use domain to catch errors in koa

packages/plugin-koa/src/koa.js

@@ -1,3 +1,5 @@
+/* eslint node/no-deprecated-api: [error, {ignoreModuleItems: ["domain"]}] */
+const domain = require('domain')
 const clone = require('@bugsnag/core/lib/clone-client')
 const extractRequestInfo = require('./request-info')
 
@@ -14,6 +16,8 @@ module.exports = {
   name: 'koa',
   load: client => {
     const requestHandler = async (ctx, next) => {
+      const dom = domain.create()
+
       // Get a client to be scoped to this request. If sessions are enabled, use the
       // resumeSession() call to get a session client, otherwise, clone the existing client.
       const requestClient = client._config.autoTrackSessions ? client.resumeSession() : clone(client)
@@ -27,7 +31,21 @@ module.exports = {
         event.addMetadata('request', metadata)
       }, true)
 
+      // unhandled errors caused by this request
+      dom.on('error', (err) => {
+        const event = client.Event.create(err, false, handledState, 'koa middleware', 1)
+        ctx.bugsnag._notify(event, () => {}, (e, event) => {
+          if (e) client._logger.error('Failed to send event to Bugsnag')
+          ctx.bugsnag._config.onUncaughtException(err, event, client._logger)
+        })
+        if (!ctx.response.headersSent) {
+          ctx.response.status = 500
+        }
+      })
+
+      dom.enter()
       await next()
+      dom.exit()
     }
 
     requestHandler.v1 = function * (next) {

test/node/features/fixtures/koa/scenarios/app.js

@@ -62,11 +62,6 @@ app.use(async (ctx, next) => {
       throw new Error('error in async callback')
     }, 100)
     ctx.body = 'ok'
-  } else if (ctx.path === '/reject-async-callback') {
-    setTimeout(function () {
-      Promise.reject(new Error('reject in async callback')).catch(next)
-    }, 100)
-    ctx.body = 'ok'
   } else if (ctx.path === '/unhandled-reject-async-callback') {
     setTimeout(function () {
       Promise.reject(new Error('unhandled reject in async callback'))

test/node/features/koa.feature

@@ -127,26 +127,17 @@ Scenario: a thrown error in an async callback
   Then the error is valid for the error reporting API version "4" for the "Bugsnag Node" notifier
   And the event "unhandled" is true
   And the event "severity" equals "error"
-  And the event "severityReason.type" equals "unhandledException"
+  And the event "severityReason.type" equals "unhandledErrorMiddleware"
   And the exception "errorClass" equals "Error"
   And the exception "message" equals "error in async callback"
   And the event "request.url" equals "http://koa/throw-async-callback"
   And the event "request.httpMethod" equals "GET"
 
-Scenario: a handled promise rejection in an async callback
-  Then I open the URL "http://koa/reject-async-callback" and get a 200 response
-  And I wait to receive an error
-  Then the error is valid for the error reporting API version "4" for the "Bugsnag Node" notifier
-  And the event "unhandled" is true
-  And the event "severity" equals "error"
-  And the event "severityReason.type" equals "unhandledException"
-  And the exception "errorClass" equals "Error"
-
 Scenario: an unhandled promise rejection in an async callback
   Then I open the URL "http://koa/unhandled-reject-async-callback" and get a 200 response
   And I wait to receive an error
   Then the error is valid for the error reporting API version "4" for the "Bugsnag Node" notifier
   And the event "unhandled" is true
   And the event "severity" equals "error"
-  And the event "severityReason.type" equals "unhandledException"
+  And the event "severityReason.type" equals "unhandledPromiseRejection"
   And the exception "errorClass" equals "Error"