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An example of graphql-spring-boot microservice is available in spring-example.
Make sure Maven Central is among your repositories:
repositories {
mavenCentral()
}
Add a dependency to graphql-java-support
:
dependencies {
implementation 'com.apollographql.federation:federation-graphql-java-support:0.9.0'
}
graphql-java-support
produces a graphql.schema.GraphQLSchema
by transforming your existing schema in accordance to
the federation specification. It follows
the Builder
pattern.
Start with com.apollographql.federation.graphqljava.Federation.transform(…)
, which can receive either:
- A
GraphQLSchema
; - A
TypeDefinitionRegistry
, optionally with aRuntimeWiring
; - A String, Reader, or File declaring the schema using
the Schema Definition Language,
optionally with a
RuntimeWiring
;
and returns a SchemaTransformer
.
If your schema does not contain any types annotated with the @key
directive, nothing else is required. You can build a
transformed GraphQLSchema
with SchemaTransformer#build()
, and confirm it exposes query { _schema { sdl } }
.
Otherwise, all types annotated with @key
will be part of the _Entity
union type, and reachable
through query { _entities(representations: [Any!]!) { … } }
. Before calling SchemaTransformer#build()
, you will also
need to provide:
- A
TypeResolver
for_Entity
usingSchemaTransformer#resolveEntityType(TypeResolver)
; - A
DataFetcher
orDataFetcherFactory
for_entities
usingSchemaTransformer#fetchEntities(DataFetcher|DataFetcherFactory)
.
A minimal but complete example is available in AppConfiguration.
To make your server generate performance traces and return them along with responses to the Apollo Gateway (which then
can send them to Apollo Graph Manager), install the FederatedTracingInstrumentation
into your GraphQL
object:
GraphQL graphql = GraphQL.newGraphQL(graphQLSchema)
.instrumentation(new FederatedTracingInstrumentation())
.build();
It is generally desired to only create traces for requests that actually come from Apollo Gateway, as they aren't
helpful if you're connecting directly to your backend service for testing. In order for FederatedTracingInstrumentation
to know if the request is coming from Gateway, you should populate the tracing header information directly in the
GraphQLContext
map.
Map<Object, Object> contextMap = new HashMap<>();
String federatedTracingHeaderValue = httpRequest.getHeader(FEDERATED_TRACING_HEADER_NAME);
if (federatedTracingHeaderValue != null) {
contextMap.put(FEDERATED_TRACING_HEADER_NAME, federatedTracingHeaderValue);
}
ExecutionInput executionInput = ExecutionInput.newExecutionInput()
.graphQLContext(contextMap)
.query(queryString)
.build();
graphql.executeAsync(executionInput);