federation

Documentation

Index

• type FieldInfo
• type MergeMode
• type SchemaWithFederationInfo

Types

type FieldInfo

type FieldInfo struct {
	// Services is the set of all services that can resolve this
	// field. If a service has multiple versions, all versions
	// must be able to resolve the field.
	Services map[string]bool
}

FieldInfo holds federation-specific information for graphql.Fields used to plan and execute queries.

type MergeMode

type MergeMode string

MergeMode controls how to combine two different schemas. Union is used for two independent services, Intersection for two different versions of the same service.

const (
	// Union computes a schema that is supported by the two services combined.
	//
	// A Union is used to to combine the schema of two independent services.
	// The proxy will split a GraphQL query to ask each service the fields
	// it knows about.
	//
	// Two schemas must be compatible: Any overlapping types (eg. a field that
	// is implemented by both services, or two input types) must be compatible.
	// In practice, this means types must be identical except for non-nil
	// modifiers.
	//
	// XXX: take intersection on ENUM values to not confuse a service with a
	// type it doesn't support?
	Union MergeMode = "union"

	// Intersection computes a schema that is supported by both services.
	//
	// An Intersection is used to combine two schemas of different versions
	// of the same service. During a deploy, only of two versions might be
	// available, and so queries must be compatible with both schemas.
	//
	// Intersection computes a schema that can be executed by both services.
	// It only includes types and fields (etc.) exported by both services.
	// Overlapping types must be compatible as in a Union merge.
	//
	// One surprise might be that newly added ENUM values or UNION types might
	// be returned by the merged schema.
	Intersection MergeMode = "intersection"
)

type SchemaWithFederationInfo

type SchemaWithFederationInfo struct {
	Schema *graphql.Schema
	// Fields is a map of fields to services which they belong to
	Fields map[*graphql.Field]*FieldInfo
}

SchemaWithFederationInfo holds a graphql.Schema along with federtion-specific annotations per field.