From 6d4f2ad4581296a34c2fdb57dbdb64ac503751fe Mon Sep 17 00:00:00 2001
From: g-tejas <code@gtejas.com>
Date: Wed, 26 Jun 2024 13:01:24 +0800
Subject: [PATCH] feat(errors): revamp business logic error codes

---
 src/app/modules/core/core.errors.ts           | 30 +++++++++++++++++--
 src/app/modules/form/form.errors.ts           |  2 +-
 .../public-form/public-form.controller.ts     |  9 ++++++
 .../email-submission.controller.ts            |  1 +
 4 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/src/app/modules/core/core.errors.ts b/src/app/modules/core/core.errors.ts
index 995fe73015..d7e72dec05 100644
--- a/src/app/modules/core/core.errors.ts
+++ b/src/app/modules/core/core.errors.ts
@@ -1,3 +1,11 @@
+import tracer from 'dd-trace'
+
+import { statsdClient } from 'src/app/config/datadog-statsd-client'
+
+export const errorStatsdClient = statsdClient.childClient({
+  prefix: 'formsg.errors.',
+})
+
 /**
  * A custom base error class that encapsulates the name, message, status code,
  * and logging meta string (if any) for the error.
@@ -7,8 +15,15 @@ export class ApplicationError extends Error {
    * Meta object to be logged by the application logger, if any.
    */
   meta?: unknown
-
-  constructor(message?: string, meta?: unknown) {
+  code?: number
+  isError?: boolean
+
+  constructor(
+    message?: string,
+    meta?: unknown,
+    errorCode?: number,
+    isError?: boolean,
+  ) {
     super()
 
     Error.captureStackTrace(this, this.constructor)
@@ -18,6 +33,17 @@ export class ApplicationError extends Error {
     this.message = message || 'Something went wrong. Please try again.'
 
     this.meta = meta
+    this.code = errorCode
+    this.isError = isError
+  }
+}
+
+export const setErrorCodes = (error: ApplicationError) => {
+  const span = tracer.scope().active()
+  if (span) {
+    span.setTag('error', error.isError || false)
+    span.setTag('error.code', error.code)
+    span.setTag('error.message', error.message)
   }
 }
 
diff --git a/src/app/modules/form/form.errors.ts b/src/app/modules/form/form.errors.ts
index 5ef8cdc8cc..e1ee130a03 100644
--- a/src/app/modules/form/form.errors.ts
+++ b/src/app/modules/form/form.errors.ts
@@ -29,7 +29,7 @@ export class PrivateFormError extends ApplicationError {
     message = 'If you think this is a mistake, please contact the agency that gave you the form link.',
     formTitle: string,
   ) {
-    super(message)
+    super(message, undefined, 1001, false)
     this.formTitle = formTitle
   }
 }
diff --git a/src/app/modules/form/public-form/public-form.controller.ts b/src/app/modules/form/public-form/public-form.controller.ts
index e30fec669b..a809c2a403 100644
--- a/src/app/modules/form/public-form/public-form.controller.ts
+++ b/src/app/modules/form/public-form/public-form.controller.ts
@@ -19,6 +19,7 @@ import { isMongoError } from '../../../utils/handle-mongo-error'
 import { createReqMeta, getRequestIp } from '../../../utils/request'
 import { getFormIfPublic } from '../../auth/auth.service'
 import * as BillingService from '../../billing/billing.service'
+import { errorStatsdClient, setErrorCodes } from '../../core/core.errors'
 import { ControllerHandler } from '../../core/core.types'
 import {
   MYINFO_AUTH_CODE_COOKIE_NAME,
@@ -96,6 +97,14 @@ export const handleGetPublicForm: ControllerHandler<
     }
     const { errorMessage, statusCode } = mapRouteError(error)
 
+    errorStatsdClient.increment('', 1, {
+      code: `${error?.code}`,
+      message: error.message,
+    })
+
+    // Add error code tags to the active span for datadog
+    setErrorCodes(error)
+
     // Specialized error response for PrivateFormError.
     // This is to maintain backwards compatibility with the middleware implementation
     if (error instanceof PrivateFormError) {
diff --git a/src/app/modules/submission/email-submission/email-submission.controller.ts b/src/app/modules/submission/email-submission/email-submission.controller.ts
index 2cc6f73dde..432d15c38e 100644
--- a/src/app/modules/submission/email-submission/email-submission.controller.ts
+++ b/src/app/modules/submission/email-submission/email-submission.controller.ts
@@ -1,3 +1,4 @@
+import tracer from 'dd-trace'
 import { ok, okAsync, ResultAsync } from 'neverthrow'
 
 import {