Add metrics

Author: stevebux

lambdas/supplier-config-ingress/package.json

@@ -6,6 +6,7 @@
     "@internal/helpers": "^0.1.0",
     "@nhsdigital/nhs-notify-event-schemas-supplier-config": "^1.1.0",
     "@types/aws-lambda": "^8.10.148",
+    "aws-embedded-metrics": "^4.2.0",
     "esbuild": "^0.27.2",
     "pino": "^9.7.0",
     "zod": "^4.1.11"

lambdas/supplier-config-ingress/src/__tests__/supplier-config-ingress-handler.test.ts

@@ -1,4 +1,5 @@
 import type { SQSEvent, SQSRecord } from "aws-lambda";
+import { Unit } from "aws-embedded-metrics";
 import createSupplierConfigIngressHandler from "../handler/supplier-config-ingress-handler";
 import { Deps } from "../config/deps";
 
@@ -150,4 +151,65 @@ describe("supplierConfigHandler", () => {
       mockDeps.supplierConfigRepo.upsertSupplierConfig,
     ).not.toHaveBeenCalled();
   });
+
+  it("emits metrics for created config events", async () => {
+    const data = createSupplierConfig();
+    const record = createSqsRecord(data);
+    const event = { Records: [record] } as unknown as SQSEvent;
+
+    await handler(event);
+
+    expect(mockDeps.logger.info).toHaveBeenCalledWith(
+      expect.objectContaining({
+        entity: "supplier",
+        result: "CREATED",
+        ConfigEvents: 1,
+        _aws: expect.objectContaining({
+          CloudWatchMetrics: expect.arrayContaining([
+            expect.objectContaining({
+              Metrics: [
+                expect.objectContaining({
+                  Name: "ConfigEvents",
+                  Value: 1,
+                  Unit: Unit.Count,
+                }),
+              ],
+            }),
+          ]),
+        }),
+      }),
+    );
+  });
+
+  it("emits metrics for updated config events", async () => {
+    (
+      mockDeps.supplierConfigRepo.upsertSupplierConfig as jest.Mock
+    ).mockResolvedValue("UPDATED");
+    const data = createSupplierConfig();
+    const record = createSqsRecord(data);
+    const event = { Records: [record] } as unknown as SQSEvent;
+
+    await handler(event);
+
+    expect(mockDeps.logger.info).toHaveBeenCalledWith(
+      expect.objectContaining({
+        entity: "supplier",
+        result: "UPDATED",
+        ConfigEvents: 1,
+        _aws: expect.objectContaining({
+          CloudWatchMetrics: expect.arrayContaining([
+            expect.objectContaining({
+              Metrics: [
+                expect.objectContaining({
+                  Name: "ConfigEvents",
+                  Value: 1,
+                  Unit: Unit.Count,
+                }),
+              ],
+            }),
+          ]),
+        }),
+      }),
+    );
+  });
 });

lambdas/supplier-config-ingress/src/handler/supplier-config-ingress-handler.ts

@@ -1,8 +1,10 @@
 import type { SQSBatchResponse, SQSEvent, SQSRecord } from "aws-lambda";
 import { z } from "zod/v4";
+import { Unit } from "aws-embedded-metrics";
 import {
   $SupplierConfigEntity,
   SupplierConfigEntity,
+  SupplierConfigRepository,
 } from "@internal/datastore";
 import {
   $LetterVariant,
@@ -12,9 +14,10 @@ import {
   $SupplierPack,
   $VolumeGroup,
 } from "@nhsdigital/nhs-notify-event-schemas-supplier-config";
+import { MetricEntry, buildEMFObject } from "@internal/helpers";
 import { Deps } from "../config/deps";
 
-const $EventEnvelope = z.looseObject({
+const $EventEnvelope = z.object({
   type: z.string(),
   data: z.looseObject({ id: z.string() }),
 });
@@ -32,6 +35,12 @@ const entitySchemas: Record<SupplierConfigEntity, z.ZodType<{ id: string }>> = {
   "supplier-pack": $SupplierPack as unknown as z.ZodType<{ id: string }>,
 };
 
+type UpsertResult = Awaited<
+  ReturnType<SupplierConfigRepository["upsertSupplierConfig"]>
+>;
+
+type MetricKey = { entity: string; result: UpsertResult };
+
 function extractEntityFromType(type: string) {
   const elements = type.split(".");
   return $SupplierConfigEntity.parse(
@@ -51,11 +60,30 @@ function parseSupplierConfigFromRecord(record: SQSRecord): {
   return { entity, config };
 }
 
+function emitMetrics(
+  logger: Deps["logger"],
+  resultCounts: Map<MetricKey, number>,
+) {
+  const namespace = "supplier-config-ingress";
+  for (const [key, count] of resultCounts) {
+    const { entity, result } = key;
+    const dimensions: Record<string, string> = { entity, result };
+    const metric: MetricEntry = {
+      key: "ConfigEvents",
+      value: count,
+      unit: Unit.Count,
+    };
+    const emf = buildEMFObject(namespace, dimensions, metric);
+    logger.info(emf);
+  }
+}
+
 export default function createSupplierConfigIngressHandler(deps: Deps) {
   const { logger, supplierConfigRepo } = deps;
 
   return async (sqsEvent: SQSEvent): Promise<SQSBatchResponse> => {
     const batchItemFailures: { itemIdentifier: string }[] = [];
+    const resultCounts = new Map<MetricKey, number>();
 
     for (const record of sqsEvent.Records) {
       try {
@@ -75,6 +103,9 @@ export default function createSupplierConfigIngressHandler(deps: Deps) {
           config,
         );
 
+        const metricKey: MetricKey = { entity, result };
+        resultCounts.set(metricKey, (resultCounts.get(metricKey) || 0) + 1);
+
         logger.info(
           { entity, pk: config.id, result },
           "Supplier config upserted",
@@ -88,6 +119,8 @@ export default function createSupplierConfigIngressHandler(deps: Deps) {
       }
     }
 
+    emitMetrics(logger, resultCounts);
+
     return { batchItemFailures };
   };
 }