--- loncom/auth/migrateuser.pm	2018/11/28 05:05:30	1.36
+++ loncom/auth/migrateuser.pm	2018/12/02 14:41:19	1.37
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Starts a user off based of an existing token.
 #
-# $Id: migrateuser.pm,v 1.36 2018/11/28 05:05:30 raeburn Exp $
+# $Id: migrateuser.pm,v 1.37 2018/12/02 14:41:19 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -33,9 +33,11 @@ use LONCAPA qw(:DEFAULT :match);
 use Apache::Constants qw(:common :http :methods);
 use Apache::lonauth;
 use Apache::lonnet;
+use Apache::loncommon;
 use Apache::lonlocal;
 use Apache::lonlogin();
 use Apache::ltiauth;
+use Apache::switchserver;
 use CGI::Cookie;
 
 sub goto_login {
@@ -118,7 +120,7 @@ sub lti_check {
 }
 
 sub ip_changed {
-    my ($r,$udom,$camefrom,$dataref) = @_;
+    my ($r,$udom,$camefrom,$idsref,$dataref) = @_;
     &Apache::loncommon::content_type($r,'text/html');
     $r->send_http_header;
     if (ref($dataref) eq 'HASH') {
@@ -167,8 +169,10 @@ sub ip_changed {
         my $lonhost= $r->dir_config('lonHostID');
         my $switchto = $lonhost;
         if ($rule_in_effect ne 'offloadedto') {
-            my $hosthere;
-            my @ids=&Apache::lonnet::current_machine_ids();
+            my ($hosthere,@ids);
+            if (ref($idsref) eq 'ARRAY') {
+                @ids=@{$idsref};
+            }
             unless ($rule_in_effect eq 'balancer') {
                 if (grep(/^\Q$rule_in_effect\E$/,@ids)) {
                     $hosthere = 1;
@@ -325,17 +329,41 @@ sub conlost_userhome {
     return unless ((ref($idsref) eq 'ARRAY') && (ref($dataref) eq 'HASH'));
     my @ids = @{$idsref};
     my %data = %{$dataref};
-    my (%conlost,%posstargets);
-    my $lonhost = $r->dir_config('lonHostID');
-    $conlost{$lonhost} = 1;
+    my ($lonhost,$lowest_load,$otherserver,$is_balancer,%conlost,%posstargets);
+    $lonhost = $r->dir_config('lonHostID');
+    if (grep(/^\Q$lonhost\E$/,split(/,/,$data{'dom_balancers'}))) {
+        $is_balancer = 1;
+    }
+    $lowest_load = 30000;
     if ($data{'conlost'} ne '') {
         map { $conlost{$_} = 1; } split(/,/,$data{'conlost'});
     }
-    my ($lowest_load,$otherserver);
-    $lowest_load = 30000;
+    if ($data{'loncfail'}) {
+        if ($is_balancer) {
+            if ($lonhost ne $data{'from_balancer'}) {
+                my ($is_balancer,$posshost,$setcookie,$offloadto,$dom_balancers) =
+                    &Apache::lonnet::check_loadbalancing($data{'username'},$data{'domain'});
+                if ($is_balancer) {
+                    if (ref($offloadto) eq 'HASH') {
+                        $data{'offloadto'} = '';
+                        foreach my $key (keys(%{$offloadto})) {
+                            if (ref($offloadto->{$key}) eq 'ARRAY') {
+                                $data{'offloadto'} .= $key.'='.join(',',@{$offloadto->{$key}}).'&';
+                            }
+                        }
+                        $data{'offloadto'} =~ s/\&$//;
+                    } elsif (ref($offloadto) eq 'ARRAY') {
+                        $data{'offloadto'} = join(',',@{$offloadto});
+                    }
+                }
+            }
+        }
+    } else {
+        $conlost{$lonhost} = 1;
+        $data{'conlost'} = join(',',sort(keys(%conlost)));
+    }
     if ($data{'offloadto'} =~ /\&/) {
-        my @items = split(/\&/,$data{'offloadto'});
-        foreach my $item (@items) {
+        foreach my $item (split(/\&/,$data{'offloadto'})) {
             my ($type,$targets) = split(/\=/,$item);
             @{$posstargets{$type}} = split(/,/,$targets);
         }
@@ -347,8 +375,8 @@ sub conlost_userhome {
     }
     if (ref($posstargets{'primary'}) eq 'ARRAY') {
         foreach my $try_server (@{$posstargets{'primary'}}) {
-            next if (grep(/^\Q$try_server\E$/,@ids));
             next if ($conlost{$try_server});
+            next if ((grep(/^\Q$try_server\E$/,@ids)) && !$data{'loncfail'});
             ($otherserver,$lowest_load) =
                 &Apache::lonnet::compare_server_load($try_server,
                                                      $otherserver,
@@ -359,36 +387,109 @@ sub conlost_userhome {
     if (!$found_server) {
         if (ref($posstargets{'default'}) eq 'ARRAY') {
             foreach my $try_server (@{$posstargets{'default'}}) {
+                next if ($conlost{$try_server});
+                next if ((grep(/^\Q$try_server\E$/,@ids)) && !$data{'loncfail'});
                 ($otherserver,$lowest_load) =
-                &Apache::lonnet::compare_server_load($try_server,
-                                                     $otherserver,
-                                                     $lowest_load);
+                    &Apache::lonnet::compare_server_load($try_server,
+                                                         $otherserver,
+                                                         $lowest_load);
             }
         }
     }
     if ($otherserver ne '') {
         my $switchto = &Apache::lonnet::hostname($otherserver);
         if ($switchto ne '') {
-            my $protocol = $Apache::lonnet::protocol{$switchto};
-            $protocol = 'http' if ($protocol ne 'https');
-            my $url = $protocol.'://'.$switchto.'/adm/login?'.
-                                    'domain='.$env{'user.domain'}.
-                                    '&username='.$env{'user.name'};
-            $data{'conlost'} = join(',',sort(keys(%conlost)));
             $data{'server'} = $lonhost;
+            if ($data{'loncfail'}) {
+                delete($data{'loncfail'});
+            }
             if (grep(/^\Q$otherserver\E$/,split(/,/,$data{'dom_balancers'}))) {
-                $data{'noloadbalance'} = $otherserver; 
+                $data{'noloadbalance'} = $otherserver;
             }
-            my $token = &Apache::lonnet::tmpput(\%data,$otherserver);
-            $url .= '&token='.$token;
-            $r->send_http_header;
-            $r->print(
-                &Apache::loncommon::start_page('Switching Server ...',undef,
-                                               {'redirect'       => [0.1,$url]}).
-                                                &Apache::loncommon::end_page());
+            &do_server_switch($r,$otherserver,$switchto,$is_balancer,\%data);
             return $otherserver;
+        } else {
+            #FIXME Contents of $data{offloadto} contains invalid hostID.
+        }
+    } else {
+        my (%poss_balancers,%tried_balancers);
+        map { $poss_balancers{$_} = 1; } split(/,/,$data{'dom_balancers'});
+        map { $tried_balancers{$_} = 1; } split(/,/,$data{'tried_balancers'});
+        if (keys(%poss_balancers)) {
+            foreach my $try_server (sort(keys(%poss_balancers))) {
+                next if (grep(/^\Q$try_server\E$/,@ids));
+                next if (($data{'loncfail'}) && ($tried_balancers{$try_server}));
+                my $alreadytried;
+                foreach my $key (keys(%posstargets)) {
+                    if ((ref($posstargets{$key}) eq 'ARRAY') &&
+                        (grep(/^\Q$try_server\E$/,@{$posstargets{$key}}))) {
+                        $alreadytried = 1;
+                        last;
+                    }
+                }
+                unless ($alreadytried) {
+                    if (&Apache::lonnet::reply('ping',$try_server) eq $try_server) {
+                        $otherserver = $try_server;
+                        last;
+                    }
+                }
+            }
+        }
+        if ($otherserver ne '') {
+            my $switchto = &Apache::lonnet::hostname($otherserver);
+            if ($switchto ne '') {
+                $data{'server'} = $lonhost;
+                $data{'loncfail'} = $lonhost;
+                $tried_balancers{$otherserver} = 1;
+                $data{'tried_balancers'} = join(',',sort(keys(%tried_balancers)));
+                &do_server_switch($r,$otherserver,$switchto,$is_balancer,\%data);
+                return $otherserver;
+            } else {
+                #FIXME Contents of $data{'dom_balancers'} contains invalid hostID.
+            }  
+        } else {
+            if ($data{'loncfail'}) {
+                #FIXME Nowhere to go. 
+            } else {
+                # FIXME Send back to a balancer (no token); different balancer if this is a balancer.
+                # Send command to balancer to exclude this host using http instead on lonc/lond
+            }
         }
     }
+    return;
+}
+
+sub do_server_switch {
+    my ($r,$otherserver,$switchto,$is_balancer,$dataref) = @_;
+    if (ref($dataref) eq 'HASH') {
+        my $domain = $dataref->{'domain'};
+        my $username = $dataref->{'username'};
+        # If this is a balancer set a balancer cookie unless browser already sent
+        # LON-CAPA load balancer cookie which points at the target server.
+        if ($is_balancer) {
+            my $newcookieid;
+            my ($found_server,$balancer_cookie) = &Apache::lonnet::check_for_balancer_cookie($r,1);
+            unless (($found_server eq $otherserver) &&
+                    ($balancer_cookie =~ /^\Q$domain\E_\Q$username\E_/)) {
+                $newcookieid =
+                    &Apache::switchserver::balancer_cookieid($r,$otherserver,$username,$domain);
+                if ($newcookieid) {
+                    $dataref->{'balcookie'} = $newcookieid;
+                }
+            }
+        }
+        my $token = &Apache::lonnet::tmpput($dataref,$otherserver);
+        my $protocol = $Apache::lonnet::protocol{$otherserver};
+        $protocol = 'http' if ($protocol ne 'https');
+        my $url = $protocol.'://'.$switchto.'/adm/login?domain='.$domain.
+                                 '&username='.$username.'&token='.$token;
+        $r->send_http_header;
+        $r->print(
+        &Apache::loncommon::start_page('Switching Server ...',undef,
+                                       {'redirect'       => [0.1,$url]}).
+        &Apache::loncommon::end_page());
+    }
+    return;
 }
 
 sub log_switch {
@@ -436,24 +537,33 @@ sub handler {
     if (!defined($data{'username'}) || !defined($data{'domain'})) {
         return &goto_login($r,undef,\%data);
     }
+    my ($home,@ids);
+    @ids=&Apache::lonnet::current_machine_ids();
     if ($data{'ip'} ne $ENV{'REMOTE_ADDR'}) {
         &Apache::lonnet::logthis('IP change when session migration requested -- was: '.
                  $data{'ip'}.'; now: '.$ENV{'REMOTE_ADDR'}.' for '.$data{'username'}.':'.$data{'domain'});
-	return &ip_changed($r,$data{'domain'},$data{'server'},\%data);
+	return &ip_changed($r,$data{'domain'},$data{'server'},\@ids,\%data);
     }
-
-    my $home=&Apache::lonnet::homeserver($data{'username'},$data{'domain'});
-    if ($home eq 'no_host') {
-        if (($data{'home'} ne '') && (&Apache::lonnet::hostname($data{'home'}))) {
-            &Apache::lonnet::reconlonc($data{'home'});
-            $home=&Apache::lonnet::homeserver($data{'username'},$data{'domain'});
-            if ($home eq 'no_host') {
-                my @ids=&Apache::lonnet::current_machine_ids();
-                unless (grep(/^\Q$data{'home'}\E$/,@ids)) {
-                    if (&Apache::lonnet::reply('ping',$data{'home'}) eq 'con_lost') {
-                        my $otherserver = &conlost_userhome($r,\@ids,\%data);
-                        if ($otherserver ne '') {
-                            &Apache::lonnet::logthis("No connection to home server ($data{'home'}) for $data{'username'}:$data{'domain'}. Switching to $otherserver");
+    if ($data{'loncfail'}) {
+        &Apache::lonnet::logthis('Returned from '.$data{'server'}.' -- no connection to library node or other access node(s)');
+        my $otherserver = &conlost_userhome($r,\@ids,\%data);
+        if ($otherserver ne '') {
+            &Apache::lonnet::logthis("Switching to $otherserver");
+        }
+        return OK;
+    } else {
+        $home=&Apache::lonnet::homeserver($data{'username'},$data{'domain'});
+        if ($home eq 'no_host') {
+            if (($data{'home'} ne '') && (&Apache::lonnet::hostname($data{'home'}))) {
+                &Apache::lonnet::reconlonc($data{'home'});
+                $home=&Apache::lonnet::homeserver($data{'username'},$data{'domain'});
+                if ($home eq 'no_host') {
+                    unless (grep(/^\Q$data{'home'}\E$/,@ids)) {
+                        if (&Apache::lonnet::reply('ping',$data{'home'}) eq 'con_lost') {
+                            my $otherserver = &conlost_userhome($r,\@ids,\%data);
+                            if ($otherserver ne '') {
+                                &Apache::lonnet::logthis("No connection to home server ($data{'home'}) for $data{'username'}:$data{'domain'}. Switching to $otherserver");
+                            }
                             return OK;
                         }
                     }
@@ -488,6 +598,16 @@ sub handler {
         $extra_env = $lti_env;
     }
 
+    if (($data{'conlost'}) && ($data{'server'})) {
+        my @conlosts = split(/,/,$data{'conlost'});
+        my $switchfrom = $data{'server'};
+        if (@conlosts) {
+            if (grep(/^\Q$switchfrom\E$/,@conlosts)) {
+                &log_switch($r,\%data,$extra_env);
+            }
+        }
+    }
+
     my %form;
     if ($data{'symb'} ne '') {
         $form{'symb'} = $data{'symb'};
@@ -499,16 +619,6 @@ sub handler {
         $form{'noloadbalance'} = $data{'noloadbalance'};
     }
 
-    if (($data{'conlost'}) && ($data{'server'})) {
-        my @conlosts = split(/,/,$data{'conlost'});
-        my $switchfrom = $data{'server'};
-        if (@conlosts) {
-            if (grep(/^\Q$switchfrom\E$/,@conlosts)) {
-                &log_switch($r,\%data,$extra_env);
-            }
-        }
-    }
-
     if (!$data{'role'}) {
 	my $handle = &Apache::lonnet::check_for_valid_session($r);
 	if ($handle) {