Support passing error objects to HealthCheckError

README.md

@@ -53,7 +53,8 @@ const options = {
   // health check options
   healthChecks: {
     '/healthcheck': healthCheck,    // a function returning a promise indicating service health,
-    verbatim: true // [optional = false] use object returned from /healthcheck verbatim in response
+    verbatim: true, // [optional = false] use object returned from /healthcheck verbatim in response,
+    __unsafeExposeStackTraces: true // [optional = false] return stack traces in error response if healthchecks throw errors
   },
   caseInsensitive, // [optional] whether given health checks routes are case insensitive (defaults to false)
 

lib/terminus.js

@@ -34,7 +34,22 @@ async function sendSuccess (res, { info, verbatim }) {
 }
 
 async function sendFailure (res, options) {
-  const { error, onSendFailureDuringShutdown } = options
+  const { error, onSendFailureDuringShutdown, exposeStackTraces } = options
+
+  function replaceErrors (_, value) {
+    if (value instanceof Error) {
+      const error = {}
+
+      Object.getOwnPropertyNames(value).forEach(function (key) {
+        if (exposeStackTraces !== true && key === 'stack') return
+        error[key] = value[key]
+      })
+
+      return error
+    }
+
+    return value
+  }
 
   if (onSendFailureDuringShutdown) {
     await onSendFailureDuringShutdown()
@@ -46,7 +61,7 @@ async function sendFailure (res, options) {
       status: 'error',
       error: error,
       details: error
-    }))
+    }, replaceErrors))
   }
   res.end(FAILURE_RESPONSE)
 }
@@ -73,7 +88,7 @@ function decorateWithHealthCheck (server, state, options) {
           info = await healthCheck()
         } catch (error) {
           logger('healthcheck failed', error)
-          return sendFailure(res, { error: error.causes })
+          return sendFailure(res, { error: error.causes, exposeStackTraces: healthChecks.__unsafeExposeStackTraces })
         }
         return sendSuccess(res, { info, verbatim: healthChecks.verbatim })
       }

lib/terminus.spec.js

@@ -8,6 +8,8 @@ const fetch = require('node-fetch')
 const { createTerminus } = require('./terminus')
 const { HealthCheckError } = require('./terminus-error')
 
+process.setMaxListeners(100) // Removes node's built in max listeners warning while we're testing
+
 describe('Terminus', () => {
   let server
 
@@ -214,43 +216,117 @@ describe('Terminus', () => {
       expect(loggerRan).to.eql(true)
     })
 
-    it('includes error on reject', async () => {
-      let onHealthCheckRan = false
-
-      createTerminus(server, {
-        healthChecks: {
-          '/health': () => {
-            onHealthCheckRan = true
-            const myError = new HealthCheckError('failed', {
-              fornite: 'client down',
-              redis: {
-                disk: 100
-              }
-            })
-            return Promise.reject(myError)
+    describe('includes error on reject', async () => {
+      const errors = [
+        new Error('test error 1'),
+        new Error('test error 2')
+      ]
+
+      it('Returns custom objects as errors', async () => {
+        let onHealthCheckRan = false
+
+        createTerminus(server, {
+          healthChecks: {
+            '/health': () => {
+              onHealthCheckRan = true
+              const myError = new HealthCheckError('failed', {
+                fornite: 'client down',
+                redis: {
+                  disk: 100
+                }
+              })
+              return Promise.reject(myError)
+            }
           }
-        }
+        })
+        server.listen(8000)
+
+        const res = await fetch('http://localhost:8000/health')
+        expect(res.status).to.eql(503)
+        expect(onHealthCheckRan).to.eql(true)
+        const json = await res.json()
+        expect(json).to.deep.eql({
+          status: 'error',
+          error: {
+            fornite: 'client down',
+            redis: {
+              disk: 100
+            }
+          },
+          details: {
+            fornite: 'client down',
+            redis: {
+              disk: 100
+            }
+          }
+        })
       })
-      server.listen(8000)
 
-      const res = await fetch('http://localhost:8000/health')
-      expect(res.status).to.eql(503)
-      expect(onHealthCheckRan).to.eql(true)
-      const json = await res.json()
-      expect(json).to.deep.eql({
-        status: 'error',
-        error: {
-          fornite: 'client down',
-          redis: {
-            disk: 100
+      it('Returns error objects as errors and does not include stack traces by default', async () => {
+        let onHealthCheckRan = false
+        createTerminus(server, {
+          healthChecks: {
+            '/health': () => {
+              onHealthCheckRan = true
+              const myError = new HealthCheckError('failed', errors)
+              return Promise.reject(myError)
+            }
           }
-        },
-        details: {
-          fornite: 'client down',
-          redis: {
-            disk: 100
+        })
+
+        server.listen(8000)
+
+        const res = await fetch('http://localhost:8000/health')
+        expect(res.status).to.eql(503)
+        expect(onHealthCheckRan).to.eql(true)
+        const json = await res.json()
+
+        const errorMessages = [{
+          message: errors[0].message
+        }, {
+          message: errors[1].message
+        }]
+
+        expect(json).to.deep.eql({
+          status: 'error',
+          error: errorMessages,
+          details: errorMessages
+        })
+      })
+
+      it('Returns error objects as errors and includes stack traces if __unsafeExposeStackTraces is set', async () => {
+        let onHealthCheckRan = false
+        createTerminus(server, {
+          healthChecks: {
+            '/health': () => {
+              onHealthCheckRan = true
+              const myError = new HealthCheckError('failed', errors)
+              return Promise.reject(myError)
+            },
+            __unsafeExposeStackTraces: true
           }
-        }
+        })
+
+        server.listen(8000)
+
+        const res = await fetch('http://localhost:8000/health')
+        expect(res.status).to.eql(503)
+        expect(onHealthCheckRan).to.eql(true)
+        const json = await res.json()
+
+        const errorMessages = [{
+          message: errors[0].message,
+          stack: errors[0].stack.toString()
+        }, {
+          message: errors[1].message,
+          stack: errors[1].stack.toString()
+        }]
+
+        expect(json).to.deep.eql({
+          status: 'error',
+          error: errorMessages,
+          details: errorMessages
+        })
       })
     })
 

typings/index.d.ts

@@ -8,9 +8,8 @@ declare module "@godaddy/terminus" {
   }
 
   export type HealthCheckMap = {
-    [key: string]: HealthCheck | boolean;
-  } | {
-    verbatim: boolean
+    verbatim?: boolean
+    __unsafeExposeStackTraces?: boolean;
     [key: string]: HealthCheck | boolean;
   }