com.google.gerrit.server.git.MultiProgressMonitor Maven / Gradle / Ivy
// Copyright (C) 2012 The Android Open Source Project
//
// Licensed 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 com.google.gerrit.server.git;
import static com.google.gerrit.server.DeadlineChecker.getTimeoutFormatter;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import com.google.common.base.Strings;
import com.google.common.flogger.FluentLogger;
import com.google.common.util.concurrent.UncheckedExecutionException;
import com.google.gerrit.server.CancellationMetrics;
import com.google.gerrit.server.cancellation.RequestStateProvider;
import com.google.inject.assistedinject.Assisted;
import com.google.inject.assistedinject.AssistedInject;
import java.io.IOException;
import java.io.OutputStream;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ProgressMonitor;
/**
* Progress reporting interface that multiplexes multiple sub-tasks.
*
* Output is of the format:
*
*
* Task: subA: 1, subB: 75% (3/4) (-)\r
* Task: subA: 2, subB: 75% (3/4), subC: 1 (\)\r
* Task: subA: 2, subB: 100% (4/4), subC: 1 (|)\r
* Task: subA: 4, subB: 100% (4/4), subC: 4, done \n
*
*
* Callers should try to keep task and sub-task descriptions short, since the output should fit
* on one terminal line. (Note that git clients do not accept terminal control characters, so true
* multi-line progress messages would be impossible.)
*
*
Whether the client is disconnected or the deadline is exceeded can be checked by {@link
* #checkIfCancelled(RequestStateProvider.OnCancelled)}. This allows the worker thread to react to
* cancellations and abort its execution and finish gracefully. After a cancellation has been
* signaled the worker thread has 10 * {@link #maxIntervalNanos} to react to the cancellation and
* finish gracefully. If the worker thread doesn't finish gracefully in time after the cancellation
* has been signaled, the future executing the task is forcefully cancelled which means that the
* worker thread gets interrupted and an internal error is returned to the client. To react to
* cancellations it is recommended that the task opens a {@link
* com.google.gerrit.server.cancellation.RequestStateContext} in a try-with-resources block to
* register the {@link MultiProgressMonitor} as a {@link RequestStateProvider}. This way the worker
* thread gets aborted by a {@link com.google.gerrit.server.cancellation.RequestCancelledException}
* when the request is cancelled which allows the worker thread to handle the cancellation
* gracefully by catching this exception (e.g. to return a proper error message). {@link
* com.google.gerrit.server.cancellation.RequestCancelledException} is only thrown when the worker
* thread checks for cancellation via {@link
* com.google.gerrit.server.cancellation.RequestStateContext#abortIfCancelled()}. E.g. this is done
* whenever {@link com.google.gerrit.server.logging.TraceContext.TraceTimer} is opened/closed.
*/
public class MultiProgressMonitor implements RequestStateProvider {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
/** Constant indicating the total work units cannot be predicted. */
public static final int UNKNOWN = 0;
private static final char[] SPINNER_STATES = new char[] {'-', '\\', '|', '/'};
private static final char NO_SPINNER = ' ';
public enum TaskKind {
INDEXING,
RECEIVE_COMMITS;
}
/** Handle for a sub-task. */
public class Task implements ProgressMonitor {
private final String name;
private final int total;
private int count;
private int lastPercent;
Task(String subTaskName, int totalWork) {
this.name = subTaskName;
this.total = totalWork;
}
/**
* Indicate that work has been completed on this sub-task.
*
*
Must be called from a worker thread.
*
* @param completed number of work units completed.
*/
@Override
public void update(int completed) {
boolean w = false;
synchronized (MultiProgressMonitor.this) {
count += completed;
if (total != UNKNOWN) {
int percent = count * 100 / total;
if (percent > lastPercent) {
lastPercent = percent;
w = true;
}
}
}
if (w) {
wakeUp();
}
}
/**
* Indicate that this sub-task is finished.
*
*
Must be called from a worker thread.
*/
public void end() {
if (total == UNKNOWN && getCount() > 0) {
wakeUp();
}
}
@Override
public void start(int totalTasks) {}
@Override
public void beginTask(String title, int totalWork) {}
@Override
public void endTask() {}
@Override
public boolean isCancelled() {
return false;
}
public int getCount() {
synchronized (MultiProgressMonitor.this) {
return count;
}
}
}
public interface Factory {
MultiProgressMonitor create(OutputStream out, TaskKind taskKind, String taskName);
MultiProgressMonitor create(
OutputStream out,
TaskKind taskKind,
String taskName,
long maxIntervalTime,
TimeUnit maxIntervalUnit);
}
private final CancellationMetrics cancellationMetrics;
private final OutputStream out;
private final TaskKind taskKind;
private final String taskName;
private final List tasks = new CopyOnWriteArrayList<>();
private int spinnerIndex;
private char spinnerState = NO_SPINNER;
private boolean done;
private boolean clientDisconnected;
private boolean deadlineExceeded;
private boolean forcefulTermination;
private Optional timeout = Optional.empty();
private final long maxIntervalNanos;
/**
* Create a new progress monitor for multiple sub-tasks.
*
* @param out stream for writing progress messages.
* @param taskName name of the overall task.
*/
@AssistedInject
private MultiProgressMonitor(
CancellationMetrics cancellationMetrics,
@Assisted OutputStream out,
@Assisted TaskKind taskKind,
@Assisted String taskName) {
this(cancellationMetrics, out, taskKind, taskName, 500, MILLISECONDS);
}
/**
* Create a new progress monitor for multiple sub-tasks.
*
* @param out stream for writing progress messages.
* @param taskName name of the overall task.
* @param maxIntervalTime maximum interval between progress messages.
* @param maxIntervalUnit time unit for progress interval.
*/
@AssistedInject
private MultiProgressMonitor(
CancellationMetrics cancellationMetrics,
@Assisted OutputStream out,
@Assisted TaskKind taskKind,
@Assisted String taskName,
@Assisted long maxIntervalTime,
@Assisted TimeUnit maxIntervalUnit) {
this.cancellationMetrics = cancellationMetrics;
this.out = out;
this.taskKind = taskKind;
this.taskName = taskName;
maxIntervalNanos = NANOSECONDS.convert(maxIntervalTime, maxIntervalUnit);
}
/**
* Wait for a task managed by a {@link Future}, with no timeout.
*
* @see #waitFor(Future, long, TimeUnit, long, TimeUnit)
*/
public T waitFor(Future workerFuture) {
try {
return waitFor(
workerFuture,
/* taskTimeoutTime= */ 0,
/* taskTimeoutUnit= */ null,
/* cancellationTimeoutTime= */ 0,
/* cancellationTimeoutUnit= */ null);
} catch (TimeoutException e) {
throw new IllegalStateException("timout exception without setting a timeout", e);
}
}
/**
* Wait for a task managed by a {@link Future}.
*
* Must be called from the main thread, not a worker thread. Once a worker thread
* calls {@link #end()}, the future has an additional {@code maxInterval} to finish before it is
* forcefully cancelled and {@link ExecutionException} is thrown.
*
* @param workerFuture a future that returns when worker threads are finished.
* @param taskTimeoutTime overall timeout for the task; the future gets a cancellation signal
* after this timeout is exceeded; non-positive values indicate no timeout.
* @param taskTimeoutUnit unit for overall task timeout.
* @param cancellationTimeoutTime timeout for the task to react to the cancellation signal; if the
* task doesn't terminate within this time it is forcefully cancelled; non-positive values
* indicate no timeout.
* @param cancellationTimeoutUnit unit for the cancellation timeout.
* @throws TimeoutException if this thread or a worker thread was interrupted, the worker was
* cancelled, or timed out waiting for a worker to call {@link #end()}.
*/
public T waitFor(
Future workerFuture,
long taskTimeoutTime,
TimeUnit taskTimeoutUnit,
long cancellationTimeoutTime,
TimeUnit cancellationTimeoutUnit)
throws TimeoutException {
long overallStart = System.nanoTime();
long cancellationNanos =
cancellationTimeoutTime > 0
? NANOSECONDS.convert(cancellationTimeoutTime, cancellationTimeoutUnit)
: 0;
long deadline;
if (taskTimeoutTime > 0) {
timeout = Optional.of(NANOSECONDS.convert(taskTimeoutTime, taskTimeoutUnit));
deadline = overallStart + timeout.get();
} else {
deadline = 0;
}
synchronized (this) {
long left = maxIntervalNanos;
while (!done) {
long start = System.nanoTime();
try {
NANOSECONDS.timedWait(this, left);
} catch (InterruptedException e) {
throw new UncheckedExecutionException(e);
}
// Send an update on every wakeup (manual or spurious), but only move
// the spinner every maxInterval.
long now = System.nanoTime();
if (deadline > 0 && now > deadline) {
if (!deadlineExceeded) {
logger.atFine().log(
"deadline exceeded after %sms, signaling cancellation (timeout=%sms, task=%s(%s))",
MILLISECONDS.convert(now - overallStart, NANOSECONDS),
MILLISECONDS.convert(now - deadline, NANOSECONDS),
taskKind,
taskName);
}
deadlineExceeded = true;
// After setting deadlineExceeded = true give the cancellationNanos to react to the
// cancellation and return gracefully.
if (now > deadline + cancellationNanos) {
// The worker didn't react to the cancellation, cancel it forcefully by an interrupt.
workerFuture.cancel(true);
forcefulTermination = true;
if (workerFuture.isCancelled()) {
logger.atWarning().log(
"MultiProgressMonitor worker killed after %sms, cancelled (timeout=%sms, task=%s(%s))",
MILLISECONDS.convert(now - overallStart, NANOSECONDS),
MILLISECONDS.convert(now - deadline, NANOSECONDS),
taskKind,
taskName);
if (taskKind == TaskKind.RECEIVE_COMMITS) {
cancellationMetrics.countForcefulReceiveTimeout();
}
}
break;
}
}
left -= now - start;
if (left <= 0) {
moveSpinner();
left = maxIntervalNanos;
}
sendUpdate();
if (!done && workerFuture.isDone()) {
// The worker may not have called end() explicitly, which is likely a
// programming error.
logger.atWarning().log(
"MultiProgressMonitor worker did not call end() before returning (task=%s(%s))",
taskKind, taskName);
end();
}
}
if (deadlineExceeded && !forcefulTermination && taskKind == TaskKind.RECEIVE_COMMITS) {
cancellationMetrics.countGracefulReceiveTimeout();
}
sendDone();
}
// The loop exits as soon as the worker calls end(), but we give it another
// 2 x maxIntervalNanos to finish up and return.
try {
return workerFuture.get(2 * maxIntervalNanos, NANOSECONDS);
} catch (InterruptedException | CancellationException e) {
logger.atWarning().withCause(e).log(
"unable to finish processing (task=%s(%s))", taskKind, taskName);
throw new UncheckedExecutionException(e);
} catch (TimeoutException e) {
workerFuture.cancel(true);
throw e;
} catch (ExecutionException e) {
throw new UncheckedExecutionException(e);
}
}
private synchronized void wakeUp() {
notifyAll();
}
/**
* Begin a sub-task.
*
* @param subTask sub-task name.
* @param subTaskWork total work units in sub-task, or {@link #UNKNOWN}.
* @return sub-task handle.
*/
public Task beginSubTask(String subTask, int subTaskWork) {
Task task = new Task(subTask, subTaskWork);
tasks.add(task);
return task;
}
/**
* End the overall task.
*
* Must be called from a worker thread.
*/
public synchronized void end() {
done = true;
wakeUp();
}
private void sendDone() {
spinnerState = NO_SPINNER;
StringBuilder s = format();
boolean any = false;
for (Task t : tasks) {
if (t.count != 0) {
any = true;
break;
}
}
if (any) {
s.append(",");
}
s.append(" done \n");
send(s);
}
private void moveSpinner() {
spinnerIndex = (spinnerIndex + 1) % SPINNER_STATES.length;
spinnerState = SPINNER_STATES[spinnerIndex];
}
private void sendUpdate() {
send(format());
}
private StringBuilder format() {
StringBuilder s = new StringBuilder().append("\r").append(taskName).append(':');
if (!tasks.isEmpty()) {
boolean first = true;
for (Task t : tasks) {
int count = t.getCount();
if (count == 0) {
continue;
}
if (!first) {
s.append(',');
} else {
first = false;
}
s.append(' ');
if (!Strings.isNullOrEmpty(t.name)) {
s.append(t.name).append(": ");
}
if (t.total == UNKNOWN) {
s.append(count);
} else {
s.append(String.format("%d%% (%d/%d)", count * 100 / t.total, count, t.total));
}
}
}
if (spinnerState != NO_SPINNER) {
// Don't output a spinner until the alarm fires for the first time.
s.append(" (").append(spinnerState).append(')');
}
return s;
}
private void send(StringBuilder s) {
if (!clientDisconnected) {
try {
out.write(Constants.encode(s.toString()));
out.flush();
} catch (IOException e) {
logger.atWarning().withCause(e).log(
"Sending progress to client failed. Stop sending updates for task %s(%s)",
taskKind, taskName);
clientDisconnected = true;
}
}
}
@Override
public void checkIfCancelled(OnCancelled onCancelled) {
if (clientDisconnected) {
onCancelled.onCancel(RequestStateProvider.Reason.CLIENT_CLOSED_REQUEST, /* message= */ null);
} else if (deadlineExceeded) {
onCancelled.onCancel(
RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED,
timeout
.map(
taskKind == TaskKind.RECEIVE_COMMITS
? getTimeoutFormatter("receive.timeout")
: getTimeoutFormatter("timeout"))
.orElse(null));
}
}
}