1package RRDp; 2 3=head1 NAME 4 5RRDp - Attach RRDtool from within a perl script via a set of pipes; 6 7=head1 SYNOPSIS 8 9use B<RRDp> 10 11B<RRDp::start> I<path to RRDtool executable> 12 13B<RRDp::cmd> I<rrdtool commandline> 14 15$answer = B<RRD::read> 16 17$status = B<RRD::end> 18 19B<$RRDp::user>, B<$RRDp::sys>, B<$RRDp::real>, B<$RRDp::error_mode>, B<$RRDp::error> 20 21=head1 DESCRIPTION 22 23With this module you can safely communicate with the RRDtool. 24 25After every B<RRDp::cmd> you have to issue an B<RRDp::read> command to get 26B<RRDtool>s answer to your command. The answer is returned as a pointer, 27in order to speed things up. If the last command did not return any 28data, B<RRDp::read> will return an undefined variable. 29 30If you import the PERFORMANCE variables into your namespace, 31you can access RRDtool's internal performance measurements. 32 33=over 8 34 35=item use B<RRDp> 36 37Load the RRDp::pipe module. 38 39=item B<RRDp::start> I<path to RRDtool executable> 40 41start RRDtool. The argument must be the path to the RRDtool executable 42 43=item B<RRDp::cmd> I<rrdtool commandline> 44 45pass commands on to RRDtool. check the RRDtool documentation for 46more info on the RRDtool commands. 47 48=item $answer = B<RRDp::read> 49 50read RRDtool's response to your command. Note that the $answer variable will 51only contain a pointer to the returned data. The reason for this is, that 52RRDtool can potentially return quite excessive amounts of data 53and we don't want to copy this around in memory. So when you want to 54access the contents of $answer you have to use $$answer which dereferences 55the variable. 56 57=item $status = B<RRDp::end> 58 59terminates RRDtool and returns RRDtool's status ... 60 61=item B<$RRDp::user>, B<$RRDp::sys>, B<$RRDp::real> 62 63these variables will contain totals of the user time, system time and 64real time as seen by RRDtool. User time is the time RRDtool is 65running, System time is the time spend in system calls and real time 66is the total time RRDtool has been running. 67 68The difference between user + system and real is the time spent 69waiting for things like the hard disk and new input from the perl 70script. 71 72=item B<$RRDp::error_mode> and B<$RRDp::error> 73 74If you set the variable $RRDp::error_mode to the value 'catch' before you run RRDp::read a potential 75ERROR message will not cause the program to abort but will be returned in this variable. If no error 76occurs the variable will be empty. 77 78 $RRDp::error_mode = 'catch'; 79 RRDp::cmd qw(info file.rrd); 80 print $RRDp::error if $RRDp::error; 81 82=back 83 84 85=head1 EXAMPLE 86 87 use RRDp; 88 RRDp::start "/usr/local/bin/rrdtool"; 89 RRDp::cmd qw(create demo.rrd --step 100 90 DS:in:GAUGE:100:U:U 91 RRA:AVERAGE:0.5:1:10); 92 $answer = RRDp::read; 93 print $$answer; 94 ($usertime,$systemtime,$realtime) = ($RRDp::user,$RRDp::sys,$RRDp::real); 95 96=head1 SEE ALSO 97 98For more information on how to use RRDtool, check the manpages. 99 100=head1 AUTHOR 101 102Tobias Oetiker <tobi@oetiker.ch> 103 104=cut 105#' this is to make cperl.el happy 106 107use strict; 108use Fcntl; 109use Carp; 110use IO::Handle; 111use IPC::Open2; 112use vars qw($Sequence $RRDpid $VERSION); 113my $Sequence; 114my $RRDpid; 115 116# Prototypes 117 118sub start ($); 119sub cmd (@); 120sub end (); 121sub read (); 122 123$VERSION=1.2030; 124 125sub start ($){ 126 croak "rrdtool is already running" 127 if defined $Sequence; 128 $Sequence = 'S'; 129 my $rrdtool = shift @_; 130 $RRDpid = open2 \*RRDreadHand,\*RRDwriteHand, $rrdtool,"-" 131 or croak "Can't Start rrdtool: $!"; 132 RRDwriteHand->autoflush(); #flush after every write 133 fcntl RRDreadHand, F_SETFL,O_NONBLOCK|O_NDELAY; #make readhandle NON BLOCKING 134 return $RRDpid; 135} 136 137 138sub read () { 139 croak "RRDp::read can only be called after RRDp::cmd" 140 unless $Sequence eq 'C'; 141 $RRDp::error = undef; 142 $Sequence = 'R'; 143 my $inmask = 0; 144 my $srbuf; 145 my $minibuf; 146 my $buffer; 147 my $nfound; 148 my $timeleft; 149 my $ERR = 0; 150 vec($inmask,fileno(RRDreadHand),1) = 1; # setup select mask for Reader 151 while (1) { 152 my $rout; 153 $nfound = select($rout=$inmask,undef,undef,2); 154 if ($nfound == 0 ) { 155 # here, we could do something sensible ... 156 next; 157 } 158 sysread(RRDreadHand,$srbuf,4096); 159 $minibuf .= $srbuf; 160 while ($minibuf =~ s|^(.+?)\n||s) { 161 my $line = $1; 162 # print $line,"\n"; 163 $RRDp::error = undef; 164 if ($line =~ m|^ERROR|) { 165 $RRDp::error_mode eq 'catch' ? $RRDp::error = $line : croak $line; 166 $ERR = 1; 167 } 168 elsif ($line =~ m|^OK u:([\d\.]+) s:([\d\.]+) r:([\d\.]+)|){ 169 ($RRDp::sys,$RRDp::user,$RRDp::real)=($1,$2,$3); 170 return $ERR == 1 ? undef : \$buffer; 171 } else { 172 $buffer .= $line. "\n"; 173 } 174 } 175 } 176} 177 178sub cmd (@){ 179 croak "RRDp::cmd can only be called after RRDp::read or RRDp::start" 180 unless $Sequence eq 'R' or $Sequence eq 'S'; 181 $Sequence = 'C'; 182 my $cmd = join " ", @_; 183 if ($Sequence ne 'S') { 184 } 185 $cmd =~ s/\n/ /gs; 186 $cmd =~ s/\s/ /gs; 187 print RRDwriteHand "$cmd\n"; 188} 189 190sub end (){ 191 croak "RRDp::end can only be called after RRDp::start" 192 unless $Sequence; 193 close RRDwriteHand; 194 close RRDreadHand; 195 $Sequence = undef; 196 waitpid $RRDpid,0; 197 return $? 198} 199 2001; 201