CCM-11602: MAX LIMIT envar and added into test context

Author: masl2

infrastructure/terraform/components/api/README.md

@@ -12,7 +12,6 @@ No requirements.
 | <a name="input_aws_account_id"></a> [aws\_account\_id](#input\_aws\_account\_id) | The AWS Account ID (numeric) | `string` | n/a | yes |
 | <a name="input_ca_pem_filename"></a> [ca\_pem\_filename](#input\_ca\_pem\_filename) | Filename for the CA truststore file within the s3 bucket | `string` | `null` | no |
 | <a name="input_component"></a> [component](#input\_component) | The variable encapsulating the name of this component | `string` | `"supapi"` | no |
-| <a name="input_default_get_limit"></a> [default\_get\_limit](#input\_default\_get\_limit) | Default limit to apply to GET requests that support pagination | `number` | `2500` | no |
 | <a name="input_default_tags"></a> [default\_tags](#input\_default\_tags) | A map of default tags to apply to all taggable resources within the component | `map(string)` | `{}` | no |
 | <a name="input_enable_backups"></a> [enable\_backups](#input\_enable\_backups) | Enable backups | `bool` | `false` | no |
 | <a name="input_environment"></a> [environment](#input\_environment) | The name of the tfscaffold environment | `string` | n/a | yes |
@@ -23,6 +22,7 @@ No requirements.
 | <a name="input_log_level"></a> [log\_level](#input\_log\_level) | The log level to be used in lambda functions within the component. Any log with a lower severity than the configured value will not be logged: https://docs.python.org/3/library/logging.html#levels | `string` | `"INFO"` | no |
 | <a name="input_log_retention_in_days"></a> [log\_retention\_in\_days](#input\_log\_retention\_in\_days) | The retention period in days for the Cloudwatch Logs events to be retained, default of 0 is indefinite | `number` | `0` | no |
 | <a name="input_manually_configure_mtls_truststore"></a> [manually\_configure\_mtls\_truststore](#input\_manually\_configure\_mtls\_truststore) | Manually manage the truststore used for API Gateway mTLS (e.g. for prod environment) | `bool` | `false` | no |
+| <a name="input_max_get_limit"></a> [max\_get\_limit](#input\_max\_get\_limit) | Default limit to apply to GET requests that support pagination | `number` | `2500` | no |
 | <a name="input_parent_acct_environment"></a> [parent\_acct\_environment](#input\_parent\_acct\_environment) | Name of the environment responsible for the acct resources used, affects things like DNS zone. Useful for named dev environments | `string` | `"main"` | no |
 | <a name="input_project"></a> [project](#input\_project) | The name of the tfscaffold project | `string` | n/a | yes |
 | <a name="input_region"></a> [region](#input\_region) | The AWS Region | `string` | n/a | yes |

infrastructure/terraform/components/api/module_lambda_get_letters.tf

@@ -38,7 +38,7 @@ module "get_letters" {
   lambda_env_vars = {
     LETTERS_TABLE_NAME = aws_dynamodb_table.letters.name,
     LETTER_TTL_HOURS   = var.letter_table_ttl_hours,
-    DEFAULT_LIMIT      = var.default_get_limit,
+    MAX_LIMIT          = var.max_get_limit,
   }
 }
 

infrastructure/terraform/components/api/variables.tf

@@ -111,7 +111,7 @@ variable "letter_table_ttl_hours" {
   default     = 24
 }
 
-variable "default_get_limit" {
+variable "max_get_limit" {
   type        = number
   description = "Default limit to apply to GET requests that support pagination"
   default     = 2500

lambdas/api-handler/src/handlers/__tests__/get-letters.test.ts

@@ -3,14 +3,27 @@ import type { Context } from 'aws-lambda';
 import { mockDeep } from 'jest-mock-extended';
 import { makeApiGwEvent } from './utils/test-utils';
 import * as letterService from '../../services/letter-operations';
+import { getEnvars } from '../get-letters';
 
 jest.mock('../../services/letter-operations');
 
 describe('API Lambda handler', () => {
 
+  const originalEnv = process.env;
+
   beforeEach(() => {
     jest.resetAllMocks();
-    process.env.DEFAULT_LIMIT = '100';
+    jest.resetModules();
+    process.env = { ...originalEnv };
+    process.env.MAX_LIMIT = '2500';
+  });
+
+  afterEach(() => {
+    process.env = originalEnv;
+  });
+
+  it('uses process.env.MAX_LIMIT for max limit set', async () => {
+    expect(getEnvars().maxLimit).toBe(2500);
   });
 
   it('returns 200 OK with basic paginated resources', async () => {

lambdas/api-handler/src/handlers/get-letters.ts

@@ -6,9 +6,15 @@ import pino from 'pino';
 
 const letterRepo = createLetterRepository();
 const log = pino();
-const DEFAULT_LIMIT = process.env.DEFAULT_LIMIT || '2500';
+
+export const getEnvars = (): { maxLimit: number } => ({
+  maxLimit: parseInt(process.env.MAX_LIMIT!)
+});
 
 export const getLetters: APIGatewayProxyHandler = async (event) => {
+
+  const { maxLimit } = getEnvars();
+
   if (event.path === "/letters") {
     const supplierId = event.headers ? event.headers["NHSD-Supplier-ID"] : undefined;
 
@@ -42,25 +48,29 @@ export const getLetters: APIGatewayProxyHandler = async (event) => {
       };
     }
 
-    let limit = event.queryStringParameters?.limit || DEFAULT_LIMIT;
-
-    let limitNumber = Number(limit);
-
-    if (isNaN(limitNumber)) {
-      log.info({
-        description: "limit parameter is not a number",
-        limit,
-      });
-      return {
-        statusCode: 400,
-        body: "Invalid Request: limit parameter must be a positive number not greater than 2500",
-      };
+    let limitNumber;
+
+    if (event.queryStringParameters?.limit) {
+      let limitParam = event.queryStringParameters?.limit;
+      limitNumber = Number(limitParam);
+      if (isNaN(limitNumber)) {
+        log.info({
+          description: "limit parameter is not a number",
+          limitParam,
+        });
+        return {
+          statusCode: 400,
+          body: "Invalid Request: limit parameter must be a positive number not greater than 2500",
+        };
+      }
+    } else {
+      limitNumber = maxLimit;
     }
 
-    if (limitNumber < 0 || limitNumber > 2500) {
+    if (limitNumber < 0 || limitNumber > maxLimit) {
       log.info({
         description: "Limit value is invalid",
-        limit,
+        limitNumber,
       });
       return {
         statusCode: 400,
@@ -80,7 +90,7 @@ export const getLetters: APIGatewayProxyHandler = async (event) => {
     log.info({
       description: 'Pending letters successfully fetched',
       supplierId,
-      limit,
+      limitNumber,
       status,
       lettersCount: letters.length
     });