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module Elasticsearch
module Model
# Provides support for easily and efficiently importing large amounts of
# records from the including class into the index.
#
# @see ClassMethods#import
#
module Importing
# When included in a model, adds the importing methods.
#
# @example Import all records from the `Article` model
#
# Article.import
#
# @see #import
#
def self.included(base)
base.__send__ :extend, ClassMethods
adapter = Adapter.from_class(base)
base.__send__ :include, adapter.importing_mixin
base.__send__ :extend, adapter.importing_mixin
end
module ClassMethods
# Import all model records into the index
#
# The method will pick up correct strategy based on the `Importing` module
# defined in the corresponding adapter.
#
# @param options [Hash] Options passed to the underlying `__find_in_batches`method
# @param block [Proc] Optional block to evaluate for each batch
#
# @yield [Hash] Gives the Hash with the Elasticsearch response to the block
#
# @return [Fixnum] Number of errors encountered during importing
#
# @example Import all records into the index
#
# Article.import
#
# @example Set the batch size to 100
#
# Article.import batch_size: 100
#
# @example Process the response from Elasticsearch
#
# Article.import do |response|
# puts "Got " + response['items'].select { |i| i['index']['error'] }.size.to_s + " errors"
# end
#
# @example Delete and create the index with appropriate settings and mappings
#
# Article.import force: true
#
# @example Refresh the index after importing all batches
#
# Article.import refresh: true
#
# @example Import the records into a different index/type than the default one
#
# Article.import index: 'my-new-index', type: 'my-other-type'
#
# @example Pass an ActiveRecord scope to limit the imported records
#
# Article.import scope: 'published'
#
# @example Pass an ActiveRecord query to limit the imported records
#
# Article.import query: -> { where(author_id: author_id) }
#
# @example Transform records during the import with a lambda
#
# transform = lambda do |a|
# {index: {_id: a.id, _parent: a.author_id, data: a.__elasticsearch__.as_indexed_json}}
# end
#
# Article.import transform: transform
#
# @example Update the batch before yielding it
#
# class Article
# # ...
# def self.enrich(batch)
# batch.each do |item|
# item.metadata = MyAPI.get_metadata(item.id)
# end
# batch
# end
# end
#
# Article.import preprocess: :enrich
#
# @example Return an array of error elements instead of the number of errors, eg.
# to try importing these records again
#
# Article.import return: 'errors'
#
def import(options={}, &block)
errors = []
refresh = options.delete(:refresh) || false
target_index = options.delete(:index) || index_name
target_type = options.delete(:type) || document_type
transform = options.delete(:transform) || __transform
return_value = options.delete(:return) || 'count'
unless transform.respond_to?(:call)
raise ArgumentError,
"Pass an object responding to `call` as the :transform option, #{transform.class} given"
end
if options.delete(:force)
self.create_index! force: true, index: target_index
elsif !self.index_exists? index: target_index
raise ArgumentError,
"#{target_index} does not exist to be imported into. Use create_index! or the :force option to create it."
end
__find_in_batches(options) do |batch|
response = client.bulk \
index: target_index,
type: target_type,
body: __batch_to_bulk(batch, transform)
yield response if block_given?
errors += response['items'].select { |k, v| k.values.first['error'] }
end
self.refresh_index! if refresh
case return_value
when 'errors'
errors
else
errors.size
end
end
def __batch_to_bulk(batch, transform)
batch.map { |model| transform.call(model) }
end
end
end
end
end