[SES-PHASE-1-8] - PLU-744: add bounce rate tracking (exploration)

packages/backend/src/apps/postman/__tests__/actions/send-transactional-email.test.ts

@@ -73,6 +73,10 @@ vi.mock('@/models/email-suppression-entry', () => ({
   },
 }))
 
+vi.mock('@/helpers/metrics', () => ({
+  incrementMetric: vi.fn(),
+}))
+
 describe('send transactional email', () => {
   let $: IGlobalVariable
 

packages/backend/src/apps/postman/common/email-helper.ts

@@ -8,6 +8,7 @@ import appConfig from '@/config/app'
 import HttpError from '@/errors/http'
 import { getLdFlagValue } from '@/helpers/launch-darkly'
 import logger from '@/helpers/logger'
+import { incrementMetric } from '@/helpers/metrics'
 import { getSesClient, shouldUseSes } from '@/helpers/ses-email-helper'
 import EmailSuppressionEntry from '@/models/email-suppression-entry'
 
@@ -158,6 +159,7 @@ async function sendViaSes(
       }),
     }),
   )
+  incrementMetric('ses.email.sent')
 
   // TODO: remove this log once the SES rollout is verified and stable.
   logger.info('Email sent via SES', {

packages/backend/src/helpers/metrics.ts

@@ -0,0 +1,10 @@
+import tracer from './tracer'
+
+export function incrementMetric(
+  name: string,
+  tags: Record<string, string> = {},
+): void {
+  tracer.dogstatsd.increment(name, 1, {
+    ...tags,
+  })
+}

packages/backend/src/helpers/process-ses-event.ts

@@ -1,4 +1,5 @@
 import logger from '@/helpers/logger'
+import { incrementMetric } from '@/helpers/metrics'
 import { SesEvent, SesEventType } from '@/helpers/ses-event-parser'
 import EmailSuppressionEntry from '@/models/email-suppression-entry'
 
@@ -28,6 +29,11 @@ export async function processSesEvent(data: SesEventInput): Promise<void> {
   if (sesEvent.eventType === SesEventType.Bounce) {
     const { bounceType, bounceSubType, bouncedRecipients } = sesEvent.bounce
 
+    incrementMetric('ses.email.bounce', {
+      bounce_type: bounceType,
+      bounce_sub_type: bounceSubType ?? 'unknown',
+    })
+
     if (bounceType === 'Permanent') {
       // TODO: add micro-optimisation for upsertSuppression to blacklist multiple recipient emails in phase 2
       for (const recipient of bouncedRecipients) {
@@ -64,6 +70,10 @@ export async function processSesEvent(data: SesEventInput): Promise<void> {
   if (sesEvent.eventType === SesEventType.Complaint) {
     const { complainedRecipients, complaintFeedbackType } = sesEvent.complaint
 
+    incrementMetric('ses.email.complaint', {
+      complaint_feedback_type: complaintFeedbackType ?? 'other',
+    })
+
     if (complaintFeedbackType === 'not-spam') {
       // Auto-whitelist: recipient marked the email as not-spam
       const emails = complainedRecipients.map((r) => r.emailAddress)

packages/backend/src/helpers/ses-email-helper.ts

@@ -4,6 +4,7 @@ import { fromTemporaryCredentials } from '@aws-sdk/credential-providers'
 import appConfig from '@/config/app'
 
 import logger from './logger'
+import { incrementMetric } from './metrics'
 
 let sesClient: SESv2Client | null = null
 
@@ -82,6 +83,7 @@ export async function sendEmailViaSes({
         }),
       }),
     )
+    incrementMetric('ses.email.sent')
   } catch (e) {
     logger.error('Error sending email via SES', {
       error: e,