package test.r2.transport.http.client;
import com.linkedin.common.callback.SimpleCallback;
import com.linkedin.r2.transport.http.client.ExponentialBackOffRateLimiter;
import com.linkedin.r2.transport.http.client.RateLimiter;
import com.linkedin.r2.transport.http.client.RateLimiter.Task;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import org.testng.Assert;
import org.testng.annotations.AfterClass;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;
/**
* @author Ang Xu
* @version $Revision: $
*/
public class TestRateLimiter
{
private final long MAXPERIOD = 600;
private ScheduledExecutorService _executor;
@BeforeClass
public void setUp()
{
_executor = Executors.newSingleThreadScheduledExecutor();
}
@AfterClass
public void tearDown()
{
_executor.shutdown();
}
@Test
public void testSimple() throws Exception
{
final int total = 10;
// NB on Solaris x86 there seems to be an extra 10ms that gets added to the period; need
// to figure this out. For now set the period high enough that period + 10 will be within
// the tolerance.
final int period = 100;
final CountDownLatch latch = new CountDownLatch(total);
final Task incr = new Task()
{
@Override
public void run(SimpleCallback doneCallback)
{
latch.countDown();
doneCallback.onDone();
}
};
RateLimiter limiter = new ExponentialBackOffRateLimiter(period, period, period, _executor);
limiter.setPeriod(period);
long start = System.currentTimeMillis();
long lowTolerance = (total * period) * 4 / 5;
long highTolerance = (total * period) * 5 / 4;
for (int i = 0; i < total * period; i++)
{
limiter.submit(incr);
}
Assert.assertTrue(latch.await(highTolerance, TimeUnit.MILLISECONDS),
"Should have finished within " + highTolerance + "ms");
long t = System.currentTimeMillis() - start;
Assert.assertTrue(t > lowTolerance, "Should have finished after " + lowTolerance + "ms (took " + t + ")");
}
@Test
public void testMaxRunningTasks() throws Exception
{
final int total = 20;
final int maxRunning = 5;
final int period = 100;
final Random rand = new Random();
final CountDownLatch latch = new CountDownLatch(total);
final AtomicInteger totalStarted = new AtomicInteger();
final AtomicInteger totalFinished = new AtomicInteger();
final Task r = new Task()
{
@Override
public void run(final SimpleCallback callback)
{
totalStarted.incrementAndGet();
int delay = period + rand.nextInt(period);
_executor.schedule(new Runnable()
{
@Override
public void run()
{
totalFinished.incrementAndGet();
callback.onDone();
}
}, delay, TimeUnit.MILLISECONDS);
latch.countDown();
}
};
RateLimiter limiter = new ExponentialBackOffRateLimiter(period, period, period, _executor, maxRunning);
limiter.setPeriod(period);
for (int i = 0; i < total; ++i)
{
limiter.submit(r);
}
// check the current number of concurrent tasks every 100ms.
for (int i = 0; i < total * 2; ++i)
{
int currentRunning = totalStarted.get() - totalFinished.get();
Assert.assertTrue(currentRunning <= maxRunning,
"Should have less than " + maxRunning + " concurrent tasks");
Thread.sleep(period);
}
Assert.assertTrue(latch.await(30, TimeUnit.SECONDS));
Assert.assertEquals(total, totalStarted.get());
}
@Test
public void testSetPeriod() throws Exception
{
final RateLimiter rl = new ExponentialBackOffRateLimiter(0, MAXPERIOD, 20, _executor);
final ScheduledFuture<?> future = _executor.scheduleAtFixedRate(new Runnable()
{
private int _period = 300;
@Override
public void run()
{
rl.setPeriod(_period);
_period += 50;
}
}, 0, 100, TimeUnit.MILLISECONDS);
RateLimiterRunner runner = new RateLimiterRunner(System.currentTimeMillis());
rl.submit(runner);
Assert.assertTrue(runner.getElapsedTime() <= MAXPERIOD, "Elapsed Time exceed MAX Period");
future.cancel(false);
}
private class RateLimiterRunner implements Task
{
private long _startTime;
private long _elapsedTime;
private final CountDownLatch _count;
public RateLimiterRunner(long start)
{
_startTime = start;
_count = new CountDownLatch(1);
}
@Override
public void run(SimpleCallback callback)
{
_elapsedTime = System.currentTimeMillis() - _startTime;
_count.countDown();
callback.onDone();
}
public long getElapsedTime() throws Exception
{
if (!_count.await(MAXPERIOD*2, TimeUnit.MILLISECONDS))
throw new Exception("CountDownLatch Timeout");
else
return _elapsedTime;
}
}
}