--- loncom/loncnew 2003/07/02 01:31:55 1.13
+++ loncom/loncnew 2003/09/15 09:24:49 1.23
@@ -2,13 +2,12 @@
# The LearningOnline Network with CAPA
# lonc maintains the connections to remote computers
#
-# $Id: loncnew,v 1.13 2003/07/02 01:31:55 foxr Exp $
+# $Id: loncnew,v 1.23 2003/09/15 09:24:49 foxr Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
-#
-# LON-CAPA is free software; you can redistribute it and/or modify
+## LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
@@ -27,7 +26,7 @@
# http://www.lon-capa.org/
#
#
-# new lonc handles n requestors spread out bver m connections to londs.
+# new lonc handles n request out bver m connections to londs.
# This module is based on the Event class.
# Development iterations:
# - Setup basic event loop. (done)
@@ -46,6 +45,55 @@
# Change log:
# $Log: loncnew,v $
+# Revision 1.23 2003/09/15 09:24:49 foxr
+# Add use strict and fix all the fallout from that.
+#
+# Revision 1.22 2003/09/02 10:34:47 foxr
+# - Fix errors in host dead detection logic (too many cases where the
+# retries left were not getting incremented or just not checked).
+# - Added some additional status to the ps axuww display:
+# o Remaining retries on a host.
+# o >>> DEAD <<< indicator if I've given up on a host.
+# - Tested the SIGHUP will reset the retries remaining count (thanks to
+# the above status stuff, and get allow the loncnew to re-try again
+# on the host (thanks to the log).
+#
+# Revision 1.21 2003/08/26 09:19:51 foxr
+# How embarrassing... put in the SocketTimeout function in loncnew and forgot
+# to actually hook it into the LondTransaction. Added this to MakeLondConnection
+# where it belongs... hopefully transactions (not just connection attempts) will
+# timeout more speedily than the socket errors will catch it.
+#
+# Revision 1.20 2003/08/25 18:48:11 albertel
+# - fixing a forgotten ;
+#
+# Revision 1.19 2003/08/19 09:31:46 foxr
+# Get socket directory from configuration rather than the old hard coded test
+# way that I forgot to un-hard code.
+#
+# Revision 1.18 2003/08/06 09:52:29 foxr
+# Also needed to remember to fail in-flight transactions if their sends fail.
+#
+# Revision 1.17 2003/08/03 00:44:31 foxr
+# 1. Correct handling of connection failure: Assume it means the host is
+# unreachable and fail all of the queued transactions. Note that the
+# inflight transactions should fail on their own time due either to timeout
+# or send/receive failures.
+# 2. Correct handling of logs for forced death signals. Pull the signal
+# from the event watcher.
+#
+# Revision 1.16 2003/07/29 02:33:05 foxr
+# Add SIGINT processing to child processes to toggle annoying trace mode
+# on/off.. will try to use this to isolate the compute boud process issue.
+#
+# Revision 1.15 2003/07/15 02:07:05 foxr
+# Added code for lonc/lond transaction timeouts. Who knows if it works right.
+# The intent is for a timeout to fail any transaction in progress and kill
+# off the sockt that timed out.
+#
+# Revision 1.14 2003/07/03 02:10:18 foxr
+# Get all of the signals to work correctly.
+#
# Revision 1.13 2003/07/02 01:31:55 foxr
# Added kill -HUP logic (restart).
#
@@ -55,7 +103,7 @@
# Revision 1.10 2003/06/24 02:46:04 foxr
# Put a limit on the number of times we'll retry a connection.
# Start getting the signal stuff put in as well...note that need to get signals
-# going or else 6the client will permanently give up on dead servers.
+# going or else the client will permanently give up on dead servers.
#
# Revision 1.9 2003/06/13 02:38:43 foxr
# Add logging in 'expected format'
@@ -69,7 +117,7 @@
# complete coding to support deferred transactions.
#
#
-
+use strict;
use lib "/home/httpd/lib/perl/";
use lib "/home/foxr/newloncapa/types";
use Event qw(:DEFAULT );
@@ -93,12 +141,12 @@ use LONCAPA::HashIterator;
#
# Disable all signals we might receive from outside for now.
#
-$SIG{QUIT} = IGNORE;
-$SIG{HUP} = IGNORE;
-$SIG{USR1} = IGNORE;
-$SIG{INT} = IGNORE;
-$SIG{CHLD} = IGNORE;
-$SIG{__DIE__} = IGNORE;
+#$SIG{QUIT} = IGNORE;
+#$SIG{HUP} = IGNORE;
+#$SIG{USR1} = IGNORE;
+#$SIG{INT} = IGNORE;
+#$SIG{CHLD} = IGNORE;
+#$SIG{__DIE__} = IGNORE;
# Read the httpd configuration file to get perl variables
@@ -117,13 +165,14 @@ my $MaxConnectionCount = 10; # Will get
my $ClientConnection = 0; # Uniquifier for client events.
my $DebugLevel = 0;
+my $NextDebugLevel= 10; # So Sigint can toggle this.
my $IdleTimeout= 3600; # Wait an hour before pruning connections.
#
# The variables below are only used by the child processes.
#
my $RemoteHost; # Name of host child is talking to.
-my $UnixSocketDir= "/home/httpd/sockets";
+my $UnixSocketDir= $perlvar{'lonSockDir'};
my $IdleConnections = Stack->new(); # Set of idle connections
my %ActiveConnections; # Connections to the remote lond.
my %ActiveTransactions; # LondTransactions in flight.
@@ -132,6 +181,7 @@ my $WorkQueue = Queue->new(); # Qu
my $ConnectionCount = 0;
my $IdleSeconds = 0; # Number of seconds idle.
my $Status = ""; # Current status string.
+my $RecentLogEntry = "";
my $ConnectionRetries=5; # Number of connection retries allowed.
my $ConnectionRetriesLeft=5; # Number of connection retries remaining.
@@ -208,6 +258,7 @@ sub Log {
my $execdir = $perlvar{'lonDaemons'};
my $fh = IO::File->new(">>$execdir/logs/lonc.log");
my $msg = sprintf($finalformat, $message);
+ $RecentLogEntry = $msg;
print $fh $msg;
@@ -230,7 +281,7 @@ sub GetPeername {
my $peerip;
if($AdrFamily == AF_INET) {
($peerport, $peerip) = sockaddr_in($peer);
- my $peername = gethostbyaddr($iaddr, $AdrFamily);
+ my $peername = gethostbyaddr($peerip, $AdrFamily);
return $peername;
} elsif ($AdrFamily == AF_UNIX) {
my $peerfile;
@@ -251,7 +302,7 @@ sub Debug {
my $level = shift;
my $message = shift;
if ($level <= $DebugLevel) {
- print $message." host = ".$RemoteHost."\n";
+ Log("INFO", "-Debug- $message host = $RemoteHost");
}
}
@@ -281,6 +332,23 @@ sub ShowStatus {
=pod
+=head 2 SocketTimeout
+
+ Called when an action on the socket times out. The socket is
+ destroyed and any active transaction is failed.
+
+
+=cut
+sub SocketTimeout {
+ my $Socket = shift;
+
+ KillSocket($Socket); # A transaction timeout also counts as
+ # a connection failure:
+ $ConnectionRetriesLeft--;
+}
+
+=pod
+
=head2 Tick
Invoked each timer tick.
@@ -290,8 +358,12 @@ Invoked each timer tick.
sub Tick {
my $client;
- ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount);
-
+ if($ConnectionRetriesLeft > 0) {
+ ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
+ ." Retries remaining: ".$ConnectionRetriesLeft);
+ } else {
+ ShowStatus(GetServerHost()." >> DEAD <<");
+ }
# Is it time to prune connection count:
@@ -299,13 +371,19 @@ sub Tick {
($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
$IdleSeconds++;
if($IdleSeconds > $IdleTimeout) { # Prune a connection...
- $Socket = $IdleConnections->pop();
+ my $Socket = $IdleConnections->pop();
KillSocket($Socket);
}
} else {
$IdleSeconds = 0; # Reset idle count if not idle.
}
-
+ #
+ # For each inflight transaction, tick down its timeout counter.
+ #
+ foreach my $item (keys %ActiveTransactions) {
+ my $Socket = $ActiveTransactions{$item}->getServer();
+ $Socket->Tick();
+ }
# Do we have work in the queue, but no connections to service them?
# If so, try to make some new connections to get things going again.
#
@@ -316,10 +394,16 @@ sub Tick {
my $Connections = ($Requests <= $MaxConnectionCount) ?
$Requests : $MaxConnectionCount;
Debug(1,"Work but no connections, start ".$Connections." of them");
- for ($i =0; $i < $Connections; $i++) {
- MakeLondConnection();
+ my $successCount = 0;
+ for (my $i =0; $i < $Connections; $i++) {
+ $successCount += MakeLondConnection();
+ }
+ if($successCount == 0) { # All connections failed:
+ Debug(1,"Work in queue failed to make any connectiouns\n");
+ EmptyQueue(); # Fail pending transactions with con_lost.
}
} else {
+ ShowStatus(GetServerHost()." >>> DEAD!!! <<<");
Debug(1,"Work in queue, but gave up on connections..flushing\n");
EmptyQueue(); # Connections can't be established.
}
@@ -371,7 +455,7 @@ sub ServerToIdle {
# If there's work to do, start the transaction:
- $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
+ my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
unless($reqdata eq undef) {
Debug(9, "Queue gave request data: ".$reqdata->getRequest());
&StartRequest($Socket, $reqdata);
@@ -443,6 +527,12 @@ sub ClientWritable {
} else { # Partial string sent.
$Watcher->data(substr($Data, $result));
+ if($result == 0) { # client hung up on us!!
+ Log("INFO", "lonc pipe client hung up on us!");
+ $Watcher->cancel;
+ $Socket->shutdown(2);
+ $Socket->close();
+ }
}
} else { # Error of some sort...
@@ -499,7 +589,7 @@ sub CompleteTransaction {
StartClientReply($Transaction, $data);
} else { # Delete deferred transaction file.
Log("SUCCESS", "A delayed transaction was completed");
- LogPerm("S:$Client:".$Transaction->getRequest());
+ LogPerm("S:$Transaction->getClient() :".$Transaction->getRequest());
unlink $Transaction->getFile();
}
}
@@ -560,12 +650,16 @@ Parameters:
sub FailTransaction {
my $transaction = shift;
+ Log("WARNING", "Failing transaction ".$transaction->getRequest());
Debug(1, "Failing transaction: ".$transaction->getRequest());
if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
my $client = $transaction->getClient();
Debug(1," Replying con_lost to ".$transaction->getRequest());
StartClientReply($transaction, "con_lost\n");
}
+ if($ConnectionRetriesLeft <= 0) {
+ Log("CRITICAL", "Host marked dead: ".GetServerHost());
+ }
}
@@ -577,6 +671,7 @@ sub FailTransaction {
=cut
sub EmptyQueue {
+ $ConnectionRetriesLeft--; # Counts as connection failure too.
while($WorkQueue->Count()) {
my $request = $WorkQueue->dequeue(); # This is a transaction
FailTransaction($request);
@@ -591,7 +686,7 @@ Close all connections open on lond prior
=cut
sub CloseAllLondConnections {
- foreach $Socket (keys %ActiveConnections) {
+ foreach my $Socket (keys %ActiveConnections) {
KillSocket($Socket);
}
}
@@ -622,6 +717,7 @@ nonzero if we are allowed to create a ne
sub KillSocket {
my $Socket = shift;
+ Log("WARNING", "Shutting down a socket");
$Socket->Shutdown();
# If the socket came from the active connection set,
@@ -642,7 +738,7 @@ sub KillSocket {
# work queue, the work all gets failed with con_lost.
#
if($ConnectionCount == 0) {
- EmptyQueue;
+ EmptyQueue();
}
}
@@ -711,25 +807,28 @@ sub LondReadable {
my $Socket = $Watcher->data;
my $client = undef;
- &Debug(6,"LondReadable called state = ".$State);
+ &Debug(6,"LondReadable called state = ".$Socket->GetState());
my $State = $Socket->GetState(); # All action depends on the state.
SocketDump(6, $Socket);
my $status = $Socket->Readable();
+
&Debug(2, "Socket->Readable returned: $status");
if($status != 0) {
# bad return from socket read. Currently this means that
# The socket has become disconnected. We fail the transaction.
+ Log("WARNING",
+ "Lond connection lost.");
if(exists($ActiveTransactions{$Socket})) {
- Debug(3,"Lond connection lost failing transaction");
FailTransaction($ActiveTransactions{$Socket});
}
$Watcher->cancel();
KillSocket($Socket);
+ $ConnectionRetriesLeft--; # Counts as connection failure
return;
}
SocketDump(6,$Socket);
@@ -763,6 +862,10 @@ sub LondReadable {
} elsif ($State eq "Idle") {
# If necessary, complete a transaction and then go into the
# idle queue.
+ # Note that a trasition to idle indicates a live lond
+ # on the other end so reset the connection retries.
+ #
+ $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
$Watcher->cancel();
if(exists($ActiveTransactions{$Socket})) {
Debug(8,"Completing transaction!!");
@@ -875,6 +978,7 @@ sub LondWritable {
# We'll treat this as if the socket got disconnected:
Log("WARNING", "Connection to ".$RemoteHost.
" has been disconnected");
+ FailTransaction($ActiveTransactions{$Socket});
$Watcher->cancel();
KillSocket($Socket);
return;
@@ -974,8 +1078,7 @@ sub QueueDelayed {
Debug(4, "Delayed path: ".$path);
opendir(DIRHANDLE, $path);
- @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
- Debug(4, "Got ".$alldelayed." delayed files");
+ my @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
closedir(DIRHANDLE);
my $dfname;
my $reqfile;
@@ -1017,7 +1120,7 @@ sub MakeLondConnection {
$ConnectionRetriesLeft--;
return 0; # Failure.
} else {
- $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
+
# The connection needs to have writability
# monitored in order to send the init sequence
# that starts the whole authentication/key
@@ -1030,8 +1133,9 @@ sub MakeLondConnection {
&Debug(9,"MakeLondConnection got socket: ".$Socket);
}
-
- $event = Event->io(fd => $Socket,
+ $Connection->SetTimeoutCallback(\&SocketTimeout);
+
+ my $event = Event->io(fd => $Socket,
poll => 'w',
cb => \&LondWritable,
data => $Connection,
@@ -1087,7 +1191,7 @@ sub StartRequest {
$ActiveTransactions{$Lond} = $Request;
$Lond->InitiateTransaction($Request->getRequest());
- $event = Event->io(fd => $Socket,
+ my $event = Event->io(fd => $Socket,
poll => "w",
cb => \&LondWritable,
data => $Lond,
@@ -1129,8 +1233,15 @@ sub QueueTransaction {
Debug(8,"Must queue...");
$WorkQueue->enqueue($requestData);
if($ConnectionCount < $MaxConnectionCount) {
- Debug(4,"Starting additional lond connection");
- MakeLondConnection();
+ if($ConnectionRetriesLeft > 0) {
+ Debug(4,"Starting additional lond connection");
+ if(MakeLondConnection() == 0) {
+ EmptyQueue(); # Fail transactions, can't make connection.
+ }
+ } else {
+ ShowStatus(GetServerHost()." >>> DEAD !!!! <<<");
+ EmptyQueue(); # It's worse than that ... he's dead Jim.
+ }
}
} else { # Can start the request:
Debug(8,"Can start...");
@@ -1288,6 +1399,28 @@ sub SetupLoncListener {
fd => $socket);
}
+=pod
+
+=head2 ChildStatus
+
+Child USR1 signal handler to report the most recent status
+into the status file.
+
+We also use this to reset the retries count in order to allow the
+client to retry connections with a previously dead server.
+=cut
+sub ChildStatus {
+ my $event = shift;
+ my $watcher = $event->w;
+
+ Debug(2, "Reporting child status because : ".$watcher->data);
+ my $docdir = $perlvar{'lonDocRoot'};
+ my $fh = IO::File->new(">>$docdir/lon-status/loncstatus.txt");
+ print $fh $$."\t".$RemoteHost."\t".$Status."\t".
+ $RecentLogEntry."\n";
+ $ConnectionRetriesLeft = $ConnectionRetries;
+}
+
=pod
=head2 SignalledToDeath
@@ -1298,17 +1431,35 @@ Called in response to a signal that caus
sub SignalledToDeath {
- Debug(2,"Signalled to death!");
- my ($signal) = @_;
+ my $event = shift;
+ my $watcher= $event->w;
+
+ Debug(2,"Signalled to death! via ".$watcher->data);
+ my ($signal) = $watcher->data;
chomp($signal);
Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
."died through "."\"$signal\"");
LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
."\"$signal\"");
- die("Signal abnormal end");
exit 0;
}
+
+=head2 ToggleDebug
+
+This sub toggles trace debugging on and off.
+
+=cut
+
+sub ToggleDebug {
+ my $Current = $DebugLevel;
+ $DebugLevel = $NextDebugLevel;
+ $NextDebugLevel = $Current;
+
+ Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
+
+}
+
=head2 ChildProcess
This sub implements a child process for a single lonc daemon.
@@ -1318,14 +1469,22 @@ This sub implements a child process for
sub ChildProcess {
- # For now turn off signals.
-
- $SIG{QUIT} = \&SignalledToDeath;
- $SIG{HUP} = IGNORE;
- $SIG{USR1} = IGNORE;
- $SIG{INT} = DEFAULT;
- $SIG{CHLD} = IGNORE;
- $SIG{__DIE__} = \&SignalledToDeath;
+ #
+ # Signals must be handled by the Event framework...
+#
+
+ Event->signal(signal => "QUIT",
+ cb => \&SignalledToDeath,
+ data => "QUIT");
+ Event->signal(signal => "HUP",
+ cb => \&ChildStatus,
+ data => "HUP");
+ Event->signal(signal => "USR1",
+ cb => \&ChildStatus,
+ data => "USR1");
+ Event->signal(signal => "INT",
+ cb => \&ToggleDebug,
+ data => "INT");
SetupTimer();
@@ -1337,7 +1496,7 @@ sub ChildProcess {
# Setup the initial server connection:
- # &MakeLondConnection(); // let first work requirest do it.
+ # &MakeLondConnection(); // let first work requirest do� it.
Debug(9,"Entering event loop");
@@ -1355,14 +1514,15 @@ sub CreateChild {
my $host = shift;
$RemoteHost = $host;
Log("CRITICAL", "Forking server for ".$host);
- $pid = fork;
+ my $pid = fork;
if($pid) { # Parent
+ $RemoteHost = "Parent";
$ChildHash{$pid} = $RemoteHost;
sigprocmask(SIG_UNBLOCK, $sigset);
} else { # child.
ShowStatus("Connected to ".$RemoteHost);
- $SIG{INT} = DEFAULT;
+ $SIG{INT} = 'DEFAULT';
sigprocmask(SIG_UNBLOCK, $sigset);
ChildProcess; # Does not return.
}
@@ -1399,11 +1559,13 @@ if ($childpid != 0) {
#
ShowStatus("Parent writing pid file:");
-$execdir = $perlvar{'lonDaemons'};
+my $execdir = $perlvar{'lonDaemons'};
open (PIDSAVE, ">$execdir/logs/lonc.pid");
print PIDSAVE "$$\n";
close(PIDSAVE);
+
+
if (POSIX::setsid() < 0) {
print "Could not create new session\n";
exit -1;
@@ -1416,7 +1578,7 @@ Log("CRITICAL", "--------------- Startin
my $HostIterator = LondConnection::GetHostIterator;
while (! $HostIterator->end()) {
- $hostentryref = $HostIterator->get();
+ my $hostentryref = $HostIterator->get();
CreateChild($hostentryref->[0]);
$HostIterator->next();
}
@@ -1430,14 +1592,15 @@ ShowStatus("Parent keeping the flock");
# Set up parent signals:
#
-$SIG{INT} = \&KillThemAll;
-$SIG{TERM} = \&KillThemAll;
+$SIG{INT} = \&Terminate;
+$SIG{TERM} = \&Terminate;
$SIG{HUP} = \&Restart;
+$SIG{USR1} = \&CheckKids;
while(1) {
- $deadchild = wait();
+ my $deadchild = wait();
if(exists $ChildHash{$deadchild}) { # need to restart.
- $deadhost = $ChildHash{$deadchild};
+ my $deadhost = $ChildHash{$deadchild};
delete($ChildHash{$deadchild});
Log("WARNING","Lost child pid= ".$deadchild.
"Connected to host ".$deadhost);
@@ -1446,6 +1609,34 @@ while(1) {
}
}
+
+
+=pod
+
+=head1 CheckKids
+
+ Since kids do not die as easily in this implementation
+as the previous one, there is no need to restart the
+dead ones (all dead kids get restarted when they die!!)
+The only thing this function does is to pass USR1 to the
+kids so that they report their status.
+
+=cut
+
+sub CheckKids {
+ Debug(2, "Checking status of children");
+ my $docdir = $perlvar{'lonDocRoot'};
+ my $fh = IO::File->new(">$docdir/lon-status/loncstatus.txt");
+ my $now=time;
+ my $local=localtime($now);
+ print $fh "LONC status $local - parent $$ \n\n";
+ foreach my $pid (keys %ChildHash) {
+ Debug(2, "Sending USR1 -> $pid");
+ kill 'USR1' => $pid; # Tell Child to report status.
+ sleep 1; # Wait so file doesn't intermix.
+ }
+}
+
=pod
=head1 Restart
@@ -1457,7 +1648,7 @@ the config file.
=cut
sub Restart {
- KillThemAll; # First kill all the children.
+ &KillThemAll; # First kill all the children.
Log("CRITICAL", "Restarting");
my $execdir = $perlvar{'lonDaemons'};
unlink("$execdir/logs/lonc.pid");
@@ -1469,26 +1660,42 @@ sub Restart {
=head1 KillThemAll
Signal handler that kills all children by sending them a
-SIGINT. Responds to sigint and sigterm.
+SIGHUP. Responds to sigint and sigterm.
=cut
sub KillThemAll {
Debug(2, "Kill them all!!");
local($SIG{CHLD}) = 'IGNORE'; # Our children >will< die.
- foreach $pid (keys %ChildHash) {
+ foreach my $pid (keys %ChildHash) {
my $serving = $ChildHash{$pid};
Debug(2, "Killing lonc for $serving pid = $pid");
ShowStatus("Killing lonc for $serving pid = $pid");
Log("CRITICAL", "Killing lonc for $serving pid = $pid");
- kill('INT', $pid);
+ kill 'QUIT' => $pid;
+ delete($ChildHash{$pid});
}
- Log("CRITICAL", "Killing the master process.");
- exit
+ my $execdir = $perlvar{'lonDaemons'};
+ unlink("$execdir/logs/lonc.pid");
+
}
=pod
+=head1 Terminate
+
+Terminate the system.
+
+=cut
+
+sub Terminate {
+ KillThemAll;
+ Log("CRITICAL","Master process exiting");
+ exit 0;
+
+}
+=pod
+
=head1 Theory
The event class is used to build this as a single process with an