Module: DynaModel::Query::ClassMethods

Defined in:
lib/dyna_model/query.rb

Instance Method Summary collapse

Instance Method Details

#count_range(hash_value, options = {}) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/dyna_model/query.rb', line 105

def count_range(hash_value, options={})
  raise ArgumentError, "no range_key specified for this table" if self.dynamo_db_table.range_keys.blank?
  results = self.dynamo_db_table.query(hash_value, options.merge(select: :count))
  Response.new(results).count
end

#read(hash_value, range_value_or_options = nil, options = nil) ⇒ Object 



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# File 'lib/dyna_model/query.rb', line 21

def read(hash_value, range_value_or_options=nil, options=nil)
  if self.range_key.nil?
    item_attrs = self.dynamo_db_table.get_item(hash_value, range_value_or_options || {})[:item]
    return nil if item_attrs.nil?
    self.obj_from_attrs(Table.values_from_response_hash(item_attrs), (range_value_or_options || {}))
  else
    raise ArgumentError, "This table requires a range_key_value" if range_value_or_options.nil?
    self.read_range(hash_value, (options || {}).merge(range: { self.range_key[:attribute_name].to_sym.eq => range_value_or_options})).first
  end
end

#read_first(hash_value, options = {}) ⇒ Object 



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# File 'lib/dyna_model/query.rb', line 111

def read_first(hash_value, options={})
  self.read_range(hash_value, options).first
end

#read_guid(guid, options = {}) ⇒ Object 



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# File 'lib/dyna_model/query.rb', line 11

def read_guid(guid, options={})
  return nil if guid.blank?
  if self.range_key
    hash_value, range_value = guid.split(self.guid_delimiter)
    self.read(hash_value, range_value, options)
  else
    self.read(guid, options)
  end
end

#read_multiple(keys, options = {}) ⇒ Object 



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# File 'lib/dyna_model/query.rb', line 32

def read_multiple(keys, options={})
  results_map = {}
  results = self.dynamo_db_table.batch_get_item(keys, options)
  results[:responses][self.dynamo_db_table_name(options[:shard_name])].each do |result|
    attrs = Response.strip_attr_types(result)
    obj = self.obj_from_attrs(attrs, options)
    if self.dynamo_db_table.range_keys.present? && primary_range_key = self.dynamo_db_table.range_keys.find{|rk| rk[:primary_range_key] }
      (results_map[attrs[self.dynamo_db_table.hash_key[:attribute_name]]] ||= {})[attrs[primary_range_key[:attribute_name]]] = obj
    else
      results_map[attrs[self.dynamo_db_table.hash_key[:attribute_name]]] = obj
    end
  end
  results_map
end

#read_range(hash_value, options = {}) ⇒ Object

Read results up to the limit

read_range("1", :range => { :varname.gte => "2"}, :limit => 10)

Loop results in given batch size until limit is hit or no more results

read_range("1", :range => { :varname.eq => "2"}, :batch => 10, :limit => 1000)

Raises:

  • (ArgumentError) 


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# File 'lib/dyna_model/query.rb', line 51

def read_range(hash_value, options={})
  raise ArgumentError, "no range_key specified for this table" if self.dynamo_db_table.range_keys.blank? && self.global_secondary_indexes.blank?
  aggregated_results = []

  # Useful if doing pagination where you would need the last key evaluated
  return_last_evaluated_key = options.delete(:return_last_evaluated_key)
  batch_size = options.delete(:batch) || DEFAULT_BATCH_SIZE
  max_results_limit = options[:limit]
  if options[:limit] && options[:limit] > batch_size
    options.merge!(:limit => batch_size)
  end

  results = self.dynamo_db_table.query(hash_value, options)
  response = Response.new(results)

  results[:member].each do |result|
    attrs = Response.strip_attr_types(result)
    aggregated_results << self.obj_from_attrs(attrs, options)
  end

  if response.more_results?
    results_returned = response.count
    batch_iteration = 0
    Timeout::timeout(QUERY_TIMEOUT) do
      while response.more_results?
        if max_results_limit && (delta_results_limit = (max_results_limit-results_returned)) < batch_size
          break if delta_results_limit == 0
          options.merge!(limit: delta_results_limit)
        else
          options.merge!(limit: batch_size)
        end

        results = self.dynamo_db_table.query(hash_value, options.merge(exclusive_start_key: response.last_evaluated_key))
        response = Response.new(results)
        results[:member].each do |result|
          attrs = Response.strip_attr_types(result)
          aggregated_results << self.obj_from_attrs(attrs, options)
        end
        results_returned += response.count
        batch_iteration += 1
      end
    end
  end

  if return_last_evaluated_key
    {
      last_evaluated_key: response.last_evaluated_key,
      members: aggregated_results
    }
  else
    aggregated_results
  end
end

#scan(options = {}) ⇒ Object

:count=>10, :scanned_count=>10, :last_evaluated_key=>“guid”=>{:s=>“11f82550-5c5d-11e3-9b55-d311a43114ca”}} :manual_batching => true|false

return results with last_evaluated_key instead of automatically looping through (useful to throttle or )



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# File 'lib/dyna_model/query.rb', line 118

def scan(options={})
  aggregated_results = []

  batch_size = options.delete(:batch) || DEFAULT_BATCH_SIZE
  max_results_limit = options[:limit]
  options[:limit] = batch_size

  results = self.dynamo_db_table.scan(options)
  response = Response.new(results)

  results[:member].each do |result|
    attrs = Response.strip_attr_types(result)
    aggregated_results << self.obj_from_attrs(attrs, options)
  end

  if response.more_results? && !options[:manual_batching]
    results_returned = response.count
    batch_iteration = 0
    Timeout::timeout(QUERY_TIMEOUT) do
      while response.more_results?
        if max_results_limit && (delta_results_limit = (max_results_limit-results_returned)) < batch_size
          break if delta_results_limit == 0
          options.merge!(limit: delta_results_limit)
        else
          options.merge!(limit: batch_size)
        end

        results = dynamo_table.scan(options.merge(exclusive_start_key: response.last_evaluated_key))
        response = Response.new(results)
        results[:member].each do |result|
          attrs = Response.strip_attr_types(result)
          aggregated_results << self.obj_from_attrs(attrs, options)
        end
        results_returned += response.count
        batch_iteration += 1
      end
    end
  end

  if options[:manual_batching]
    response_hash = {
      results: aggregated_results,
      last_evaluated_key: results[:last_evaluated_key]
    }
    response_hash.merge!(consumed_capacity: results[:consumed_capacity]) if results[:consumed_capacity]
    response_hash
  else
    aggregated_results
  end
end