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Diff for /loncom/loncnew between versions 1.12 and 1.20

version 1.12, 2003/07/02 01:12:35	version 1.20, 2003/08/25 18:48:11
Line 7	Line 7
# Copyright Michigan State University Board of Trustees	# Copyright Michigan State University Board of Trustees
#	#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).	# 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	# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or	# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.	# (at your option) any later version.
Line 27	Line 26
# http://www.lon-capa.org/	# 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.	# This module is based on the Event class.
# Development iterations:	# Development iterations:
# - Setup basic event loop. (done)	# - Setup basic event loop. (done)
Line 46	Line 45

# Change log:	# Change log:
# $Log$	# $Log$
# Revision 1.12 2003/07/02 01:12:35 foxr	# Revision 1.20 2003/08/25 18:48:11 albertel
# - Add some debugging to killthemall	# - fixing a forgotten ;
# - Add better error handling to LondReadable	#
# - Remove tick logging in the timer handler.	# 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).
#	#
# Revision 1.11 2003/06/25 01:54:44 foxr	# Revision 1.11 2003/06/25 01:54:44 foxr
# Fix more problems with transaction failure.	# Fix more problems with transaction failure.
Line 95 use LONCAPA::HashIterator;	Line 122 use LONCAPA::HashIterator;
#	#
# Disable all signals we might receive from outside for now.	# Disable all signals we might receive from outside for now.
#	#
$SIG{QUIT} = IGNORE;	#$SIG{QUIT} = IGNORE;
$SIG{HUP} = IGNORE;	#$SIG{HUP} = IGNORE;
$SIG{USR1} = IGNORE;	#$SIG{USR1} = IGNORE;
$SIG{INT} = IGNORE;	#$SIG{INT} = IGNORE;
$SIG{CHLD} = IGNORE;	#$SIG{CHLD} = IGNORE;
$SIG{__DIE__} = IGNORE;	#$SIG{__DIE__} = IGNORE;


# Read the httpd configuration file to get perl variables	# Read the httpd configuration file to get perl variables
Line 119 my $MaxConnectionCount = 10; # Will get	Line 146 my $MaxConnectionCount = 10; # Will get
my $ClientConnection = 0; # Uniquifier for client events.	my $ClientConnection = 0; # Uniquifier for client events.

my $DebugLevel = 0;	my $DebugLevel = 0;
	my $NextDebugLevel= 10; # So Sigint can toggle this.
my $IdleTimeout= 3600; # Wait an hour before pruning connections.	my $IdleTimeout= 3600; # Wait an hour before pruning connections.

#	#
# The variables below are only used by the child processes.	# The variables below are only used by the child processes.
#	#
my $RemoteHost; # Name of host child is talking to.	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 $IdleConnections = Stack->new(); # Set of idle connections
my %ActiveConnections; # Connections to the remote lond.	my %ActiveConnections; # Connections to the remote lond.
my %ActiveTransactions; # LondTransactions in flight.	my %ActiveTransactions; # LondTransactions in flight.
Line 134 my $WorkQueue = Queue->new(); # Qu	Line 162 my $WorkQueue = Queue->new(); # Qu
my $ConnectionCount = 0;	my $ConnectionCount = 0;
my $IdleSeconds = 0; # Number of seconds idle.	my $IdleSeconds = 0; # Number of seconds idle.
my $Status = ""; # Current status string.	my $Status = ""; # Current status string.
	my $RecentLogEntry = "";
my $ConnectionRetries=5; # Number of connection retries allowed.	my $ConnectionRetries=5; # Number of connection retries allowed.
my $ConnectionRetriesLeft=5; # Number of connection retries remaining.	my $ConnectionRetriesLeft=5; # Number of connection retries remaining.

Line 210 sub Log {	Line 239 sub Log {
my $execdir = $perlvar{'lonDaemons'};	my $execdir = $perlvar{'lonDaemons'};
my $fh = IO::File->new(">>$execdir/logs/lonc.log");	my $fh = IO::File->new(">>$execdir/logs/lonc.log");
my $msg = sprintf($finalformat, $message);	my $msg = sprintf($finalformat, $message);
	$RecentLogEntry = $msg;
print $fh $msg;	print $fh $msg;


Line 253 sub Debug {	Line 283 sub Debug {
my $level = shift;	my $level = shift;
my $message = shift;	my $message = shift;
if ($level <= $DebugLevel) {	if ($level <= $DebugLevel) {
print $message." host = ".$RemoteHost."\n";	Log("INFO", "-Debug- $message host = $RemotHost");
}	}
}	}

Line 283 sub ShowStatus {	Line 313 sub ShowStatus {

=pod	=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);
	}

	=pod

=head2 Tick	=head2 Tick

Invoked each timer tick.	Invoked each timer tick.
Line 307 sub Tick {	Line 352 sub Tick {
} else {	} else {
$IdleSeconds = 0; # Reset idle count if not idle.	$IdleSeconds = 0; # Reset idle count if not idle.
}	}
	#
	# For each inflight transaction, tick down its timeout counter.
	#
	foreach $item (keys %ActiveTransactions) {
	my $Socket = $ActiveTransactions{$item}->getServer();
	$Socket->Tick();
	}
# Do we have work in the queue, but no connections to service them?	# 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.	# If so, try to make some new connections to get things going again.
#	#
Line 445 sub ClientWritable {	Line 496 sub ClientWritable {

} else { # Partial string sent.	} else { # Partial string sent.
$Watcher->data(substr($Data, $result));	$Watcher->data(substr($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...	} else { # Error of some sort...
Line 562 Parameters:	Line 619 Parameters:

sub FailTransaction {	sub FailTransaction {
my $transaction = shift;	my $transaction = shift;
	Log("WARNING", "Failing transaction ".$transaction->getRequest());
Debug(1, "Failing transaction: ".$transaction->getRequest());	Debug(1, "Failing transaction: ".$transaction->getRequest());
if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.	if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
my $client = $transaction->getClient();	my $client = $transaction->getClient();
Line 624 nonzero if we are allowed to create a ne	Line 682 nonzero if we are allowed to create a ne
sub KillSocket {	sub KillSocket {
my $Socket = shift;	my $Socket = shift;

	Log("WARNING", "Shutting down a socket");
$Socket->Shutdown();	$Socket->Shutdown();

# If the socket came from the active connection set,	# If the socket came from the active connection set,
Line 720 sub LondReadable {	Line 779 sub LondReadable {

SocketDump(6, $Socket);	SocketDump(6, $Socket);
my $status = $Socket->Readable();	my $status = $Socket->Readable();

&Debug(2, "Socket->Readable returned: $status");	&Debug(2, "Socket->Readable returned: $status");

if($status != 0) {	if($status != 0) {
# bad return from socket read. Currently this means that	# bad return from socket read. Currently this means that
# The socket has become disconnected. We fail the transaction.	# The socket has become disconnected. We fail the transaction.

	Log("WARNING",
	"Lond connection lost.");
if(exists($ActiveTransactions{$Socket})) {	if(exists($ActiveTransactions{$Socket})) {
Debug(3,"Lond connection lost failing transaction");
FailTransaction($ActiveTransactions{$Socket});	FailTransaction($ActiveTransactions{$Socket});
}	}
$Watcher->cancel();	$Watcher->cancel();
Line 877 sub LondWritable {	Line 938 sub LondWritable {
# We'll treat this as if the socket got disconnected:	# We'll treat this as if the socket got disconnected:
Log("WARNING", "Connection to ".$RemoteHost.	Log("WARNING", "Connection to ".$RemoteHost.
" has been disconnected");	" has been disconnected");
	FailTransaction($ActiveTransactions{$Socket});
$Watcher->cancel();	$Watcher->cancel();
KillSocket($Socket);	KillSocket($Socket);
return;	return;
Line 1132 sub QueueTransaction {	Line 1194 sub QueueTransaction {
$WorkQueue->enqueue($requestData);	$WorkQueue->enqueue($requestData);
if($ConnectionCount < $MaxConnectionCount) {	if($ConnectionCount < $MaxConnectionCount) {
Debug(4,"Starting additional lond connection");	Debug(4,"Starting additional lond connection");
MakeLondConnection();	if(MakeLondConnection() == 0) {
	EmptyQueue(); # Fail transactions, can't make connection.
	}
}	}
} else { # Can start the request:	} else { # Can start the request:
Debug(8,"Can start...");	Debug(8,"Can start...");
Line 1290 sub SetupLoncListener {	Line 1354 sub SetupLoncListener {
fd => $socket);	fd => $socket);
}	}

	=pod

	=head2 ChildStatus

	Child USR1 signal handler to report the most recent status
	into the status file.

	=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";
	}

=pod	=pod

=head2 SignalledToDeath	=head2 SignalledToDeath
Line 1300 Called in response to a signal that caus	Line 1383 Called in response to a signal that caus


sub SignalledToDeath {	sub SignalledToDeath {
Debug(2,"Signalled to death!");	my $event = shift;
my ($signal) = @_;	my $watcher= $event->w;

	Debug(2,"Signalled to death! via ".$watcher->data);
	my ($signal) = $watcher->data;
chomp($signal);	chomp($signal);
Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "	Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
."died through "."\"$signal\"");	."died through "."\"$signal\"");
LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "	LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
."\"$signal\"");	."\"$signal\"");
die("Signal abnormal end");
exit 0;	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	=head2 ChildProcess

This sub implements a child process for a single lonc daemon.	This sub implements a child process for a single lonc daemon.
Line 1320 This sub implements a child process for	Line 1421 This sub implements a child process for
sub ChildProcess {	sub ChildProcess {


# For now turn off signals.	#
	# Signals must be handled by the Event framework...
$SIG{QUIT} = \&SignalledToDeath;	#
$SIG{HUP} = IGNORE;
$SIG{USR1} = IGNORE;	Event->signal(signal => "QUIT",
$SIG{INT} = DEFAULT;	cb => \&SignalledToDeath,
$SIG{CHLD} = IGNORE;	data => "QUIT");
$SIG{__DIE__} = \&SignalledToDeath;	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();	SetupTimer();

Line 1339 sub ChildProcess {	Line 1448 sub ChildProcess {

# Setup the initial server connection:	# Setup the initial server connection:

# &MakeLondConnection(); // let first work requirest do it.	# &MakeLondConnection(); // let first work requirest do it.


Debug(9,"Entering event loop");	Debug(9,"Entering event loop");
Line 1359 sub CreateChild {	Line 1468 sub CreateChild {
Log("CRITICAL", "Forking server for ".$host);	Log("CRITICAL", "Forking server for ".$host);
$pid = fork;	$pid = fork;
if($pid) { # Parent	if($pid) { # Parent
	$RemoteHost = "Parent";
$ChildHash{$pid} = $RemoteHost;	$ChildHash{$pid} = $RemoteHost;
sigprocmask(SIG_UNBLOCK, $sigset);	sigprocmask(SIG_UNBLOCK, $sigset);

Line 1406 open (PIDSAVE, ">$execdir/logs/lonc.pid"	Line 1516 open (PIDSAVE, ">$execdir/logs/lonc.pid"
print PIDSAVE "$$\n";	print PIDSAVE "$$\n";
close(PIDSAVE);	close(PIDSAVE);



if (POSIX::setsid() < 0) {	if (POSIX::setsid() < 0) {
print "Could not create new session\n";	print "Could not create new session\n";
exit -1;	exit -1;
Line 1432 ShowStatus("Parent keeping the flock");	Line 1544 ShowStatus("Parent keeping the flock");
# Set up parent signals:	# Set up parent signals:
#	#

$SIG{INT} = \&KillThemAll;	$SIG{INT} = \&Terminate;
$SIG{TERM} = \&KillThemAll;	$SIG{TERM} = \&Terminate;
	$SIG{HUP} = \&Restart;
	$SIG{USR1} = \&CheckKids;

while(1) {	while(1) {
$deadchild = wait();	$deadchild = wait();
Line 1448 while(1) {	Line 1561 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 $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

	Signal handler for HUP... all children are killed and
	we self restart. This is an el-cheapo way to re read
	the config file.

	=cut

	sub Restart {
	KillThemAll; # First kill all the children.
	Log("CRITICAL", "Restarting");
	my $execdir = $perlvar{'lonDaemons'};
	unlink("$execdir/logs/lonc.pid");
	exec("$execdir/lonc");
	}

=pod	=pod

=head1 KillThemAll	=head1 KillThemAll

Signal handler that kills all children by sending them a	Signal handler that kills all children by sending them a
SIGINT. Responds to sigint and sigterm.	SIGHUP. Responds to sigint and sigterm.

=cut	=cut

Line 1465 sub KillThemAll {	Line 1624 sub KillThemAll {
Debug(2, "Killing lonc for $serving pid = $pid");	Debug(2, "Killing lonc for $serving pid = $pid");
ShowStatus("Killing lonc for $serving pid = $pid");	ShowStatus("Killing lonc for $serving pid = $pid");
Log("CRITICAL", "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.");	my $execdir = $perlvar{'lonDaemons'};
exit	unlink("$execdir/logs/lonc.pid");

}	}

=pod	=pod

	=head1 Terminate

	Terminate the system.

	=cut

	sub Terminate {
	KillThemAll;
	Log("CRITICAL","Master process exiting");
	exit 0;

	}
	=pod

=head1 Theory	=head1 Theory

The event class is used to build this as a single process with an	The event class is used to build this as a single process with an

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Removed from v.1.12
changed lines
	Added in v.1.20