--- loncom/loncnew 2003/08/19 09:31:46 1.19
+++ loncom/loncnew 2003/10/07 11:23:03 1.27
@@ -2,7 +2,7 @@
# The LearningOnline Network with CAPA
# lonc maintains the connections to remote computers
#
-# $Id: loncnew,v 1.19 2003/08/19 09:31:46 foxr Exp $
+# $Id: loncnew,v 1.27 2003/10/07 11:23:03 foxr Exp $
#
# Copyright Michigan State University Board of Trustees
#
@@ -45,6 +45,42 @@
# Change log:
# $Log: loncnew,v $
+# Revision 1.27 2003/10/07 11:23:03 foxr
+# Installed and tested code to process reinit in parent server.
+#
+# Revision 1.26 2003/09/30 11:11:17 foxr
+# Add book-keeping hashes to support the re-init procedure.
+#
+# Revision 1.25 2003/09/23 11:22:14 foxr
+# Tested ability to receive sigusr2 This is now logged and must be
+# properly implemented as a re-read of hosts and re-init of appropriate
+# children.
+#
+# Revision 1.24 2003/09/16 09:46:42 foxr
+# Added skeletal infrastructure to support SIGUSR2 update hosts request.
+#
+# 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.
@@ -81,7 +117,7 @@
# 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'
@@ -95,7 +131,7 @@
# complete coding to support deferred transactions.
#
#
-
+use strict;
use lib "/home/httpd/lib/perl/";
use lib "/home/foxr/newloncapa/types";
use Event qw(:DEFAULT );
@@ -119,12 +155,6 @@ 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
@@ -137,6 +167,8 @@ 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.
@@ -150,7 +182,7 @@ my $IdleTimeout= 3600; # Wait an hour b
# The variables below are only used by the child processes.
#
my $RemoteHost; # Name of host child is talking to.
-my $UnixSocketDir= $perlvar{'lonSockDir'}
+my $UnixSocketDir= $perlvar{'lonSockDir'};
my $IdleConnections = Stack->new(); # Set of idle connections
my %ActiveConnections; # Connections to the remote lond.
my %ActiveTransactions; # LondTransactions in flight.
@@ -259,7 +291,7 @@ 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;
@@ -280,7 +312,7 @@ sub Debug {
my $level = shift;
my $message = shift;
if ($level <= $DebugLevel) {
- Log("INFO", "-Debug- $message host = $RemotHost");
+ Log("INFO", "-Debug- $message host = $RemoteHost");
}
}
@@ -320,7 +352,9 @@ sub ShowStatus {
sub SocketTimeout {
my $Socket = shift;
- KillSocket($Socket);
+ KillSocket($Socket); # A transaction timeout also counts as
+ # a connection failure:
+ $ConnectionRetriesLeft--;
}
=pod
@@ -334,8 +368,12 @@ Invoked each timer tick.
sub Tick {
my $client;
- ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount);
-
+ if($ConnectionRetriesLeft > 0) {
+ ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount
+ ." Retries remaining: ".$ConnectionRetriesLeft);
+ } else {
+ ShowStatus(GetServerHost()." >> DEAD <<");
+ }
# Is it time to prune connection count:
@@ -343,7 +381,7 @@ sub Tick {
($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 {
@@ -352,7 +390,7 @@ sub Tick {
#
# For each inflight transaction, tick down its timeout counter.
#
- foreach $item (keys %ActiveTransactions) {
+ foreach my $item (keys %ActiveTransactions) {
my $Socket = $ActiveTransactions{$item}->getServer();
$Socket->Tick();
}
@@ -366,10 +404,16 @@ 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.
}
@@ -421,7 +465,7 @@ 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, $reqdata);
@@ -555,7 +599,7 @@ sub CompleteTransaction {
StartClientReply($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 $Transaction->getFile();
}
}
@@ -623,6 +667,9 @@ sub FailTransaction {
Debug(1," Replying con_lost to ".$transaction->getRequest());
StartClientReply($transaction, "con_lost\n");
}
+ if($ConnectionRetriesLeft <= 0) {
+ Log("CRITICAL", "Host marked dead: ".GetServerHost());
+ }
}
@@ -634,6 +681,7 @@ sub FailTransaction {
=cut
sub EmptyQueue {
+ $ConnectionRetriesLeft--; # Counts as connection failure too.
while($WorkQueue->Count()) {
my $request = $WorkQueue->dequeue(); # This is a transaction
FailTransaction($request);
@@ -648,7 +696,7 @@ Close all connections open on lond prior
=cut
sub CloseAllLondConnections {
- foreach $Socket (keys %ActiveConnections) {
+ foreach my $Socket (keys %ActiveConnections) {
KillSocket($Socket);
}
}
@@ -700,7 +748,7 @@ sub KillSocket {
# work queue, the work all gets failed with con_lost.
#
if($ConnectionCount == 0) {
- EmptyQueue;
+ EmptyQueue();
}
}
@@ -769,7 +817,7 @@ 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.
@@ -790,6 +838,7 @@ sub LondReadable {
}
$Watcher->cancel();
KillSocket($Socket);
+ $ConnectionRetriesLeft--; # Counts as connection failure
return;
}
SocketDump(6,$Socket);
@@ -823,6 +872,10 @@ 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{$Socket})) {
Debug(8,"Completing transaction!!");
@@ -1035,8 +1088,7 @@ sub QueueDelayed {
Debug(4, "Delayed path: ".$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;
@@ -1078,7 +1130,7 @@ sub MakeLondConnection {
$ConnectionRetriesLeft--;
return 0; # Failure.
} else {
- $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
+
# The connection needs to have writability
# monitored in order to send the init sequence
# that starts the whole authentication/key
@@ -1091,8 +1143,9 @@ sub MakeLondConnection {
&Debug(9,"MakeLondConnection got socket: ".$Socket);
}
-
- $event = Event->io(fd => $Socket,
+ $Connection->SetTimeoutCallback(\&SocketTimeout);
+
+ my $event = Event->io(fd => $Socket,
poll => 'w',
cb => \&LondWritable,
data => $Connection,
@@ -1148,7 +1201,7 @@ 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,
@@ -1190,9 +1243,14 @@ sub QueueTransaction {
Debug(8,"Must queue...");
$WorkQueue->enqueue($requestData);
if($ConnectionCount < $MaxConnectionCount) {
- Debug(4,"Starting additional lond connection");
- if(MakeLondConnection() == 0) {
- EmptyQueue(); # Fail transactions, can't make connection.
+ if($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:
@@ -1358,6 +1416,8 @@ sub SetupLoncListener {
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;
@@ -1368,6 +1428,7 @@ sub ChildStatus {
my $fh = IO::File->new(">>$docdir/lon-status/loncstatus.txt");
print $fh $$."\t".$RemoteHost."\t".$Status."\t".
$RecentLogEntry."\n";
+ $ConnectionRetriesLeft = $ConnectionRetries;
}
=pod
@@ -1463,15 +1524,16 @@ sub CreateChild {
my $host = shift;
$RemoteHost = $host;
Log("CRITICAL", "Forking server for ".$host);
- $pid = fork;
+ my $pid = fork;
if($pid) { # Parent
$RemoteHost = "Parent";
- $ChildHash{$pid} = $RemoteHost;
+ $ChildHash{$pid} = $host;
+ $HostToPid{$host}= $pid;
sigprocmask(SIG_UNBLOCK, $sigset);
} else { # child.
ShowStatus("Connected to ".$RemoteHost);
- $SIG{INT} = DEFAULT;
+ $SIG{INT} = 'DEFAULT';
sigprocmask(SIG_UNBLOCK, $sigset);
ChildProcess; # Does not return.
}
@@ -1508,7 +1570,7 @@ if ($childpid != 0) {
#
ShowStatus("Parent writing pid file:");
-$execdir = $perlvar{'lonDaemons'};
+my $execdir = $perlvar{'lonDaemons'};
open (PIDSAVE, ">$execdir/logs/lonc.pid");
print PIDSAVE "$$\n";
close(PIDSAVE);
@@ -1527,8 +1589,9 @@ Log("CRITICAL", "--------------- Startin
my $HostIterator = LondConnection::GetHostIterator;
while (! $HostIterator->end()) {
- $hostentryref = $HostIterator->get();
+ my $hostentryref = $HostIterator->get();
CreateChild($hostentryref->[0]);
+ $HostHash{$hostentryref->[0]} = $hostentryref->[4];
$HostIterator->next();
}
$RemoteHost = "Parent Server";
@@ -1545,11 +1608,13 @@ $SIG{INT} = \&Terminate;
$SIG{TERM} = \&Terminate;
$SIG{HUP} = \&Restart;
$SIG{USR1} = \&CheckKids;
+$SIG{USR2} = \&UpdateKids; # LonManage update request.
while(1) {
- $deadchild = wait();
+ my $deadchild = wait();
if(exists $ChildHash{$deadchild}) { # need to restart.
- $deadhost = $ChildHash{$deadchild};
+ my $deadhost = $ChildHash{$deadchild};
+ delete($HostToPid{$deadhost});
delete($ChildHash{$deadchild});
Log("WARNING","Lost child pid= ".$deadchild.
"Connected to host ".$deadhost);
@@ -1579,7 +1644,7 @@ sub CheckKids {
my $now=time;
my $local=localtime($now);
print $fh "LONC status $local - parent $$ \n\n";
- foreach $pid (keys %ChildHash) {
+ 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.
@@ -1588,6 +1653,114 @@ 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
@@ -1597,7 +1770,7 @@ 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");
@@ -1616,7 +1789,7 @@ SIGHUP. Responds to sigint and sigterm.
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");