Net::Telnet Error handling/trapping
in [Perl]
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From: Chris G. on 5 Feb 2007 16:38 I have a script that reads in a csv files, parses the data, and uses the info to run down a list of IP addresses and make telnet connections to them. I do this to automate the backing up of my Foundry switch configurations. This works great until I have an error. When I have an error at connect time, it catches the error and reports it, just like I want. However, it doesn't recover from the error and never makes any more connections to the other switches, even though it says it does. Here is my (relevant) code: use warnings; use strict; use Net::Telnet; sub GetCF; sub GetCF { my $telnet; $telnet = new Net::Telnet ( Timeout=>10, Host=>$ip, Errmode=>\&uhoh, ); <skipping commands executed after the connection is established> } sub uhoh { if ( $@ ne "") { print ("$@\n"); } else { print "Success\n"; } }
From: Martijn Lievaart on 5 Feb 2007 16:50 On Mon, 05 Feb 2007 13:38:47 -0800, Chris G. wrote: > I have a script that reads in a csv files, parses the data, and uses the > info to run down a list of IP addresses and make telnet connections to > them. I do this to automate the backing up of my Foundry switch > configurations. This works great until I have an error. When I have an > error at connect time, it catches the error and reports it, just like I > want. However, it doesn't recover from the error and never makes any > more connections to the other switches, even though it says it does. I use rancid for this. Actually I use it to backup the configs, but when it's installed, it's a great way to run commands on any of the installed network devices. And obviously parse the results in Perl. And I actually had bad experiences with Net::Telnet to access Cisco routers. It would sometimes just act weird. Never got to the bottom of it though. HTH, M4
From: DJ Stunks on 5 Feb 2007 18:51 On Feb 5, 2:38 pm, "Chris G." <nos...(a)example.com> wrote: > I have a script that reads in a csv files, parses the data, and uses the > info to run down a list of IP addresses and make telnet connections to > them. I do this to automate the backing up of my Foundry switch > configurations. This works great until I have an error. When I have an > error at connect time, it catches the error and reports it, just like I > want. However, it doesn't recover from the error and never makes any > more connections to the other switches, even though it says it does. > > Here is my (relevant) code: > > use warnings; > use strict; > use Net::Telnet; > > sub GetCF; > > sub GetCF { > my $telnet; > $telnet = new Net::Telnet ( Timeout=>10, > Host=>$ip, > Errmode=>\&uhoh, > ); > > <skipping commands executed after the connection is established> > > } > > sub uhoh { > if ( $@ ne "") { > print ("$@\n"); > } else { > print "Success\n"; > } > > } how about something like this: #!/usr/bin/perl use warnings; use strict; use Net::Telnet; my $t = Net::Telnet->new( Timeout => 10, Errmode => sub { warn $_[0] }, ); HOST: while ( my ($user,$pass,$host) = split /[,\n]/, <DATA> ) { $t->open( $host ) or next HOST; $t->login( $user,$pass ) or next HOST; # do something with $t telnet session $t->close; } __DATA__ user1,pass1,host1.example.com user2,pass2,host1.example.com user1,pass1,host2.example.com user2,pass2,host2.example.com -jp PS - in the future please post only complete scripts including sample data. if this means you have to do a little extra work putting together a good question, you will be the better for it :-)
From: Chris G. on 6 Feb 2007 11:20 DJ, I would have posted the entire script, but it's >220 lines of code. Do you really want all that code??? I will post it, if you want. I understand the reasoning behind your request. I was just trying to save some bandwidth for others. DJ Stunks wrote: > PS - in the future please post only complete scripts including sample > data. if this means you have to do a little extra work putting > together a good question, you will be the better for it :-) >
From: Chris G. on 6 Feb 2007 11:23
Hi, I like this idea and see that I did not provide enough information. I apologize. But, in what you have given me, this is a good start for future thinking. In the code below, you do the $t->open( $host ) or next HOST; If I use that, what happens to that current attempt to open the telnet session? Does that just go away and the script continues? I will get some more info and post it to help clarify why I ask. Regards, Chris DJ Stunks wrote: > how about something like this: > > #!/usr/bin/perl > > use warnings; > use strict; > > use Net::Telnet; > > my $t = Net::Telnet->new( Timeout => 10, > Errmode => sub { warn $_[0] }, > ); > > HOST: > while ( my ($user,$pass,$host) = split /[,\n]/, <DATA> ) { > > $t->open( $host ) or next HOST; > $t->login( $user,$pass ) or next HOST; > > # do something with $t telnet session > > $t->close; > } > > __DATA__ > user1,pass1,host1.example.com > user2,pass2,host1.example.com > user1,pass1,host2.example.com > user2,pass2,host2.example.com > > -jp |