/ 
Data-Chronicle-0.19
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 PostgreSQL for future retrieval.

Transparent

This modules hides all the internal details including distribution, caching, and database structure from the 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.

EXAMPLE

my $d = get_some_log_data();

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

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

#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);

METHODS

cache_reader

cache_reader should be an instance of RedisDB.

dbic

dbic should be an instance of DBIx::Connector.

get

Example:

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

Query for the latest data under "category1::name1" from the cache reader. Will return `undef` if the data does not exist.

mget

Example:

my @values = mget([["category1", "name1"], ["category2", "name2"], ...]);

Query for the latest data under "category1::name1", "category2::name2", etc from the cache reader. Will return an arrayref containing results in the same ordering, with `undef` if the data does not exist.

get_for

Example:

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.

get_for_period

Example:

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

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

get_history

Example:

my $data = get_history("category1", "name1", 1);

Query Pg archive for the data under "category1::name1" at the provided number of revisions in the past.

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