=pod
=encoding utf-8
=head1 NAME
Transform::Alert - Transform alerts from one type to another type
=head1 SYNOPSIS
# In your configuration
BaseDir /opt/transalert
<Input test_in>
Type POP3
Interval 60 # seconds (default)
<ConnOpts>
Username bob
Password mail4fun
# See Net::POP3->new
Host mail.foobar.org
Port 110 # default
Timeout 120 # default
</ConnOpts>
<Template>
TemplateFile test_in/foo_sys_email.re
OutputName test_out
</Template>
<Template>
TemplateFile test_in/server01_email.re
Munger test_in/Munger.pm MyMunger->munge
OutputName test_out
</Template>
</Input>
<Output test_out>
Type Syslog
TemplateFile outputs/test.tt
# See Net::Syslog->new
<ConnOpts>
Name TransformAlert
Facility local4
Priority info
SyslogHost syslog.foobar.org
SyslogPort 514 # default
</ConnOpts>
</Output>
# On a prompt
> transalert_ctl -c file.conf -l file.log -p file.pid
=head1 DESCRIPTION
Ever have a need to transform one kind of alertE<sol>message into another? For example:
=over
=item *
Taking a bunch of alert emails and converting them into Syslogs
=item *
Converting Syslog alerts to SNMP traps
=item *
Converting SNMP traps to Syslogs
=item *
Traps to email
=item *
Anything to anything
=back
Then this platform delivers.
Transform::Alert is a highly extensible platform to transform alerts from anything to anything else. Everything is ran through a configuration
file, a couple of templates, and L<Transform::Alert's daemon app|transalert_ctl>.
Or to show it with a UTF8 drawing, the platform works like this:
Input ──┬── InTemplate ────────────── Output + OutTemplate
├── InTemplate + Munger ──┬── Output + OutTemplate
│ └── Output + OutTemplate
├── InTemplate + Munger ──┬── Output + OutTemplate
└── InTemplate ───────────┘
Input ──┬── InTemplate ────────────── Output + OutTemplate
└── InTemplate + Munger ───── Output + OutTemplate
All L<inputs|Transform::Alert::Input> and L<outputs|Transform::Alert::Output> are separate modules, so if there isn't a protocol available, they
are easy to make. Input templates use a multi-line regular expression with named captures to categorize the variables. Output templates are
L<TT|Template::Toolkit> templates with a C<<< [% var %] >>> syntax. If you need to transform the data after it's been captured, you can use a "munger"
module to play with the variables any way you see fit.
=encoding utf-8
=head1 DETAILS
=head2 Configuration Format
The configuration uses an Apache-based format (via L<Config::General>). There's a number of elements required within the config file:
=head3 BaseDir
BaseDir [dir]
The base directory is used as a starting point for the daemon and any of the relative paths in the config file. The C<<< BaseDir >>> option itself
can use a relative path, in which case will start at the config path.
=head3 Input
<Input [name]> # one or more
Type [type]
Interval [seconds] # optional; default is 60s
# <ConnOpts> section; module-specific
# <Template> sections
</Input>
The C<<< Input >>> section specifies a single input source. All C<<< Input >>> sections must be named. Multiple C<<< Input >>> sections can be specified, but the
name must be unique. (Currently, the input name isn't used, but this may change in the future.)
The C<<< Type >>> specifies the type of input used. This maps to a C<<< Transform::Alert::Input::* >>> class. More information about the different modules
be found with the corresponding documentation.
The C<<< Interval >>> specifies how frequently the input should be checked (in seconds). Server-based input shouldn't be checked too often, as it
might be considered abusive. To prevent overruns, the input will only be re-checked after the interval is complete. (In other words, the
"last finished" time is recorded, not the "last start".)
There is one C<<< ConnOpts >>> section in each input. The options will be specific to each type, so look there for documentation.
The engine may someday be changed to have multi-processed inputs, but the need isn't immediate right now. (Patches welcome.)
=head3 Template
<Input ...>
<Template> # one or more
# Template/File can be optional
TemplateFile [file] # not used with Template
Template "[String]" # not used with TemplateFile
Munger [file] [class]->[method] # optional
OutputName test_out # one or more
</Template>
</Input>
All C<<< Input >>> sections must have one or more C<<< Template >>> sections. As messages are being processed, each message is tested on all of the
templates. Input messages will be ran through B<all> templates tied to that input, even if that message matched a previous template. To prevent
a message from matching multiple templates, make sure they are reasonably unique.
All templates must either have a C<<< TemplateFile >>> or C<<< Template >>> option. In most cases, you should stick with file-based templates, as inline
templates are whitespace sensitive, and should only be used for single line REs.
If you don't set a Template option, a template file is not used. Without a Munger to validate the hash, these templates will be accepted (and
sent to the outputs), as long as it passes data.
The optional C<<< Munger >>> option can be used to specify a module used in changing the variables between the input and output. (More details about
L<Mungers further down|/Mungers>.) The option itself can be expressed in a number of ways:
Munger File.pm
Munger File.pm->method
Munger File.pm My::Munger
Munger My::Munger
Munger My::Munger->method
Munger File.pm My::Munger->method # preferred
If a class isn't specified, the first package name found in the file is used. If the method is missing, the default is C<<< munge >>>. If there
isn't a file specified, it will try to load the class like C<<< use/require >>>. (Technically, you could take advantage of the C<<< . >>> path in C<<< %INC >>>,
but it's better to just provide the filename.)
If both C<<< Template/File >>> & C<<< Munger >>> options are passed, it will test both forms as an AND-based match, testing the text form via template
first. This has the benefit of using the input templates as a "gatekeeper", and can be used to delegate different templates to different
Mungers. Any named captures from the input template will be passed as a C<<< t >>> hash in the variables to the Munger.
The C<<< OutputName >>> options provide the name of the Output sources to use after a template match is found. (These sources are defined below.)
More that one option means that the alert will be sent to multiple sources.
=head3 Output
<Output [name]> # one or more
Type [type]
TemplateFile [file] # not used with Template
Template "[String]" # not used with TemplateFile
# <ConnOpts> section; module-specific
</Output>
Like C<<< Input >>>, C<<< Output >>> sections need to be uniquely named. This name is used with the C<<< OutputName >>> option above. Also like C<<< Input >>>, the
C<<< Type >>> functions the same way (mapping to a C<<< Transform::Alert::Output::* >>> class), and C<<< ConnOpts >>> contains all of the module-specific options.
Similar to C<<< Template >>> sections, the C<<< Output >>> section must either have a C<<< TemplateFile >>> or a C<<< Template >>> option. However, you can only use a
single template per C<<< Output >>>. If you need more, use another section with most of the same options.
=head2 Directory Structure
Depending on how large your setup is, you may want to create a directory structure like this:
/opt/transalert # config, log, PID
/opt/transalert/input1 # various input template directories
/opt/transalert/input2
/opt/transalert/input3
/opt/transalert/outputs # single directory for output templates
If your set up is small, you can get away with a single directory, or at least single inputE<sol>output directories. Just be sure to use the logE<sol>PID
options in L<transalert_ctl>, so that they are put in the right directory.
=head2 Input Templates
Input templates are basically big multi-line regular expressions. These are NOT C<<< /x >>> whitespace-insensitive regular expressions, as those
would make copyE<sol>pasting large bodies of text more difficult. (There's an assumption that most input templates will have more static text than
freeform RE parts.) Besides, you can still use a C<<< (?x...) >>> construct for whitespace-insensitivity and comments. Also, leading and trailing
whitespace is removed, so stray whitespace should not be an issue there. RE templates are also put into a C<<< ^$re$ >>>, with beginE<sol>end symbols,
which can easily be overriden with C<<< .* >>>.
Please note that a matched template doesn't stop the matching process, so make sure the templates are unique enough if you don't want to
match multiple templates.
Here's an example using an email template:
[\s\S]*\QTo: <alert@foobar.org>
From: <alert@foobar.org>
Subject: Email Alert - \E(?<subject>[^\n]+)
Date: (?<date>[^\n]+)
[\s\S]+
We found a problem on this device:
\QName :\E (?<name>\w+)
\QProblem :\E (?<problem>[^\n]+)
\QTicket #:\E (?<ticket>\w+)
.*
Of course, this is taking some assumptions about the order and format of headers, but if this is coming from an automated platform that uses
the same mail server, there really shouldn't be much change at all. If you need finer control of the verification process, you can make use
of L<Mungers|/Mungers>.
=head2 Output Templates
Output templates use L<Template::Toolkit>. If you want a quick and dirty lesson on how they work, check out L<Template::Manual::Syntax>. If
B<that> is too wordy for you, then just remember that variables are replaced with a C<<< [% t.var %] >>> syntax.
The variables passed to the Output (or Munger, if specified) will look like this:
{
t => {
# text form variables acquired from the input RE template
},
p => {
# preparsed hash variables, sent by the Input module
}
}
For a structure of the C<<< p >>> hash passed, look at the documentation for that input module (under C<<< Preparsed Hash >>>). Note that Munger mangling
could totally change the structure of the hash passed to the Outputs, depending on what it returns.
Here's an example output template that looks similar to the input one above:
To: [% t.to %]
From: [% t.from %]
Subject: Email Alert - [% t.subject %]
Date: [% t.date %]
We found a problem on this device:
Name : [% t.name %]
Problem : [% t.problem %]
Ticket #: [% t.ticket %]
=head2 Mungers
Mungers are an optional second piece to the input template structure. Regular expressions, as powerful as they are with finding and capturing
information, only do just that. Sometimes you need to warp the information you've captured to fit the mold that the output can use. Or
sometimes you need to validate the input in a better fashion than REs can provide. Mungers fit both of those roles.
Mungers are basically freeform Perl modules that transform andE<sol>or validate the input data passed to it. Here's an example munger, straight
from the test platform:
package TestMunger;
sub munge {
my ($class, $vars, $tmpl_grp) = @_;
$vars->{t}{thingy} = delete $vars->{t}{item};
return int rand(2) ? $vars : undef;
}
1;
This munger does two (useless) things: change the name of the C<<< item >>> variable to C<<< thingy >>>, and randomly reject the input. But, this munger
could just as easily do anything Perl can do to transform and validate the data.
All mungers are called by their class (ie: C<<< TestMunger->munge >>>), so all of them should have a package name. They should also return either
C<<< undef >>> (as a rejection) or the variable list (as a hashref). If the input ends up with multiple alerts, a munger can also pass an arrayref
(of hashrefs), and they will be sent to the outputs individually.
A munger could also become the B<primary> piece for input transformationE<sol>validation by not specifying a Template option.
Mungers are also passed the L<TemplateGrp|Transform::Alert::TemplateGrp> object. This is mostly used as a way to hook into the log, like:
$tmpl_grp->log->debug("Munger didn't like Message Body");
=head2 Variable Passing
If you're still confused on the variable passing, look at it this way:
Input ──┬── $text ───── InTemplate ───── t => { %+ } ──┬── Munger ───── { ??? } ───── Out...
└── $hash ────────────────────── p => $hash ──┘
Input ──┬── $text ────────────────────── t => { } ──┬── Munger ───── { ??? } ───── Out...
└── $hash ────────────────────── p => $hash ──┘
Input ──┬── $text ───── InTemplate ───── t => { %+ } ──┬───────────────────────────── Out...
└── $hash ────────────────────── p => $hash ──┘
Input ──┬── $text ────────────────────── t => { } ──┬── Munger ───── [ { ??? }, ── Out...
└── $hash ────────────────────── p => $hash ──┘ { ??? }, ── Out...
{ ??? } ] ─ Out...
...OutTemplate ───── $str ───── Output
=head1 CAVEATS
=over
=item *
This doesn't work on Windows. Blame L<Proc::ProcessTable>. Or rather, L<this bug|https://rt.cpan.org/Ticket/Display.html?id=75931>.
=back
=over
=item *
One would consider this a grand feat of over-engineering, which doesn't apply to every single protocol cleanly. For example,
=back
email input templates alone probably shouldn't be used, as header order might change, and the SNMP I/O doesn't translate to text
very well. YMMV.
=head1 TODO
=over
=item *
Moar IE<sol>O:
=back
Inputs Outputs
------ -------
HTTP::Atom
HTTP::RSS
File::CSV File::CSV
File::Text File::Text
IRC
=over
=item *
L<Pegex> support for input templates, maybe when we stop playing with the syntax :)
=item *
Multi-threaded andE<sol>or -processed inputsE<sol>outputs
=back
=head1 AVAILABILITY
The project homepage is L<https://github.com/SineSwiper/Transform-Alert/wiki>.
The latest version of this module is available from the Comprehensive Perl
Archive Network (CPAN). Visit L<http://www.perl.com/CPAN/> to find a CPAN
site near you, or see L<https://metacpan.org/module/Transform::Alert/>.
=for :stopwords cpan testmatrix url annocpan anno bugtracker rt cpants kwalitee diff irc mailto metadata placeholders metacpan
=head1 SUPPORT
=head2 Internet Relay Chat
You can get live help by using IRC ( Internet Relay Chat ). If you don't know what IRC is,
please read this excellent guide: L<http://en.wikipedia.org/wiki/Internet_Relay_Chat>. Please
be courteous and patient when talking to us, as we might be busy or sleeping! You can join
those networks/channels and get help:
=over 4
=item *
irc.perl.org
You can connect to the server at 'irc.perl.org' and join this channel: #web-simple then talk to this person for help: SineSwiper.
=back
=head2 Bugs / Feature Requests
Please report any bugs or feature requests via L<L<https://github.com/SineSwiper/Transform-Alert/issues>|GitHub>.
=head1 AUTHOR
Brendan Byrd <BBYRD@CPAN.org>
=head1 COPYRIGHT AND LICENSE
This software is Copyright (c) 2013 by Brendan Byrd.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)