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Merge pull request #228 from oleg-nenashev/feature/JENKINS-48055

[JENKINS-48055] - Introduce convenient Channel retrieval methods in Callables.
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oleg-nenashev committed Nov 17, 2017
2 parents 33692ca + 1515498 commit 9b8fd56e780f0c042c8ac35333e87faba8c5f81f
@@ -23,11 +23,18 @@
*/
package hudson.remoting;

import org.jenkinsci.remoting.ChannelStateException;
import org.jenkinsci.remoting.RoleSensitive;
import org.jenkinsci.remoting.SerializableOnlyOverRemoting;

import javax.annotation.Nonnull;
import java.io.IOException;
import java.io.NotSerializableException;
import java.io.Serializable;

//TODO: Make it SerializableOnlyOverRemoting?
// Oleg Nenashev: Formally there is no reason for that, you can serialize object over whatever binary stream and then
// execute it on remote side if it has channel instance. Likely YAGNI, but I can imagine such Pipeline context class implementation.
/**
* Represents computation to be done on a remote system.
*
@@ -40,4 +47,46 @@
* or throws some exception.
*/
V call() throws T;

/**
* Gets a channel for the operation inside callable.
* @return Channel Instance
* @throws ChannelStateException Channel is not associated with the thread
* @since TODO
*/
@Nonnull
default Channel getChannelOrFail() throws ChannelStateException {
final Channel ch = Channel.current();
if (ch == null) {
// This logic does not prevent from improperly serializing objects within Remoting calls.
// If it happens in API calls in external usages, we wish good luck with diagnosing Remoting issues
// and leaks in ExportTable.
//TODO: maybe there is a way to actually diagnose this case?
final Thread t = Thread.currentThread();
throw new ChannelStateException("The calling thread " + t + " has no associated channel. "
+ "The current object " + this + " is " + SerializableOnlyOverRemoting.class +
", but it is likely being serialized/deserialized without the channel");
}
return ch;
}

/**
* Gets an open channel, which is ready to accept commands.
*
* It is a convenience method for cases, when a callable needs to invoke call backs on the master.
* In such case the requests will be likely failed by {@linkplain UserRequest} logic anyway, but it is better to fail fast.
*
* @return Channel instance
* @throws ChannelStateException The channel is closing down or has been closed.
* Also happens if the channel is not associated with the thread at all.
* @since TODO
*/
@Nonnull
default Channel getOpenChannelOrFail() throws ChannelStateException {
final Channel ch = getChannelOrFail();
if (ch.isClosingOrClosed()) {
throw new ChannelClosedException("The associated channel " + ch + " is closing down or has closed down", ch.getCloseRequestCause());
}
return ch;
}
}
@@ -1,5 +1,7 @@
package hudson.remoting;

import org.jenkinsci.remoting.ChannelStateException;

import java.io.IOException;
import javax.annotation.CheckForNull;
import javax.annotation.Nonnull;
@@ -9,7 +11,7 @@
*
* @author Kohsuke Kawaguchi
*/
public class ChannelClosedException extends IOException {
public class ChannelClosedException extends ChannelStateException {
/**
* @deprecated
* Use {@link #ChannelClosedException(Throwable)} or {@link #ChannelClosedException(java.lang.String, java.lang.Throwable)}.
@@ -893,7 +893,7 @@ public RPCRequest(int oid, Method m, Object[] arguments, ClassLoader cl) {
}

public Serializable call() throws Throwable {
return perform(Channel.currentOrFail());
return perform(getChannelOrFail());
}

@Override
@@ -134,9 +134,10 @@ public static ListeningPort create(VirtualChannel ch, final int acceptingPort, F

return ch.call(new Callable<ListeningPort,IOException>() {
public ListeningPort call() throws IOException {
final Channel channel = getOpenChannelOrFail(); // We initialize it early, so the forwarder won's start its daemon if the channel is shutting down
PortForwarder t = new PortForwarder(acceptingPort, proxy);
t.start();
return Channel.currentOrFail().export(ListeningPort.class,t);
return channel.export(ListeningPort.class,t);
}

@Override
@@ -0,0 +1,46 @@
/*
*
* The MIT License
*
* Copyright (c) 2017 CloudBees, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
*/

package org.jenkinsci.remoting;

import java.io.IOException;

/**
* Indicates invalid state of the channel during the operation.
*
* @author Oleg Nenashev
* @since TODO
*/
public class ChannelStateException extends IOException {

public ChannelStateException(String message) {
super(message);
}

public ChannelStateException(String message, Throwable cause) {
super(message, cause);
}
}
@@ -130,7 +130,7 @@ public void testWaitForRemoteProperty() throws Exception {
private static class WaitForRemotePropertyCallable extends CallableBase<Void, Exception> {
public Void call() throws Exception {
Thread.sleep(500);
Channel.currentOrFail().setProperty("foo","bar");
getChannelOrFail().setProperty("foo","bar");
return null;
}
}
@@ -204,7 +204,7 @@ public static Test suite() throws Exception {

private static class RemotePropertyVerifier extends CallableBase<Object, IOException> {
public Object call() throws IOException {
Object o = Channel.currentOrFail().getRemoteProperty("test");
Object o = getOpenChannelOrFail().getRemoteProperty("test");
assertEquals(o.getClass().getName(), CLASSNAME);
assertTrue(Channel.class.getClassLoader() != o.getClass().getClassLoader());
assertTrue(o.getClass().getClassLoader() instanceof RemoteClassLoader);
@@ -1175,7 +1175,7 @@ public void run() {

@Override
public String call() throws IOException {
System.out.println("Hello from: " + Channel.currentOrFail());
System.out.println("Hello from: " + getChannelOrFail());
return null;
}

@@ -1193,7 +1193,7 @@ public CreateSaturationTestProxy(hudson.remoting.Pipe pipe) {
}

public ISaturationTest call() throws IOException {
return Channel.currentOrFail().export(ISaturationTest.class, new ISaturationTest() {
return getOpenChannelOrFail().export(ISaturationTest.class, new ISaturationTest() {
private InputStream in;

public void ensureConnected() throws IOException {

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