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Merge pull request #12201 from jetty/fix/jetty-10.0.x/improve-ThreadLimitHandler 

Jetty 10.0.x: Improve ThreadLimitHandler
This commit is contained in:
Joakim Erdfelt 2024-08-26 11:59:07 -05:00 committed by GitHub
parent 79f473ee4b d1a9ca1156
commit f277b0aaa6
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GPG Key ID: B5690EEEBB952194
2 changed files with 78 additions and 15 deletions
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63
jetty-server/src/main/java/org/eclipse/jetty/server/handler/ThreadLimitHandler.java
View File

@ -21,10 +21,12 @@ import java.util.ArrayDeque;
import java.util.Deque;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.atomic.AtomicInteger;
import javax.servlet.AsyncContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@ -73,7 +75,7 @@ public class ThreadLimitHandler extends HandlerWrapper
private final boolean _rfc7239;
private final String _forwardedHeader;
private final IncludeExcludeSet<String, InetAddress> _includeExcludeSet = new IncludeExcludeSet<>(InetAddressSet.class);
private final ConcurrentMap<String, Remote> _remotes = new ConcurrentHashMap<>();
private final ConcurrentHashMap<String, Remote> _remotes = new ConcurrentHashMap<>();
private volatile boolean _enabled;
private int _threadLimit = 10;
@ -179,6 +181,17 @@ public class ThreadLimitHandler extends HandlerWrapper
}
else
{
request.getServletContext().addListener(new ServletRequestListener()
{
@Override
public void requestDestroyed(ServletRequestEvent sre)
{
// Use a compute method to remove the Remote instance as it is necessary for
// the ref counter release and the removal to be atomic.
_remotes.computeIfPresent(remote._ip, (k, v) -> v._referenceCounter.release() ? null : v);
}
});
// Do we already have a future permit from a previous invocation?
Closeable permit = (Closeable)baseRequest.getAttribute(PERMIT);
try
@ -250,14 +263,18 @@ public class ThreadLimitHandler extends HandlerWrapper
if (limit <= 0)
return null;
remote = _remotes.get(ip);
if (remote == null)
// Use a compute method to create or retain the Remote instance as it is necessary for
// the ref counter increment or the instance creation to be mutually exclusive.
// The map MUST be a CHM as it guarantees the remapping function is only called once.
remote = _remotes.compute(ip, (k, v) ->
{
Remote r = new Remote(ip, limit);
remote = _remotes.putIfAbsent(ip, r);
if (remote == null)
remote = r;
}
if (v != null)
{
v._referenceCounter.retain();
return v;
}
return new Remote(k, limit);
});
baseRequest.setAttribute(REMOTE, remote);
@ -321,11 +338,17 @@ public class ThreadLimitHandler extends HandlerWrapper
return (comma >= 0) ? forwardedFor.substring(comma + 1).trim() : forwardedFor;
}
int getRemoteCount()
{
return _remotes.size();
}
private static final class Remote implements Closeable
{
private final String _ip;
private final int _limit;
private final AutoLock _lock = new AutoLock();
private final ReferenceCounter _referenceCounter = new ReferenceCounter();
private int _permits;
private Deque<CompletableFuture<Closeable>> _queue = new ArrayDeque<>();
private final CompletableFuture<Closeable> _permitted = CompletableFuture.completedFuture(this);
@ -429,4 +452,26 @@ public class ThreadLimitHandler extends HandlerWrapper
}
}
}
private static class ReferenceCounter
{
private final AtomicInteger references = new AtomicInteger(1);
public void retain()
{
if (references.getAndUpdate(c -> c == 0 ? 0 : c + 1) == 0)
throw new IllegalStateException("released " + this);
}
public boolean release()
{
int ref = references.updateAndGet(c ->
{
if (c == 0)
throw new IllegalStateException("already released " + this);
return c - 1;
});
return ref == 0;
}
}
}

26
jetty-server/src/test/java/org/eclipse/jetty/server/handler/ThreadLimitHandlerTest.java
View File

@ -16,6 +16,7 @@ package org.eclipse.jetty.server.handler;
import java.io.IOException;
import java.net.Socket;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import javax.servlet.ServletException;
@ -35,6 +36,7 @@ import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.awaitility.Awaitility.await;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;
@ -83,7 +85,9 @@ public class ThreadLimitHandlerTest
response.setStatus(HttpStatus.OK_200);
}
});
_server.setHandler(handler);
ContextHandler contextHandler = new ContextHandler("/");
contextHandler.setHandler(handler);
_server.setHandler(contextHandler);
_server.start();
last.set(null);
@ -97,6 +101,8 @@ public class ThreadLimitHandlerTest
last.set(null);
_local.getResponse("GET / HTTP/1.0\r\nForwarded: for=1.2.3.4\r\n\r\n");
assertThat(last.get(), Matchers.is("0.0.0.0"));
await().atMost(5, TimeUnit.SECONDS).until(handler::getRemoteCount, is(0));
}
@Test
@ -112,7 +118,9 @@ public class ThreadLimitHandlerTest
return super.getThreadLimit(ip);
}
};
_server.setHandler(handler);
ContextHandler contextHandler = new ContextHandler("/");
contextHandler.setHandler(handler);
_server.setHandler(contextHandler);
_server.start();
last.set(null);
@ -130,6 +138,8 @@ public class ThreadLimitHandlerTest
last.set(null);
_local.getResponse("GET / HTTP/1.0\r\nX-Forwarded-For: 1.1.1.1\r\nX-Forwarded-For: 6.6.6.6,1.2.3.4\r\nForwarded: for=1.2.3.4\r\n\r\n");
assertThat(last.get(), Matchers.is("1.2.3.4"));
await().atMost(5, TimeUnit.SECONDS).until(handler::getRemoteCount, is(0));
}
@Test
@ -145,7 +155,9 @@ public class ThreadLimitHandlerTest
return super.getThreadLimit(ip);
}
};
_server.setHandler(handler);
ContextHandler contextHandler = new ContextHandler("/");
contextHandler.setHandler(handler);
_server.setHandler(contextHandler);
_server.start();
last.set(null);
@ -163,6 +175,8 @@ public class ThreadLimitHandlerTest
last.set(null);
_local.getResponse("GET / HTTP/1.0\r\nX-Forwarded-For: 1.1.1.1\r\nForwarded: for=6.6.6.6; for=1.2.3.4\r\nX-Forwarded-For: 6.6.6.6\r\nForwarded: proto=https\r\n\r\n");
assertThat(last.get(), Matchers.is("1.2.3.4"));
await().atMost(5, TimeUnit.SECONDS).until(handler::getRemoteCount, is(0));
}
@Test
@ -201,7 +215,9 @@ public class ThreadLimitHandlerTest
}
}
});
_server.setHandler(handler);
ContextHandler contextHandler = new ContextHandler("/");
contextHandler.setHandler(handler);
_server.setHandler(contextHandler);
_server.start();
Socket[] client = new Socket[10];
@ -237,5 +253,7 @@ public class ThreadLimitHandlerTest
Thread.sleep(10);
}
assertThat(count.get(), is(0));
await().atMost(5, TimeUnit.SECONDS).until(handler::getRemoteCount, is(0));
}
}