/ 
Data-Chronicle-0.04
River stage one • 1 direct dependent • 1 total dependent
/ Data::Chronicle::Reader

NAME

Data::Chronicle::Reader - Provides reading from an efficient data storage for volatile and time-based data

DESCRIPTION

This module contains helper methods which can be used to store and retrieve information on an efficient storage with below properties:

Timeliness

It is assumed that data to be stored are time-based meaning they change over time and the latest version is most important for us.

Efficient

The module uses Redis cache to provide efficient data storage and retrieval.

Persistent

In addition to caching every incoming data, it is also stored in PostgresSQL for future retrieval.

Transparent

This modules hides all the details about distribution, caching, database structure and ... from developer. He only needs to call a method to save data and another method to retrieve it. All the underlying complexities are handled by the module.

There are three important methods this module provides:

set

Given a category, name and value stores the JSONified value in Redis and PostgreSQL database under "category::name" group and also stores current system time as the timestamp for the data (Which can be used for future retrieval if we want to get data as of a specific time). Note that the value MUST be either hash-ref or array-ref.

get

Given a category and name returns the latest version of the data according to current Redis cache

get_for

Given a category, name and timestamp returns version of data under "category::name" as of the given date (using a DB lookup).

Example

my $d = get_some_log_data();

my $chronicle_w = Data::Chronicle::Writer->new( 
   cache_writer => $writer,
   db_handle    => $dbh);

my $chronicle_r = Data::Chronicle::Reader->new( 
   cache_reader => $reader, 
   db_handle    => $dbh);


#store data into Chronicle - each time we call `set` it will also store 
#a copy of the data for historical data retrieval
$chronicle_w->set("log_files", "syslog", $d);

#retrieve latest data stored for syslog under log_files category
my $dt = $chronicle_r->get("log_files", "syslog");

#find historical data for `syslog` at given point in time
my $some_old_data = $chronicle_r->get_for("log_files", "syslog", $epoch1);

my $data = get("category1", "name1")

Query for the latest data under "category1::name1" from Redis.

my $data = get_for("category1", "name1", 1447401505)

Query Pg archive for the data under "category1::name1" at or exactly before the given epoch/Date::Utility.

my $data = get_for_period("category1", "name1", 1447401505, 1447401900)

Query Pg historical data and return records whose date is between given period.

AUTHOR

Binary.com, <support at binary.com>

BUGS

Please report any bugs or feature requests to bug-data-chronicle at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Data-Chronicle. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Data::Chronicle::Reader

You can also look for information at:

ACKNOWLEDGEMENTS

LICENSE AND COPYRIGHT

Copyright 2016 Binary.com.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.