fix: default to not generate ftv1 traces

Federation tracing should only be enabled if the Router/Gateway sends the proper ftv1 header and value. We want to default to false so we are not wasting CPU cycles tracking resolvers and building the extensions if it not going to be used

https://www.apollographql.com/docs/federation/metrics/

Supersedes: #368

graphql-java-support/src/main/java/com/apollographql/federation/graphqljava/tracing/FederatedTracingInstrumentation.java

@@ -499,7 +499,7 @@ public boolean shouldTrace(ExecutionInput executionInput) {
         return FEDERATED_TRACING_HEADER_VALUE.equals(
             executionInput.getGraphQLContext().get(FEDERATED_TRACING_HEADER_NAME));
       }
-      return true;
+      return false;
     }
   }
 }

graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/tracing/FederatedTracingInstrumentationTest.java

@@ -85,7 +85,7 @@ void setupSchema() {
   void testTracing() throws InvalidProtocolBufferException {
     Map<String, Object> result =
         graphql
-            .execute("{ widgets { foo, baz: bar }, listOfLists { foo }, listOfScalars }")
+            .execute(createExecutionInput("{ widgets { foo, baz: bar }, listOfLists { foo }, listOfScalars }"))
             .toSpecification();
 
     Object extensions = result.get("extensions");
@@ -173,7 +173,7 @@ void testTracing() throws InvalidProtocolBufferException {
 
   @Test
   void testTracingParseErrors() throws InvalidProtocolBufferException {
-    Map<String, Object> result = graphql.execute("{ widgets { foo }").toSpecification();
+    Map<String, Object> result = graphql.execute(createExecutionInput("{ widgets { foo }")).toSpecification();
 
     Object extensions = result.get("extensions");
     assertTrue(extensions instanceof Map);
@@ -192,7 +192,7 @@ void testTracingParseErrors() throws InvalidProtocolBufferException {
 
   @Test
   void testTracingValidationErrors() throws InvalidProtocolBufferException {
-    Map<String, Object> result = graphql.execute("{ widgets { notARealThing } }").toSpecification();
+    Map<String, Object> result = graphql.execute(createExecutionInput("{ widgets { notARealThing } }")).toSpecification();
 
     Object extensions = result.get("extensions");
     assertTrue(extensions instanceof Map);
@@ -263,11 +263,10 @@ void testBringYourOwnContextSignalsToTracePredicate() {
   void testTracingWithGraphQLContextMap() {
     ExecutionInput input = ExecutionInput.newExecutionInput("{widgets {foo}}").build();
 
-    // Because the special header isn't there, we fallback to the default behavior
     Map<String, Object> result = graphql.execute(input).toSpecification();
     Object extensions = result.get("extensions");
-    assertTrue(extensions instanceof Map);
-    assertTrue(((Map) extensions).containsKey("ftv1"));
+    // Because the special header isn't there, we fallback to the default behavior of not generating ftv1
+    assertNull(extensions);
 
     // Try again with the header having the wrong value.
     Map<String, Object> context = new HashMap<>();
@@ -285,4 +284,10 @@ void testTracingWithGraphQLContextMap() {
     assertTrue(extensions instanceof Map);
     assertTrue(((Map) extensions).containsKey("ftv1"));
   }
+
+  private static ExecutionInput createExecutionInput(String query) {
+    return ExecutionInput.newExecutionInput(query)
+      .graphQLContext(Map.of(FEDERATED_TRACING_HEADER_NAME, FEDERATED_TRACING_HEADER_VALUE))
+      .build();
+  }
 }