Module: Dynamoid::Adapter::AwsSdk

Extended by:
AwsSdk
Included in:
AwsSdk
Defined in:
lib/dynamoid/adapter/aws_sdk.rb

Overview

The AwsSdk adapter provides support for the AWS-SDK for Ruby gem. More information is available at that Gem's Github page: https://github.com/amazonwebservices/aws-sdk-for-ruby

Constant Summary

@@connection = 
nil

Instance Method Summary (collapse)

Instance Method Details

- (Object) batch_delete_item(options)

Delete many items at once from DynamoDB. More efficient than delete each item individually.

or Dynamoid::Adapter::AwsSdk.batch_delete_item('table1' => [['hk1', 'rk2'], ['hk1', 'rk2']]]))

Examples:

Delete IDs 1 and 2 from the table testtable

Dynamoid::Adapter::AwsSdk.batch_delete_item('table1' => ['1', '2'])

Parameters:

  • options (Hash) —

    the hash of tables and IDs to delete

Returns:

  • nil



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 90

def batch_delete_item(options)
  return nil if options.all?{|k, v| v.empty?}
  options.each do |t, ids|
    Array(ids).in_groups_of(25, false) do |group|
      batch = AWS::DynamoDB::BatchWrite.new(:config => @@connection.config)
      batch.delete(t,group)
      batch.process!          
    end
  end
  nil
end

- (Hash) batch_get_item(table_ids, options = {})

Get many items at once from DynamoDB. More efficient than getting each item individually.

Examples:

Retrieve IDs 1 and 2 from the table testtable

Dynamoid::Adapter::AwsSdk.batch_get_item({'table1' => ['1', '2']}, :consistent_read => true)

Parameters:

  • table_ids (Hash) —

    the hash of tables and IDs to retrieve

  • options (Hash) (defaults to: {}) —

    to be passed to underlying BatchGet call

Returns:

  • (Hash) —

    a hash where keys are the table names and the values are the retrieved items

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 64

def batch_get_item(table_ids, options = {})
  hash = Hash.new{|h, k| h[k] = []}
  return hash if table_ids.all?{|k, v| v.empty?}
  table_ids.each do |t, ids|
    Array(ids).in_groups_of(100, false) do |group|
      batch = AWS::DynamoDB::BatchGet.new(:config => @@connection.config)
      batch.table(t, :all, Array(group), options) unless group.nil? || group.empty?
      batch.each do |table_name, attributes|
        hash[table_name] << attributes.symbolize_keys!
      end
    end
  end
  hash
end

- (AWS::DynamoDB::Connection) connect!

Establish the connection to DynamoDB.

Call DynamoDB new, with no parameters. Make sure the aws.yml file or aws.rb file, refer the link for more details. https://github.com/amazonwebservices/aws-sdk-for-ruby 1. Create config/aws.yml as follows: Fill in your AWS Access Key ID and Secret Access Key http://aws.amazon.com/security-credentials access_key_id: REPLACE_WITH_ACCESS_KEY_ID secret_access_key: REPLACE_WITH_SECRET_ACCESS_KEY (or) 2, Create config/initializers/aws.rb as follows: load the libraries require 'aws' log requests using the default rails logger AWS.config(:logger => Rails.logger) load credentials from a file config_path = File.expand_path(File.dirname(FILE)+"/../aws.yml") AWS.config(YAML.load(File.read(config_path))) Additionally include any of the dynamodb paramters as needed (eg: if you would like to change the dynamodb endpoint, then add the parameter in the following paramter in the file aws.yml or aws.rb dynamo_db_endpoint : dynamodb.ap-southeast-1.amazonaws.com)

Returns:

  • (AWS::DynamoDB::Connection) —

    the raw DynamoDB connection

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 40

def connect!
@@connection = AWS::DynamoDB.new
end

- (AWS::DynamoDB::Connection) connection

Return the established connection.

Returns:

  • (AWS::DynamoDB::Connection) —

    the raw DynamoDB connection

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 49

def connection
  @@connection
end

- (Integer) count(table_name)

Number of items from a table

Parameters:

  • table_name (String) —

    the name of the table

Returns:

  • (Integer) —

    the number of items from a table

Since:

  • 0.6.1



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 281

def count(table_name)
  table = get_table(table_name)
  table.items.count
end

- (Object) create_table(table_name, key = :id, options = {})

Create a table on DynamoDB. This usually takes a long time to complete.

Parameters:

  • table_name (String) —

    the name of the table to create

  • key (Symbol) (defaults to: :id) —

    the table's primary key (defaults to :id)

  • options (Hash) (defaults to: {}) —

    provide a range_key here if you want one for the table

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 109

def create_table(table_name, key = :id, options = {})
  Dynamoid.logger.info "Creating #{table_name} table. This could take a while."
  options[:hash_key] ||= {key.to_sym => :string}
  read_capacity = options[:read_capacity] || Dynamoid::Config.read_capacity
  write_capacity = options[:write_capacity] || Dynamoid::Config.write_capacity
  table = @@connection.tables.create(table_name, read_capacity, write_capacity, options)
  sleep 0.5 while table.status == :creating
  return table
end

- (Object) delete_item(table_name, key, options = {})

Removes an item from DynamoDB.

Parameters:

  • table_name (String) —

    the name of the table

  • key (String) —

    the hash key of the item to delete

  • range_key (Number) —

    the range key of the item to delete, required if the table has a composite key

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 126

def delete_item(table_name, key, options = {})
  range_key = options.delete(:range_key)
  table = get_table(table_name)
  result = table.items.at(key, range_key)
  result.delete unless result.attributes.to_h.empty?
  true
end

- (Object) delete_table(table_name)

Deletes an entire table from DynamoDB. Only 10 tables can be in the deleting state at once, so if you have more this method may raise an exception.

Parameters:

  • table_name (String) —

    the name of the table to destroy

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 140

def delete_table(table_name)
  Dynamoid.logger.info "Deleting #{table_name} table. This could take a while."
  table = @@connection.tables[table_name]
  table.delete
  sleep 0.5 while table.exists? == true
end

- (Hash) get_item(table_name, key, options = {})

Fetches an item from DynamoDB.

Parameters:

  • table_name (String) —

    the name of the table

  • key (String) —

    the hash key of the item to find

  • range_key (Number) —

    the range key of the item to find, required if the table has a composite key

Returns:

  • (Hash) —

    a hash representing the raw item in DynamoDB

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 158

def get_item(table_name, key, options = {})
  range_key = options.delete(:range_key)
  table = get_table(table_name)

  result = table.items.at(key, range_key).attributes.to_h(options)

  if result.empty?
    nil
  else
    result.symbolize_keys!
  end
end

- (Object) get_table(table_name)

TODO:

Add an UpdateTable method.



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 261

def get_table(table_name)
  unless table = table_cache[table_name]
    table = @@connection.tables[table_name]
    table.load_schema
    table_cache[table_name] = table
  end
  table
end

- (Object) list_tables

List all tables on DynamoDB.

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 184

def list_tables
  @@connection.tables.collect(&:name)
end

- (Object) put_item(table_name, object, options = nil)

Persists an item on DynamoDB.

Parameters:

  • table_name (String) —

    the name of the table

  • object (Object) —

    a hash or Dynamoid object to persist

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 194

def put_item(table_name, object, options = nil)
  table = get_table(table_name)
  table.items.create(
    object.delete_if{|k, v| v.nil? || (v.respond_to?(:empty?) && v.empty?)},
    options || {}
  )
rescue AWS::DynamoDB::Errors::ConditionalCheckFailedException => e
  raise Dynamoid::Errors::ConditionalCheckFailedException        
end

- (Enumerator) query(table_name, opts = {})

Query the DynamoDB table. This employs DynamoDB's indexes so is generally faster than scanning, but is only really useful for range queries, since it can only find by one hash key at once. Only provide one range key to the hash.

Parameters:

  • table_name (String) —

    the name of the table

  • opts (Hash) (defaults to: {}) —

    the options to query the table with

Options Hash (opts):

  • :hash_value (String) —

    the value of the hash key to find

  • :range_value (Range) —

    find the range key within this range

  • :range_greater_than (Number) —

    find range keys greater than this

  • :range_less_than (Number) —

    find range keys less than this

  • :range_gte (Number) —

    find range keys greater than or equal to this

  • :range_lte (Number) —

    find range keys less than or equal to this

Returns:

  • (Enumerator) —

    an iterator of all matching items

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 220

def query(table_name, opts = {})
  table = get_table(table_name)

  Enumerator.new do |yielder|
    consistent_opts = { :consistent_read => opts[:consistent_read] || false }
    if table.composite_key?
      table.items.query(opts).each do |data|
        if opts.has_key? :select
          yielder.yield data.attributes.symbolize_keys!
        else
          yielder.yield data.attributes.to_h(consistent_opts).symbolize_keys!
        end
      end
    else
      yielder.yield get_item(table_name, opts[:hash_value])
    end
  end
end

- (Enumerator) scan(table_name, scan_hash, select_opts)

Scan the DynamoDB table. This is usually a very slow operation as it naively filters all data on the DynamoDB servers.

Parameters:

  • table_name (String) —

    the name of the table

  • scan_hash (Hash) —

    a hash of attributes: matching records will be returned by the scan

Returns:

  • (Enumerator) —

    an iterator of all matching items

Since:

  • 0.2.0



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 248

def scan(table_name, scan_hash, select_opts)
  table = get_table(table_name)
  Enumerator.new do |yielder|
    table.items.where(scan_hash).select(select_opts).each do |data|
      yielder.yield data.attributes.symbolize_keys!
    end
  end
end

- (Object) table_cache 



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 270

def table_cache
  @table_cache ||= {}
end

- (Object) update_item(table_name, key, options = {}, &block) 



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# File 'lib/dynamoid/adapter/aws_sdk.rb', line 171

def update_item(table_name, key, options = {}, &block)
  range_key = options.delete(:range_key)
  conditions = options.delete(:conditions) || {}
  table = get_table(table_name)
  item = table.items.at(key, range_key)
  item.attributes.update(conditions.merge(:return => :all_new), &block)
rescue AWS::DynamoDB::Errors::ConditionalCheckFailedException
  raise Dynamoid::Errors::ConditionalCheckFailedException
end