Federated tracing is not included in the response even though HTTP header 'apollo-federation-include-trace': 'ftv1' is provided

[michalkrajcovic]

Version v4.4.0 commit 370 changed the federated tracing to not generate ftv1 traces by default. The result is that tracing information is never returned in the response.

FederatedTracingInstrumentation#shouldTrace checks whether ExecutionInput#getGraphQLContext map contains the entry ‘apollo-federation-include-trace with value ‘ftv1’.

That key ‘apollo-federation-include-trace with value ‘ftv1’ is not present in the GraphQLContext map even though HTTP header 'apollo-federation-include-trace': 'ftv1' is provided. The result is that federated tracing is not present in the response.

Step to reproduce:

1. check out https://github.com/apollographql/federation-jvm-spring-example (spring-boot 3.3.0, federation-graphql-java-support 5.3.0)
2. enable federated tracing in the product subgraph

@Bean
public GraphQlSourceBuilderCustomizer customizer(FederationSchemaFactory factory) {
 return builder -> builder.schemaFactory(factory::createGraphQLSchema).instrumentation(List.of(new FederatedTracingInstrumentation()));
}

3. Run the product service ./gradlew :products-subgraph:bootRun
4. Query product service

curl --location 'http://localhost:8080/graphql' \
--header 'apollo-federation-include-trace: ftv1' \
--header 'Content-Type: application/json' \
--data '{"query":"query ExampleQuery {\n    products {\n        id\n        name\n        description\n    }\n}","variables":{}}'

5. Field extensions": { "ftv1": "..." } } is not present

The workaround is custom shouldTracePredicate:

new FederatedTracingInstrumentation(new FederatedTracingInstrumentation.Options(false, executionInput -> true))

[dariuszkuc]

Hello 👋,
Federation JVM is a low level library that only relies on graphql-java and is unaware of any web frameworks (e.g. Spring). FederatedTracingInstrumentation relies on the appropriate value being set in the context - it is up to you to ensure that the values are populated from the incoming request (see README and spring-graphql example. ).

Tracing should only happen if ftv1 value is set and it should generally only be set on a small sample of transactions. Your workaround sets it always to true which means that every request would calculate the tracing information regardless whether router asks for it or not.

[michalkrajcovic]

Hi @dariuszkuc

thanks for pointing me into the right direction.

Would it make sense to update the federation-jvm-spring-example to have a Spring Boot example of how to configure the federated tracing? That repo is mentioned as 'Federation JVM example integrations' in the README you just posted. Or please reference spring-graphql example in the README as well.