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Added ability to parse the hosts.tab file including added stuff for the
adaptively connecting lonc.  See sub read_hosts(file).  Returns a
reference to a hash that is stocked with references to arrays containing
the configuration parameters for each host... question for all?
Should the hash contain references to hashes so the parameters can be
looked up by name rather than array index? What's preferred?

    1: # The LearningOnline Network with CAPA
    2: # Configuration file reader
    3: #
    4: # $Id: Configuration.pm,v 1.9 2003/04/09 00:52:37 foxr Exp $
    5: #
    6: #
    7: # Copyright Michigan State University Board of Trustees
    8: #
    9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
   10: #
   11: # LON-CAPA is free software; you can redistribute it and/or modify
   12: # it under the terms of the GNU General Public License as published by
   13: # the Free Software Foundation; either version 2 of the License, or
   14: # (at your option) any later version.
   15: #
   16: # LON-CAPA is distributed in the hope that it will be useful,
   17: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   18: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   19: # GNU General Public License for more details.
   20: #
   21: # You should have received a copy of the GNU General Public License
   22: # along with LON-CAPA; if not, write to the Free Software
   23: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   24: #
   25: # /home/httpd/html/adm/gpl.txt
   26: #
   27: # http://www.lon-capa.org/
   28: #
   29: # YEAR=2002
   30: #
   31: ###
   32: 
   33: # POD documentation is at the end of this short module.
   34: 
   35: package LONCAPA::Configuration;
   36: 
   37: $VERSION = sprintf("%d.%02d", q$Revision: 1.9 $ =~ /(\d+)\.(\d+)/);
   38: 
   39: use strict;
   40: 
   41: my $confdir='/etc/httpd/conf/';
   42: 
   43: # ------------------- Subroutine read_conf: read LON-CAPA server configuration.
   44: # This subroutine reads PerlSetVar values out of specified web server
   45: # configuration files.
   46: sub read_conf
   47:   {
   48:     my (@conf_files)=@_;
   49:     my %perlvar;
   50:     foreach my $filename (@conf_files,'loncapa_apache.conf')
   51:       {
   52: 	open(CONFIG,'<'.$confdir.$filename) or
   53: 	    die("Can't read $confdir$filename");
   54: 	while (my $configline=<CONFIG>)
   55: 	  {
   56: 	    if ($configline =~ /^[^\#]*PerlSetVar/)
   57: 	      {
   58: 		my ($unused,$varname,$varvalue)=split(/\s+/,$configline);
   59: 		chomp($varvalue);
   60: 		$perlvar{$varname}=$varvalue;
   61: 	      }
   62: 	  }
   63: 	close(CONFIG);
   64:       }
   65:     my $perlvarref=\%perlvar;
   66:     return ($perlvarref);
   67:   }
   68: 
   69: #---------------------- Subroutine read_hosts: Read a LON-CAPA hosts.tab
   70: # formatted configuration file.
   71: #
   72: my $RequiredCount = 5;		# Required item count in hosts.tab.
   73: my $DefaultMaxCon = 5;		# Default value for maximum connections.
   74: my $DefaultIdle   = 1000;       # Default connection idle time in seconds.
   75: my $DefaultMinCon = 0;          # Default value for minimum connections.
   76: sub read_hosts {
   77:     my $Filename = shift;
   78:     my %HostsTab;
   79:     
   80:     open(CONFIG,'<'.$Filename) or die("Can't read $Filename");
   81:     while (my $line = <CONFIG>) {
   82: 	my @items = split(/:/, $line);
   83: 	if (scalar @items == $RequiredCount) {	# Have only all required items:
   84: 	    $items[$RequiredCount] = $DefaultMaxCon;
   85: 	}
   86: 	if(scalar @items == $RequiredCount + 1) { # Have up through maxcon.
   87: 	    $items[$RequiredCount+1] = $DefaultIdle;
   88: 	}
   89: 	if(scalar @items == $RequiredCount + 2) { # Have up through idle.
   90: 	    $items[$RequiredCount+2] = $DefaultMinCon;
   91: 	}
   92: 	{
   93: 	    my @list = @items;	# probably not needed but I'm unsure of 
   94: 				# about the scope of item so...
   95: 	    $HostsTab{@list[0]} = \@list; 
   96: 	}
   97:     }
   98:     close(CONFIG);
   99:     my $hostref = \%HostsTab;
  100:     return ($hostref);
  101: }
  102: 
  103: 1;
  104: __END__
  105: 
  106: =pod
  107: 
  108: =head1 NAME
  109: 
  110: B<LONCAPA::Configuration> - configuration file reader
  111: 
  112: =head1 SYNOPSIS
  113: 
  114:  use lib '/home/httpd/lib/perl/';
  115:  use LONCAPA::Configuration;
  116: 
  117:  LONCAPA::Configuration::read_conf('loncapa.conf');
  118:  LONCAPA::Configuration::read_hosts(filename);
  119: 
  120: =head1 DESCRIPTION
  121: 
  122: Many different parts of the LON-CAPA software need to reads in the
  123: machine-specific configuration information.  These included scripts
  124: controlling the TCP/IP layer (e.g. F<lonc> and F<lond>), testing scripts
  125: (e.g. test_weblayer.pl and sqltest.pl), and utility scripts
  126: (e.g. clusterstatus.pl and metadata_keywords.pl).
  127: 
  128: The following methods are available:
  129: 
  130: =over 4
  131: 
  132: =item $perlvarref = LONCAPA::Configuration::read_conf( @filename_list );
  133: 
  134: On a typical LON-CAPA server, the filename list argument will consist of
  135: just one element, "loncapa.conf".
  136: 
  137: If there are multiple elements within the filename list, then these
  138: filenames are processed consecutively.
  139: 
  140: A hash reference is returned and consists of those values which
  141: have been initialized from the configuration filenames indicated
  142: in the arguments.
  143: 
  144: If multiple file names define the same hash key, then priority is
  145: given toward the B<last> file name processed.
  146: 
  147: =back
  148: 
  149: =over 4
  150: =item $hostinfo = LONCAPA::Configuration::read_hosts(filename);
  151: 
  152:   The parameter is the name of a file in hosts.tab form.  The file is read and
  153: parsed.  The return value is a reference to a hash.   The hash is indexed by
  154: host and each element of the has is in turn a reference to an anonymous list
  155: containing:
  156: 
  157: =over 4
  158: =item host
  159:    The loncapa hostname of the system. (This may be different than the 
  160:    network hostname, see below).
  161: =item domain
  162:    The loncapa domain in which the host lives.
  163: =item role
  164:     The role of the system, currently allowed values are access for an
  165:     access server and library for a library server.
  166: =item dns
  167:     The DNS hostname of the system. 
  168: =item ip
  169:     The IP address corresponding to the dns hostname of the system.
  170: =item maxconn 
  171:     The maximum number of connections this system should hold to the
  172:     target system's lond.  If the file has no value, a default is supplied
  173:     here by the function.
  174: =item idle
  175:     The number of seconds the oldest idle connection can be idle before it
  176:     should be adaptively dropped.  If the file has no value, a default
  177:     is supplied by the function.
  178: =item mincon
  179:     The minimum number of connections this system should hold to the
  180:     target system's lond.  If the file has no value, a default is supplied by
  181:     the funciton.
  182: 
  183: =back
  184: 
  185: =back
  186: 
  187: 
  188: 
  189: =head1 AUTHORS
  190: 
  191: This library is free software; you can redistribute it and/or
  192: modify it under the same terms as LON-CAPA itself.
  193: 
  194: =cut