NAME

Mail::Log::Trace - Trace an email through the mailsystem logs.

SYNOPSIS

  use Mail::Log::Trace;
  
  my $tracer = Mail::Log::Trace::SUBCLASS->new({log_file => 'path/to/log'});
  $tracer->set_message_id('message_id');
  $tracer->find_message();
  my $from_address = $tracer->get_from_address();
  
  etc.

DESCRIPTION

This is the root-level class for a mail tracer: It allows you to search for and find messages in maillogs. Accessors are provided for info common to most maillogs: Specific subclasses may have further accessors depending on their situation.

Probably the two methods most commonly used (and sort of the point of this module) are find_message and find_message_info. Both are simply stubs for subclasses to implement: The first is defined to find the first (or first from current location...) mention of the specified message in the log. Depending on the log format that may or may not be the only mention, and there may be information missing/incomplete at that point.

find_message_info should find all information about a specific message in the log. (Well, all information about a specific instance of the message: If there are multiple messages that would match the info provided it must find info on the first found.) That may mean searching through the log for other information.

If you just need to find if the message exists, use find_message: it will be faster (or at the least, the same speed. It should never be slower.)

USAGE

This is a an object-orientend module, with specific methods documented below.

The string coersion is overloaded to return the class name, and the file we are working with. Boolean currently checks to see if we were able to open the file. (Which is kinda silly, as we'd throw an error if we couldn't.)

All times are expected to be in Unix epoc-time format.

new (constructor)

The base constructor for the Mail::Log::Trace classes. It takes inital values for the following in a hash: from_address, to_address, message_id, log_file. The only required value is the path to the logfile.

  use Mail::Log::Trace;
  my $object = Mail::Log::Trace->new({ from_address => 'from@example.com',
                                       to_address   => 'to@example.com',
                                       message_id   => 'messg.id.string',
                                       log_file     => 'path/to/log',
                                       ...
                                      });

SETTERS

set_from_address

Sets the from address of the message we are looking for.

set_message_id

Sets the message_id of the message we are looking for. (Check with the specific parser class for what that means in a particular log format.)

set_recieved_time

Sets the recieved time of the message we are looking for. (The time this machine got the message.)

set_sent_time

Sets the sent time of the message we are looking for. (The time this machine sent the message.)

set_relay_host

Sets the relay host of the message we are looking for. Commonly either the relay we recieved it from, or the relay we sent it to. (Depending on the logfile.)

set_subject

Sets the subject of the message we are looking for.

set_parser_class

Sets the parser class to use when searching the log file. A subclass will have a 'default' parser that it will normally use: This is to allow easy site-specific logfile formats based on more common formats. To use you would subclass the default parser for the log file format of the base program to handle the site's specific changes.

Takes the name of a class as a string, and will throw an exception (Mail::Log::Exceptions::InvalidParameter) if that class name doesn't start with Mail::Log::Parse.

set_log

Sets the log file we are searching throuh. Takes a full or relative path. If it doesn't exist, or can't be read by the current user, it will throw an exception. (Mail::Log::Exceptions::LogFile) Note that it does not try to open it immedeately. That will be done at first attempt to read from the logfile.

set_to_address

Sets the to address of the message we are looking for. Multiple addresses can be specified, they will all be added, with duplicates skipped. This method completely clears the array: there will be no addresses in the list except those given to it. Duplicates will be consolidated: Only one of any particular address will be in the final array.

As a special case, passing undef to this will set the array to undef.

add_to_address

Adds to the list of to addresses we are looking for. It does not delete the array first.

Duplicates will be consolidated, so that the array will only have one of any given address. (No matter the order they are given in.)

remove_to_address

Removes a single to address from the array.

GETTERS

get_from_address

Gets the from address. (Either as set using the setter, or as found in the log.)

get_to_address

Gets the to address array. (Either as set using the setters, or as found in the log.)

Will return a reference to an array, or 'undef' if the to address has not been set/found.

get_message_id

Gets the message_id. (Either as set using the setter, or as found in the log.)

get_subject

Gets the message subject. (Either as set using the setter, or as found in the log.)

get_recieved_time

Gets the recieved time. (Either as set using the setter, or as found in the log.)

get_sent_time

Gets the sent time. (Either as set using the setter, or as found in the log.)

get_relay_host

Gets the relay host. (Either as set using the setter, or as found in the log.)

get_log

Returns the path to the logfile we are reading.

get_connect_time

Returns the time the remote host connected to this host to send the message.

get_disconnect_time

Returns the time the remote host disconnected from this host after sending the message.

get_delay

Returns the total delay in this stage in processing the message.

get_all_info

Returns message info as returned from the parser, for more direct/complete access.

(It's probably a good idea to avoid using this, but it is useful and arguably needed under certain circumstances.)

Utility subroutines

clear_message_info

Clears all known information on the current message, but not on the log.

Use to start searching for a new message.

find_message

Finds the first/next occurance of a message in the log. Can be passed any of the above information in a hash format.

Default is to search forward in the log: If you have already done a search, this will start searching where the previous search ended. To start over at the beginning of the logfile, set from_start as true in the parameter hash.

This method needs to be overridden by the subclass: by default it will throw an Mail::Log::Exceptions::Unimplemented error.

find_message_info

Finds as much information as possible about a specific occurance of a message in the logfile. Acts much the same as find_message, other than the fact that once it finds a message it will do any searching necarry to find all information on that message connection.

(Also needs to be implemented by subclasses.)

SUBCLASSING

There are two ways to subclass Mail::Log::Trace: The standard way, and the automatic way. The old way is fairly straightforward: You create the accessors for all the subclass-specific information, and overide find_message, find_message_info, and _parse_args. (Making sure for _parse_args that you call the SUPER version.)

Or you can try to let Mail::Log::Trace do as much of that as possible, and only do find_message and find_message_info.

To do the latter, you need to override several of the following list of methods:

  _requested_public_accessors
  _requested_public_set_only
  _requested_public_get_only
  _requested_array_accessors
  _requested_special_accessors
  _requested_cleared_parameters
  _set_as_message_info

That looks like a long list, but it is very rare that you'll need to override all of them, and all they need to do is return a static list of keys that you want the relevant action taken on.

The first five build accessors for you, of the form get_$key, set_$key for standard public, _get_$key and _set_key for private accessors (note that if you request a private setter, you'll also get a public getter, and vice-versa), and get_$key, set_$key, add_$key and remove_$key for keys which store arrays. All of these have been heavily optimised for speed.

The last two set what keys are cleared when you call clear_message_info and what keys will be checked when _parse_args is called. (If none of those are present, an exception will be thrown, saying there is no message-specific data.)

_requested_special_accessors requires a little more discussion. Unlike the rest, it expects not an array, but a hash (not a hashref: a hash). The keys of the hash are the keys that will have accessors built for them (public, single, only), and the values are code references to parsing/validation functions.

An example:

  sub _requested_special_accessors { 
      return ( year => sub {  my ($self, $year) = @_;
                              return '____INVALID__VALUE____' if $year < 1970;
                              my $maillog = $self->_get_log_parser();
                              if (defined($maillog)) {
                                  $maillog->set_year($year);
                              }
                              return $year;
                           },
              );
  };

The above is from Mail::Log::Trace::Postfix, and is for the key 'year'. The coderef in this case does both validation and some extra action. The action is to call $self-_get_log_parser()->set_year()> on the year being passed. (Because in this case the parser needs to have the year to return info correctly.) The validation is to check to make sure the year is greater than 1970. (The birth of UNIX, so we are unlikey to handle any logs earlier than that.) If it is not, the special value ____INVALID__VALUE____ is returned. This will cause an exception to be thrown. If the value is valid, it is returned.

The purpose of all the above is to allow subclasses to check values, do any parsing that is needed, and to any other actions that may be needed. (This is in contrast to the normal accessors, which just store the value given blindly.)

Note that undef should always be considered a valid value.

Normally keys should be in the 'public_accessors' list: those accessors are much faster.

These accessors are built at run time, when the object is first created. This means object creation is fairly expensive.

Of course, you still need to write find_message and find_message_info...

Mail::Log::Trace is a cached inside-out object. If you don't know what that means, you can probably ignore it. However if you need to store object state data (and aren't using the convience accessors), it may be useful to know that $$self == refaddr $self.

UTILITY SUBROUTINES

THESE ARE ONLY FOR USE BY SUBCLASSES

There are a few subroutines especially for use by subclasses.

_set_message_raw_info

Give this the raw message info, in whatever format the parser gives it. The user should hopefully never want it, but just in case...

_set_log_parser

Sets the log parser. Takes a reference to a parser object.

_get_log_parser

Returns the log parser object.

_get_parser_class

Returns the name of the class the user wants you to use to parse the file.

Please take it under advisement.

BUGS

None known at the moment... (I am nervious about the way I'm storing some of these coderefs. So far I haven't run into problems, but I'm not entirely sure there aren't any. If you start getting weird behaviour when using multiple Mail::Log::Trace subclasses at once, please tell me.)

REQUIRES

Scalar::Util, Mail::Log::Exceptions.

Some subclass, and probably a Mail::Log::Parse class to be useful.

HISTORY

1.1.1 Feb 2, 2009 - Fixed a minor issue that could cause problems with multiple subclass objects exisiting at the same time.

1.1.0 Dec 23, 2008 - Major re-write to make subclassing easier. Or possibly more confusing.

1.00.03 Dec 5, 2208 - Licence clarification.

1.00.02 Dec 2, 2008 - I really mean it this time.

1.00.01 Dec 1, 2008 - Requirements fix, no code changes.

1.00.00 Nov 28, 2008 - original version.

AUTHOR

    Daniel T. Staal
    CPAN ID: DSTAAL
    dstaal@usa.net

COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

This copyright will expire in 30 years, or five years after the author's death, whichever occurs last, at which time the code be released to the public domain.