Re^6: Problem with Net::SSH::Expect on unavailable hosts

I tried the timeout, but the result was the same. The debugging output that I get basically shows nothing from $!, and the return value of $ssh->run_ssh() is always 1, regardless if it's a success or failure.

Here is the result of enabling debugging (for the offending server -- hugger):

Spawned 'ssh -e none  sebrint@hugger'
        spawn id(4)
        Pid: 22388
        Tty: /dev/pts/7
        Expect::spawn('Expect=GLOB(0x8074f40)','ssh -e none  sebrint@h
+ugger') called at /vol/perl/5.8/lib/site_perl/5.8.1/Net/SSH/Expect.pm
+ line 132
        Net::SSH::Expect::run_ssh('Net::SSH::Expect=ARRAY(0x8074f58)')
+ called at ./dumpadm_oz.pl line 33
        eval {...} called at ./dumpadm_oz.pl line 32
Starting EXPECT pattern matching...
        Expect::expect('Expect=GLOB(0x8074f40)',2,'-re','(?-xism:[\s\S
+]+)') called at /vol/perl/5.8/lib/site_perl/5.8.1/Net/SSH/Expect.pm l
+ine 580
        Net::SSH::Expect::_sec_expect('Net::SSH::Expect=ARRAY(0x8074f5
+8)',2,'-re','(?-xism:[\s\S]+)') called at /vol/perl/5.8/lib/site_perl
+/5.8.1/Net/SSH/Expect.pm line 419
        Net::SSH::Expect::read_all('Net::SSH::Expect=ARRAY(0x8074f58)'
+,2) called at ./dumpadm_oz.pl line 47
ssh: connect to host hugger port 22: Connection refused
Starting EXPECT pattern matching...
        Expect::expect('Expect=GLOB(0x8074f40)',2,'-re','(?-xism:[\s\S
+]+)') called at /vol/perl/5.8/lib/site_perl/5.8.1/Net/SSH/Expect.pm l
+ine 580
        Net::SSH::Expect::_sec_expect('Net::SSH::Expect=ARRAY(0x8074f5
+8)',2,'-re','(?-xism:[\s\S]+)') called at /vol/perl/5.8/lib/site_perl
+/5.8.1/Net/SSH/Expect.pm line 420
        Net::SSH::Expect::read_all('Net::SSH::Expect=ARRAY(0x8074f58)'
+,2) called at ./dumpadm_oz.pl line 47
Closing spawn id(4).
        Expect::hard_close('Expect=GLOB(0x8074f40)') called at /vol/pe
+rl/5.8/lib/site_perl/5.8.1/Expect.pm line 894
        Expect::_multi_expect(2,'undef','ARRAY(0x81a82b8)') called at 
+/vol/perl/5.8/lib/site_perl/5.8.1/Expect.pm line 565
        Expect::expect('Expect=GLOB(0x8074f40)',2,'-re','(?-xism:[\s\S
+]+)') called at /vol/perl/5.8/lib/site_perl/5.8.1/Net/SSH/Expect.pm l
+ine 580
        Net::SSH::Expect::_sec_expect('Net::SSH::Expect=ARRAY(0x8074f5
+8)',2,'-re','(?-xism:[\s\S]+)') called at /vol/perl/5.8/lib/site_perl
+/5.8.1/Net/SSH/Expect.pm line 420
        Net::SSH::Expect::read_all('Net::SSH::Expect=ARRAY(0x8074f58)'
+,2) called at ./dumpadm_oz.pl line 47
spawn id(4) closed.
SSHProcessError The ssh process was terminated. at ./dumpadm_oz.pl lin
+e 47
Closing spawn id(4).
        Expect::hard_close('Expect=GLOB(0x8074f40)') called at /vol/pe
+rl/5.8/lib/site_perl/5.8.1/Expect.pm line 1621
        Expect::DESTROY('Expect=GLOB(0x8074f40)') called at ./dumpadm_
+oz.pl line 0
        eval {...} called at ./dumpadm_oz.pl line 0
[download]

Thanks!

Comment on Re^6: Problem with Net::SSH::Expect on unavailable hosts Download Code

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Re^7: Problem with Net::SSH::Expect on unavailable hosts by jrsimmon (Hermit) on Jul 02, 2009 at 16:07 UTC
Ok, after looking into Expect a bit more, I think we've made this a bit more complicated than it needs to be. The read_all() method of Net::SSH::Expect calls the get_expect() in the same package. Per the doc, the get_expect() method will die if the Expect object does not have a valid ssh connection. So...Just wrap your call to read_all() in an eval to catch the die and you should be good. You're original code, modified in this way: `my $ssh = Net::SSH::Expect->new ( host => "$current_server", user => "$user", raw_pty => 1 ); # test the login eval { $login_output = $ssh->run_ssh(); }; # I've tried to capture $@ or $! here but it never gives me an +ything useful my $rc = eval{($ssh->read_all(2) =~ />\s\|$\s\z/) or die "whe +re's the remote prompt?";}; unless($rc =~ /$your_expected_output_match_pattern/){ &MOVE_ON_TO_THE_NEXT_HOST; } $ssh->exec("stty raw -echo");` [download] There are some other things that you should probably clean up in this example, like the poorly named $login_output and not checking the return value of the first eval (or $login_output for that matter). I'll assume you either plan to do that or were just a bit too aggressive in summarizing your code for this example.	[reply] [d/l]
Re^8: Problem with Net::SSH::Expect on unavailable hosts by sierpinski (Chaplain) on Jul 02, 2009 at 16:22 UTC
Thanks a ton, that did the trick. I turned my 'manual debugging' back on, and saw that it skipped the offending host immediately and went on to the next one. As for cleaning up, you are right on both counts, I had a lot of print statements in there trying to discern where the problems were, tons of lines commented out, etc. I also plan to go back and capture all the return values, but was going to wait until I got the error resolved. The only thing now that's left is to have it notify me that a server is unavailable, and that's the easy part... thanks so much for your help!! -Tim	[reply]
Re^7: Problem with Net::SSH::Expect on unavailable hosts by jrsimmon (Hermit) on Jul 02, 2009 at 15:36 UTC
Ok, this is straight out of a script I use frequently to setup a ssh tunnel. Replace $ssh->login() with your call to $ssh->run_ssh() or modify your script to use id/pwd auth. I haven't been able to recreate the script bombing out, so I'm not sure whether this will fix your problem or not -- speaking of which, have you made sure that you're at the current level for Net::SSH::Expect? `#sometimes the connection isn't ready to login yet, so we try up to +max_retry_count times before giving up my $retry_count = 0; while(1){ $rc = eval{$ssh->login();}; last if defined $rc; last if $retry_count >= $max_retry_count; $retry_count++; sleep 1; }` [download] Now that I've looked at Expect.pm a little more closely, I can see that I'm not using $ssh->login() correctly...but it does seem to work. So give it a shot and I'll look for a better way of doing the retry loop.	[reply] [d/l]