DynamoDB

The Drupal DynamoDB module provides integration with AWS DynamoDB services. Current integration provides a basic database wrapper for use with DynamoDB.

Features

• DynamoDB table CRUD operations: create, delete, update and list tables
• DynamoDB write, read, update and query data.
• Option to use multiple DynamoDB instances.
• Granular settings per each DynamoDB instance / table.
• Database service which follows core connection layer
• Ability to query default instance, or any other.
• Simplicity in use as any other database implementation.

Available methods

Data query / write.

• query
• scan
• getItem
• putItem
• updateItem
• deleteItem
• batchWriteItem
• batchGetItem

Table actions.

• createTable
• updateTable
• deleteTable
• listTables

Settings

Similar to the core database settings array with DynamoDB integration we can define DynamoDB connection details

$settings['dynamodb_client'] = [
  'default' => [
    'endpoint'   => 'http://dynamodb:8000',
    'region'   => 'us-west-1',
    'version'  => 'latest',
    'aws_access_key' => 'dummy',
    'aws_secret_key' => 'dummy',
    'aws_billing' => [
      "BillingMode" => "PAY_PER_REQUEST",
    ],
    'consistent_read' => FALSE,
    'table_settings' => [
      'key_value' => [
        'consistent_read' => TRUE,
      ]
    ]
  ]
];

• Note that aws_billing and consistent_read can be defined per instances but as well per each table separately under the key table_settings. In above example we set that consistent_read is FALSE, but for key_value table is set to TRUE.

• aws_billing values are required, you can set your billing mode to PAY_PER_REQUEST or PROVISIONED. If you set to PROVISIONED then you need to define capacity, as example below

    'aws_billing' => [
      'ProvisionedThroughput' => [
        'ReadCapacityUnits' => 10,
        'WriteCapacityUnits' => 5,
      ],
      "BillingMode" => "PROVISIONED",
    ],
  

Note that read consistency (consistent_read option inside settings) can effect your billing and as well results which you could get back from DynamoDb. See more details below.

Read more about:

• Billing parameters
• Read consistency

Important Whilst needs of different projects could be different, for that reason billing and read consistency can be defined through settings per an instance or per each table. As well, read consistency can be set inside each query which you perform if you choose to add ConsistencyRead => TRUE inside your query.

Examples of usage

Initialize connection - default instance

# Drupal core MySQL.
Drupal::database();

# DynamoDB - access to DynamoDB through Drupal wrapper.
DynamoDb::database();

# DynamoDB - access directly to DynamoDB, without Drupal wrapper.
DynamoDb::rawDatabase();

Initialize connection - different instance

# Drupal core MySQL.
Drupal::database('mysql_replica');

# DynamoDB
DynamoDb::database('my_second_instances');

Fetch data from key_value table

# DynamoDB - uses arrays as parameters for query to be executed.

  $params = [
    'TableName' => $this->table,
    'Key' => [
      'collection' => [
        'S' => $this->collection,
      ],
      'name' => [
        'S' => $key,
      ],
    ],
    'ProjectionExpression' => '#val',
    'ExpressionAttributeNames' => [
      '#val' => 'value',
    ],
  ];

  $result = $this->dynamodb->getItem($params);

• you can see more examples in dynamodb_keyvalue submodule

KeyValue

• drop-in replacement for the core KeyValueStore which uses MySQL as default storage
• support for key_value and key_value_expire storages
• enable the submodule

IMPORTANT: key_value is essential for Drupal site to be working properly. First enable the submodule, and during that process, migration would be performed of entries from MySQL tables to new DynamoDB tables. After the submodule is enabled, add parameters change in your services.yml file.

parameters:
factory.keyvalue.expirable:
keyvalue_expirable_default: keyvalue.expirable.dynamodb
factory.keyvalue:
default: keyvalue.dynamodb

Session

TBD - implement DynamoDB sessions.

DynamoDB documentation

• https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStartedDynamoDB.html
• https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Introduction.html