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package org.dcache.srm.scheduler;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Multimap;
import com.google.common.collect.MultimapBuilder;
import com.google.common.primitives.Ints;
import com.google.common.util.concurrent.AbstractExecutionThreadService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Required;
import org.springframework.dao.DataAccessException;
import java.util.Collection;
import java.util.Formatter;
import java.util.Map;
import java.util.Timer;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.dcache.srm.SRMAuthorizationException;
import org.dcache.srm.SRMException;
import org.dcache.srm.SRMInternalErrorException;
import org.dcache.srm.SRMInvalidRequestException;
import org.dcache.srm.request.Job;
import org.dcache.srm.scheduler.spi.SchedulingStrategy;
import org.dcache.srm.scheduler.spi.SchedulingStrategyProvider;
import org.dcache.srm.scheduler.spi.TransferStrategy;
import org.dcache.srm.scheduler.spi.TransferStrategyProvider;
import org.dcache.srm.util.JDC;
import org.dcache.srm.v2_2.TStatusCode;
import static com.google.common.base.Preconditions.*;
import static com.google.common.base.Strings.padEnd;
import static com.google.common.base.Strings.repeat;
public class Scheduler <T extends Job>
{
private static final Logger LOGGER =
LoggerFactory.getLogger(Scheduler.class);
private final Class<T> type;
private int maxRequests;
// thread pool related variables
private final ExecutorService pooledExecutor;
// ready state related variables
private int maxReadyJobs;
// async wait state related variables
private int maxInProgress;
private final String id;
private volatile boolean running;
//
// this timer is used for tracking the expiration of retry timeout
private final Timer retryTimer;
// this will contain the number of
private final long timeStamp = System.currentTimeMillis();
private long queuesUpdateMaxWait = 60 * 1000;
private static volatile Map<String, Scheduler<?>> schedulers = ImmutableMap.of();
private final WorkSupplyService workSupplyService;
private final CopyOnWriteArrayList<StateChangeListener> listeners = new CopyOnWriteArrayList<>();
private SchedulingStrategy schedulingStrategy;
private TransferStrategy transferStrategy;
private String schedulingStrategyName;
private String transferStrategyName;
private Multimap<State,Long> jobs = MultimapBuilder.enumKeys(State.class).hashSetValues().build();
public static Scheduler<?> getScheduler(String id)
{
return schedulers.get(id);
}
public static synchronized void addScheduler(String id, Scheduler<?> scheduler)
{
schedulers = ImmutableMap.<String, Scheduler<?>>builder()
.putAll(schedulers)
.put(id, scheduler)
.build();
}
public Scheduler(String id, Class<T> type)
{
this.type = type;
this.id = checkNotNull(id);
checkArgument(!id.isEmpty(), "need non-empty string as an id");
workSupplyService = new WorkSupplyService();
retryTimer = new Timer();
pooledExecutor = Executors.newCachedThreadPool();
addScheduler(id, this);
}
@Required
public void setSchedulingStrategyProvider(SchedulingStrategyProvider provider)
{
schedulingStrategyName = provider.getName();
schedulingStrategy = provider.createStrategy(this);
}
@Required
public void setTransferStrategyProvider(TransferStrategyProvider provider)
{
transferStrategyName = provider.getName();
transferStrategy = provider.createStrategy(this);
}
public void start() throws IllegalStateException
{
synchronized (this) {
checkState(!running, "Scheduler is running.");
running = true;
}
workSupplyService.startAsync().awaitRunning();
}
public void stop()
{
synchronized (this) {
checkState(running, "Scheduler is not running.");
running = false;
}
workSupplyService.stopAsync().awaitTerminated();
retryTimer.cancel();
pooledExecutor.shutdownNow();
}
/**
* Places a job in the queue.
*
* The job is moved to the QUEUED state. The job will be moved to the INPROGRESS state
* in accordance with the scheduling strategy of this scheduler.
*
* This action is subject to request limits and may cause the job to be failed
* immediately if the limits are exceeded.
*/
public void queue(Job job) throws IllegalStateTransition
{
checkState(running, "Scheduler is not running");
checkOwnership(job);
LOGGER.trace("queue is called for job with id={} in state={}", job.getId(), job.getState());
job.wlock();
try {
if (job.getState().isFinal()) {
throw new IllegalStateException("Cannot queue job in state " + job.getState());
} else if (threadQueue(job)) {
job.setState(State.QUEUED, "Queued.");
} else {
LOGGER.warn("Maximum request limit reached.");
job.setState(State.FAILED, "Site busy: Too many queued requests.");
}
} finally {
job.wunlock();
}
}
/**
* Requests the job's run method to be called from this scheduler's thread pool.
*/
public void execute(Job job)
{
checkState(running, "Scheduler is not running");
checkOwnership(job);
LOGGER.trace("execute is called for job with id={} in state={}", job.getId(), job.getState());
pooledExecutor.execute(new JobWrapper(job));
}
public synchronized int getTotalQueued()
{
return jobs.get(State.QUEUED).size();
}
private int getTotalInprogress()
{
return jobs.get(State.INPROGRESS).size();
}
public synchronized int getTotalRQueued()
{
return jobs.get(State.RQUEUED).size();
}
public synchronized int getTotalReady()
{
return jobs.get(State.READY).size();
}
public void tryToReadyJob(Job job)
{
if (transferStrategy.canTransfer(job)) {
try {
job.setState(State.READY, "Execution succeeded.");
} catch (IllegalStateTransition ist) {
//nothing more we can do here
LOGGER.error("Illegal State Transition : {}", ist.getMessage());
}
}
}
private boolean threadQueue(Job job)
{
if (getTotalRequests() < getMaxRequests()) {
schedulingStrategy.add(job);
workSupplyService.distributeWork();
return true;
}
return false;
}
private synchronized int getTotalRequests()
{
return jobs.size();
}
public double getLoad()
{
return (getTotalQueued() + getTotalInprogress()) / (double) getMaxInProgress();
}
public long getTimestamp()
{
return timeStamp;
}
/**
* This class is responsible for keeping the PoolExecutors busy with jobs
* taken from the priority- and non-priority queues.
*/
private class WorkSupplyService extends AbstractExecutionThreadService
{
private boolean hasBeenNotified;
@Override
public void run()
{
try {
while (isRunning()) {
try {
updateThreadQueue();
synchronized (this) {
if (!hasBeenNotified) {
//logger.debug("Scheduler(id="+getId()+").run() waiting for events...");
wait(queuesUpdateMaxWait);
}
hasBeenNotified = false;
}
} catch (SRMInvalidRequestException e) {
LOGGER.error("Sheduler(id={}) detected an SRM error: {}", getId(), e.toString());
} catch (RuntimeException e) {
LOGGER.error("Sheduler(id=" + getId() + ") detected a bug", e);
}
}
} catch (InterruptedException e) {
LOGGER.error("Sheduler(id=" + getId() +
") terminating update thread, since it caught an InterruptedException",
e);
}
//we are interrupted,
//terminating thread
}
@Override
public void triggerShutdown()
{
distributeWork();
}
public synchronized void distributeWork()
{
hasBeenNotified = true;
notify();
}
@Override
public String serviceName()
{
return "Scheduler-" + id;
}
private void updateThreadQueue()
throws SRMInvalidRequestException, InterruptedException
{
Long id;
while (getTotalInprogress() < getMaxInProgress() && (id = schedulingStrategy.remove()) != null) {
Job job = Job.getJob(id, type);
job.wlock();
try {
if (job.getState() == org.dcache.srm.scheduler.State.QUEUED) {
try {
job.setState(org.dcache.srm.scheduler.State.INPROGRESS, "In progress.");
execute(job);
} catch (IllegalStateTransition e) {
LOGGER.error("Bug detected.", e);
try {
job.setState(org.dcache.srm.scheduler.State.FAILED, e.getMessage());
} catch (IllegalStateTransition ignored) {
}
}
}
} finally {
job.wunlock();
}
}
}
}
private class JobWrapper implements Runnable
{
private final Job job;
public JobWrapper(Job job)
{
this.job = job;
}
@Override
public void run()
{
try (JDC ignored = job.applyJdc()) {
try {
try {
try {
job.run();
} catch (SRMAuthorizationException e) {
LOGGER.warn(e.toString());
throw e;
} catch (DataAccessException e) {
LOGGER.error(e.toString());
throw new SRMInternalErrorException("Database access error.", e);
}
} catch (SRMException e) {
job.wlock();
try {
if (!job.getState().isFinal()) {
job.setStateAndStatusCode(State.FAILED, e.getMessage(), e.getStatusCode());
}
} finally {
job.wunlock();
}
} catch (RuntimeException | IllegalStateTransition e) {
LOGGER.error("Bug detected by SRM Scheduler", e);
job.wlock();
try {
if (!job.getState().isFinal()) {
job.setStateAndStatusCode(State.FAILED, "Internal error: " + e.toString(), TStatusCode.SRM_INTERNAL_ERROR);
}
} finally {
job.wunlock();
}
}
} catch (IllegalStateTransition e) {
LOGGER.error("Bug detected by SRM Scheduler", e);
} catch (Throwable t) {
Thread thread = Thread.currentThread();
thread.getUncaughtExceptionHandler().uncaughtException(thread, t);
}
} finally {
workSupplyService.distributeWork();
}
}
}
public void addStateChangeListener(StateChangeListener listener)
{
listeners.add(listener);
}
public void removeStateChangeListener(StateChangeListener listener)
{
listeners.remove(listener);
}
public void stateChanged(Job job, State oldState, State newState)
{
checkNotNull(job);
synchronized (this) {
jobs.remove(oldState, job.getId());
if (!newState.isFinal()) {
jobs.put(newState, job.getId());
}
}
LOGGER.debug("state changed for job id {} from {} to {}", job.getId(), oldState, newState);
for (StateChangeListener listener : listeners) {
listener.stateChanged(job, oldState, newState);
}
}
/**
* Getter for property id.
*
* @return Value of property id.
*/
public String getId()
{
return id;
}
/**
* Getter for property maxReadyJobs.
*
* @return Value of property maxReadyJobs.
*/
public synchronized int getMaxReadyJobs()
{
return maxReadyJobs;
}
/**
* Setter for property maxReadyJobs.
*
* @param maxReadyJobs New value of property maxReadyJobs.
*/
public synchronized void setMaxReadyJobs(int maxReadyJobs)
{
this.maxReadyJobs = maxReadyJobs;
}
/**
* Getter for property maxThreadQueueSize.
*
* @return Value of property maxThreadQueueSize.
*/
public synchronized int getMaxRequests()
{
return maxRequests;
}
public synchronized void setMaxRequests(int maxRequests)
{
this.maxRequests = maxRequests;
}
public synchronized int getMaxInProgress()
{
return maxInProgress;
}
public synchronized void setMaxInprogress(int maxAsyncWaitJobs)
{
this.maxInProgress = maxAsyncWaitJobs;
}
public String toString()
{
StringBuilder sb = new StringBuilder();
getInfo(sb);
return sb.toString();
}
/**
* Helper class for formatting the info output.
*/
private static class InfoFormatter
{
private final Formatter formatter;
private final int fieldWidth;
private final int baseWidth;
private final String field2;
private final String field2NoState;
public InfoFormatter(Appendable appendable, int fieldWidth, int width1, int width2)
{
this.formatter = new Formatter(appendable);
this.fieldWidth = fieldWidth;
this.baseWidth = Ints.max(width1, width2 - fieldWidth - 4) + 1;
this.field2 = String.format(" %%-%ds %%%dd [%%s]\n", baseWidth + fieldWidth + 4, fieldWidth);
this.field2NoState = String.format(" %%-%ds %%%dd\n", baseWidth + fieldWidth + 4, fieldWidth);
}
public void field(String description, int count, State state)
{
format(field2, padEnd(description + " ", baseWidth + fieldWidth + 4, '.'), count, state);
}
public void field(String description, int count)
{
format(field2NoState, padEnd(description + " ", baseWidth + fieldWidth + 4, '.'), count);
}
public void line()
{
format(" %s\n", repeat("-", baseWidth + 2 * fieldWidth + 6));
}
public Formatter format(String format, Object... args)
{
return formatter.format(format, args);
}
}
public synchronized void getInfo(Appendable appendable)
{
int fieldWidth = Math.max(3, String.valueOf(getMaxRequests()).length());
InfoFormatter formatter =
new InfoFormatter(appendable, fieldWidth,
Ints.max(24, 20 + fieldWidth),
28 + fieldWidth);
formatter.field("Queued", getTotalQueued(), State.QUEUED);
formatter.field("In progress (max " + getMaxInProgress() + ")", getTotalInprogress(), State.INPROGRESS);
if (getTotalRQueued() + getMaxReadyJobs() + getTotalReady() > 0) {
formatter.field("Queued for transfer", getTotalRQueued(), State.RQUEUED);
formatter.field("Waiting for transfer (max " + getMaxReadyJobs() + ")", getTotalReady(), State.READY);
}
formatter.line();
formatter.field("Total requests (max " + getMaxRequests() + ")", getTotalRequests());
formatter.format("\n");
formatter.format(" Scheduling strategy : %s\n", schedulingStrategyName);
formatter.format(" Transfer strategy : %s\n", transferStrategyName);
formatter.format(" Scheduler ID : %s\n", id);
}
private static void printQueue(StringBuilder sb, Collection<Long> queue)
{
if (queue.isEmpty()) {
sb.append("Queue is empty\n");
} else {
int index = 0;
for (long nextId : queue) {
sb.append("queue element # ").append(index).append(" : ").append(nextId).append('\n');
index++;
}
}
}
public synchronized void printThreadQueue(StringBuilder sb)
{
sb.append("ThreadQueue :\n");
printQueue(sb, jobs.get(State.QUEUED));
}
public synchronized void printReadyQueue(StringBuilder sb)
{
sb.append("ReadyQueue :\n");
printQueue(sb, jobs.get(State.RQUEUED));
}
public Class<T> getType()
{
return type;
}
private void checkOwnership(Job job)
{
if (!getType().isInstance(job)) {
throw new IllegalArgumentException("Scheduler " + getId() + " doesn't accept " + job.getClass() + '.');
}
if (!id.equals(job.getSchedulerId()) || timeStamp != job.getSchedulerTimeStamp()) {
throw new IllegalArgumentException("Job " + job.getId() + " doesn't belong to scheduler " + getId() + '.');
}
}
}