Class: GraphQL::Stitching::Supergraph

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

Defined Under Namespace

Classes: 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 84

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

  @resolvers = resolvers
  @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 80

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 82

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 82

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 77

def schema
  @schema
end

Class Method Details

.from_definition(schema, executables:) ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 18

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)

    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] << Resolver.new(
        type_name: kwargs.fetch(:type_name, type_name),
        location: kwargs[:location],
        key: kwargs[:key],
        field: kwargs[:field],
        list: kwargs[:list] || false,
        arg: kwargs[:arg],
        arg_type_name: kwargs[:arg_type_name],
        representations: kwargs[:representations] || false,
      )
    end

    next unless type.kind.fields?

    type.fields.each do |field_name, field|
      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.rb', line 12

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 208

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.frozen? ? request.context.dup : request.context,
      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 175

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 229

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 179

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 241

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 183

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 191

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 187

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") => ["id", ...]



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# File 'lib/graphql/stitching/supergraph.rb', line 249

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).tap(&:uniq!)
    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") => ["id", ...]



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# File 'lib/graphql/stitching/supergraph.rb', line 261

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] ||= begin
    location_fields = fields_by_type_and_location[type_name][location] || []
    location_fields & possible_keys_for_type(type_name)
  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 271

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] = [Resolver.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 171

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

#to_definition ⇒ Object 



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# File 'lib/graphql/stitching/supergraph.rb', line 115

def to_definition
  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)
      resolvers_for_type.each do |resolver|
        existing = type.directives.find do |d|
          kwargs = d.arguments.keyword_arguments
          d.graphql_name == ResolverDirective.graphql_name &&
            kwargs[:location] == resolver.location &&
            kwargs[:key] == resolver.key &&
            kwargs[:field] == resolver.field &&
            kwargs[:arg] == resolver.arg &&
            kwargs.fetch(:list, false) == resolver.list &&
            kwargs.fetch(:representations, false) == resolver.representations
        end

        type.directive(ResolverDirective, **{
          type_name: (resolver.type_name if resolver.type_name != type_name),
          location: resolver.location,
          key: resolver.key,
          field: resolver.field,
          list: resolver.list || nil,
          arg: resolver.arg,
          arg_type_name: resolver.arg_type_name,
          representations: resolver.representations || nil,
        }.tap(&:compact!)) if existing.nil?
      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?

      locations_for_field.each do |location|
        existing = field.directives.find do |d|
          d.graphql_name == SourceDirective.graphql_name &&
            d.arguments.keyword_arguments[:location] == location
        end

        field.directive(SourceDirective, location: location) if existing.nil?
      end
    end
  end

  @schema.to_definition
end