Hi Sebastian, the graphv interface outputs the graph in a 'sane' way so that RRDp could capture it if it was enhanced accordingly ...
cheers tobi Today Sebastian Harl wrote: > Hi, > > (This is a follow-up to Debian bug report #251701 [1]. The text also > mentions bug report #182217, which can be found at [2].) > > [1] http://bugs.debian.org/251701 > [2] http://bugs.debian.org/182217 > > On Sun, May 30, 2004 at 01:20:18PM +0200, Robert Lindgren wrote: > > Package: librrdp-perl > > Version: 1.0.46-3 > > Severity: normal > > > > The fix for #182217 looks to break librrdp-perl, when running > > RRDp::cmd "graph - ......" rrdtool doesn't get the the rest of of the > > command and waits forever in: > > > > robert 25577 21.3 0.6 2268 1036 pts/1 S 13:18 0:00 > > /usr/bin/rrdtool - > > r...@zeppelin:/usr/local/nagios/sbin# strace -p 25577 > > read(0, > > > > when - is changed to an image everything works ok. > > > > This is quite bad since it breaks all cgi's trying to make a graph on > > the fly. > > This can be reproduced by using a small script like: > > #! /usr/bin/perl > > use RRDp; > > RRDp::start "/usr/bin/rrdtool"; > > if (! -e "bts#251701.rrd") { > RRDp::cmd 'create bts#251701.rrd --step 300 > DS:ds:GAUGE:600:U:U > RRA:AVERAGE:0.5:1:1200 > RRA:MIN:0.5:12:2400 > RRA:MAX:0.5:12:2400 > RRA:AVERAGE:0.5:12:2400'; > > RRDp::read; > } > > RRDp::cmd 'graph - --imgformat PNG > --end now --start end-3600s --width 400 > DEF:ds=bts#251701.rrd:ds:AVERAGE > LINE1:ds#0000FF:ds\l'; > > my $img = RRDp::read; > # ... > > By now (rrdtool 1.3), the problem is the following: > > RRDp::read() expects the output to be terminated by a line matching > "^OK(<system information>)?". However, when outputting a PNG, the > output is most likely not terminated by a newline, so RRDp::read sits > there waiting for that magic line forever. > > I'm not sure how to properly solve that. We don't get an end-of-file > marker at that point, so we cannot simply wait for that. One possible > way would be to look for "OK ..." at the _end_ of a line. However, since > <system information> is optional, we'd get a "false positive" if the > output includes "OK" at the end of _some_ line, which, I suppose, might > very well happen e.g. when outputting some binary image data. (Btw., > this is already true for "OK" at the beginning of a line which could be > seen as a bug as well.) > > Another way would be to tune the output of the rrdtool server process > and return the status (possibly including the number of bytes in the > following output) before printing the output of the command. Obviously, > this would require to cache all output. Also, this would break all > existing applications that use the rrdtool server. > > Any comments and feedback would be very appreciated. > > Cheers, > Sebastian > > -- Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland http://it.oetiker.ch t...@oetiker.ch ++41 62 775 9902 / sb: -9900 -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
