--- loncom/loncnew 2003/07/02 01:12:35 1.12
+++ loncom/loncnew 2003/08/03 00:44:31 1.17
@@ -2,13 +2,12 @@
# The LearningOnline Network with CAPA
# lonc maintains the connections to remote computers
#
-# $Id: loncnew,v 1.12 2003/07/02 01:12:35 foxr Exp $
+# $Id: loncnew,v 1.17 2003/08/03 00:44:31 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)
@@ -46,10 +45,28 @@
# Change log:
# $Log: loncnew,v $
-# Revision 1.12 2003/07/02 01:12:35 foxr
-# - Add some debugging to killthemall
-# - Add better error handling to LondReadable
-# - Remove tick logging in the timer handler.
+# 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
# Fix more problems with transaction failure.
@@ -95,12 +112,12 @@ 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
@@ -119,6 +136,7 @@ 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.
#
@@ -134,6 +152,7 @@ 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.
@@ -210,6 +229,7 @@ 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;
@@ -253,7 +273,7 @@ sub Debug {
my $level = shift;
my $message = shift;
if ($level <= $DebugLevel) {
- print $message." host = ".$RemoteHost."\n";
+ Log("INFO", "-Debug- $message host = $RemotHost");
}
}
@@ -283,6 +303,21 @@ 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);
+}
+
+=pod
+
=head2 Tick
Invoked each timer tick.
@@ -307,7 +342,13 @@ sub Tick {
} else {
$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?
# If so, try to make some new connections to get things going again.
#
@@ -445,6 +486,12 @@ 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...
@@ -562,6 +609,7 @@ 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();
@@ -624,6 +672,7 @@ 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,
@@ -720,14 +769,16 @@ sub LondReadable {
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();
@@ -1132,7 +1183,9 @@ sub QueueTransaction {
$WorkQueue->enqueue($requestData);
if($ConnectionCount < $MaxConnectionCount) {
Debug(4,"Starting additional lond connection");
- MakeLondConnection();
+ if(MakeLondConnection() == 0) {
+ EmptyQueue(); # Fail transactions, can't make connection.
+ }
}
} else { # Can start the request:
Debug(8,"Can start...");
@@ -1290,6 +1343,25 @@ sub SetupLoncListener {
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 $$."\t".$RemoteHost."\t".$Status."\t".
+ $RecentLogEntry."\n";
+}
+
=pod
=head2 SignalledToDeath
@@ -1300,17 +1372,35 @@ Called in response to a signal that caus
sub SignalledToDeath {
- Debug(2,"Signalled to death!");
- my ($signal) = @_;
+ my $event = shift;
+ my $watcher= $event->w;
+
+ Debug(2,"Signalled to death! via ".$watcher->data);
+ my ($signal) = $watcher->data;
chomp($signal);
Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
."died through "."\"$signal\"");
LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
."\"$signal\"");
- die("Signal abnormal end");
exit 0;
}
+
+=head2 ToggleDebug
+
+This sub toggles trace debugging on and off.
+
+=cut
+
+sub ToggleDebug {
+ my $Current = $DebugLevel;
+ $DebugLevel = $NextDebugLevel;
+ $NextDebugLevel = $Current;
+
+ Log("SUCCESS", "New debugging level for $RemoteHost now $DebugLevel");
+
+}
+
=head2 ChildProcess
This sub implements a child process for a single lonc daemon.
@@ -1320,14 +1410,22 @@ This sub implements a child process for
sub ChildProcess {
- # For now turn off signals.
-
- $SIG{QUIT} = \&SignalledToDeath;
- $SIG{HUP} = IGNORE;
- $SIG{USR1} = IGNORE;
- $SIG{INT} = DEFAULT;
- $SIG{CHLD} = IGNORE;
- $SIG{__DIE__} = \&SignalledToDeath;
+ #
+ # Signals must be handled by the Event framework...
+#
+
+ Event->signal(signal => "QUIT",
+ cb => \&SignalledToDeath,
+ data => "QUIT");
+ Event->signal(signal => "HUP",
+ cb => \&ChildStatus,
+ data => "HUP");
+ Event->signal(signal => "USR1",
+ cb => \&ChildStatus,
+ data => "USR1");
+ Event->signal(signal => "INT",
+ cb => \&ToggleDebug,
+ data => "INT");
SetupTimer();
@@ -1339,7 +1437,7 @@ sub ChildProcess {
# Setup the initial server connection:
- # &MakeLondConnection(); // let first work requirest do it.
+ # &MakeLondConnection(); // let first work requirest do� it.
Debug(9,"Entering event loop");
@@ -1359,6 +1457,7 @@ sub CreateChild {
Log("CRITICAL", "Forking server for ".$host);
$pid = fork;
if($pid) { # Parent
+ $RemoteHost = "Parent";
$ChildHash{$pid} = $RemoteHost;
sigprocmask(SIG_UNBLOCK, $sigset);
@@ -1406,6 +1505,8 @@ open (PIDSAVE, ">$execdir/logs/lonc.pid"
print PIDSAVE "$$\n";
close(PIDSAVE);
+
+
if (POSIX::setsid() < 0) {
print "Could not create new session\n";
exit -1;
@@ -1432,9 +1533,10 @@ 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();
@@ -1448,12 +1550,58 @@ 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
=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
@@ -1465,14 +1613,30 @@ sub KillThemAll {
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