keep the same parent span for prepare, execute and format

the spans for execute were considered root spans and did not appear
under the graphql_request span

Author: Geoffroy Couprie

apollo-router-core/src/query_planner/model.rs

@@ -242,7 +242,6 @@ impl PlanNode {
             Arc::clone(&service_registry),
             Arc::clone(&schema),
         )
-        .instrument(tracing::info_span!("execution"))
         .await;
 
         // TODO: this is not great but there is no other way

apollo-router/src/apollo_router.rs

@@ -2,6 +2,7 @@ use apollo_router_core::prelude::graphql::*;
 use derivative::Derivative;
 use futures::prelude::*;
 use std::sync::Arc;
+use tracing::{Instrument, Span};
 use tracing_futures::WithSubscriber;
 
 /// The default router of Apollo, suitable for most use cases.
@@ -88,6 +89,7 @@ pub struct ApolloPreparedQuery {
 impl PreparedQuery for ApolloPreparedQuery {
     #[tracing::instrument(level = "debug")]
     async fn execute(self, request: Arc<Request>) -> ResponseStream {
+        let span = Span::current();
         stream::once(
             async move {
                 let response_task = self
@@ -98,13 +100,17 @@ impl PreparedQuery for ApolloPreparedQuery {
                         Arc::clone(&request),
                         Arc::clone(&self.service_registry),
                         Arc::clone(&self.schema),
-                    );
-                let query_task = self.query_cache.get_query(&request.query);
+                    )
+                    .instrument(tracing::info_span!(parent: &span, "execution"));
+                let query_task = self
+                    .query_cache
+                    .get_query(&request.query)
+                    .instrument(tracing::info_span!(parent: &span, "query_parsing"));
 
                 let (mut response, query) = tokio::join!(response_task, query_task);
 
                 if let Some(query) = query {
-                    tracing::debug_span!("format_response").in_scope(|| {
+                    tracing::debug_span!(parent: &span, "format_response").in_scope(|| {
                         query.format_response(&mut response, request.operation_name.as_deref())
                     });
                 }