Class: Dynomite::Item::Indexes::Finder

Inherits:
Object
  • Object
show all
Extended by:
Memoist
Includes:
Client
Defined in:
lib/dynomite/item/indexes/finder.rb

Instance Method Summary collapse

Constructor Details

#initialize(source, query) ⇒ Finder

Returns a new instance of Finder.



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# File 'lib/dynomite/item/indexes/finder.rb', line 6

def initialize(source, query)
  @source, @query = source, query
end

Instance Method Details

#find(index_name = nil) ⇒ Object 



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# File 'lib/dynomite/item/indexes/finder.rb', line 10

def find(index_name=nil)
  if index_name # explicit index name
    index = @source.indexes.find { |i| i.index_name == index_name }
    if index
      return index
    else
      logger.info <<~EOL
        WARN: Index #{index_name} specified but not found for table #{@source.table_name}
        Falling back to auto-discovery of indexes
      EOL
    end
  end

  # auto-discover
  find_primary_key_index || find_secondary_index
end

#find_primary_key_index ⇒ Object 



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# File 'lib/dynomite/item/indexes/finder.rb', line 27

def find_primary_key_index
  PrimaryIndex.new(@source.primary_key_fields) if primary_key_found?
end

#find_secondary_index ⇒ Object

It’s possible to have multiple indexes with the same partition and sort key. Will use the first one we find.



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# File 'lib/dynomite/item/indexes/finder.rb', line 41

def find_secondary_index
  @source.indexes.find do |i|
    # If query field has comparision expression like
    #   Product.where("category.in": ["Electronics"]).count
    # then it wont match, which is correct.
    intersect = query_fields & i.fields
    intersect == i.fields
  end
end

#primary_key_found? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dynomite/item/indexes/finder.rb', line 31

def primary_key_found?
  if @source.composite_key?
    query_fields.include?(@source.partition_key_field) && query_fields.include?(@source.sort_key_field)
  else
    query_fields.include?(@source.partition_key_field)
  end
end

#query_fields ⇒ Object 



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# File 'lib/dynomite/item/indexes/finder.rb', line 51

def query_fields
  @query[:where].inject([]) do |result, where_group|
    result += where_group.fields
  end.uniq.sort.map(&:to_s)
end