/**
* This method tries to compute the name of the host that's reachable by all the other nodes.
*
* <p>Since it's possible that the slave is not reachable from the master (it may be behind a
* firewall, connecting to master via JNLP), this method may return null.
*
* <p>It's surprisingly tricky for a machine to know a name that other systems can get to,
* especially between things like DNS search suffix, the hosts file, and YP.
*
* <p>So the technique here is to compute possible interfaces and names on the slave, then try to
* ping them from the master, and pick the one that worked.
*
* <p>The computation may take some time, so it employs caching to make the successive lookups
* faster.
*
* @since 1.300
* @return null if the host name cannot be computed (for example because this computer is offline,
* because the slave is behind the firewall, etc.)
*/
public String getHostName() throws IOException, InterruptedException {
if (hostNameCached)
// in the worst case we end up having multiple threads computing the host name simultaneously,
// but that's not harmful, just wasteful.
return cachedHostName;
VirtualChannel channel = getChannel();
if (channel == null) return null; // can't compute right now
for (String address : channel.call(new ListPossibleNames())) {
try {
InetAddress ia = InetAddress.getByName(address);
if (!(ia instanceof Inet4Address)) {
LOGGER.fine(address + " is not an IPv4 address");
continue;
}
if (!ComputerPinger.checkIsReachable(ia, 3)) {
LOGGER.fine(address + " didn't respond to ping");
continue;
}
cachedHostName = ia.getCanonicalHostName();
hostNameCached = true;
return cachedHostName;
} catch (IOException e) {
// if a given name fails to parse on this host, we get this error
LOGGER.log(Level.FINE, "Failed to parse " + address, e);
}
}
// allow the administrator to manually specify the host name as a fallback. HUDSON-5373
cachedHostName = channel.call(new GetFallbackName());
hostNameCached = true;
return cachedHostName;
}
public static CommandOutputContent runOnNode(Node node, String name, String... command) {
String content = "Exception occurred while retrieving command content";
VirtualChannel chan = node.getChannel();
if (chan == null) {
content = "No connection to node";
} else {
try {
content = chan.call(new CommandLauncher(command));
} catch (IOException e) {
final LogRecord lr =
new LogRecord(Level.FINE, "Could not retrieve command content from {0}");
lr.setParameters(new Object[] {getNodeName(node)});
lr.setThrown(e);
LOGGER.log(lr);
} catch (InterruptedException e) {
final LogRecord lr =
new LogRecord(Level.FINE, "Could not retrieve command content from {0}");
lr.setParameters(new Object[] {getNodeName(node)});
lr.setThrown(e);
LOGGER.log(lr);
}
}
return new CommandOutputContent(name, content);
}
@Override
protected T monitor(Computer c) throws IOException, InterruptedException {
VirtualChannel ch = c.getChannel();
if (ch != null) {
Callable<T, IOException> cc = createCallable(c);
if (cc != null) return ch.call(cc);
}
return null;
}
/** Starts a new privilege-escalated environment, execute a closure, and shut it down. */
public static <V, T extends Throwable> V execute(
TaskListener listener, String rootUsername, String rootPassword, final Callable<V, T> closure)
throws T, IOException, InterruptedException {
VirtualChannel ch = start(listener, rootUsername, rootPassword);
try {
return ch.call(closure);
} finally {
ch.close();
ch.join(3000); // give some time for orderly shutdown, but don't block forever.
}
}
private void install(Computer c, TaskListener listener) {
try {
final List<SlaveRestarter> restarters = new ArrayList<SlaveRestarter>(SlaveRestarter.all());
VirtualChannel ch = c.getChannel();
if (ch==null) return; // defensive check
List<SlaveRestarter> effective = ch.call(new Callable<List<SlaveRestarter>, IOException>() {
public List<SlaveRestarter> call() throws IOException {
Engine e = Engine.current();
if (e == null) return null; // not running under Engine
try {
Engine.class.getMethod("addListener", EngineListener.class);
} catch (NoSuchMethodException _) {
return null; // running with older version of remoting that doesn't support adding listener
}
// filter out ones that doesn't apply
for (Iterator<SlaveRestarter> itr = restarters.iterator(); itr.hasNext(); ) {
SlaveRestarter r = itr.next();
if (!r.canWork())
itr.remove();
}
e.addListener(new EngineListenerAdapter() {
@Override
public void onDisconnect() {
try {
for (SlaveRestarter r : restarters) {
try {
LOGGER.info("Restarting slave via "+r);
r.restart();
} catch (Exception x) {
LOGGER.log(SEVERE, "Failed to restart slave with "+r, x);
}
}
} finally {
// if we move on to the reconnection without restart,
// don't let the current implementations kick in when the slave loses connection again
restarters.clear();
}
}
});
return restarters;
}
});
listener.getLogger().println("Effective SlaveRestarter on " + c.getDisplayName() + ": " + effective);
} catch (Throwable e) {
e.printStackTrace(listener.error("Failed to install restarter"));
}
}
/** Performs all monitoring concurrently. */
@Override
protected Map<Computer, T> monitor() throws InterruptedException {
Map<Computer, Future<T>> futures = new HashMap<Computer, Future<T>>();
for (Computer c : Jenkins.getInstance().getComputers()) {
try {
VirtualChannel ch = c.getChannel();
futures.put(c, null); // sentinel value
if (ch != null) {
Callable<T, ?> cc = createCallable(c);
if (cc != null) futures.put(c, ch.callAsync(cc));
}
} catch (RuntimeException e) {
LOGGER.log(
WARNING, "Failed to monitor " + c.getDisplayName() + " for " + getDisplayName(), e);
} catch (IOException e) {
LOGGER.log(
WARNING, "Failed to monitor " + c.getDisplayName() + " for " + getDisplayName(), e);
}
}
final long now = System.currentTimeMillis();
final long end = now + getMonitoringTimeOut();
final Map<Computer, T> data = new HashMap<Computer, T>();
for (Entry<Computer, Future<T>> e : futures.entrySet()) {
Computer c = e.getKey();
Future<T> f = futures.get(c);
data.put(c, null); // sentinel value
if (f != null) {
try {
data.put(c, f.get(Math.max(0, end - System.currentTimeMillis()), MILLISECONDS));
} catch (RuntimeException x) {
LOGGER.log(
WARNING, "Failed to monitor " + c.getDisplayName() + " for " + getDisplayName(), x);
} catch (ExecutionException x) {
LOGGER.log(
WARNING, "Failed to monitor " + c.getDisplayName() + " for " + getDisplayName(), x);
} catch (TimeoutException x) {
LOGGER.log(
WARNING, "Failed to monitor " + c.getDisplayName() + " for " + getDisplayName(), x);
}
}
}
return data;
}
/** Dumps the contents of the export table. */
public void doDumpExportTable(StaplerRequest req, StaplerResponse rsp)
throws IOException, ServletException, InterruptedException {
// this is a debug probe and may expose sensitive information
checkPermission(Jenkins.ADMINISTER);
rsp.setContentType("text/plain");
PrintWriter w = new PrintWriter(rsp.getCompressedWriter(req));
VirtualChannel vc = getChannel();
if (vc instanceof Channel) {
w.println("Master to slave");
((Channel) vc).dumpExportTable(w);
w.flush(); // flush here once so that even if the dump from the slave fails, the client
// gets some useful info
w.println("\n\n\nSlave to master");
w.print(vc.call(new DumpExportTableTask()));
} else {
w.println(Messages.Computer_BadChannel());
}
w.close();
}
public String getShellOrDefault(VirtualChannel channel) {
if (shell != null) return shell;
String interpreter = null;
try {
interpreter = channel.call(new Shellinterpreter());
} catch (IOException e) {
LOGGER.warning(e.getMessage());
} catch (InterruptedException e) {
LOGGER.warning(e.getMessage());
}
if (interpreter == null) {
interpreter = getShellOrDefault();
}
return interpreter;
}
/** Obtains the heap dump in an HPROF file. */
public static FilePath getHeapDump(VirtualChannel channel)
throws IOException, InterruptedException {
return channel.call(
new MasterToSlaveCallable<FilePath, IOException>() {
public FilePath call() throws IOException {
final File hprof = File.createTempFile("hudson-heapdump", "hprof");
hprof.delete();
try {
MBeanServer server = ManagementFactory.getPlatformMBeanServer();
server.invoke(
new ObjectName("com.sun.management:type=HotSpotDiagnostic"),
"dumpHeap",
new Object[] {hprof.getAbsolutePath(), true},
new String[] {String.class.getName(), boolean.class.getName()});
return new FilePath(hprof);
} catch (JMException e) {
throw new IOException(e);
}
}
private static final long serialVersionUID = 1L;
});
}
public static Future<Map<String, String>> getThreadDumpAsync(VirtualChannel channel)
throws IOException, InterruptedException {
if (channel == null)
return new AsyncFutureImpl<Map<String, String>>(Collections.singletonMap("N/A", "offline"));
return channel.callAsync(new GetThreadDump());
}
public static Map<String, String> getThreadDump(VirtualChannel channel)
throws IOException, InterruptedException {
if (channel == null) return Collections.singletonMap("N/A", "N/A");
return channel.call(new GetThreadDump());
}
public static Map<Object, Object> getSystemProperties(VirtualChannel channel)
throws IOException, InterruptedException {
if (channel == null) return Collections.<Object, Object>singletonMap("N/A", "N/A");
return channel.call(new GetSystemProperties());
}
/** Executes Groovy script remotely. */
public static String executeGroovy(String script, @Nonnull VirtualChannel channel)
throws IOException, InterruptedException {
return channel.call(new Script(script));
}
