Class: GraphQL::Stitching::Supergraph

Inherits:
Object
  • Object
show all
Defined in:
lib/graphql/stitching/supergraph.rb,
lib/graphql/stitching/supergraph/key_directive.rb,
lib/graphql/stitching/supergraph/to_definition.rb,
lib/graphql/stitching/supergraph/source_directive.rb,
lib/graphql/stitching/supergraph/resolver_directive.rb

Overview

Supergraph is the singuar representation of a stitched graph. It provides the combined GraphQL schema and delegation maps used to route selections across subgraph locations.

Defined Under Namespace

Classes: KeyDirective, PathNode, ResolverDirective, SourceDirective

Constant Summary collapse

SUPERGRAPH_LOCATION = 
"__super"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(schema:, fields: {}, resolvers: {}, executables: {}) ⇒ Supergraph

Returns a new instance of Supergraph.



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# File 'lib/graphql/stitching/supergraph.rb', line 21

def initialize(schema:, fields: {}, resolvers: {}, executables: {})
  @schema = schema
  @schema.use(GraphQL::Schema::AlwaysVisible)

  @resolvers = resolvers
  @resolvers_by_version = nil
  @fields_by_type_and_location = nil
  @locations_by_type = nil
  @memoized_introspection_types = nil
  @memoized_schema_fields = {}
  @memoized_schema_types = nil
  @possible_keys_by_type = {}
  @possible_keys_by_type_and_location = {}
  @static_validator = nil

  # add introspection types into the fields mapping
  @locations_by_type_and_field = memoized_introspection_types.each_with_object(fields) do |(type_name, type), memo|
    next unless type.kind.fields?

    memo[type_name] = type.fields.keys.each_with_object({}) do |field_name, m|
      m[field_name] = [SUPERGRAPH_LOCATION]
    end
  end.freeze

  # validate and normalize executable references
  @executables = executables.each_with_object({ SUPERGRAPH_LOCATION => @schema }) do |(location, executable), memo|
    if self.class.validate_executable!(location, executable)
      memo[location.to_s] = executable
    end
  end.freeze
end

Instance Attribute Details

#executables ⇒ Hash<String, Executable> (readonly)

Returns a map of executable resources by location.

Returns:

  • (Hash<String, Executable>) —

    a map of executable resources by location.



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# File 'lib/graphql/stitching/supergraph.rb', line 17

def executables
  @executables
end

#locations_by_type_and_field ⇒ Object (readonly)

Returns the value of attribute locations_by_type_and_field.



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# File 'lib/graphql/stitching/supergraph.rb', line 19

def locations_by_type_and_field
  @locations_by_type_and_field
end

#resolvers ⇒ Object (readonly)

Returns the value of attribute resolvers.



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# File 'lib/graphql/stitching/supergraph.rb', line 19

def resolvers
  @resolvers
end

#schema ⇒ GraphQL::Schema (readonly)

Returns the composed schema for the supergraph.

Returns:

  • (GraphQL::Schema) —

    the composed schema for the supergraph.



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# File 'lib/graphql/stitching/supergraph.rb', line 14

def schema
  @schema
end

Class Method Details

.from_definition(schema, executables:) ⇒ Object 



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# File 'lib/graphql/stitching/supergraph/to_definition.rb', line 15

def from_definition(schema, executables:)
  schema = GraphQL::Schema.from_definition(schema) if schema.is_a?(String)
  field_map = {}
  resolver_map = {}
  possible_locations = {}
  introspection_types = schema.introspection_system.types.keys

  schema.types.each do |type_name, type|
    next if introspection_types.include?(type_name)

    # Collect/build key definitions for each type
    locations_by_key = type.directives.each_with_object({}) do |directive, memo|
      next unless directive.graphql_name == KeyDirective.graphql_name

      kwargs = directive.arguments.keyword_arguments
      memo[kwargs[:key]] ||= []
      memo[kwargs[:key]] << kwargs[:location]
    end

    key_definitions = locations_by_key.each_with_object({}) do |(key, locations), memo|
      memo[key] = TypeResolver.parse_key(key, locations)
    end

    # Collect/build resolver definitions for each type
    type.directives.each do |directive|
      next unless directive.graphql_name == ResolverDirective.graphql_name

      kwargs = directive.arguments.keyword_arguments
      resolver_map[type_name] ||= []
      resolver_map[type_name] << TypeResolver.new(
        location: kwargs[:location],
        type_name: kwargs.fetch(:type_name, type_name),
        field: kwargs[:field],
        list: kwargs[:list] || false,
        key: key_definitions[kwargs[:key]],
        arguments: TypeResolver.parse_arguments_with_type_defs(kwargs[:arguments], kwargs[:argument_types]),
      )
    end

    next unless type.kind.fields?

    type.fields.each do |field_name, field|
      # Collection locations for each field definition
      field.directives.each do |d|
        next unless d.graphql_name == SourceDirective.graphql_name

        location = d.arguments.keyword_arguments[:location]
        field_map[type_name] ||= {}
        field_map[type_name][field_name] ||= []
        field_map[type_name][field_name] << location
        possible_locations[location] = true
      end
    end
  end

  executables = possible_locations.keys.each_with_object({}) do |location, memo|
    executable = executables[location] || executables[location.to_sym]
    if validate_executable!(location, executable)
      memo[location] = executable
    end
  end

  new(
    schema: schema,
    fields: field_map,
    resolvers: resolver_map,
    executables: executables,
  )
end

.validate_executable!(location, executable) ⇒ Object

Raises:



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# File 'lib/graphql/stitching/supergraph/to_definition.rb', line 9

def validate_executable!(location, executable)
  return true if executable.is_a?(Class) && executable <= GraphQL::Schema
  return true if executable && executable.respond_to?(:call)
  raise StitchingError, "Invalid executable provided for location `#{location}`."
end

Instance Method Details

#execute_at_location(location, source, variables, request) ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 97

def execute_at_location(location, source, variables, request)
  executable = executables[location]

  if executable.nil?
    raise StitchingError, "No executable assigned for #{location} location."
  elsif executable.is_a?(Class) && executable <= GraphQL::Schema
    executable.execute(
      query: source,
      variables: variables,
      context: request.context.to_h,
      validate: false,
    )
  elsif executable.respond_to?(:call)
    executable.call(request, source, variables)
  else
    raise StitchingError, "Missing valid executable for #{location} location."
  end
end

#fields ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 64

def fields
  @locations_by_type_and_field.reject { |k, _v| memoized_introspection_types[k] }
end

#fields_by_type_and_location ⇒ Object

inverts fields map to provide fields for a type/location "Type" => "location" => ["field1", "field2", ...]



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# File 'lib/graphql/stitching/supergraph.rb', line 118

def fields_by_type_and_location
  @fields_by_type_and_location ||= @locations_by_type_and_field.each_with_object({}) do |(type_name, fields), memo|
    memo[type_name] = fields.each_with_object({}) do |(field_name, locations), memo|
      locations.each do |location|
        memo[location] ||= []
        memo[location] << field_name
      end
    end
  end
end

#locations ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 68

def locations
  @executables.keys.reject { _1 == SUPERGRAPH_LOCATION }
end

#locations_by_type ⇒ Object

"Type" => ["location1", "location2", ...]



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# File 'lib/graphql/stitching/supergraph.rb', line 130

def locations_by_type
  @locations_by_type ||= @locations_by_type_and_field.each_with_object({}) do |(type_name, fields), memo|
    memo[type_name] = fields.values.flatten.uniq
  end
end

#memoized_introspection_types ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 72

def memoized_introspection_types
  @memoized_introspection_types ||= schema.introspection_system.types
end

#memoized_schema_fields(type_name) ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 80

def memoized_schema_fields(type_name)
  @memoized_schema_fields[type_name] ||= begin
    fields = memoized_schema_types[type_name].fields
    @schema.introspection_system.dynamic_fields.each do |field|
      fields[field.name] ||= field # adds __typename
    end

    if type_name == @schema.query.graphql_name
      @schema.introspection_system.entry_points.each do |field|
        fields[field.name] ||= field # adds __schema, __type
      end
    end

    fields
  end
end

#memoized_schema_types ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 76

def memoized_schema_types
  @memoized_schema_types ||= @schema.types
end

#possible_keys_for_type(type_name) ⇒ Object

collects all possible resolver keys for a given type ("Type") => [Key("id"), ...]



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# File 'lib/graphql/stitching/supergraph.rb', line 138

def possible_keys_for_type(type_name)
  @possible_keys_by_type[type_name] ||= begin
    if type_name == @schema.query.graphql_name
      GraphQL::Stitching::EMPTY_ARRAY
    else
      @resolvers[type_name].map(&:key).uniq(&:to_definition)
    end
  end
end

#possible_keys_for_type_and_location(type_name, location) ⇒ Object

collects possible resolver keys for a given type and location ("Type", "location") => [Key("id"), ...]



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# File 'lib/graphql/stitching/supergraph.rb', line 150

def possible_keys_for_type_and_location(type_name, location)
  possible_keys_by_type = @possible_keys_by_type_and_location[type_name] ||= {}
  possible_keys_by_type[location] ||= possible_keys_for_type(type_name).select do |key|
    next true if key.locations.include?(location)

    # Outbound-only locations without resolver queries may dynamically match primitive keys
    location_fields = fields_by_type_and_location[type_name][location] || GraphQL::Stitching::EMPTY_ARRAY
    location_fields.include?(key.primitive_name)
  end
end

#resolvers_by_version ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 58

def resolvers_by_version
  @resolvers_by_version ||= resolvers.values.tap(&:flatten!).each_with_object({}) do |resolver, memo|
    memo[resolver.version] = resolver
  end
end

#route_type_to_locations(type_name, start_location, goal_locations) ⇒ Object

For a given type, route from one origin location to one or more remote locations used to connect a partial type across locations via resolver queries



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# File 'lib/graphql/stitching/supergraph.rb', line 163

def route_type_to_locations(type_name, start_location, goal_locations)
  key_count = possible_keys_for_type(type_name).length

  if key_count.zero?
    # nested root scopes have no resolver keys and just return a location
    goal_locations.each_with_object({}) do |goal_location, memo|
      memo[goal_location] = [TypeResolver.new(location: goal_location)]
    end

  elsif key_count > 1
    # multiple keys use an A* search to traverse intermediary locations
    route_type_to_locations_via_search(type_name, start_location, goal_locations)

  else
    # types with a single key attribute must all be within a single hop of each other,
    # so can use a simple match to collect resolvers for the goal locations.
    @resolvers[type_name].each_with_object({}) do |resolver, memo|
      if goal_locations.include?(resolver.location)
        memo[resolver.location] = [resolver]
      end
    end
  end
end

#static_validator ⇒ GraphQL::StaticValidation::Validator

Returns static validator for the supergraph schema.

Returns:

  • (GraphQL::StaticValidation::Validator) —

    static validator for the supergraph schema.



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# File 'lib/graphql/stitching/supergraph.rb', line 54

def static_validator
  @static_validator ||= @schema.static_validator
end

#to_definition ⇒ Object 



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# File 'lib/graphql/stitching/supergraph/to_definition.rb', line 86

def to_definition
  if @schema.directives[KeyDirective.graphql_name].nil?
    @schema.directive(KeyDirective)
  end
  if @schema.directives[ResolverDirective.graphql_name].nil?
    @schema.directive(ResolverDirective)
  end
  if @schema.directives[SourceDirective.graphql_name].nil?
    @schema.directive(SourceDirective)
  end

  @schema.types.each do |type_name, type|
    if resolvers_for_type = @resolvers.dig(type_name)
      # Apply key directives for each unique type/key/location
      # (this allows keys to be composite selections and/or omitted from the supergraph schema)
      keys_for_type = resolvers_for_type.each_with_object({}) do |resolver, memo|
        memo[resolver.key.to_definition] ||= Set.new
        memo[resolver.key.to_definition].merge(resolver.key.locations)
      end

      keys_for_type.each do |key, locations|
        locations.each do |location|
          params = { key: key, location: location }

          unless has_directive?(type, KeyDirective.graphql_name, params)
            type.directive(KeyDirective, **params)
          end
        end
      end

      # Apply resolver directives for each unique query resolver
      resolvers_for_type.each do |resolver|
        params = {
          location: resolver.location,
          field: resolver.field,
          list: resolver.list? || nil,
          key: resolver.key.to_definition,
          arguments: resolver.arguments.map(&:to_definition).join(", "),
          argument_types: resolver.arguments.map(&:to_type_definition).join(", "),
          type_name: (resolver.type_name if resolver.type_name != type_name),
        }

        unless has_directive?(type, ResolverDirective.graphql_name, params)
          type.directive(ResolverDirective, **params.tap(&:compact!))
        end
      end
    end

    next unless type.kind.fields?

    type.fields.each do |field_name, field|
      locations_for_field = @locations_by_type_and_field.dig(type_name, field_name)
      next if locations_for_field.nil?

      # Apply source directives to annotate the possible locations of each field
      locations_for_field.each do |location|
        params = { location: location }

        unless has_directive?(field, SourceDirective.graphql_name, params)
          field.directive(SourceDirective, **params)
        end
      end
    end
  end

  @schema.to_definition
end