Get the variant details

Author: nhsd-david-wass

infrastructure/terraform/components/api/locals.tf

@@ -20,15 +20,16 @@ locals {
   destination_arn = "arn:aws:logs:${var.region}:${var.shared_infra_account_id}:destination:nhs-main-obs-firehose-logs"
 
   common_lambda_env_vars = {
-    LETTERS_TABLE_NAME       = aws_dynamodb_table.letters.name,
-    MI_TABLE_NAME            = aws_dynamodb_table.mi.name,
-    LETTER_TTL_HOURS         = 12960, # 18 months * 30 days * 24 hours
-    MI_TTL_HOURS             = 2160   # 90 days * 24 hours
-    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}/${var.environment}/letters"
+    LETTERS_TABLE_NAME         = aws_dynamodb_table.letters.name,
+    MI_TABLE_NAME              = aws_dynamodb_table.mi.name,
+    LETTER_TTL_HOURS           = 12960, # 18 months * 30 days * 24 hours
+    MI_TTL_HOURS               = 2160   # 90 days * 24 hours
+    SUPPLIER_ID_HEADER         = "nhsd-supplier-id",
+    APIM_CORRELATION_HEADER    = "nhsd-correlation-id",
+    DOWNLOAD_URL_TTL_SECONDS   = 60
+    SNS_TOPIC_ARN              = "${module.eventsub.sns_topic.arn}",
+    EVENT_SOURCE               = "/data-plane/supplier-api/${var.group}/${var.environment}/letters"
+    SUPPLIER_CONFIG_TABLE_NAME = aws_dynamodb_table.supplier-configuration.name
   }
 
   core_pdf_bucket_arn        = "arn:aws:s3:::comms-${var.core_account_id}-eu-west-2-${var.core_environment}-api-stg-pdf-pipeline"

infrastructure/terraform/components/api/module_lambda_supplier_allocator.tf

@@ -82,4 +82,18 @@ data "aws_iam_policy_document" "supplier_allocator_lambda" {
       module.sqs_letter_updates.sqs_queue_arn
     ]
   }
+
+  statement {
+    sid    = "AllowDynamoDBAccess"
+    effect = "Allow"
+
+    actions = [
+      "dynamodb:GetItem",
+      "dynamodb:Query"
+    ]
+
+    resources = [
+      aws_dynamodb_table.supplier-configuration.arn
+    ]
+  }
 }

internal/datastore/src/index.ts

@@ -3,5 +3,6 @@ export * from "./errors";
 export * from "./mi-repository";
 export * from "./letter-repository";
 export * from "./supplier-repository";
+export * from "./supplier-config-repository";
 export { default as LetterQueueRepository } from "./letter-queue-repository";
 export { default as DBHealthcheck } from "./healthcheck";

internal/datastore/src/supplier-config-repository.ts

@@ -0,0 +1,28 @@
+import { DynamoDBDocumentClient, GetCommand } from "@aws-sdk/lib-dynamodb";
+import { Logger } from "pino";
+import { $LetterVariant, LetterVariant } from "./SupplierConfigDomain";
+
+export type SupplierConfigRepositoryConfig = {
+  supplierConfigTableName: string;
+};
+
+export class SupplierConfigRepository {
+  constructor(
+    readonly ddbClient: DynamoDBDocumentClient,
+    readonly log: Logger,
+    readonly config: SupplierConfigRepositoryConfig,
+  ) {}
+
+  async getLetterVariant(variantId: string): Promise<LetterVariant> {
+    const result = await this.ddbClient.send(
+      new GetCommand({
+        TableName: this.config.supplierConfigTableName,
+        Key: { PK: "LETTER_VARIANT", SK: variantId },
+      }),
+    );
+    if (!result.Item) {
+      throw new Error(`Letter variant with id ${variantId} not found`);
+    }
+    return $LetterVariant.parse(result.Item);
+  }
+}

lambdas/supplier-allocator/src/config/__tests__/deps.test.ts

@@ -2,6 +2,7 @@ import type { Deps } from "lambdas/supplier-allocator/src/config/deps";
 
 describe("createDependenciesContainer", () => {
   const env = {
+    SUPPLIER_CONFIG_TABLE_NAME: "SupplierConfigTable",
     VARIANT_MAP: {
       lv1: {
         supplierId: "supplier1",
@@ -25,19 +26,30 @@ describe("createDependenciesContainer", () => {
       })),
     }));
 
+    // Repo client
+    jest.mock("@internal/datastore", () => ({
+      SupplierConfigRepository: jest.fn(),
+    }));
+
     // Env
     jest.mock("../env", () => ({ envVars: env }));
   });
 
   test("constructs deps and wires repository config correctly", async () => {
     // get current mock instances
     const { createLogger } = jest.requireMock("@internal/helpers");
-
+    const { SupplierConfigRepository } = jest.requireMock(
+      "@internal/datastore",
+    );
     // eslint-disable-next-line @typescript-eslint/no-require-imports
     const { createDependenciesContainer } = require("../deps");
     const deps: Deps = createDependenciesContainer();
     expect(createLogger).toHaveBeenCalledTimes(1);
-
+    expect(SupplierConfigRepository).toHaveBeenCalledTimes(1);
+    const supplierConfigRepoCtorArgs = SupplierConfigRepository.mock.calls[0];
+    expect(supplierConfigRepoCtorArgs[2]).toEqual({
+      supplierConfigTableName: "SupplierConfigTable",
+    });
     expect(deps.env).toEqual(env);
   });
 });

lambdas/supplier-allocator/src/config/__tests__/env.test.ts

@@ -15,6 +15,7 @@ describe("lambdaEnv", () => {
   });
 
   it("should load all environment variables successfully", () => {
+    process.env.SUPPLIER_CONFIG_TABLE_NAME = "SupplierConfigTable";
     process.env.VARIANT_MAP = `{
       "lv1": {
         "supplierId": "supplier1",
@@ -25,6 +26,7 @@ describe("lambdaEnv", () => {
     const { envVars } = require("../env");
 
     expect(envVars).toEqual({
+      SUPPLIER_CONFIG_TABLE_NAME: "SupplierConfigTable",
       VARIANT_MAP: {
         lv1: {
           supplierId: "supplier1",

lambdas/supplier-allocator/src/config/deps.ts

@@ -1,18 +1,40 @@
+import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
+import { DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb";
 import { SQSClient } from "@aws-sdk/client-sqs";
 import { Logger } from "pino";
 import { createLogger } from "@internal/helpers";
+import { SupplierConfigRepository } from "@internal/datastore";
 import { EnvVars, envVars } from "./env";
 
 export type Deps = {
+  supplierConfigRepo: SupplierConfigRepository;
   logger: Logger;
   env: EnvVars;
   sqsClient: SQSClient;
 };
 
+function createDocumentClient(): DynamoDBDocumentClient {
+  const ddbClient = new DynamoDBClient({});
+  return DynamoDBDocumentClient.from(ddbClient);
+}
+
+function createSupplierConfigRepository(
+  log: Logger,
+  // eslint-disable-next-line @typescript-eslint/no-shadow
+  envVars: EnvVars,
+): SupplierConfigRepository {
+  const config = {
+    supplierConfigTableName: envVars.SUPPLIER_CONFIG_TABLE_NAME,
+  };
+
+  return new SupplierConfigRepository(createDocumentClient(), log, config);
+}
+
 export function createDependenciesContainer(): Deps {
   const log = createLogger({ logLevel: envVars.PINO_LOG_LEVEL });
 
   return {
+    supplierConfigRepo: createSupplierConfigRepository(log, envVars),
     logger: log,
     env: envVars,
     sqsClient: new SQSClient({}),

lambdas/supplier-allocator/src/config/env.ts

@@ -10,6 +10,7 @@ const LetterVariantSchema = z.record(
 export type LetterVariant = z.infer<typeof LetterVariantSchema>;
 
 const EnvVarsSchema = z.object({
+  SUPPLIER_CONFIG_TABLE_NAME: z.string(),
   PINO_LOG_LEVEL: z.coerce.string().optional(),
   VARIANT_MAP: z.string().transform((str, _) => {
     const parsed = JSON.parse(str);

lambdas/supplier-allocator/src/handler/__tests__/allocate-handler.test.ts

@@ -7,6 +7,7 @@ import {
   $LetterEvent,
   LetterEvent,
 } from "@nhsdigital/nhs-notify-event-schemas-supplier-api/src/events/letter-events";
+import { SupplierConfigRepository } from "@internal/datastore";
 import createSupplierAllocatorHandler from "../allocate-handler";
 import { Deps } from "../../config/deps";
 import { EnvVars } from "../../config/env";
@@ -139,8 +140,16 @@ describe("createSupplierAllocatorHandler", () => {
     } as unknown as jest.Mocked<SQSClient>;
 
     mockedDeps = {
+      supplierConfigRepo: {
+        getLetterVariant: jest.fn().mockResolvedValue({
+          id: "variant1",
+          supplierId: "supplier1",
+          specId: "spec1",
+        }),
+      } as unknown as SupplierConfigRepository,
       logger: { error: jest.fn(), info: jest.fn() } as unknown as pino.Logger,
       env: {
+        SUPPLIER_CONFIG_TABLE_NAME: "SupplierConfigTable",
         VARIANT_MAP: {
           lv1: {
             supplierId: "supplier1",

lambdas/supplier-allocator/src/handler/allocate-handler.ts

@@ -1,7 +1,7 @@
 import { SQSBatchItemFailure, SQSEvent, SQSHandler } from "aws-lambda";
 import { SendMessageCommand } from "@aws-sdk/client-sqs";
 import { LetterRequestPreparedEvent } from "@nhsdigital/nhs-notify-event-schemas-letter-rendering-v1";
-
+import { LetterVariant } from "internal/datastore/src/SupplierConfigDomain";
 import { LetterRequestPreparedEventV2 } from "@nhsdigital/nhs-notify-event-schemas-letter-rendering";
 import z from "zod";
 import { Deps } from "../config/deps";
@@ -46,7 +46,23 @@ function validateType(event: unknown) {
   }
 }
 
+async function getVariantDetails(variantId: string, deps: Deps) {
+  deps.logger.info({
+    description: "Fetching letter variant details from database",
+    variantId,
+  });
+
+  const variantDetails: LetterVariant =
+    await deps.supplierConfigRepo.getLetterVariant(variantId);
+  deps.logger.info({
+    description: "Fetched letter variant details",
+    variantId,
+    variantDetails,
+  });
+}
+
 function getSupplier(letterEvent: PreparedEvents, deps: Deps): SupplierSpec {
+  getVariantDetails(letterEvent.data.letterVariantId, deps);
   return resolveSupplierForVariant(letterEvent.data.letterVariantId, deps);
 }