Handle non-Error objects thrown as error gracefully, still attempt to report them in a useful way

src/features/notify.ts

@@ -56,26 +56,50 @@ export class NotifyFeature implements Feature {
     this.logger('destroy')
   }
 
-  notifyError (err: Error, context?: ErrorContext) {
+  getSafeError (err): Error {
+    if (err instanceof Error) return err
+
+    let message: string
+    try {
+      message = `Non-error value: ${JSON.stringify(err)}`
+    } catch (e) {
+      // We might land here if the error value was not serializable (it might contain
+      // circular references for example), or if user code was ran as part of the
+      // serialization and that code threw an error.
+      // As alternative, we can try converting the error to a string instead:
+      try {
+        message = `Unserializable non-error value: ${String(e)}`
+        // Intentionally not logging the second error anywhere, because we would need
+        // to protect against errors while doing *that* as well. (For example, the second
+        // error's "toString" property may crash or not exist.)
+      } catch (e2) {
+        // That didn't work. So, report a totally unknown error that resists being converted
+        // into any usable form.
+        // Again, we don't even attempt to look at that third error for the same reason as
+        // described above.
+        message = `Unserializable non-error value that cannot be converted to a string`
+      }
+    }
+    if (message.length > 1000) message = message.substr(0, 1000) + '...'
+
+    return new Error(message)
+  }
+
+  notifyError (err: Error | string | {}, context?: ErrorContext) {
     // set default context
     if (typeof context !== 'object') {
       context = { }
     }
 
-    if (!(err instanceof Error)) {
-      console.error('You must use notifyError with an Error object, ignoring')
-      console.trace()
-      return -1
-    }
-
     if (this.transport === undefined) {
       return this.logger(`Tried to send error without having transporter available`)
     }
 
+    const safeError = this.getSafeError(err)
     const payload = {
-      message: err.message,
-      stack: err.stack,
-      name: err.name,
+      message: safeError.message,
+      stack: safeError.stack,
+      name: safeError.name,
       metadata: context
     }
 
@@ -89,10 +113,12 @@ export class NotifyFeature implements Feature {
       console.error(error)
     }
 
+    const safeError = this.getSafeError(error)
+
     const payload = {
-      message: error.message,
-      stack: error.stack,
-      name: error.name
+      message: safeError.message,
+      stack: safeError.stack,
+      name: safeError.name
     }
 
     if (ServiceManager.get('transport')) {
@@ -107,10 +133,12 @@ export class NotifyFeature implements Feature {
 
     console.error(error)
 
+    const safeError = this.getSafeError(error)
+
     const payload = {
-      message: error.message,
-      stack: error.stack,
-      name: error.name
+      message: safeError.message,
+      stack: safeError.stack,
+      name: safeError.name
     }
 
     if (ServiceManager.get('transport')) {
@@ -132,10 +160,11 @@ export class NotifyFeature implements Feature {
       error : true
     })
     return function errorHandler (err, req, res, next) {
+      const safeError = this.getSafeError(err)
       const payload = {
-        message: err.message,
-        stack: err.stack,
-        name: err.name,
+        message: safeError.message,
+        stack: safeError.stack,
+        name: safeError.name,
         metadata: {
           http: {
             url: req.url,
@@ -167,10 +196,11 @@ export class NotifyFeature implements Feature {
       try {
         await next()
       } catch (err) {
+        const safeError = this.getSafeError(err)
         const payload = {
-          message: err.message,
-          stack: err.stack,
-          name: err.name,
+          message: safeError.message,
+          stack: safeError.stack,
+          name: safeError.name,
           metadata: {
             http: {
               url: ctx.request.url,

src/pmx.ts

@@ -176,7 +176,7 @@ export default class PMX {
    * Notify an error to PM2 Plus/Enterprise, note that you can attach a context to it
    * to provide more insight about the error
    */
-  notifyError (error: Error, context?: ErrorContext) {
+  notifyError (error: Error | string | {}, context?: ErrorContext) {
     const notify = this.featureManager.get('notify') as NotifyFeature
     return notify.notifyError(error, context)
   }

test/fixtures/apiNotifyChild.ts

@@ -2,4 +2,8 @@
 import * as pmx from '../../src/index'
 
 pmx.init()
-pmx.notifyError(new Error('myNotify'))
+try {
+  throw new Error('myNotify')
+} catch (err) {
+  pmx.notifyError(err)
+}