Simplify getCurrentHub and inherit hub from previous domain

Author: kamilogorek

packages/hub/src/hub.ts

@@ -325,28 +325,16 @@ export function getCurrentHub(): Hub {
     registry.hub = new Hub();
   }
 
-  let domain = null;
   try {
-    domain = process.domain as SentryDomain;
+    const domain = process.domain as SentryDomain;
+    domain.__SENTRY__ = domain.__SENTRY__ || {};
+    if (!domain.__SENTRY__.hub || domain.__SENTRY__.hub.isOlderThan(API_VERSION)) {
+      domain.__SENTRY__.hub = new Hub(registry.hub.getStackTop().client, Scope.clone(registry.hub.getStackTop().scope));
+    }
+    return domain.__SENTRY__.hub;
   } catch (_Oo) {
-    // We do not have process
-  }
-
-  if (!domain) {
     return registry.hub;
   }
-
-  let carrier = domain.__SENTRY__;
-  if (!carrier) {
-    domain.__SENTRY__ = carrier = {};
-  }
-
-  if (!carrier.hub) {
-    const top = registry.hub.getStackTop();
-    carrier.hub = top ? new Hub(top.client, Scope.clone(top.scope)) : new Hub();
-  }
-
-  return carrier.hub;
 }
 
 /**

packages/node/package.json

@@ -16,6 +16,7 @@
   },
   "dependencies": {
     "@sentry/core": "4.1.1",
+    "@sentry/hub": "4.1.1",
     "@sentry/types": "4.1.0",
     "@sentry/utils": "4.1.1",
     "cookie": "0.3.1",

packages/node/src/handlers.ts

@@ -205,6 +205,11 @@ function parseRequest(
   return event;
 }
 
+/** Domain interface with attached Hub */
+interface SentryDomain extends NodeJS.Domain {
+  __SENTRY__?: Carrier;
+}
+
 /** JSDoc */
 export function requestHandler(options?: {
   request?: boolean;
@@ -218,11 +223,25 @@ export function requestHandler(options?: {
     res: http.ServerResponse,
     next: (error?: any) => void,
   ): void {
-    const local = domain.create();
+    const alreadyRunningDomain = process.domain as SentryDomain;
+    let alreadyRunningDomainHub: Hub | undefined;
+
+    if (alreadyRunningDomain) {
+      if (alreadyRunningDomain.__SENTRY__) {
+        alreadyRunningDomainHub = alreadyRunningDomain.__SENTRY__.hub;
+      }
+    }
+
+    const local = domain.create() as SentryDomain;
     local.add(req);
     local.add(res);
     local.on('error', next);
     local.run(() => {
+      if (alreadyRunningDomainHub) {
+        local.__SENTRY__ = {
+          hub: alreadyRunningDomainHub,
+        };
+      }
       getCurrentHub().configureScope(scope =>
         scope.addEventProcessor(async (event: SentryEvent) => parseRequest(event, req, options)),
       );