use stored distDir value in rewrite frames integration

Author: lobsterkatie

packages/nextjs/src/index.server.ts

@@ -1,6 +1,7 @@
 import { RewriteFrames } from '@sentry/integrations';
 import { configureScope, getCurrentHub, init as nodeInit, Integrations } from '@sentry/node';
-import { logger } from '@sentry/utils';
+import { escapeStringForRegex, logger } from '@sentry/utils';
+import * as path from 'path';
 
 import { instrumentServer } from './utils/instrumentServer';
 import { MetadataBuilder } from './utils/metadataBuilder';
@@ -29,7 +30,6 @@ export function init(options: NextjsOptions): void {
   const metadataBuilder = new MetadataBuilder(options, ['nextjs', 'node']);
   metadataBuilder.addSdkMetadata();
   options.environment = options.environment || process.env.NODE_ENV;
-  // TODO capture project root and store in an env var for RewriteFrames?
   addServerIntegrations(options);
   // Right now we only capture frontend sessions for Next.js
   options.autoSessionTracking = false;
@@ -47,25 +47,29 @@ function sdkAlreadyInitialized(): boolean {
   return !!hub.getClient();
 }
 
-const SOURCEMAP_FILENAME_REGEX = /^.*\/\.next\//;
-
-const defaultRewriteFramesIntegration = new RewriteFrames({
-  iteratee: frame => {
-    frame.filename = frame.filename?.replace(SOURCEMAP_FILENAME_REGEX, 'app:///_next/');
-    return frame;
-  },
-});
-
-const defaultHttpTracingIntegration = new Integrations.Http({ tracing: true });
-
 function addServerIntegrations(options: NextjsOptions): void {
+  // This value is injected at build time, based on the output directory specified in the build config
+  const distDirName = (global as typeof global & { __rewriteFramesDistDir__: string }).__rewriteFramesDistDir__;
+  // nextjs always puts the build directory at the project root level, which is also where you run `next start` from, so
+  // we can read in the project directory from the currently running process
+  const distDirAbsPath = path.resolve(process.cwd(), distDirName);
+  const SOURCEMAP_FILENAME_REGEX = new RegExp(escapeStringForRegex(distDirAbsPath));
+
+  const defaultRewriteFramesIntegration = new RewriteFrames({
+    iteratee: frame => {
+      frame.filename = frame.filename?.replace(SOURCEMAP_FILENAME_REGEX, 'app:///_next');
+      return frame;
+    },
+  });
+
   if (options.integrations) {
     options.integrations = addIntegration(defaultRewriteFramesIntegration, options.integrations);
   } else {
     options.integrations = [defaultRewriteFramesIntegration];
   }
 
   if (options.tracesSampleRate !== undefined || options.tracesSampler !== undefined) {
+    const defaultHttpTracingIntegration = new Integrations.Http({ tracing: true });
     options.integrations = addIntegration(defaultHttpTracingIntegration, options.integrations, {
       Http: { keyPath: '_tracing', value: true },
     });