Annotation of loncom/lonr, revision 1.13

1.1       www         1: #!/usr/bin/perl
                      2: #
                      3: # The LearningOnline Network with CAPA
1.3       www         4: # Connect to R CAS
1.1       www         5: #
1.13    ! raeburn     6: # $Id: lonr,v 1.12 2018/10/29 02:57:30 raeburn Exp $
1.1       www         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 $subj="LON: User ID mismatch";
1.12      raeburn   159:     system("echo 'User ID mismatch.  lonr must be run as user www.' |".
1.13    ! raeburn   160:            " mail -s '$subj' $emailto > /dev/null");
1.1       www       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);
1.5       www       272: #	$command->log_file("$execdir/logs/lonr.session.log");
1.1       www       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);
1.6       www       278:             print $command ("library(phpSerialize);\n");
                    279: 	    &getroutput($command);
                    280:             &sync($command);
1.1       www       281:             my $syntaxerr = 0;
                    282:             while (my $cmd=<$client>) {
                    283:                 &status('Processing command');
                    284:                 print $command &unescape($cmd);
1.2       www       285:                 my ($reply,$syntaxerr) = &getroutput($command);
1.1       www       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++;
1.9       raeburn   319:         my $digits = length($counter);
                    320:         if ($digits > 10) {
1.8       raeburn   321:             $counter = 1;
                    322:         }
1.9       raeburn   323: 	my $expect=$counter;
                    324: 	print $command "print($expect,digits=$digits);\n";
1.1       www       325: 	while (1) {
                    326: 	    my $output=&getroutput($command);
1.8       raeburn   327:             chomp($output);
                    328: 	    if (($output=~/^\Q$expect\E/) || ($output=~/^Error\:/)) {
1.1       www       329: 		return;
                    330: 	    }
                    331: 	}
                    332:     }
                    333: }
                    334: 
                    335: sub getroutput {
                    336:     my ($command)=@_;
1.7       raeburn   337:     my $regexp = '>\s+$';
1.1       www       338:     my $syntaxerr=0;
                    339:     my $timeout = 20;
                    340:     my (undef,$error,$matched,$output) =
                    341: 	$command->expect($timeout, -re => $regexp);
                    342:     if ($matched eq 'Incorrect syntax:') {
                    343: 	$syntaxerr = 1;
                    344: 	if (wantarray) {
                    345: 	    return ($matched,$syntaxerr);
                    346: 	} else {
                    347: 	    return $matched;
                    348: 	}
                    349:     }
                    350:     if ($error) {
                    351: 	return 'Error: '.$error;
                    352:     }
                    353: 
1.11      raeburn   354: #
                    355: # Extract data from lines returned by R:
                    356: #   including: (a) indexed output, e.g., line starts with [1] etc. (index excluded)
                    357: #              (b) support for legacy use of &cas("R") to retreve matrix and data.frame
                    358: #                  i.e., unserialized data, in which lines may begin [1,] or 1
                    359: #                  respectively. The approved method for retrieving these types of
                    360: #                  data is to use &cas_hashref(), which uses phpSerialize() to 
                    361: #                  serialize the output (thereby eliminating the need for the second
                    362: #                  regexp in the "elsif" when looping over the lines of output.
                    363: #   excluding: echo of actual (final) expression originally passed to R excluded by 
                    364: #              checking for trailing semicolon. 
                    365: #
                    366: 
1.1       www       367:     my $realoutput='';
                    368:     foreach my $line (split(/\n/,$output)) {
1.10      raeburn   369:         $line=~s/\s$//gs;
                    370:         if ($line=~/^Error\:/) { $syntaxerr=1; next; }
1.11      raeburn   371:         if (my ($result)=($line=~/^\s*\[\d+\]\s*(.*)/)) {
                    372:             $realoutput.=$result."\n";
                    373:         } elsif (($line !~ /\;$/) && (my ($result)=($line=~/^(?:\[\d+\,\]|\d+)\s*(.*)/))) {
                    374:             $realoutput.=$result."\n";
                    375:         }
1.1       www       376:     }
                    377:     if (wantarray) {
                    378:         return ($realoutput,$syntaxerr);
                    379:     } else {
                    380:         return $realoutput;
                    381:     }
                    382: }

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