Prior to this commit, the WebFlux and WebMVC infrastructure would only
support subscriptions over the WebSocket and RSocket transports.
This commit adds the `GraphQlSseHandler` implementations for both web
frameworks. This handler will send GraphQL responses as as stream of
Server-Sent Events, over an HTTP response with the "text/event-stream"
content type.
This implementation only supports the "Distinct connections mode" and
will reject all operations other than Subscriptions.
This commit also enhances the `HttpGraphQlTransport` client transport to
support subscriptions over this new protocol.
Closes gh-309
Prior to this commit, GraphQL Request Observations would not record
errors as Observation errors, because with GraphQL errors can partially
affect the response and there can be multiple. Instead, an invalid
request (for example) would lead to a `"graphql.outcome", "REQUEST_ERROR"`
low cardinality KeyValue. In this case, developers would not know what
type of error occured nor if there were multiple.
This commit records all errors listed in the GraphQL as
Observation.Event on the request Observation. Such events are usually
handled by the tracing handler and are recorded as span annotations for
traces. Other `ObservationHandler` annotations can leverage events in a
different fashion.
Closes gh-859
This adds support for date values to JsonKeysetCursorStrategy by default
when Jackson is on the classpath and also updates the documentation to
provide guidance.
Closes gh-684
Prior to this commit, the request execution observation would have a
context of type `RequestReplyReceiverContext` to directly deal with
tracing propagation at the transport level. This approach doesn't work
anymore as the parent observation is not properly set on the resulting
trace, even if it is manually set in the instrumentation.
This commit revisits the request observation setup and turns its context
into a regular `Observation.Context`. Tracing propagation should be
dealt with directly at the transport level by an underlying observation.
This is the case already for Spring Framework HTTP server observations.
As a result, the `PropagationWebGraphQlInterceptor` is deprecated with
no replacement and should not be used anymore.
Fixes gh-675
