ref(node): Refactor node source fetching into integration

packages/nextjs/test/index.server.test.ts

@@ -1,4 +1,3 @@
-import { BaseClient } from '@sentry/core';
 import { RewriteFrames } from '@sentry/integrations';
 import * as SentryNode from '@sentry/node';
 import { getCurrentHub, NodeClient } from '@sentry/node';
@@ -17,7 +16,6 @@ const global = getGlobalObject();
 (global as typeof global & { __rewriteFramesDistDir__: string }).__rewriteFramesDistDir__ = '.next';
 
 const nodeInit = jest.spyOn(SentryNode, 'init');
-const captureEvent = jest.spyOn(BaseClient.prototype, 'captureEvent');
 const logError = jest.spyOn(logger, 'error');
 
 describe('Server init()', () => {
@@ -91,7 +89,7 @@ describe('Server init()', () => {
     expect(currentScope._tags.vercel).toBeUndefined();
   });
 
-  it('adds 404 transaction filter', () => {
+  it('adds 404 transaction filter', async () => {
     init({
       dsn: 'https://dogsarebadatkeepingsecrets@squirrelchasers.ingest.sentry.io/12312012',
       tracesSampleRate: 1.0,
@@ -102,8 +100,10 @@ describe('Server init()', () => {
     const transaction = hub.startTransaction({ name: '/404' });
     transaction.finish();
 
+    // We need to flush because the event processor pipeline is async whereas transaction.finish() is sync.
+    await SentryNode.flush();
+
     expect(sendEvent).not.toHaveBeenCalled();
-    expect(captureEvent.mock.results[0].value).toBeUndefined();
     expect(logError).toHaveBeenCalledWith(new SentryError('An event processor returned null, will not send event.'));
   });
 

packages/node/src/backend.ts

@@ -16,7 +16,7 @@ export class NodeBackend extends BaseBackend<NodeOptions> {
    */
   // eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/explicit-module-boundary-types
   public eventFromException(exception: any, hint?: EventHint): PromiseLike<Event> {
-    return eventFromException(this._options, exception, hint);
+    return eventFromException(exception, hint);
   }
 
   /**

packages/node/src/eventbuilder.ts

@@ -16,7 +16,7 @@ import { extractStackFromError, parseError, parseStack, prepareFramesForEvent }
  * Builds and Event from a Exception
  * @hidden
  */
-export function eventFromException(options: Options, exception: unknown, hint?: EventHint): PromiseLike<Event> {
+export function eventFromException(exception: unknown, hint?: EventHint): PromiseLike<Event> {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   let ex: any = exception;
   const providedMechanism: Mechanism | undefined =
@@ -48,7 +48,7 @@ export function eventFromException(options: Options, exception: unknown, hint?:
   }
 
   return new SyncPromise<Event>((resolve, reject) =>
-    parseError(ex as Error, options)
+    parseError(ex as Error)
       .then(event => {
         addExceptionTypeValue(event, undefined, undefined);
         addExceptionMechanism(event, mechanism);
@@ -81,16 +81,11 @@ export function eventFromMessage(
   return new SyncPromise<Event>(resolve => {
     if (options.attachStacktrace && hint && hint.syntheticException) {
       const stack = hint.syntheticException ? extractStackFromError(hint.syntheticException) : [];
-      void parseStack(stack, options)
-        .then(frames => {
-          event.stacktrace = {
-            frames: prepareFramesForEvent(frames),
-          };
-          resolve(event);
-        })
-        .then(null, () => {
-          resolve(event);
-        });
+      const frames = parseStack(stack);
+      event.stacktrace = {
+        frames: prepareFramesForEvent(frames),
+      };
+      resolve(event);
     } else {
       resolve(event);
     }

packages/node/src/integrations/contextlines.ts

@@ -0,0 +1,140 @@
+import { getCurrentHub } from '@sentry/core';
+import { Event, EventProcessor, Integration } from '@sentry/types';
+import { addContextToFrame } from '@sentry/utils';
+import { readFile } from 'fs';
+import { LRUMap } from 'lru_map';
+
+import { NodeClient } from '../client';
+
+const FILE_CONTENT_CACHE = new LRUMap<string, string | null>(100);
+const DEFAULT_LINES_OF_CONTEXT = 7;
+
+// TODO: Replace with promisify when minimum supported node >= v8
+function readTextFileAsync(path: string): Promise<string> {
+  return new Promise((resolve, reject) => {
+    readFile(path, 'utf8', (err, data) => {
+      if (err) reject(err);
+      else resolve(data);
+    });
+  });
+}
+
+/**
+ * Resets the file cache. Exists for testing purposes.
+ * @hidden
+ */
+export function resetFileContentCache(): void {
+  FILE_CONTENT_CACHE.clear();
+}
+
+interface ContextLinesOptions {
+  /**
+   * Sets the number of context lines for each frame when loading a file.
+   * Defaults to 7.
+   *
+   * Set to 0 to disable loading and inclusion of source files.
+   **/
+  frameContextLines?: number;
+}
+
+/** Add node modules / packages to the event */
+export class ContextLines implements Integration {
+  /**
+   * @inheritDoc
+   */
+  public static id: string = 'ContextLines';
+
+  /**
+   * @inheritDoc
+   */
+  public name: string = ContextLines.id;
+
+  public constructor(private readonly _options: ContextLinesOptions = {}) {}
+
+  /**
+   * @inheritDoc
+   */
+  public setupOnce(addGlobalEventProcessor: (callback: EventProcessor) => void): void {
+    // This is only here to copy frameContextLines from init options if it hasn't
+    // been set via this integrations constructor.
+    //
+    // TODO: Remove on next major!
+    if (this._options.frameContextLines === undefined) {
+      const initOptions = getCurrentHub().getClient<NodeClient>()?.getOptions();
+      // eslint-disable-next-line deprecation/deprecation
+      this._options.frameContextLines = initOptions?.frameContextLines;
+    }
+
+    const contextLines =
+      this._options.frameContextLines !== undefined ? this._options.frameContextLines : DEFAULT_LINES_OF_CONTEXT;
+
+    addGlobalEventProcessor(event => this.addSourceContext(event, contextLines));
+  }
+
+  /** Processes an event and adds context lines */
+  public async addSourceContext(event: Event, contextLines: number): Promise<Event> {
+    const frames = event.exception?.values?.[0].stacktrace?.frames;
+
+    if (frames && contextLines > 0) {
+      const filenames: Set<string> = new Set();
+
+      for (const frame of frames) {
+        if (frame.filename) {
+          filenames.add(frame.filename);
+        }
+      }
+
+      const sourceFiles = await readSourceFiles(filenames);
+
+      for (const frame of frames) {
+        if (frame.filename && sourceFiles[frame.filename]) {
+          try {
+            const lines = (sourceFiles[frame.filename] as string).split('\n');
+            addContextToFrame(lines, frame, contextLines);
+          } catch (e) {
+            // anomaly, being defensive in case
+            // unlikely to ever happen in practice but can definitely happen in theory
+          }
+        }
+      }
+    }
+
+    return event;
+  }
+}
+
+/**
+ * This function reads file contents and caches them in a global LRU cache.
+ *
+ * @param filenames Array of filepaths to read content from.
+ */
+async function readSourceFiles(filenames: Set<string>): Promise<Record<string, string | null>> {
+  const sourceFiles: Record<string, string | null> = {};
+
+  for (const filename of filenames) {
+    const cachedFile = FILE_CONTENT_CACHE.get(filename);
+    // We have a cache hit
+    if (cachedFile !== undefined) {
+      // If stored value is null, it means that we already tried, but couldn't read the content of the file. Skip.
+      if (cachedFile === null) {
+        continue;
+      }
+
+      // Otherwise content is there, so reuse cached value.
+      sourceFiles[filename] = cachedFile;
+      continue;
+    }
+
+    let content: string | null = null;
+    try {
+      content = await readTextFileAsync(filename);
+    } catch (_) {
+      //
+    }
+
+    FILE_CONTENT_CACHE.set(filename, content);
+    sourceFiles[filename] = content;
+  }
+
+  return sourceFiles;
+}

packages/node/src/integrations/index.ts

@@ -4,3 +4,4 @@ export { OnUncaughtException } from './onuncaughtexception';
 export { OnUnhandledRejection } from './onunhandledrejection';
 export { LinkedErrors } from './linkederrors';
 export { Modules } from './modules';
+export { ContextLines } from './contextlines';