I'm trying to get some scripting finished to deploy changes en masse to about 400 Cisco devices. I've got a perl script modified from MrAudit that's using Net::Telnet::Cisco and for the life of me, I can't figure out the named parameter component.
In the documentation, they have:
$ok = $obj->cmd($string);
$ok = $obj->cmd(String => $string,
[Output => $ref,]
[Prompt => $match,]
[Timeout => $secs,]
[Cmd_remove_mode => $mode,]);
#output = $obj->cmd($string);
#output = $obj->cmd(String => $string,
[Output => $ref,]
[Prompt => $match,]
[Timeout => $secs,]
[Cmd_remove_mode => $mode,]
[Normalize_cmd => $boolean,]);
And my code is:
$testString is the test command I'm running against the device, $userTest1 is an array being cast where I want the output to be stored.
$::OPENRTR->cmd(String=>$testString,[Timeout=>5,Output=>$userTest1,]);
And every single time, no matter which component I modify or try and write it a different way, I get a variation of the error:
Odd number of elements in hash assignment at(filename)
bad named parameter "ARRAY(0x2e46460)" given to Net::Telnet::Cisco::cmd() at mrAudit-TACACSMod.pl line 279
I know it has to be something simple, but it's just flying right by. Any help would be appreciated.
I think the square brackets in the documentation just show the arguments are optional, you shouldn't use them in real code:
$OPENRTR->cmd( String => $testString,
Timeout => 5,
Output => $userTest1);
Related
I have a perl code like this:
use constant OPERATING_MODE_MAIN_ADMIN => 'super_admin';
use constant OPERATING_MODE_ADMIN => 'admin';
use constant OPERATING_MODE_USER => 'user';
sub system_details
{
return {
operating_modes => {
values => [OPERATING_MODE_MAIN_ADMIN, OPERATING_MODE_ADMIN, OPERATING_MODE_USER],
help => {
'super_admin' => 'The system displays the settings for super admin',
'admin' => 'The system displays settings for normal admin',
'user' => 'No settings are displayed. Only user level pages.'
}
},
log_level => {
values => [qw(FATAL ERROR WARN INFO DEBUG TRACE)],
help => "http://search.cpan.org/~mschilli/Log-Log4perl-1.49/lib/Log/Log4perl.pm#Log_Levels"
},
};
}
How will I access the "value" fields and "help" fields of each key from another subroutine? Suppose I want the values of operating_mode alone or log_level alone?
The system_details() returns a hashref, which has two keys with values being hashrefs. So you can dereference the sub's return and assign into a hash, and then extract what you need
my %sys = %{ system_details() };
my #loglevel_vals = #{ $sys{log_level}->{values} };
my $help_msg = $sys{log_level}->{help};
The #loglevel_vals array contains FATAL, ERROR etc, while $help_msg has the message string.
This makes an extra copy of a hash while one can work with a reference, as in doimen's answer
my $sys = system_details();
my #loglevel_vals = #{ $sys->{log_level}->{values} };
But as the purpose is to interrogate the data in another sub it also makes sense to work with a local copy, what is generally safer (against accidentally changing data in the caller).
There are modules that help with deciphering complex data structures, by displaying them. This helps devising ways to work with data. Often quoted is Data::Dumper, which also does more than show data. Some of the others are meant to simply display the data. A couple of nice ones are Data::Dump and Data::Printer.
my $sys = system_details;
my $log_level = $sys->{'log_level'};
my #values = #{ $log_level->{'values'} };
my $help = $log_level->{'help'};
If you need to introspect the type of structure stored in help (for example help in operating_mode is a hash, but in log_level it is a string), use the ref builtin func.
I have a Perl script that pulls a table from a SQL database ($row variable) and attempts to do a MongoDB update like so:
my $res = $users->update({"meeting_id" => $row[0]},
{'$set' => {
"meeting_id" => $row[0],
"case_id" => $row[1],
"case_desc" => $row[2],
"date" => $row[3],
"start_time" => $row[4],
"end_time" => $row[5],
#"mediator_LawyerID" => $row[6],
"mediator_LawyerIDs" => \#medLawIds,
"case_number" => $row[6],
"case_name" => $row[7],
"location" => $row[8],
"number_of_parties" => $row[9],
"case_manager" => $row[10],
"last_updated" => $row[11],
"meeting_result" => $row[12],
"parties" => \#partyList
}},
{'upsert' => 1}) or die "I ain't update!!!";
My client now wants ICS style calendar invites sent to their mediators. Thus, I need to know whether an update or insert happened. The documentation for MongoDB::UpdateResult implies that this is how you access such a property:
my $id = $res->upserted_id;
So I tried:
bless ($res,"MongoDB::UpdateResult");
my $id = $res->upserted_id;
After this code $id is like:
HASH(0x356f8fc)
Are these the actual IDs? If so, how do I convert to a hexadecimal string that can be cast to Mongo's ObjectId type? It should be noted I know absolutely nothing about perl; if more of the code is relevant, at request I will post any section ASAP. Its 300 lines so I didn't want to include the whole file off the bat.
EDIT: I should mention before anyone suggests this that using update_one instead of update returns the exact same result.
HASH(0x356f8fc) is a Perl Hash reference. It's basically some kind of (internal) memory address of some data.
The easiest way to get the contents is Data::Dumper:
use Data::Dumper
[...]
my $result = $res->upserted_id;
print Dumper($result);
HASH(0x356f8fc) is just the human readable representation of the real pointer. You must dump it in the same process and can't pass it from one to another.
You'll probably end up with something like
`my $id = $result->{_id};`
See the PerlRef manpage for details.
See also the MongoDB documentation about write concern.
PS: Also remember that you could use your own IDs for MongoDB. You don't need to work with the generated ones.
I'm trying to write a simple data manipulation language in Perl (read-only, it's meant to transform SQL-inspired queries into filters and properties to use with vSphere Perl API: http://pubs.vmware.com/vsphere-60/topic/com.vmware.perlsdk.pg.doc/viperl_advancedtopics.5.1.html_)
I currently have something similar to lexer output if I understand it properly - a list of tokens like this (Data::Dumper prints array of hashes):
$VAR1 = {
'word' => 'SHOW',
'part' => 'verb',
'position' => 0
};
$VAR2 = {
'part' => 'bareword',
'word' => 'name,',
'position' => 1
};
$VAR3 = {
'word' => 'cpu,',
'part' => 'bareword',
'position' => 2
};
$VAR4 = {
'word' => 'ram',
'part' => 'bareword',
'position' => 3
};
Now what I'd like to do is to build a syntax tree. The documentation I've seen so far is mostly on using modules and generating grammars from BNF, but at the moment I can't wrap my head around it.
I'd like to tinker with relatively simple procedural code, probably recursive, to make some ugly implementation myself.
What I'm currently thinking about is building a string of $token->{'part'}s like this:
my $parts = 'verb bareword bareword ... terminator';
and then running a big and ugly regular expression against it, (ab)using Perl's capability to embed code into regular expressions: http://perldoc.perl.org/perlretut.html#A-bit-of-magic:-executing-Perl-code-in-a-regular-expression:
$parts =~ /
^verb(?{ do_something_smart })\s # Statement always starts with a verb
(bareword\s(?{ do_something_smart }))+ # Followed by one or more barewords
| # Or
# Other rules duct taped here
/x;
Whatever I've found so far requires solid knowledge of CS and/or linguistics, and I'm failing to even understand it.
What should I do about lexer output to start understanding and tinker with proper parsing? Something like 'build a set of temporary hashes representing smaller part of statement' or 'remove substrings until the string is empty and then validate what you get'.
I'm aware of the Dragon Book and SICP, but I'd like something lighter at this time.
Thanks!
As mentioned in a couple of comments above, but here again as a real answer:
You might like Parser::MGC. (Disclaimer: I'm the author of Parser::MGC)
Start by taking your existing (regexp?) definitions of various kinds of token, and turn them into "token_..." methods by using the generic_token method.
From here, you can start to build up methods to parse larger and larger structures of your grammar, by using the structure-building methods.
As for actually building an AST - it's possibly simplest to start with to simply emit HASH references with keys containing named parts of your structure. It's hard to tell a grammatical structure from your example given in the question, but you might for instance have a concept of a "command" that is a "verb" followed by some "nouns". You might parse that using:
sub parse_command
{
my $self = shift;
my $verb = $self->token_verb;
my $nouns = $self->sequence_of( sub { $self->token_noun } );
# $nouns here will be an ARRAYref
return { type => "command", verb => $verb, nouns => $nouns };
}
It's usually around this point in writing a parser that I decide I want some actual typed objects instead of mere hash references. One easy way to do this is via another of my modules, Struct::Dumb:
use Struct::Dumb qw( -named_constructors );
struct Command => [qw( verb nouns )];
...
return Command( verb => $verb, nouns => $nouns );
In my Perl script, I have subroutine that is called hundreds of times with as many different sets of parameters, as the only values that are sent in are ones that differ from the defaults. (It goes without saying that the number of permutations and combinations is very large) To make it more robust, I would like to do some checking on the parameters. Here is a shrunken version of my subroutine (the actual version has dozens of parameters with very specific, sometimes lengthy names):
# Obtain any parameters that differ from the defaults and send for processing
sub importantSub
{
my %params =
(
commandType => 5,
commandId => 38,
channel1Enable => 0,
channel2Enable => 0,
channel3Enable => 0,
channel4Enable => 0,
channel5Enable => 0,
channel6Enable => 0,
channel7Enable => 0,
channel8Enable => 0,
channel9Enable => 0,
channel10Enable => 0,
# This goes on for a VERY long time
#_
);
# Make sure we have exactly as many keys as we expect - verify that
# no additional parameters were added (Real version has 92)
if( keys(%params) != 92 )
{
croak("Unexpected parameter in hash!");
}
return &$privateProcessingFunction('Data Path Configuration', \%params);
}
As you can see, I currently do a check to see if the number of values is the same, as if something is sent in as "chan1Enable" instead of "channel1Enable", it will throw that number off.
But with so many calls to the subroutine from multiple other scripts written by multiple other engineers, I would like to find a way to find WHICH value was incorrect (e.g. Don't just say that there was an unexpected parameter, say that "chan1Enable" was invalid). Furthermore, if multiple values were incorrect, I'd like to list all of them.
What is the most efficient way to do this?
(I ask about efficiency since the function is currently called in over 400 different ways and that will likely continue to grow as the application expands.)
There are two kinds of errors: supplying an unrecognized parameter, or failing to supply a recognized parameter. You'll have to worry about the second issue as you edit the list of parameters and make sure that the new parameters are used consistently throughout the application.
The best and easiest solution is to use another hash.
my #params = qw(commandType commandId channel1Enabled ...);
my %copy = %params;
my #validation_errors = ();
# are all the required parameters present?
foreach my $param (#params) {
if (not exists $copy{$param}) {
push #validation_errors, "Required param '$param' is missing.";
}
delete $copy{$param};
}
# since we have delete'd all the recognized parameters,
# anything left is unrecognized
foreach my $param (keys %copy) {
push #validation_errors, "Unrecognized param '$param' = '$copy{$param}' in input.";
}
if (#validation_errors) {
die "errors in input:\n", join("\n", #validation_errors);
}
I recommend using a formal tool to help validate your parameters your passing in. Params::Validate is tried and true, while Type::Params is a recent take on the problem space, allowing you to use same set of constraints that you would also use with Moo or Moose.
Here's the kind of diagnostic that Params::Validate would give you for
an unrecognized parameter:
use Params::Validate ':all';
sub foo {
my %p = validate(#_, {
first_required => 1,
second_required => 1,
first_optional => 0.
});
}
foo( boom => 'zoom' );
Results in:
The following parameter was passed in the call to main::foo but was not listed in the validation options: boom
at /tmp/t.pl line 7
main::foo('boom', 'zoom') called at /tmp/t.pl line 14
I am struggling with the following declaration of a hash in Perl:
my %xmlStructure = {
hostname => $dbHost,
username => $dbUsername,
password => $dbPassword,
dev_table => $dbTable,
octopus => {
alert_dir => $alert_dir,
broadcast_id => $broadcast_id,
system_id => $system_id,
subkey => $subkey
}
};
I've been googling, but I haven't been able to come up with a solution, and every modification I make ends up in another warning or in results that I do not want.
Perl complaints with the following text:
Reference found where even-sized list expected at ./configurator.pl line X.
I am doing it that way, since I want to use the module:
XML::Simple
In order to generate a XML file with the following structure:
<settings>
<username></username>
<password></password>
<database></database>
<hostname></hostname>
<dev_table></dev_table>
<octopus>
<alert_dir></alert_dir>
<broadcast_id></broadcast_id>
<subkey></subkey>
</octopus>
</settings>
so sometthing like:
my $data = $xmlFile->XMLout(%xmlStructure);
warn Dumper($data);
would display the latter xml sample structure.
Update:
I forgot to mention that I also tried using parenthesis instead of curly braces for the hash reference, and eventhough it seems to work, the XML file is not written properly:
I end up with the following structure:
<settings>
<dev_table>5L3IQWmNOw==</dev_table>
<hostname>gQMgO3/hvMjc</hostname>
<octopus>
<alert_dir>l</alert_dir>
<broadcast_id>l</broadcast_id>
<subkey>l</subkey>
<system_id>l</system_id>
</octopus>
<password>dZJomteHXg==</password>
<username>sjfPIQ==</username>
</settings>
Which is not exactly wrong, but I'm not sure if I'm going to have problems latter on as the XML file grows bigger. The credentials are encrypted using RC4 algorith, but I am encoding in base 64 to avoid any misbehavior with special characters.
Thanks
{} are used for hash references. To declare a hash use normal parentheses ():
my %xmlStructure = (
hostname => $dbHost,
username => $dbUsername,
password => $dbPassword,
dev_table => $dbTable,
octopus => {
alert_dir => $alert_dir,
broadcast_id => $broadcast_id,
system_id => $system_id,
subkey => $subkey
}
);
See also perldoc perldsc - Perl Data Structures Cookbook.
For your second issue, you should keep in mind that XML::Simple is indeed too simple for most applications. If you need a specific layout, you're better off with a different way of producing the XML, say, using HTML::Template. For example (I quoted variable names for illustrative purposes):
#!/usr/bin/env perl
use strict; use warnings;
use HTML::Template;
my $tmpl = HTML::Template->new(filehandle => \*DATA);
$tmpl->param(
hostname => '$dbHost',
username => '$dbUsername',
password => '$dbPassword',
dev_table => '$dbTable',
octopus => [
{
alert_dir => '$alert_dir',
broadcast_id => '$broadcast_id',
system_id => '$system_id',
subkey => '$subkey',
}
]
);
print $tmpl->output;
__DATA__
<settings>
<username><TMPL_VAR username></username>
<password><TMPL_VAR password></password>
<database><TMPL_VAR database></database>
<hostname><TMPL_VAR hostname></hostname>
<dev_table><TMPL_VAR dev_table></dev_table>
<octopus><TMPL_LOOP octopus>
<alert_dir><TMPL_VAR alert_dir></alert_dir>
<broadcast_id><TMPL_VAR broadcast_id></broadcast_id>
<subkey><TMPL_VAR subkey></subkey>
<system_id><TMPL_VAR system_id></system_id>
</TMPL_LOOP></octopus>
</settings>
Output:
<settings>
<username>$dbUsername</username>
<password>$dbPassword</password>
<database></database>
<hostname>$dbHost</hostname>
<dev_table>$dbTable</dev_table>
<octopus>
<alert_dir>$alert_dir</alert_dir>
<broadcast_id>$broadcast_id</broadcast_id>
<subkey>$subkey</subkey>
<system_id>$system_id</system_id>
</octopus>
</settings>
You're using the curly braces { ... } to construct a reference to an anonymous hash. You should either assign that to a scalar, or change the { ... } to standard parentheses ( ... ).