--- loncom/loncnew 2003/09/15 09:24:49 1.23
+++ loncom/loncnew 2003/12/15 23:30:57 1.36
@@ -2,7 +2,7 @@
# The LearningOnline Network with CAPA
# lonc maintains the connections to remote computers
#
-# $Id: loncnew,v 1.23 2003/09/15 09:24:49 foxr Exp $
+# $Id: loncnew,v 1.36 2003/12/15 23:30:57 albertel Exp $
#
# Copyright Michigan State University Board of Trustees
#
@@ -43,83 +43,8 @@
# - Detect transmission timeouts.
#
-# 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).
-#
-# Revision 1.11 2003/06/25 01:54:44 foxr
-# Fix more problems with transaction failure.
-#
-# 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 the client will permanently give up on dead servers.
-#
-# Revision 1.9 2003/06/13 02:38:43 foxr
-# Add logging in 'expected format'
-#
-# Revision 1.8 2003/06/11 02:04:35 foxr
-# Support delayed transactions... this is done uniformly by encapsulating
-# transactions in an object ... a LondTransaction that is implemented by
-# LondTransaction.pm
-#
-# Revision 1.7 2003/06/03 01:59:39 foxr
-# complete coding to support deferred transactions.
-#
-#
use strict;
use lib "/home/httpd/lib/perl/";
-use lib "/home/foxr/newloncapa/types";
use Event qw(:DEFAULT );
use POSIX qw(:signal_h);
use POSIX;
@@ -141,12 +66,6 @@ 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;
# Read the httpd configuration file to get perl variables
@@ -159,13 +78,15 @@ my %perlvar = %{$perlvarref};
# parent and shared variables.
my %ChildHash; # by pid -> host.
+my %HostToPid; # By host -> pid.
+my %HostHash; # by loncapaname -> IP.
my $MaxConnectionCount = 10; # Will get from config later.
my $ClientConnection = 0; # Uniquifier for client events.
my $DebugLevel = 0;
-my $NextDebugLevel= 10; # So Sigint can toggle this.
+my $NextDebugLevel= 2; # So Sigint can toggle this.
my $IdleTimeout= 3600; # Wait an hour before pruning connections.
#
@@ -182,8 +103,8 @@ 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.
+my $ConnectionRetries=2; # Number of connection retries allowed.
+my $ConnectionRetriesLeft=2; # Number of connection retries remaining.
#
# The hash below gives the HTML format for log messages
@@ -289,7 +210,6 @@ sub GetPeername {
return $peerfile;
}
}
-#----------------------------- Timer management ------------------------
=pod
=head2 Debug
@@ -346,6 +266,7 @@ sub SocketTimeout {
# a connection failure:
$ConnectionRetriesLeft--;
}
+#----------------------------- Timer management ------------------------
=pod
@@ -380,9 +301,13 @@ sub Tick {
#
# For each inflight transaction, tick down its timeout counter.
#
- foreach my $item (keys %ActiveTransactions) {
- my $Socket = $ActiveTransactions{$item}->getServer();
- $Socket->Tick();
+
+ foreach my $item (keys %ActiveConnections) {
+ my $State = $ActiveConnections{$item}->data->GetState();
+ if ($State ne 'Idle') {
+ Debug(5,"Ticking Socket $State $item");
+ $ActiveConnections{$item}->data->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.
@@ -393,18 +318,18 @@ sub Tick {
if ($ConnectionRetriesLeft > 0) {
my $Connections = ($Requests <= $MaxConnectionCount) ?
$Requests : $MaxConnectionCount;
- Debug(1,"Work but no connections, start ".$Connections." of them");
+ Debug(5,"Work but no connections, start ".$Connections." of them");
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");
+ Debug(5,"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");
+ Debug(5,"Work in queue, but gave up on connections..flushing\n");
EmptyQueue(); # Connections can't be established.
}
@@ -429,7 +354,7 @@ Trigger disconnections of idle sockets.
sub SetupTimer {
Debug(6, "SetupTimer");
- Event->timer(interval => 1, debug => 1, cb => \&Tick );
+ Event->timer(interval => 1, cb => \&Tick );
}
=pod
@@ -451,19 +376,19 @@ sub ServerToIdle {
my $Socket = shift; # Get the socket.
delete($ActiveTransactions{$Socket}); # Server has no transaction
- &Debug(6, "Server to idle");
+ &Debug(5, "Server to idle");
# If there's work to do, start the transaction:
my $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
- unless($reqdata eq undef) {
- Debug(9, "Queue gave request data: ".$reqdata->getRequest());
+ if ($reqdata ne undef) {
+ Debug(5, "Queue gave request data: ".$reqdata->getRequest());
&StartRequest($Socket, $reqdata);
} else {
# There's no work waiting, so push the server to idle list.
- &Debug(8, "No new work requests, server connection going idle");
+ &Debug(5, "No new work requests, server connection going idle");
$IdleConnections->push($Socket);
}
}
@@ -509,7 +434,7 @@ sub ClientWritable {
# request.
&Debug(9,"Send result is ".$result." Defined: ".defined($result));
- if(defined($result)) {
+ if($result ne undef) {
&Debug(9, "send result was defined");
if($result == length($Data)) { # Entire string sent.
&Debug(9, "ClientWritable data all written");
@@ -580,7 +505,7 @@ The transaction that is being completed.
=cut
sub CompleteTransaction {
- &Debug(6,"Complete transaction");
+ &Debug(5,"Complete transaction");
my $Socket = shift;
my $Transaction = shift;
@@ -619,7 +544,6 @@ sub StartClientReply {
&Debug(8," Reply was: ".$data);
my $Serial = $ActiveClients{$Client};
my $desc = sprintf("Connection to lonc client %d",
-
$Serial);
Event->io(fd => $Client,
poll => "w",
@@ -733,7 +657,7 @@ sub KillSocket {
delete($ActiveConnections{$Socket});
}
$ConnectionCount--;
-
+ if ($ConnectionCount < 0) { $ConnectionCount = 0; }
# If the connection count has gone to zero and there is work in the
# work queue, the work all gets failed with con_lost.
#
@@ -868,7 +792,7 @@ sub LondReadable {
$ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
$Watcher->cancel();
if(exists($ActiveTransactions{$Socket})) {
- Debug(8,"Completing transaction!!");
+ Debug(5,"Completing transaction!!");
CompleteTransaction($Socket,
$ActiveTransactions{$Socket});
} else {
@@ -1115,7 +1039,7 @@ sub MakeLondConnection {
my $Connection = LondConnection->new(&GetServerHost(),
&GetServerPort());
- if($Connection == undef) { # Needs to be more robust later.
+ if($Connection eq undef) { # Needs to be more robust later.
Log("CRITICAL","Failed to make a connection with lond.");
$ConnectionRetriesLeft--;
return 0; # Failure.
@@ -1127,7 +1051,7 @@ sub MakeLondConnection {
# exchange underway.
#
my $Socket = $Connection->GetSocket();
- if($Socket == undef) {
+ if($Socket eq undef) {
die "did not get a socket from the connection";
} else {
&Debug(9,"MakeLondConnection got socket: ".$Socket);
@@ -1230,11 +1154,11 @@ sub QueueTransaction {
my $LondSocket = $IdleConnections->pop();
if(!defined $LondSocket) { # Need to queue request.
- Debug(8,"Must queue...");
+ Debug(5,"Must queue...");
$WorkQueue->enqueue($requestData);
if($ConnectionCount < $MaxConnectionCount) {
if($ConnectionRetriesLeft > 0) {
- Debug(4,"Starting additional lond connection");
+ Debug(5,"Starting additional lond connection");
if(MakeLondConnection() == 0) {
EmptyQueue(); # Fail transactions, can't make connection.
}
@@ -1272,7 +1196,7 @@ sub ClientRequest {
my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
Debug(8, "rcv: data length = ".length($thisread)
." read =".$thisread);
- unless (defined $rv && length($thisread)) {
+ unless (defined $rv && length($thisread)) {
# Likely eof on socket.
Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
close($socket);
@@ -1517,7 +1441,8 @@ sub CreateChild {
my $pid = fork;
if($pid) { # Parent
$RemoteHost = "Parent";
- $ChildHash{$pid} = $RemoteHost;
+ $ChildHash{$pid} = $host;
+ $HostToPid{$host}= $pid;
sigprocmask(SIG_UNBLOCK, $sigset);
} else { # child.
@@ -1575,11 +1500,13 @@ ShowStatus("Forking node servers");
Log("CRITICAL", "--------------- Starting children ---------------");
+LondConnection::ReadConfig; # Read standard config files.
my $HostIterator = LondConnection::GetHostIterator;
while (! $HostIterator->end()) {
my $hostentryref = $HostIterator->get();
CreateChild($hostentryref->[0]);
+ $HostHash{$hostentryref->[0]} = $hostentryref->[4];
$HostIterator->next();
}
$RemoteHost = "Parent Server";
@@ -1596,11 +1523,13 @@ $SIG{INT} = \&Terminate;
$SIG{TERM} = \&Terminate;
$SIG{HUP} = \&Restart;
$SIG{USR1} = \&CheckKids;
+$SIG{USR2} = \&UpdateKids; # LonManage update request.
while(1) {
my $deadchild = wait();
if(exists $ChildHash{$deadchild}) { # need to restart.
my $deadhost = $ChildHash{$deadchild};
+ delete($HostToPid{$deadhost});
delete($ChildHash{$deadchild});
Log("WARNING","Lost child pid= ".$deadchild.
"Connected to host ".$deadhost);
@@ -1639,6 +1568,114 @@ sub CheckKids {
=pod
+=head1 UpdateKids
+
+parent's SIGUSR2 handler. This handler:
+
+=item
+
+Rereads the hosts file.
+
+=item
+
+Kills off (via sigint) children for hosts that have disappeared.
+
+=item
+
+QUITs children for hosts that already exist (this just forces a status display
+and resets the connection retry count for that host.
+
+=item
+
+Starts new children for hosts that have been added to the hosts.tab file since
+the start of the master program and maintains them.
+
+=cut
+
+sub UpdateKids {
+
+ Log("INFO", "Updating connections via SIGUSR2");
+
+ # Just in case we need to kill our own lonc, we wait a few seconds to
+ # give it a chance to receive and relay lond's response to the
+ # re-init command.
+ #
+
+ sleep(2); # Wait a couple of seconds.
+
+ my %hosts; # Indexed by loncapa hostname, value=ip.
+
+ # Need to re-read the host table:
+
+
+ LondConnection::ReadConfig();
+ my $I = LondConnection::GetHostIterator;
+ while (! $I->end()) {
+ my $item = $I->get();
+ $hosts{$item->[0]} = $item->[4];
+ $I->next();
+ }
+
+ # The logic below is written for clarity not for efficiency.
+ # Since I anticipate that this function is only rarely called, that's
+ # appropriate. There are certainly ways to combine the loops below,
+ # and anyone wishing to obscure the logic is welcome to go for it.
+ # Note that we don't re-direct sigchild. Instead we do what's needed
+ # to the data structures that keep track of children to ensure that
+ # when sigchild is honored, no new child is born.
+ #
+
+ # For each existing child; if it's host doesn't exist, kill the child.
+
+ foreach my $child (keys %ChildHash) {
+ my $oldhost = $ChildHash{$child};
+ if (!(exists $hosts{$oldhost})) {
+ Log("CRITICAL", "Killing child for $oldhost host no longer exists");
+ delete $ChildHash{$child};
+ delete $HostToPid{$oldhost};
+ kill 'QUIT' => $child;
+ }
+ }
+ # For each remaining existing child; if it's host's ip has changed,
+ # Restart the child on the new IP.
+
+ foreach my $child (keys %ChildHash) {
+ my $oldhost = $ChildHash{$child};
+ my $oldip = $HostHash{$oldhost};
+ if ($hosts{$oldhost} ne $oldip) {
+
+ # kill the old child.
+
+ Log("CRITICAL", "Killing child for $oldhost host ip has changed...");
+ delete $ChildHash{$child};
+ delete $HostToPid{$oldhost};
+ kill 'QUIT' => $child;
+
+ # Do the book-keeping needed to start a new child on the
+ # new ip.
+
+ $HostHash{$oldhost} = $hosts{$oldhost};
+ CreateChild($oldhost);
+ }
+ }
+ # Finally, for each new host, not in the host hash, create a
+ # enter the host and create a new child.
+ # Force a status display of any existing process.
+
+ foreach my $host (keys %hosts) {
+ if(!(exists $HostHash{$host})) {
+ Log("INFO", "New host $host discovered in hosts.tab...");
+ $HostHash{$host} = $hosts{$host};
+ CreateChild($host);
+ } else {
+ kill 'HUP' => $HostToPid{$host}; # status display.
+ }
+ }
+}
+
+
+=pod
+
=head1 Restart
Signal handler for HUP... all children are killed and
@@ -1652,7 +1689,7 @@ sub Restart {
Log("CRITICAL", "Restarting");
my $execdir = $perlvar{'lonDaemons'};
unlink("$execdir/logs/lonc.pid");
- exec("$execdir/lonc");
+ exec("$execdir/loncnew");
}
=pod