Class: Chewy::Type::Syncer

Inherits:
Object show all
Defined in:
lib/chewy/type/syncer.rb

Overview

Note:

In rails 4.0 time converted to json with the precision of seconds without milliseconds used, so outdated check is not so precise there.

ATTENTION: synchronization may be slow in case when synchronized tables are missing compound index on primary key and outdated_sync_field.

This class is able to find missing and outdated documents in the ES comparing ids from the data source and the ES index. Also, if outdated_sync_field existss in the index definition, it performs comparison of this field values for each source object and corresponding ES document. Usually, this field is updated_at and if its value in the source is not equal to the value in the index - this means that this document outdated and should be reindexed.

To fetch necessary data from the source it uses adapter method Adapter::Base#import_fields, in case when the Object adapter is used it makes sense to read corresponding documentation.

If parallel option is passed to the initializer - it will fetch surce and index data in parallel and then perform outdated objects calculation in parallel processes. Also, further import (if required) will be performed in parallel as well.

See Also:

Constant Summary collapse

DEFAULT_SYNC_BATCH_SIZE = 
20_000
ISO_DATETIME = 
/\A(\d{4})-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)(\.\d+)?\z/
OUTDATED_IDS_WORKER = 
lambda do |outdated_sync_field_type, source_data_hash, index_data|
  index_data.each_with_object([]) do |(id, index_sync_value), result|
    next unless source_data_hash[id]

    outdated = if outdated_sync_field_type == 'date'
      !Chewy::Type::Syncer.dates_equal(typecast_date(source_data_hash[id]), DateTime.iso8601(index_sync_value))
    else
      source_data_hash[id] != index_sync_value
    end

    result.push(id) if outdated
  end
end
SOURCE_OR_INDEX_DATA_WORKER = 
lambda do |syncer, type|
  result = case type
  when :source
    syncer.send(:fetch_source_data)
  when :index
    syncer.send(:fetch_index_data)
  end
  {type => result}
end

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(type, parallel: nil) ⇒ Syncer

Returns a new instance of Syncer.

Parameters:

  • type (Chewy::Type) —

    chewy type

  • parallel (true, Integer, Hash) (defaults to: nil) —

    options for parallel execution or the number of processes



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# File 'lib/chewy/type/syncer.rb', line 79

def initialize(type, parallel: nil)
  @type = type
  @parallel = if !parallel || parallel.is_a?(Hash)
    parallel
  elsif parallel.is_a?(Integer)
    {in_processes: parallel}
  else
    {}
  end
end

Class Method Details

.dates_equal(one, two) ⇒ Object

Compares times with ms precision.



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# File 'lib/chewy/type/syncer.rb', line 65

def self.dates_equal(one, two)
  [one.to_i, one.usec / 1000] == [two.to_i, two.usec / 1000]
end

.typecast_date(string) ⇒ Object 



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# File 'lib/chewy/type/syncer.rb', line 54

def self.typecast_date(string)
  if string.is_a?(String) && (match = ISO_DATETIME.match(string))
    microsec = (match[7].to_r * 1_000_000).to_i
    date = "#{match[1]}-#{match[2]}-#{match[3]}T#{match[4]}:#{match[5]}:#{match[6]}.#{format('%06d', microsec)}+00:00"
    DateTime.iso8601(date)
  else
    string
  end
end

Instance Method Details

#missing_ids ⇒ Array<String>

Finds ids of all the objects that are not indexed yet or deleted from the source already.

Returns:

  • (Array<String>) —

    an array of missing ids from both sides



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# File 'lib/chewy/type/syncer.rb', line 103

def missing_ids
  return [] if source_data.blank?

  @missing_ids ||= begin
    source_data_ids = data_ids(source_data)
    index_data_ids = data_ids(index_data)

    (source_data_ids - index_data_ids).concat(index_data_ids - source_data_ids)
  end
end

#outdated_ids ⇒ Array<String>

If type supports outdated sync, it compares for the values of the type outdated_sync_field for each object and document in the source and index and returns the ids of entities which which are having different values there.

Returns:

  • (Array<String>) —

    an array of outdated ids

See Also:



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# File 'lib/chewy/type/syncer.rb', line 121

def outdated_ids
  return [] if source_data.blank? || index_data.blank? || !@type.supports_outdated_sync?
  @outdated_ids ||= begin
    if @parallel
      parallel_outdated_ids
    else
      linear_outdated_ids
    end
  end
end

#perform ⇒ Integer?

Finds all the missing and outdated ids and performs import for them.

Returns:

  • (Integer, nil) —

    the amount of missing and outdated documents reindexed, nil in case of errors



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# File 'lib/chewy/type/syncer.rb', line 93

def perform
  ids = missing_ids | outdated_ids
  return 0 if ids.blank?
  @type.import(ids, parallel: @parallel) && ids.count
end