fix(tracing): Warn if resolvers is not defined in ApolloServer config (#5850)

Log a warning instead of breaking the application when `resolvers` array is not defined in the `ApolloServer` configuration.

Author: onurtemizkan

packages/tracing/src/integrations/node/apollo.ts

@@ -35,15 +35,33 @@ export class Apollo implements Integration {
     }>('apollo-server-core');
 
     if (!pkg) {
-      logger.error('Apollo Integration was unable to require apollo-server-core package.');
+      __DEBUG_BUILD__ && logger.error('Apollo Integration was unable to require apollo-server-core package.');
       return;
     }
 
     /**
      * Iterate over resolvers of the ApolloServer instance before schemas are constructed.
      */
     fill(pkg.ApolloServerBase.prototype, 'constructSchema', function (orig: () => unknown) {
-      return function (this: { config: { resolvers: ApolloModelResolvers[] } }) {
+      return function (this: { config: { resolvers?: ApolloModelResolvers[]; schema?: unknown; modules?: unknown } }) {
+        if (!this.config.resolvers) {
+          if (__DEBUG_BUILD__) {
+            if (this.config.schema) {
+              logger.warn(
+                'Apollo integration is not able to trace `ApolloServer` instances constructed via `schema` property.',
+              );
+            } else if (this.config.modules) {
+              logger.warn(
+                'Apollo integration is not able to trace `ApolloServer` instances constructed via `modules` property.',
+              );
+            }
+
+            logger.error('Skipping tracing as no resolvers found on the `ApolloServer` instance.');
+          }
+
+          return orig.call(this);
+        }
+
         const resolvers = arrayify(this.config.resolvers);
 
         this.config.resolvers = resolvers.map(model => {

packages/tracing/src/integrations/node/graphql.ts

@@ -23,7 +23,7 @@ export class GraphQL implements Integration {
     }>('graphql/execution/execute.js');
 
     if (!pkg) {
-      logger.error('GraphQL Integration was unable to require graphql/execution package.');
+      __DEBUG_BUILD__ && logger.error('GraphQL Integration was unable to require graphql/execution package.');
       return;
     }