feat(api, safe_error_serialize): add Sentry's error handler

src/api/index.ts

@@ -1,11 +1,16 @@
 import * as express from 'express';
+import * as raven from 'raven';
 import conversionsApi from './conversions_api';
-import { errorHandler } from './middlewares';
+import { fatalErrorsHandler, recoverableErrorsHandler } from './middlewares';
 
 const router: express.Router = express.Router();
 
+//=> API endpoint roots
 router.use('/conversions', conversionsApi);
 
-router.use(errorHandler());
+//=> Install error handlers
+router.use(recoverableErrorsHandler());
+router.use(raven.errorHandler());
+router.use(fatalErrorsHandler());
 
 export default router;

src/api/middlewares.ts

@@ -5,6 +5,10 @@ import { wrapAsync } from '../express_utils';
 import { safeErrorSerialize } from '../safe_error_serialize';
 import { isKeyValid } from './api_keys_cache';
 
+interface ISentryResponse extends Response {
+    sentry?: string;
+}
+
 export function hasValidApiKey(): Handler {
     return wrapAsync(async (req: Request, res: Response, next: NextFunction): Promise<void> => {
         const authHeader = req.header('Authorization');
@@ -22,7 +26,7 @@ export function hasValidApiKey(): Handler {
     });
 }
 
-export function errorHandler(): ErrorRequestHandler {
+export function recoverableErrorsHandler(): ErrorRequestHandler {
     return (err: any, req: Request, res: Response, next: NextFunction): void => {
         //=> Headers already sent, let Express handle the thing
         if (res.headersSent) {
@@ -43,10 +47,19 @@ export function errorHandler(): ErrorRequestHandler {
             });
         }
 
-        //=> In all other cases, return a 500 error
-        res.status(500).json(safeErrorSerialize(err));
+        //=> We can't recognize this error, pass to the next error handler.
+        next(err);
+    };
+}
 
-        //=> Log it because that's unexpected
+export function fatalErrorsHandler(): ErrorRequestHandler {
+    return (err: any, req: Request, res: ISentryResponse, next: NextFunction): void => {
+        //=> We don't know what this error is, return a 500 error
+        res.status(500).json(safeErrorSerialize(err, res.sentry));
+
+        //=> Log it because that's, well, unexpected
         logger.error(err);
+
+        next();
     };
 }

src/safe_error_serialize.ts

@@ -1,10 +1,11 @@
 export interface IPlainObjectError {
     name: string;
     message: string;
+    errorId?: string;
     errors?: any[];
 }
 
-export function safeErrorSerialize(error: any): IPlainObjectError {
+export function safeErrorSerialize(error: any, sentryErrorId?: string): IPlainObjectError {
     const plainError: any = {};
 
     //=> Error name
@@ -13,6 +14,11 @@ export function safeErrorSerialize(error: any): IPlainObjectError {
     //=> Error message
     plainError.message = error.message || 'Unknown error';
 
+    //=> Set error's ID if given
+    if (sentryErrorId) {
+        plainError.errorId = sentryErrorId;
+    }
+
     //=> Serialize recursively sub-errors if any
     if (error.errors) {
         plainError.errors = error.errors.map(safeErrorSerialize);