Provide hook with access to schema mappings inspection report

[rstoyanchev]

We can expose a hook that provides access to the Report and allows applications to take some actions. The default action would be to log it, which is what we do currently.

Requested in #386 (comment).

[rstoyanchev]

Something like this, which can then be applied from a GraphQlSourceBuilderCustomizer bean with Boot:

GraphQlSource.schemaResourceBuilder()
		.schemaResources()
		.inspectSchemaMappings(report -> {
			// ...
		})
		.build();

If this is configured, we won't log the report. It'll be all up to the callback.

[danielshiplett]

Yes. I think that is a good approach with the customizer + default with the option to use our own implementation.

[bclozel]

I think we need to significantly refactor the Report contract to provide higher abstractions and prepare for new behavior.

[rstoyanchev]

@danielshiplett I've added a Consumer<SchemaReport> hook to GraphQlSource.Builder that also enables the inspection. So you can configure it, and either log and/or take any other action. If not configured, the inspection does not run. Please, have a look to see what's in the report, and give us your feedback.

[danielshiplett]

@rstoyanchev This seems to work as expected. I have created a demonstration that invokes Spring's Failure Analysis feature to stop the application and provide feedback. Here is the configuration class that does that.

Here is some example output where a single mapping and a single registration were in error:

2023-04-28T13:50:26.685-04:00  INFO 2216713 --- [  restartedMain] efaultSchemaResourceGraphQlSourceBuilder : Loaded 2 resource(s) in the GraphQL schema.
2023-04-28T13:50:26.828-04:00  WARN 2216713 --- [  restartedMain] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'routerFunctionMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Error creating bean with name 'graphQlRouterFunction' defined in class path resource [org/springframework/boot/autoconfigure/graphql/servlet/GraphQlWebMvcAutoConfiguration.class]: Unsatisfied dependency expressed through method 'graphQlRouterFunction' parameter 0: Error creating bean with name 'graphQlHttpHandler' defined in class path resource [org/springframework/boot/autoconfigure/graphql/servlet/GraphQlWebMvcAutoConfiguration.class]: Unsatisfied dependency expressed through method 'graphQlHttpHandler' parameter 0: Error creating bean with name 'webGraphQlHandler' defined in class path resource [org/springframework/boot/autoconfigure/graphql/servlet/GraphQlWebMvcAutoConfiguration.class]: Unsatisfied dependency expressed through method 'webGraphQlHandler' parameter 0: Error creating bean with name 'executionGraphQlService' defined in class path resource [org/springframework/boot/autoconfigure/graphql/GraphQlAutoConfiguration.class]: Unsatisfied dependency expressed through method 'executionGraphQlService' parameter 0: Error creating bean with name 'graphQlSource' defined in class path resource [org/springframework/boot/autoconfigure/graphql/GraphQlAutoConfiguration.class]: Failed to instantiate [org.springframework.graphql.execution.GraphQlSource]: Factory method 'graphQlSource' threw exception with message: See description
2023-04-28T13:50:26.830-04:00  INFO 2216713 --- [  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2023-04-28T13:50:26.840-04:00  INFO 2216713 --- [  restartedMain] .s.b.a.l.ConditionEvaluationReportLogger : 

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2023-04-28T13:50:26.853-04:00 ERROR 2216713 --- [  restartedMain] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Invalid schema mappings.  SchemaReport:

GraphQL schema inspection:
        Unmapped fields: {User=[comments]}
        Unmapped registrations: {User.age=UserController#age[1 args]}
        Skipped types: []


Action:

See description for details of invalid schema mappings.

[rstoyanchev]

Thanks for confirming and for the example! I noticed a few bullet items under the Status section in the README. Is there anything there that remains not done?