Apollo Federation Changelog

@cost

Introduced. Learn more.

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directive @cost(weight: Int!) on ARGUMENT_DEFINITION | ENUM | FIELD_DEFINITION | INPUT_FIELD_DEFINITION | OBJECT | SCALAR

@listSize

Introduced. Learn more.

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directive @listSize(assumedSize: Int, slicingArguments: [String!], sizedFields: [String!], requireOneSlicingArgument: Boolean = true) on FIELD_DEFINITION

@context

Introduced. Learn more.

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directive @context(name: String!) on OBJECT | INTERFACE | UNION;

@fromContext

Introduced. Learn more.

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scalar ContextFieldValue;
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directive @fromContext(field: ContextFieldValue) on ARGUMENT_DEFINITION;

Progressive @override

Added progressive @override. Learn more.

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directive @override(from: String!, label: String) on FIELD_DEFINITION

@policy

Introduced. Learn more.

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directive @policy(policies: [[federation__Policy!]!]!) on
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  | FIELD_DEFINITION
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  | OBJECT
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  | INTERFACE
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  | SCALAR
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  | ENUM

Policy

• Custom scalar representing an authorization policy. Used by new @policy directive.

@authenticated

Introduced. Learn more.

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directive @authenticated on
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    FIELD_DEFINITION
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  | OBJECT
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  | INTERFACE
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  | SCALAR
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  | ENUM

@requiresScopes

Introduced. Learn more.

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directive @requiresScopes(scopes: [[federation__Scope!]!]!) on
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    FIELD_DEFINITION
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  | OBJECT
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  | INTERFACE
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  | SCALAR
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  | ENUM

Scope

• Custom scalar representing a JWT scope. Used by new @requiresScopes directive.

Subscriptions

• Composition now supports defining the Subscription type in subgraph schemas.
• Use of GraphQL subscriptions with a federated graph requires a compatible version of the GraphOS Router. See details.

@interfaceObject

Introduced. Learn more.

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directive @interfaceObject on OBJECT

@key

Can now be applied to interface definitions to support entity interfaces.

(Previous versions of composition threw an error if @key was applied to an interface definition.)

@shareable

Added repeatable to the directive definition.

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directive @shareable repeatable on OBJECT | FIELD_DEFINITION

Additionally, composition now throws an error if @shareable is applied to fields of an interface definition.

@composeDirective

Introduced. Learn more.

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directive @composeDirective(name: String!) repeatable on SCHEMA

@requires

The fields argument can now include fields that themselves take arguments. Learn more.

(Functionality added in v2.1.2)

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type Product @key(fields: "id") {
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  id: ID!
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  weight(units: String): Int! @external
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  shippingEstimate: Int! @requires(fields: "weight(units: \"KILOGRAMS\")")
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}

@key

Added optional resolvable argument.

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directive @key(
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  fields: FieldSet!,
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  resolvable: Boolean = true 
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) repeatable on OBJECT | INTERFACE

@shareable

Introduced.

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directive @shareable on OBJECT | FIELD_DEFINITION

@inaccessible

Introduced.

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directive @inaccessible on
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  | FIELD_DEFINITION
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  | OBJECT
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  | INTERFACE
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  | UNION
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  | ARGUMENT_DEFINITION
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  | SCALAR
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  | ENUM
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  | ENUM_VALUE
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  | INPUT_OBJECT
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  | INPUT_FIELD_DEFINITION

@override

Introduced.

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directive @override(from: String!) on FIELD_DEFINITION

@link

Introduced.

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directive @link(
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  url: String,
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  as: String,
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  for: link__Purpose,
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  import: [link__Import]
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) repeatable on SCHEMA

@extends, @external, @provides, @requires, @tag

No changes.

Entities

• Entities no longer originate in a subgraph. Instead, any number of subgraphs can define the same entity and contribute fields to it.
• Multiple subgraphs can contribute the same field to an entity, if that field is marked as @shareable in every subgraph that defines it.
• Subgraphs no longer need to extend (or @extends) an entity whenever another subgraph already defines that entity.
• Each subgraph can apply any number of @key directives to an entity.
• Subgraphs must no longer apply the @external directive to their @key fields.

Value types

• To define a value type with shared fields across multiple subgraphs, those shared fields must be marked as @shareable in every subgraph that defines them.
• Value type fields can differ across subgraphs (in certain ways). For details, see Differing shared fields.

Query and Mutation

• More than one subgraph can define the same field of the Query or Mutation type, if that field is marked as @shareable in every subgraph that defines it.
• Subgraphs no longer need to apply the extend keyword (or the @extends directive) to the Query and Mutation types.

@tag

Introduced.

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directive @tag(name: String!) repeatable on
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  | FIELD_DEFINITION
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  | INTERFACE
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  | OBJECT
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  | UNION

@key

Introduced.

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directive @key(fields: _FieldSet!) repeatable on OBJECT | INTERFACE

@external

Introduced.

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directive @external on FIELD_DEFINITION

@requires

Introduced.

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directive @requires(fields: _FieldSet!) on FIELD_DEFINITION

@provides

Introduced.

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directive @provides(fields: _FieldSet!) on FIELD_DEFINITION

@extends

Introduced.

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directive @extends on OBJECT | INTERFACE

Entities

• Each entity originates in exactly one subgraph and can be extended in other subgraphs.
• An entity's originating subgraph must apply at least one @key directive to the entity definition.
• An extending subgraph must use the extend keyword (or the @extends directive) when defining another subgraph's entity.
• An extending subgraph must apply exactly one @key directive to any entity it extends. The fields of that @key must match a @key that's defined by the entity's originating subgraph.
• An extending subgraph must apply the @external directive to all @key fields of an entity it extends.
• If an entity field is defined in more than one subgraph, it must be marked as @external in all but one subgraph.

Value types

• Each subgraph that defines a value type must define that value type identically.

Query and Mutation

• More than one subgraph cannot define the same field of the Query or Mutation type.
• Every subgraph must apply the extend keyword (or the @extends directive) to the Query and Mutation types.