Class: GraphQL::Stitching::Supergraph

Inherits:
Object
  • Object
show all
Defined in:
lib/graphql/stitching/supergraph.rb,
lib/graphql/stitching/supergraph/types.rb,
lib/graphql/stitching/supergraph/from_definition.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

Modules: InterfaceType, Visibility Classes: ArgumentType, EnumType, EnumValueType, FieldType, InputObjectType, ObjectType, PathNode, ScalarType, UnionType

Constant Summary collapse

SUPERGRAPH_LOCATION = 
"__super"
BASE_TYPES = 
{
  enum: EnumType,
  input_object: InputObjectType,
  interface: InterfaceType,
  object: ObjectType,
  scalar: ScalarType,
  union: UnionType,
}.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

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

Returns a new instance of Supergraph.



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# File 'lib/graphql/stitching/supergraph.rb', line 25

def initialize(schema:, fields: {}, resolvers: {}, visibility_profiles: [], executables: {})
  @schema = schema
  @resolvers = resolvers
  @resolvers_by_version = nil
  @fields_by_type_and_location = nil
  @locations_by_type = nil
  @memoized_introspection_types = @schema.introspection_system.types
  @memoized_schema_types = @schema.types
  @memoized_schema_fields = {}
  @possible_keys_by_type = {}
  @possible_keys_by_type_and_location = {}

  # 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

  if visibility_profiles.any?
    profiles = visibility_profiles.each_with_object({ nil => {} }) { |p, m| m[p.to_s] = {} }
    @schema.use(GraphQL::Schema::Visibility, profiles: profiles)
  else
    @schema.use(GraphQL::Schema::AlwaysVisible)
  end
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 18

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 23

def locations_by_type_and_field
  @locations_by_type_and_field
end

#memoized_introspection_types ⇒ Object (readonly)

Returns the value of attribute memoized_introspection_types.



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# File 'lib/graphql/stitching/supergraph.rb', line 22

def memoized_introspection_types
  @memoized_introspection_types
end

#memoized_schema_types ⇒ Object (readonly)

Returns the value of attribute memoized_schema_types.



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

def memoized_schema_types
  @memoized_schema_types
end

#resolvers ⇒ Object (readonly)

Returns the value of attribute resolvers.



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# File 'lib/graphql/stitching/supergraph.rb', line 20

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 15

def schema
  @schema
end

Class Method Details

.from_definition(schema, executables:) ⇒ Object 



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# File 'lib/graphql/stitching/supergraph/from_definition.rb', line 12

def from_definition(schema, executables:)
  if schema.is_a?(String)
    schema = if GraphQL::Stitching.supports_visibility?
      GraphQL::Schema.from_definition(schema, base_types: BASE_TYPES)
    else
      GraphQL::Schema.from_definition(schema)
    end
  end

  field_map = {}
  resolver_map = {}
  possible_locations = {}
  visibility_profiles = if (visibility_def = schema.directives[GraphQL::Stitching.visibility_directive])
    visibility_def.get_argument("profiles").default_value
  else
    []
  end

  schema.types.each do |type_name, type|
    next if type.introspection?

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

      kwargs = d.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 == Directives::SupergraphSource.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,
    visibility_profiles: visibility_profiles,
    executables: executables,
  )
end

.validate_executable!(location, executable) ⇒ Object

Raises:



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# File 'lib/graphql/stitching/supergraph/from_definition.rb', line 6

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 98

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 73

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 119

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 77

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 131

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_schema_fields(type_name) ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 81

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

#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 139

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 151

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 67

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 164

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

#to_definition(visibility_profile: nil) ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 61

def to_definition(visibility_profile: nil)
  @schema.to_definition(context: { 
    visibility_profile: visibility_profile,
  }.tap(&:compact!))
end