NAME

Starch::Store::Amazon::DynamoDB - Starch storage backend using Amazon::DynamoDB.

SYNOPSIS

    my $starch = Starch->new(
        store => {
            class => '::Amazon::DynamoDB',
            ddb => {
                implementation => 'Amazon::DynamoDB::LWP',
                version        => '20120810',
                
                access_key   => 'access_key',
                secret_key   => 'secret_key',
                # or you specify to use an IAM role
                use_iam_role => 1,
                
                host  => 'dynamodb.us-east-1.amazonaws.com',
                scope => 'us-east-1/dynamodb/aws4_request',
                ssl   => 1,
            },
        },
    );

DESCRIPTION

This Starch store uses Amazon::DynamoDB to set and get state data.

SERIALIZATION

State data is stored in DynamoDB in an odd fashion in order to bypass some of DynamoDB's and Amazon::DynamoDB's design limitations.

  • Empty strings are stored with the value __EMPTY__ as DynamoDB does not support empty string values.

  • References are serialized using the "serializer" and prefixed with __SERIALIZED__:. DynamoDB supports array and hash-like data types, but Amazon::DynamoDB does not.

  • Undefined values are serialized as __UNDEF__, because DynamoDB does not support undefined or null values.

This funky serialization is only visibile if you look at the raw DynamoDB records. As an example, here's what the "data" in Starch::State would look like:

    {
        this => 'that',
        thing => { goose=>3 },
        those => [1,2,3],
        name => '',
        age => undef,
        biography => '    ',
    }

And here's what the record would look like in DynamoDB:

    this: 'that'
    thing: '__SERIALIZED__:{"goose":3}'
    those: '__SERIALIZED__:[1,2,3]'
    name: '__EMPTY__'
    age: '__UNDEF__'
    biography: '    '

REQUIRED ARGUMENTS

ddb

This must be set to either hash ref arguments for Amazon::DynamoDB or a pre-built object (often retrieved using a method proxy).

When configuring Starch from static configuration files using a method proxy is a good way to link your existing Amazon::DynamoDB object constructor in with Starch so that starch doesn't build its own.

OPTIONAL ARGUMENTS

consistent_read

When true this sets the ConsistentRead flag when calling get_item on the "ddb". Defaults to true.

serializer

A Data::Serializer::Raw for serializing the state data for storage when a field's value is a reference. Can be specified as string containing the serializer name, a hashref of Data::Serializer::Raw arguments, or as a pre-created Data::Serializer::Raw object. Defaults to JSON.

Consider using the JSON::XS or Sereal serializers for speed.

table

The DynamoDB table name where states are stored. Defaults to starch_states.

key_field

The field in the "table" where the state ID is stored. Defaults to __STARCH_KEY__.

expiration_field

The field in the "table" which will hold the epoch time when the state should be expired. Defaults to __STARCH_EXPIRATION__.

connect_on_create

By default when this store is first created it will issue a "get". This initializes all the LWP and other code so that, in a forked environment (such as a web server) this initialization only happens once, not on every child's first request, which otherwise would add about 50 to 100 ms to the firt request of every child.

Set this to false if you don't want this feature, defaults to true.

METHODS

create_table_args

Returns the appropriate arguments to use for calling create_table on the "ddb" object. By default it will look like this:

    {
        TableName => 'starch_states',
        ReadCapacityUnits => 10,
        WriteCapacityUnits => 10,
        AttributeDefinitions => { key => 'S' },
        KeySchema => [ 'key' ],
    }

Any arguments you pass will override those in the returned arguments.

create_table

Creates the "table" by passing any arguments to "create_table_args" and issuing the create_table command on the "ddb" object.

set

Set "set" in Starch::Store.

get

Set "get" in Starch::Store.

remove

Set "remove" in Starch::Store.

SUPPORT

Please submit bugs and feature requests to the Starch-Store-Amazon-DynamoDB GitHub issue tracker:

https://github.com/bluefeet/Starch-Store-Amazon-DynamoDB/issues

AUTHORS

    Aran Clary Deltac <bluefeet@gmail.com>

ACKNOWLEDGEMENTS

Thanks to ZipRecruiter for encouraging their employees to contribute back to the open source ecosystem. Without their dedication to quality software development this distribution would not exist.

LICENSE

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