status event source from TF envar

Author: masl2

infrastructure/terraform/components/api/module_lambda_letter_updates_transformer.tf

@@ -36,7 +36,8 @@ module "letter_updates_transformer" {
   log_subscription_role_arn = local.acct.log_subscription_role_arn
 
   lambda_env_vars = merge(local.common_lambda_env_vars, {
-    EVENTPUB_SNS_TOPIC_ARN = "${module.eventpub.sns_topic.arn}"
+    EVENTPUB_SNS_TOPIC_ARN = "${module.eventpub.sns_topic.arn}",
+    EVENT_SOURCE = "/data-plane/supplier-api/${var.group}/${var.environment}/letters"
   })
 }
 

lambdas/letter-updates-transformer/src/__tests__/letter-updates-transformer.test.ts

@@ -8,12 +8,12 @@ import {
 } from "aws-lambda";
 import { mockDeep } from "jest-mock-extended";
 import { LetterBase } from "@internal/datastore";
-import createHandler from "../letter-updates-transformer";
 import { Deps } from "../deps";
 import { EnvVars } from "../env";
-import mapLetterToCloudEvent from "../mappers/letter-mapper";
 import { LetterStatus } from "../../../api-handler/src/contracts/letters";
 import { LetterForEventPub } from "../types";
+import mapLetterToCloudEvent from "../mappers/letter-mapper";
+import createHandler from "../letter-updates-transformer";
 
 // Make crypto return consistent values, since we"re calling it in both prod and test code and comparing the values
 const realCrypto = jest.requireActual("crypto");
@@ -26,15 +26,19 @@ jest.mock("crypto", () => ({
   randomBytes: (size: number) => randomBytes[String(size)],
 }));
 
-describe("letter-updates-transformer Lambda", () => {
-  const mockedDeps: jest.Mocked<Deps> = {
+const eventSource = "/data-plane/supplier-api/supplier-api-dev/main/letters";
+
+const mockedDeps: jest.Mocked<Deps> = {
     snsClient: { send: jest.fn() } as unknown as SNSClient,
     logger: { info: jest.fn(), error: jest.fn() } as unknown as pino.Logger,
     env: {
       EVENTPUB_SNS_TOPIC_ARN: "arn:aws:sns:region:account:topic",
+      EVENT_SOURCE: eventSource,
     } as unknown as EnvVars,
   } as Deps;
 
+describe("letter-updates-transformer Lambda", () => {
+
   beforeEach(() => {
     jest.useFakeTimers();
   });
@@ -50,7 +54,7 @@ describe("letter-updates-transformer Lambda", () => {
       const newLetter = generateLetter("PRINTED");
       const expectedEntries = [
         expect.objectContaining({
-          Message: JSON.stringify(mapLetterToCloudEvent(newLetter)),
+          Message: JSON.stringify(mapLetterToCloudEvent(newLetter, eventSource)),
         }),
       ];
 
@@ -76,7 +80,7 @@ describe("letter-updates-transformer Lambda", () => {
       newLetter.reasonCode = "R1";
       const expectedEntries = [
         expect.objectContaining({
-          Message: JSON.stringify(mapLetterToCloudEvent(newLetter)),
+          Message: JSON.stringify(mapLetterToCloudEvent(newLetter, eventSource)),
         }),
       ];
 
@@ -103,7 +107,7 @@ describe("letter-updates-transformer Lambda", () => {
       newLetter.reasonCode = "R2";
       const expectedEntries = [
         expect.objectContaining({
-          Message: JSON.stringify(mapLetterToCloudEvent(newLetter)),
+          Message: JSON.stringify(mapLetterToCloudEvent(newLetter, eventSource)),
         }),
       ];
 
@@ -168,7 +172,7 @@ describe("letter-updates-transformer Lambda", () => {
       const newLetters = generateLetters(10, "PRINTED");
       const expectedEntries = newLetters.map((letter) =>
         expect.objectContaining({
-          Message: JSON.stringify(mapLetterToCloudEvent(letter)),
+          Message: JSON.stringify(mapLetterToCloudEvent(letter, eventSource)),
         }),
       );
 
@@ -197,19 +201,19 @@ describe("letter-updates-transformer Lambda", () => {
         newLetters.slice(0, 10).map((letter, index) =>
           expect.objectContaining({
             Id: expect.stringMatching(new RegExp(`-${index}$`)),
-            Message: JSON.stringify(mapLetterToCloudEvent(letter)),
+            Message: JSON.stringify(mapLetterToCloudEvent(letter, eventSource)),
           }),
         ),
         newLetters.slice(10, 20).map((letter, index) =>
           expect.objectContaining({
             Id: expect.stringMatching(new RegExp(`-${index}$`)),
-            Message: JSON.stringify(mapLetterToCloudEvent(letter)),
+            Message: JSON.stringify(mapLetterToCloudEvent(letter, eventSource)),
           }),
         ),
         newLetters.slice(20).map((letter, index) =>
           expect.objectContaining({
             Id: expect.stringMatching(new RegExp(`-${index}$`)),
-            Message: JSON.stringify(mapLetterToCloudEvent(letter)),
+            Message: JSON.stringify(mapLetterToCloudEvent(letter, eventSource)),
           }),
         ),
       ];

lambdas/letter-updates-transformer/src/env.ts

@@ -2,6 +2,7 @@ import { z } from "zod";
 
 const EnvVarsSchema = z.object({
   EVENTPUB_SNS_TOPIC_ARN: z.string(),
+  EVENT_SOURCE: z.string(),
 });
 
 export type EnvVars = z.infer<typeof EnvVarsSchema>;

lambdas/letter-updates-transformer/src/letter-updates-transformer.ts

@@ -30,7 +30,7 @@ export default function createHandler(deps: Deps): Handler<KinesisStreamEvent> {
           isChanged(record, "status") || isChanged(record, "reasonCode"),
       )
       .map((element) => extractNewLetter(element))
-      .map((element) => mapLetterToCloudEvent(element));
+      .map((element) => mapLetterToCloudEvent(element, deps.env.EVENT_SOURCE));
 
     for (const batch of generateBatches(cloudEvents)) {
       deps.logger.info({

lambdas/letter-updates-transformer/src/mappers/__tests__/letter-mapper.test.ts

@@ -14,7 +14,8 @@ describe("letter-mapper", () => {
       reasonText: "Reason text",
       updatedAt: "2025-11-24T15:55:18.000Z",
     } as Letter;
-    const event = mapLetterToCloudEvent(letter);
+    const source = "/data-plane/supplier-api/supplier-api-dev/main/letters"
+    const event = mapLetterToCloudEvent(letter, source);
 
     // Check it conforms to the letter event schema - parse will throw an error if not
     $LetterEvent.parse(event);
@@ -41,5 +42,6 @@ describe("letter-mapper", () => {
         event: event.id,
       },
     });
+    expect(event.source).toBe(source);
   });
 });

lambdas/letter-updates-transformer/src/mappers/letter-mapper.ts

@@ -5,6 +5,7 @@ import { LetterForEventPub } from "../types";
 
 export default function mapLetterToCloudEvent(
   letter: LetterForEventPub,
+  eventSource: string
 ): LetterEvent {
   const eventId = randomUUID();
   const dataschemaversion = eventSchemaPackage.version;
@@ -15,9 +16,8 @@ export default function mapLetterToCloudEvent(
     plane: "data",
     dataschema: `https://notify.nhs.uk/cloudevents/schemas/supplier-api/letter.${letter.status}.${dataschemaversion}.schema.json`,
     dataschemaversion,
-    source: "/data-plane/supplier-api/letters",
+    source: eventSource,
     subject: `letter-origin/supplier-api/letter/${letter.id}`,
-
     data: {
       domainId: letter.id as LetterEvent["data"]["domainId"],
       status: letter.status,