LoadStringVariable is a shorthand for LookupStringVariable when you do not care about the value being explicitly set.

LookupStringVariable returns the value for the given configuration variable as well as whether it was explicitly set.

SubscriptionTypeGraphQLTransportWS is for subscriptions using a WebSocket connection with 'graphql-transport-ws' as protocol.

SubscriptionTypeGraphQLWS is for subscriptions using a WebSocket connection with 'graphql-ws' as protocol.

SubscriptionTypeSSE is for Server-Sent Events (SSE) subscriptions.

SubscriptionTypeUnknown is for unknown or undefined subscriptions.

FederationEngineConfigFactory is used to create an engine config for a supergraph with multiple data sources for subgraphs.

LocalTypeFieldExtractor takes an ast.Document as input and generates the TypeField configuration for both root and child nodes.

ProxyEngineConfigFactory is used to create an engine config with a single upstream and a single data source for this upstream.

ProxyUpstreamConfig holds configuration to configure a single data source to a single upstream.