package org.jgroups.protocols;
import org.jgroups.annotations.Property;
import org.jgroups.annotations.Unsupported;
import org.jgroups.stack.IpAddress;
import org.jgroups.util.Util;
import org.jgroups.logging.Log;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
/**
* Protocol which uses an executable (e.g. /sbin/ping, or a script) to check whether a given host is up or not,
* taking 1 argument; the host name of the host to be pinged. Property 'cmd' determines the program to be executed
* (use a fully qualified name if the program is not on the path).
* @author Bela Ban
* @deprecated Use {@link org.jgroups.protocols.FD_HOST} instead. Will be removed in 4.0.
*/
@Unsupported
@Deprecated
public class FD_PING extends FD {
/** Command (script or executable) to ping a host: a return value of 0 means success, anything else is a failure.
* The only argument passed to cmd is the host's address (symbolic name or dotted-decimal IP address) */
@Property(description="Command (script or executable) to ping a host: a return value of 0 means success, anything else is a failure. Default is ping")
String cmd="ping";
@Property(description="Write the stdout of the command to the log. Default is true")
boolean verbose=true;
protected Monitor createMonitor() {
return new PingMonitor();
}
/**
* Executes the ping command. Each time the command fails, we increment num_tries. If num_tries > max_tries, we
* emit a SUSPECT message. If ping_dest changes, or we do receive traffic from ping_dest, we reset num_tries to 0.
*/
protected class PingMonitor extends Monitor {
public void run() {
if(ping_dest == null) {
if(log.isWarnEnabled())
log.warn("ping_dest is null: members=" + members + ", pingable_mbrs=" +
pingable_mbrs + ", local_addr=" + local_addr);
return;
}
// 1. execute ping command
String host=ping_dest instanceof IpAddress? ((IpAddress)ping_dest).getIpAddress().getHostAddress() : ping_dest.toString();
String command=cmd + " " + host;
if(log.isDebugEnabled())
log.debug("executing \"" + command + "\" (own address=" + local_addr + ')');
try {
Log tmp_log=verbose? log : null;
int rc=Pinger.execute(command, tmp_log);
num_heartbeats++;
if(rc == 0) { // success
num_tries.set(0);
}
else { // failure
num_tries.incrementAndGet();
if(log.isDebugEnabled())
log.debug("could not ping " + ping_dest + " (tries=" + num_tries + ')');
}
int tmp_tries=num_tries.get();
if(tmp_tries >= max_tries) {
if(log.isDebugEnabled())
log.debug("[" + local_addr + "]: could not ping " + ping_dest + " for " + (tmp_tries +1) +
" times (" + ((tmp_tries+1) * timeout) + " milliseconds), suspecting it");
// broadcast a SUSPECT message to all members - loop until
// unsuspect or view change is received
bcast_task.addSuspectedMember(ping_dest);
num_tries.set(0);
if(stats) {
num_suspect_events++;
suspect_history.add(ping_dest);
}
}
}
catch(Exception ex) {
if(log.isErrorEnabled())
log.error("failed executing command " + command, ex);
}
}
}
protected static class Pinger {
static int execute(String command, Log log) throws IOException, InterruptedException {
Process p=Runtime.getRuntime().exec(command);
InputStream in=p.getInputStream(), err=p.getErrorStream();
try {
Reader in_reader, err_reader;
in_reader=new Reader(in, log);
err_reader=new Reader(err, log);
in_reader.start();
err_reader.start();
in_reader.join();
err_reader.join();
return p.exitValue();
}
finally {
Util.close(in);
Util.close(err);
}
}
static class Reader extends Thread {
InputStreamReader in;
Log log=null;
boolean trace=false;
Reader(InputStream in, Log log) {
this.in=new InputStreamReader(in);
this.log=log;
if(log != null) {
trace=log.isTraceEnabled();
}
}
public void run() {
int c;
StringBuilder sb=new StringBuilder();
while(true) {
try {
c=in.read();
if(c == -1)
break;
sb.append((char)c);
}
catch(IOException e) {
break;
}
}
if(log.isTraceEnabled())
log.trace(sb.toString());
}
}
}
}