMOVE;
}
LOGGER.trace("handleVerification after eviction check, {}, locations {}",
pnfsId, locations);
return determineTypeFromConstraints(operation,
locations,
readableLocations);
}
public void setCompletionHandler(
FileTaskCompletionHandler completionHandler) {
this.completionHandler = completionHandler;
}
public void setLocationSelector(LocationSelector locationSelector) {
this.locationSelector = locationSelector;
}
public void setNamespace(NamespaceAccess namespace) {
this.namespace = namespace;
}
public void setPinManagerStub(CellStub pinManager) {
this.pinManager = pinManager;
}
public void setFileOpMap(FileOperationMap pnfsOpMap) {
this.fileOpMap = pnfsOpMap;
}
public void setPoolInfoMap(PoolInfoMap poolInfoMap) {
this.poolInfoMap = poolInfoMap;
}
public void setPoolStub(CellStub pools) {
this.pools = pools;
}
public void setScheduledService(ScheduledExecutorService scheduledService) {
this.scheduledService = scheduledService;
}
public void setTaskService(ExecutorService taskService) {
this.taskService = taskService;
}
/**
* <p>Checks the readable locations against the requirements.
* If previous operations on this pnfsId have already satisfied them,
* the operation should be voided.</p>
*
* @return the type of operation which should take place, if any.
*/
private Type determineTypeFromConstraints(FileOperation operation,
Collection<String> locations,
Set<String> readableLocations) {
PnfsId pnfsId = operation.getPnfsId();
Integer gindex = operation.getPoolGroup();
Integer sindex = operation.getStorageUnit();
LOGGER.trace("determineTypeFromConstraints {}, group {}, unit {}.",
pnfsId, gindex, sindex);
StorageUnitConstraints constraints
= poolInfoMap.getStorageUnitConstraints(sindex);
/*
* Countable means readable OR intentionally excluded locations.
* If there are copies missing only from excluded locations,
* do nothing.
*/
int missing = constraints.getRequired()
- poolInfoMap.getCountableLocations(locations);
Collection<String> tags = constraints.getOneCopyPer();
LOGGER.trace("{}, readable locations {}, required {}, missing {}.",
pnfsId, readableLocations, constraints.getRequired(),
missing);
Type type;
String source = null;
String target = null;
try {
/*
* Note that if the operation source or target is preset,
* the selection is skipped.
*/
if (missing < 0) {
type = Type.REMOVE;
Integer pool = operation.getTarget();
if (pool == null || !poolInfoMap.isPoolViable(pool, true)) {
target = locationSelector.selectRemoveTarget(operation,
readableLocations, tags);
}
LOGGER.trace("target to remove: {}", target);
} else if (missing > 0) {
type = Type.COPY;
Integer pool = operation.getSource();
if (pool == null || !poolInfoMap.isPoolViable(pool, false)) {
source = locationSelector.selectCopySource(operation,
readableLocations);
}
LOGGER.trace("source: {}", source);
pool = operation.getTarget();
if (pool == null || !poolInfoMap.isPoolViable(pool, true)) {
target = locationSelector.selectCopyTarget(operation, gindex,
readableLocations, tags);
}
LOGGER.trace("target to copy: {}", target);
} else {
LOGGER.trace("Nothing to do, VOID operation for {}", pnfsId);
fileOpMap.voidOperation(pnfsId);
return Type.VOID;
}
} catch (LocationSelectionException e) {
CacheException exception = CacheExceptionUtils.getCacheException(
CacheException.DEFAULT_ERROR_CODE,
FileTaskCompletionHandler.VERIFY_FAILURE_MESSAGE,
pnfsId, null, e);
completionHandler.taskFailed(pnfsId, exception);
return Type.VOID;
}
fileOpMap.updateOperation(pnfsId, source, target);
return type;
}
/**
* <p>Synchronously removes from the target location the cache entry of the
* pnfsid associated with this task. This is done via a message
* sent to a handler for this purpose on the pool itself.</p>
*/
private void removeTarget(PnfsId pnfsId, String target)
throws CacheException {
RemoveReplicaMessage msg = new RemoveReplicaMessage(target,
pnfsId);
LOGGER.trace("Sending RemoveReplicasMessage {}.", msg);
Future<RemoveReplicaMessage> future = pools.send(new CellPath(target), msg);
try {
msg = future.get();
LOGGER.trace("Returned ReplicationRepRmMessage {}.", msg);
} catch (InterruptedException | ExecutionException e) {
throw CacheExceptionUtils.getCacheException(
CacheException.SELECTED_POOL_FAILED,
FileTaskCompletionHandler.FAILED_REMOVE_MESSAGE,
pnfsId, target, e);
}
Serializable exception = msg.getErrorObject();
if (exception != null && !CacheExceptionUtils.fileNotFound(exception)) {
throw CacheExceptionUtils.getCacheException(
CacheException.SELECTED_POOL_FAILED,
FileTaskCompletionHandler.FAILED_REMOVE_MESSAGE,
pnfsId, target, (Exception) exception);
}
}
/**
* <p>Checks for necessary eviction due to pool tag changes or
* constraint change. This call will automatically set
* the offending location as the target for a remove operation,
* and will increment the operation count so that there will
* be a chance to repeat the operation in order to make a new copy.</p>
*/
private boolean shouldEvictALocation(FileOperation operation,
Collection<String> readableLocations) {
if (readableLocations.isEmpty()) {
return false;
}
Integer sunit = operation.getStorageUnit();
if (sunit == null) {
return false;
}
StorageUnitConstraints constraints
= poolInfoMap.getStorageUnitConstraints(sunit);
RemoveLocationExtractor extractor
= new RemoveLocationExtractor(
constraints.getOneCopyPer(),
poolInfoMap);
String toEvict = extractor.findALocationToEvict(readableLocations);
if (toEvict != null) {
operation.setTarget(poolInfoMap.getPoolIndex(toEvict));
int count = operation.getOpCount();
operation.setOpCount(++count);
return true;
}
return false;
}
}