File:  [LON-CAPA] / loncom / lonr
Revision 1.6: download - view: text, annotated - select for diffs
Tue Jun 23 03:01:09 2009 UTC (13 years, 5 months ago) by www
Branches: MAIN
CVS tags: version_2_9_X, version_2_9_99_0, version_2_9_1, version_2_9_0, version_2_8_99_1, version_2_8_99_0, version_2_11_0_RC3, version_2_11_0_RC2, version_2_11_0_RC1, version_2_11_0, version_2_10_X, version_2_10_1, version_2_10_0_RC2, version_2_10_0_RC1, version_2_10_0, loncapaMITrelate_1, language_hyphenation_merge, language_hyphenation, bz6209-base, bz6209, bz2851, PRINT_INCOMPLETE_base, PRINT_INCOMPLETE, HEAD, GCI_3, GCI_2, BZ4492-merge, BZ4492-feature_horizontal_radioresponse, BZ4492-feature_Support_horizontal_radioresponse, BZ4492-Support_horizontal_radioresponse
Paul Rubin's interface to R.

Works now. However, it needs additional Perl libraries, which are currently
commented out. Also, an R-package needs to be installed.

    1: #!/usr/bin/perl
    2: #
    3: # The LearningOnline Network with CAPA
    4: # Connect to R CAS
    5: #
    6: # $Id: lonr,v 1.6 2009/06/23 03:01:09 www Exp $
    7: #
    8: # Copyright Michigan State University Board of Trustees
    9: #
   10: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
   11: #
   12: # LON-CAPA is free software; you can redistribute it and/or modify
   13: # it under the terms of the GNU General Public License as published by
   14: # the Free Software Foundation; either version 2 of the License, or
   15: # (at your option) any later version.
   16: #
   17: # LON-CAPA is distributed in the hope that it will be useful,
   18: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   19: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   20: # GNU General Public License for more details.
   21: #
   22: # You should have received a copy of the GNU General Public License
   23: # along with LON-CAPA; if not, write to the Free Software
   24: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   25: #
   26: # /home/httpd/html/adm/gpl.txt
   27: #
   28: 
   29: # 
   30: # http://www.lon-capa.org/
   31: #
   32: 
   33: use Expect; 
   34: use IO::Select;
   35: use IO::Socket;
   36: use IO::File;
   37: use Symbol;
   38: use POSIX;
   39: use lib '/home/httpd/lib/perl/';
   40: use LONCAPA::Configuration;
   41:  
   42: use strict;
   43: 
   44: # global variables
   45: my $PREFORK                = 5;        # number of children to maintain
   46: my $MAX_CLIENTS_PER_CHILD  = 50;       # number of clients each child should process
   47: my $extra_children         = 0;
   48: my %children               = ();       # keys are current child process IDs
   49: my $children               = 0;        # current number of children
   50: my $status;                            # string for current status
   51: my $pidfile;                           # file containg parent process pid
   52: my $port;                              # path to UNIX socket file
   53: my %perlvar;                           # configuration file info
   54: my $lastlog;                           # last string that was logged
   55: 
   56: use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
   57: 	    $pidfile $port %perlvar $lastlog);
   58:  
   59: # ------------------------------------------------------------ Service routines 
   60: sub REAPER {                        # takes care of dead children 
   61:                                     # and R processes
   62:     $SIG{CHLD} = \&REAPER;
   63:     my $pid = wait;
   64:     if (exists($children{$pid})) {
   65: 	$children--;
   66: 	delete($children{$pid});
   67: 	if ($extra_children) {
   68: 	    $extra_children--;
   69: 	}
   70:     }    
   71: }
   72:  
   73: sub HUNTSMAN {                      # signal handler for SIGINT
   74:     local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
   75:     kill('INT' => keys(%children));
   76:     unlink($pidfile);
   77:     unlink($port);
   78:     &logthis('---- Shutdown ----');
   79:     exit;                           # clean up with dignity
   80: }
   81: 
   82: 
   83:  
   84: # --------------------------------------------------------------------- Logging
   85:  
   86: sub logthis {
   87:     my ($message)=@_;
   88:     my $execdir=$perlvar{'lonDaemons'};
   89:     my $fh=IO::File->new(">>$execdir/logs/lonr.log");
   90:     my $now=time;
   91:     my $local=localtime($now);
   92:     $lastlog=$local.': '.$message;
   93:     print $fh "$local ($$): $message\n";
   94: }
   95:  
   96: # -------------------------------------------------------------- Status setting
   97:  
   98: sub status {
   99:     my ($what)=@_;
  100:     my $now=time;
  101:     my $local=localtime($now);
  102:     $status=$local.': '.$what;
  103:     $0='lonr: '.$what.' '.$local;
  104: }
  105:  
  106: # -------------------------------------------------------- Escape Special Chars
  107:  
  108: sub escape {
  109:     my ($str)=@_;
  110:     $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
  111:     return $str;
  112: }
  113:  
  114: # ----------------------------------------------------- Un-Escape Special Chars
  115:  
  116: sub unescape {
  117:     my ($str)=@_;
  118:     $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
  119:     return $str;
  120: }
  121:  
  122: # ------------------------ grabs exception and records it to log before exiting
  123: sub catchexception {
  124:     my ($signal)=@_;
  125:     $SIG{QUIT}='DEFAULT';
  126:     $SIG{__DIE__}='DEFAULT';
  127:     chomp($signal);
  128:     &logthis("<font color=\"red\">CRITICAL: "
  129: 	     ."ABNORMAL EXIT. Child $$ died through "
  130: 	     ."\"$signal\"</font>");
  131:     die("Signal abend");
  132: }
  133: 
  134: 
  135: sub child_announce_death {
  136:     $SIG{USR1} = \&child_announce_death;
  137:     if ($extra_children < $PREFORK*10) {
  138: 	$extra_children++;
  139:     }
  140: }
  141: 
  142: # ---------------------------------------------------------------- Main program
  143: # -------------------------------- Set signal handlers to record abnormal exits
  144:  
  145:  
  146: $SIG{'QUIT'}=\&catchexception;
  147: $SIG{__DIE__}=\&catchexception;
  148: $SIG{USR1} = \&child_announce_death;
  149:  
  150: # ---------------------------------- Read loncapa_apache.conf and loncapa.conf
  151: &status("Read loncapa.conf and loncapa_apache.conf");
  152: %perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')};
  153:  
  154: # ----------------------------- Make sure this process is running from user=www
  155: my $wwwid=getpwnam('www');
  156: if ($wwwid!=$<) {
  157:     my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
  158:     my $subj="LON: User ID mismatch";
  159:     system("echo 'User ID mismatch.  lonr must be run as user www.' |\
  160:  mailto $emailto -s '$subj' > /dev/null");
  161:     exit 1;
  162: }
  163:  
  164: # --------------------------------------------- Check if other instance running
  165:  
  166: $pidfile="$perlvar{'lonDaemons'}/logs/lonr.pid";
  167:  
  168: if (-e $pidfile) {
  169:     my $lfh=IO::File->new("$pidfile");
  170:     my $pide=<$lfh>;
  171:     chomp($pide);
  172:     if (kill(0 => $pide)) { die "already running"; }
  173: }
  174: 
  175: # ------------------------------------------------------- Listen to UNIX socket
  176: &status("Opening socket");
  177:  
  178: $port = "$perlvar{'lonSockDir'}/rsock";
  179:  
  180: unlink($port);
  181:  
  182: 
  183: my $server = IO::Socket::UNIX->new(Local  => $port,
  184: 				   Type   => SOCK_STREAM,
  185: 				   Listen => 10 );
  186: if (!$server) {
  187:     my $st=120+int(rand(240));
  188: 
  189:     &logthis("<font color=blue>WARNING: ".
  190: 	     "Can't make server socket ($st secs):  .. exiting</font>");
  191: 
  192:     sleep($st);
  193:     exit;
  194: }
  195:     
  196:  
  197: # ---------------------------------------------------- Fork once and dissociate
  198:  
  199: my $fpid=fork;
  200: exit if $fpid;
  201: die("Couldn't fork: $!") unless defined($fpid);
  202:  
  203: POSIX::setsid() or die "Can't start new session: $!";
  204:  
  205: # ------------------------------------------------------- Write our PID on disk
  206:  
  207: my $execdir=$perlvar{'lonDaemons'};
  208: open(PIDSAVE,">$execdir/logs/lonr.pid");
  209: print PIDSAVE "$$\n";
  210: close(PIDSAVE);
  211: &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
  212: &status('Starting');
  213:      
  214: 
  215: # Install signal handlers.
  216: $SIG{CHLD} = \&REAPER;
  217: $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
  218:  
  219: # Fork off our children.
  220: for (1 .. $PREFORK) {
  221:     &make_new_child($server);
  222: }
  223:  
  224: # And maintain the population.
  225: while (1) {
  226:     &status('Parent process, sleeping');
  227:     sleep;                          # wait for a signal (i.e., child's death)
  228:     for (my $i = $children; $i < $PREFORK+$extra_children; $i++) {
  229:         &status('Parent process, starting child');
  230:         &make_new_child($server);           # top up the child pool
  231:     }
  232: }
  233:                                                                                 
  234: sub make_new_child {
  235:     my ($server) = @_;
  236: 
  237:     # block signal for fork
  238:     my $sigset = POSIX::SigSet->new(SIGINT);
  239:     sigprocmask(SIG_BLOCK, $sigset)
  240:         or die("Can't block SIGINT for fork: $!\n");
  241:      
  242:     die("fork: $!") unless defined(my $pid = fork);
  243:      
  244:     if ($pid) {
  245:         # Parent records the child's birth and returns.
  246:         sigprocmask(SIG_UNBLOCK, $sigset)
  247:             or die("Can't unblock SIGINT for fork: $!\n");
  248:         $children{$pid} = 1;
  249:         $children++;
  250:         return;
  251:     } else {
  252:         # Child can *not* return from this subroutine.
  253:         
  254: 	my $ppid = getppid();
  255:      
  256:         # unblock signals
  257:         sigprocmask(SIG_UNBLOCK, $sigset)
  258:             or die("Can't unblock SIGINT for fork: $!\n");
  259: 
  260:         &logthis('New process started');
  261: 
  262:         my $command=Expect->spawn('R --vanilla');
  263: 	# soft/hard_close can take awhile and we really
  264:         # don't care we just want it gone
  265: 	$SIG{INT} = sub {
  266: 	    my $pid = $command->pid();
  267: 	    kill('KILL'=>$pid);
  268: 	    exit; 
  269: 	};
  270: 
  271: 	$command->log_stdout(0);
  272: #	$command->log_file("$execdir/logs/lonr.session.log");
  273: 
  274:         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
  275:             &status('Accepting connections');
  276:             my $client = $server->accept()     or last;
  277:             &sync($command);
  278:             print $command ("library(phpSerialize);\n");
  279: 	    &getroutput($command);
  280:             &sync($command);
  281:             my $syntaxerr = 0;
  282:             while (my $cmd=<$client>) {
  283:                 &status('Processing command');
  284:                 print $command &unescape($cmd);
  285:                 my ($reply,$syntaxerr) = &getroutput($command);
  286:                 print $client &escape($reply)."\n";
  287:                 if ($syntaxerr) {
  288:                     last;
  289:                 } elsif ($reply=~/^Error\:/) {
  290:                     &logthis('Died through '.$reply);
  291: 		    kill('USR1' => $ppid);
  292:                     $client->close();
  293:                     $command->hard_close();     
  294:                     exit;
  295:                 }
  296: 	        &sync($command);
  297:                 &status('Waiting for commands');
  298:             }
  299:         }
  300: 
  301: 	kill('USR1' => $ppid);
  302: 	print $command ("q();\n");
  303:         # tidy up gracefully and finish
  304: 	sleep(15);
  305:         $command->soft_close();
  306: 
  307:         # this exit is VERY important, otherwise the child will become
  308:         # a producer of more and more children, forking yourself into
  309:         # process death.
  310:         exit;
  311:     }
  312: }
  313: 
  314: {
  315:     my $counter;
  316:     sub sync {
  317: 	my ($command)=@_;
  318: 	$counter++;
  319: 	my $expect=$counter;
  320: 	print $command "$expect;\n";
  321: 	while (1) {
  322: 	    my $output=&getroutput($command);
  323: 	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
  324: 		return;
  325: 	    }
  326: 	}
  327:     }
  328: }
  329: 
  330: sub getroutput {
  331:     my ($command)=@_;
  332:     my $regexp = '>';
  333:     my $syntaxerr=0;
  334:     my $timeout = 20;
  335:     my (undef,$error,$matched,$output) =
  336: 	$command->expect($timeout, -re => $regexp);
  337:     if ($matched eq 'Incorrect syntax:') {
  338: 	$syntaxerr = 1;
  339: 	if (wantarray) {
  340: 	    return ($matched,$syntaxerr);
  341: 	} else {
  342: 	    return $matched;
  343: 	}
  344:     }
  345:     if ($error) {
  346: 	return 'Error: '.$error;
  347:     }
  348: 
  349:     my $foundoutput=0;
  350:     my $found_label=0;
  351:     my $realoutput='';
  352:     foreach my $line (split(/\n/,$output)) {
  353:        $line=~s/\s$//gs;
  354:        if ($line=~/^Error\:/) { $syntaxerr=1; next; }
  355:        if (my ($result)=($line=~/^\[?\d+\,*\]?\s*(.*)/)) { $realoutput.=$result."\n"; }
  356:     }
  357:     if (wantarray) {
  358:         return ($realoutput,$syntaxerr);
  359:     } else {
  360:         return $realoutput;
  361:     }
  362: }

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