Skip to content

Switch letter_status_update lambda to use eventsub SNS topic #360

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
stevebux wants to merge 3 commits into
base: main
Choose a base branch
from
Open

Switch letter_status_update lambda to use eventsub SNS topic #360

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
d74a0bd
Switch letter_status_update lambda to use eventsub SNS topic
stevebux Jan 22, 2026
aabf50d
Introduce idempotency: replayed update with same ID will be ignored
stevebux Jan 23, 2026
966f6eb
Store previous status
stevebux Jan 26, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 9 additions & 0 deletions infrastructure/terraform/components/api/lambda_event_source_mapping_letter_status_update.tf
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
resource "aws_lambda_event_source_mapping" "letter_status_update" {
event_source_arn = module.letter_status_updates_queue.sqs_queue_arn
function_name = module.letter_status_update.function_name
batch_size = 10
maximum_batching_window_in_seconds = 5
function_response_types = [
"ReportBatchItemFailures"
]
}
2 changes: 2 additions & 0 deletions infrastructure/terraform/components/api/locals.tf
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,8 @@ locals {
SUPPLIER_ID_HEADER = "nhsd-supplier-id",
APIM_CORRELATION_HEADER = "nhsd-correlation-id",
DOWNLOAD_URL_TTL_SECONDS = 60
SNS_TOPIC_ARN = "${module.eventsub.sns_topic.arn}",
EVENT_SOURCE = "/data-plane/supplier-api/${var.group}/${var.environment}/letters"
}

core_pdf_bucket_arn = "arn:aws:s3:::comms-${var.core_account_id}-eu-west-2-${var.core_environment}-api-stg-pdf-pipeline"
Expand Down
16 changes: 14 additions & 2 deletions infrastructure/terraform/components/api/module_lambda_letter_status_update.tf
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,6 @@ data "aws_iam_policy_document" "letter_status_update" {
actions = [
"dynamodb:GetItem",
"dynamodb:Query",
"dynamodb:UpdateItem",
]

resources = [
Expand All @@ -79,7 +78,20 @@ data "aws_iam_policy_document" "letter_status_update" {
]

resources = [
module.letter_status_updates_queue.sqs_queue_arn
module.letter_status_updates_queue.sqs_queue_arn
]
}

statement {
sid = "AllowSNSPublish"
effect = "Allow"

actions = [
"sns:Publish"
]

resources = [
module.eventsub.sns_topic.arn
]
}
}
54 changes: 54 additions & 0 deletions internal/datastore/src/__test__/letter-repository.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -14,10 +14,12 @@ function createLetter(
supplierId: string,
letterId: string,
status: Letter["status"] = "PENDING",
eventId?: string,
): InsertLetter {
const now = new Date().toISOString();
return {
id: letterId,
eventId,
supplierId,
specificationId: "specification1",
groupId: "group1",
Expand Down Expand Up @@ -168,6 +170,7 @@ describe("LetterRepository", () => {

const updateLetter: UpdateLetter = {
id: "letter1",
eventId: "event1",
supplierId: "supplier1",
status: "REJECTED",
reasonCode: "R01",
Expand All @@ -180,6 +183,7 @@ describe("LetterRepository", () => {
"letter1",
);
expect(updatedLetter.status).toBe("REJECTED");
expect(updatedLetter.previousStatus).toBe("PENDING");
expect(updatedLetter.reasonCode).toBe("R01");
expect(updatedLetter.reasonText).toBe("Reason text");
});
Expand All @@ -199,6 +203,7 @@ describe("LetterRepository", () => {
jest.setSystemTime(new Date(2020, 1, 2));
const letterDto: UpdateLetter = {
id: "letter1",
eventId: "event1",
supplierId: "supplier1",
status: "DELIVERED",
};
Expand All @@ -215,6 +220,7 @@ describe("LetterRepository", () => {
test("can't update a letter that does not exist", async () => {
const updateLetter: UpdateLetter = {
id: "letter1",
eventId: "event1",
supplierId: "supplier1",
status: "DELIVERED",
};
Expand All @@ -233,6 +239,7 @@ describe("LetterRepository", () => {

const updateLetter: UpdateLetter = {
id: "letter1",
eventId: "event1",
supplierId: "supplier1",
status: "DELIVERED",
};
Expand All @@ -241,6 +248,52 @@ describe("LetterRepository", () => {
).rejects.toThrow("Cannot do operations on a non-existent table");
});

test("does not update a letter if the same eventId is used", async () => {
const letter = createLetter("supplier1", "letter1", "DELIVERED", "event1");
await letterRepository.putLetter(letter);

const duplicateUpdate: UpdateLetter = {
id: "letter1",
eventId: "event1",
supplierId: "supplier1",
status: "REJECTED",
reasonCode: "R01",
};
const result = await letterRepository.updateLetterStatus(duplicateUpdate);

expect(result).toBeUndefined();
const unchangedLetter = await letterRepository.getLetterById(
"supplier1",
"letter1",
);
expect(unchangedLetter.status).toBe("DELIVERED");
expect(unchangedLetter.eventId).toBe("event1");
expect(unchangedLetter.reasonCode).toBeUndefined();
});

test("updates a letter if a different eventId is used", async () => {
const letter = createLetter("supplier1", "letter1", "DELIVERED", "event1");
await letterRepository.putLetter(letter);

const duplicateUpdate: UpdateLetter = {
id: "letter1",
eventId: "event2",
supplierId: "supplier1",
status: "REJECTED",
reasonCode: "R01",
};
const result = await letterRepository.updateLetterStatus(duplicateUpdate);

expect(result).toBeDefined();
const changedLetter = await letterRepository.getLetterById(
"supplier1",
"letter1",
);
expect(changedLetter.status).toBe("REJECTED");
expect(changedLetter.eventId).toBe("event2");
expect(changedLetter.reasonCode).toBe("R01");
});

test("should return a list of letters matching status", async () => {
await letterRepository.putLetter(createLetter("supplier1", "letter1"));
await letterRepository.putLetter(createLetter("supplier1", "letter2"));
Expand Down Expand Up @@ -278,6 +331,7 @@ describe("LetterRepository", () => {

const updateLetter: UpdateLetter = {
id: "letter1",
eventId: "event1",
supplierId: "supplier1",
status: "DELIVERED",
};
Expand Down
75 changes: 45 additions & 30 deletions internal/datastore/src/letter-repository.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
UpdateCommand,
UpdateCommandOutput,
} from "@aws-sdk/lib-dynamodb";
import { ConditionalCheckFailedException } from "@aws-sdk/client-dynamodb";
import { Logger } from "pino";
import { z } from "zod";
import {
Expand Down Expand Up @@ -73,7 +74,7 @@
async unsafePutLetterBatch(letters: InsertLetter[]): Promise<void> {
let lettersDb: Letter[] = [];
for (let i = 0; i < letters.length; i++) {
const letter = letters[i];

Check warning on line 77 in internal/datastore/src/letter-repository.ts

View workflow job for this annotation

GitHub Actions / Test stage / Linting 

Variable Assigned to Object Injection Sink

if (letter) {
lettersDb.push({
Expand Down Expand Up @@ -163,32 +164,16 @@
};
}

async updateLetterStatus(letterToUpdate: UpdateLetter): Promise<Letter> {
async updateLetterStatus(
letterToUpdate: UpdateLetter,
): Promise<Letter | undefined> {
this.log.debug(
`Updating letter ${letterToUpdate.id} to status ${letterToUpdate.status}`,
);
let result: UpdateCommandOutput;
try {
let updateExpression =
"set #status = :status, updatedAt = :updatedAt, supplierStatus = :supplierStatus, #ttl = :ttl";
const expressionAttributeValues: Record<string, any> = {
":status": letterToUpdate.status,
":updatedAt": new Date().toISOString(),
":supplierStatus": `${letterToUpdate.supplierId}#${letterToUpdate.status}`,
":ttl": Math.floor(
Date.now() / 1000 + 60 * 60 * this.config.lettersTtlHours,
),
};

if (letterToUpdate.reasonCode) {
updateExpression += ", reasonCode = :reasonCode";
expressionAttributeValues[":reasonCode"] = letterToUpdate.reasonCode;
}

if (letterToUpdate.reasonText) {
updateExpression += ", reasonText = :reasonText";
expressionAttributeValues[":reasonText"] = letterToUpdate.reasonText;
}
const { expressionAttributeValues, updateExpression } =
this.buildUpdateExpression(letterToUpdate);

result = await this.ddbClient.send(
new UpdateCommand({
Expand All @@ -198,31 +183,61 @@
supplierId: letterToUpdate.supplierId,
},
UpdateExpression: updateExpression,
ConditionExpression: "attribute_exists(id)", // Ensure letter exists
ConditionExpression:
"attribute_exists(id) AND (attribute_not_exists(eventId) OR eventId <> :eventId)",
ExpressionAttributeNames: {
"#status": "status",
"#ttl": "ttl",
},
ExpressionAttributeValues: expressionAttributeValues,
ReturnValues: "ALL_NEW",
ReturnValuesOnConditionCheckFailure: "ALL_OLD",
}),
);

this.log.debug(
`Updated letter ${letterToUpdate.id} to status ${letterToUpdate.status}`,
);
return LetterSchema.parse(result.Attributes);
} catch (error) {
if (
error instanceof Error &&
error.name === "ConditionalCheckFailedException"
) {
if (error instanceof ConditionalCheckFailedException) {
if (error.Item?.eventId.S === letterToUpdate.eventId) {
this.log.warn(
`Skipping update for letter ${letterToUpdate.id}: eventId ${letterToUpdate.eventId} already processed`,
);
return undefined;
}
throw new Error(
`Letter with id ${letterToUpdate.id} not found for supplier ${letterToUpdate.supplierId}`,
);
}
throw error;
}
}

this.log.debug(
`Updated letter ${letterToUpdate.id} to status ${letterToUpdate.status}`,
);
return LetterSchema.parse(result.Attributes);
private buildUpdateExpression(letterToUpdate: UpdateLetter) {
let updateExpression = `set #status = :status, previousStatus = #status, updatedAt = :updatedAt, supplierStatus = :supplierStatus,
#ttl = :ttl, eventId = :eventId`;
const expressionAttributeValues: Record<string, any> = {
":status": letterToUpdate.status,
":updatedAt": new Date().toISOString(),
":supplierStatus": `${letterToUpdate.supplierId}#${letterToUpdate.status}`,
":ttl": Math.floor(
Date.now() / 1000 + 60 * 60 * this.config.lettersTtlHours,
),
":eventId": letterToUpdate.eventId,
};

if (letterToUpdate.reasonCode) {
updateExpression += ", reasonCode = :reasonCode";
expressionAttributeValues[":reasonCode"] = letterToUpdate.reasonCode;
}

if (letterToUpdate.reasonText) {
updateExpression += ", reasonText = :reasonText";
expressionAttributeValues[":reasonText"] = letterToUpdate.reasonText;
}
return { updateExpression, expressionAttributeValues };
}

async getLettersBySupplier(
Expand Down
3 changes: 3 additions & 0 deletions internal/datastore/src/types.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -42,9 +42,11 @@ export const LetterSchemaBase = z.object({

export const LetterSchema = LetterSchemaBase.extend({
supplierId: idRef(SupplierSchema, "id"),
eventId: z.string().optional(),
url: z.url(),
createdAt: z.string(),
updatedAt: z.string(),
previousStatus: LetterStatus.optional(),
supplierStatus: z.string().describe("Secondary index PK"),
supplierStatusSk: z.string().describe("Secondary index SK"),
ttl: z.int(),
Expand All @@ -67,6 +69,7 @@ export type InsertLetter = Omit<
>;
export type UpdateLetter = {
id: string;
eventId: string;
supplierId: string;
status: Letter["status"];
reasonCode?: string;
Expand Down
2 changes: 1 addition & 1 deletion internal/events/jest.config.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ export const baseJestConfig: Config = {
},
},

coveragePathIgnorePatterns: ["/__tests__/"],
coveragePathIgnorePatterns: ["/src/index.ts$", "/__tests__/"],
transform: { "^.+\\.ts$": "ts-jest" },
testPathIgnorePatterns: [".build"],
testMatch: ["**/?(*.)+(spec|test).[jt]s?(x)"],
Expand Down
3 changes: 2 additions & 1 deletion internal/events/package.json
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
{
"dependencies": {
"@asyncapi/bundler": "^0.6.4",
"@internal/datastore": "*",
"zod": "^4.1.11"
},
"description": "Schemas for NHS Notify Supplier API events",
Expand Down Expand Up @@ -50,5 +51,5 @@
"typecheck": "tsc --noEmit"
},
"types": "dist/index.d.ts",
"version": "1.0.9"
"version": "1.0.10"
}
2 changes: 1 addition & 1 deletion ...c/mappers/__tests__/letter-mapper.test.ts → ...rc/events/__tests__/letter-mapper.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
import { $LetterEvent } from "@nhsdigital/nhs-notify-event-schemas-supplier-api/src";
import { Letter } from "@internal/datastore";
import mapLetterToCloudEvent from "../letter-mapper";
import { mapLetterToCloudEvent } from "../letter-mapper";

describe("letter-mapper", () => {
it("maps a letter to a letter event", async () => {
Expand Down
9 changes: 5 additions & 4 deletions ...-transformer/src/mappers/letter-mapper.ts → internal/events/src/events/letter-mapper.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,10 +1,11 @@
import { LetterEvent } from "@nhsdigital/nhs-notify-event-schemas-supplier-api/src";
import { randomBytes, randomUUID } from "node:crypto";
import eventSchemaPackage from "@nhsdigital/nhs-notify-event-schemas-supplier-api/package.json";
import { LetterForEventPub } from "../types";
import { Letter } from "@internal/datastore";
import { LetterEvent } from "./letter-events";

export default function mapLetterToCloudEvent(
letter: LetterForEventPub,
// eslint-disable-next-line import-x/prefer-default-export
export function mapLetterToCloudEvent(
letter: Letter,
source: string,
): LetterEvent {
const eventId = randomUUID();
Expand Down
1 change: 1 addition & 0 deletions internal/events/src/index.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,3 +4,4 @@ export { default as DomainBase } from "./domain/domain-base";
export * from "./events/event-envelope";
export * from "./events/letter-events";
export * from "./events/mi-events";
export * from "./events/letter-mapper";
3 changes: 1 addition & 2 deletions internal/events/tsconfig.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,8 +3,7 @@
"declaration": true,
"isolatedModules": true,
"module": "commonjs",
"outDir": "dist",
"resolveJsonModule": true
"outDir": "dist"
},
"exclude": [
"node_modules",
Expand Down
2 changes: 2 additions & 0 deletions lambdas/api-handler/package.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,11 +2,13 @@
"dependencies": {
"@aws-sdk/client-dynamodb": "^3.925.0",
"@aws-sdk/client-s3": "^3.925.0",
"@aws-sdk/client-sns": "^3.925.0",
"@aws-sdk/client-sqs": "^3.925.0",
"@aws-sdk/lib-dynamodb": "^3.925.0",
"@aws-sdk/s3-request-presigner": "^3.925.0",
"@internal/datastore": "*",
"@internal/helpers": "*",
"@nhsdigital/nhs-notify-event-schemas-supplier-api": "*",
"aws-lambda": "^1.0.7",
"esbuild": "^0.25.11",
"pino": "^9.7.0",
Expand Down
Loading
Loading