Introduce dummy get letters endpoint

infrastructure/terraform/components/api/README.md

@@ -27,6 +27,7 @@ No requirements.
 | Name | Source | Version |
 |------|--------|---------|
 | <a name="module_authorizer_lambda"></a> [authorizer\_lambda](#module\_authorizer\_lambda) | git::https://github.com/NHSDigital/nhs-notify-shared-modules.git//infrastructure/modules/lambda | v2.0.4 |
+| <a name="module_get_letters"></a> [get\_letters](#module\_get\_letters) | git::https://github.com/NHSDigital/nhs-notify-shared-modules.git//infrastructure/modules/lambda | v2.0.10 |
 | <a name="module_hello_world"></a> [hello\_world](#module\_hello\_world) | git::https://github.com/NHSDigital/nhs-notify-shared-modules.git//infrastructure/modules/lambda | v2.0.10 |
 | <a name="module_kms"></a> [kms](#module\_kms) | git::https://github.com/NHSDigital/nhs-notify-shared-modules.git//infrastructure/modules/kms | v2.0.10 |
 ## Outputs

infrastructure/terraform/components/api/iam_role_api_gateway_execution_role.tf

@@ -50,6 +50,7 @@ data "aws_iam_policy_document" "api_gateway_execution_policy" {
     resources = [
       module.authorizer_lambda.function_arn,
       module.hello_world.function_arn,
+      module.get_letters.function_arn,
     ]
   }
 }

infrastructure/terraform/components/api/locals.tf

@@ -9,6 +9,7 @@ locals {
     AWS_REGION              = var.region
     AUTHORIZER_LAMBDA_ARN   = module.authorizer_lambda.function_arn
     HELLO_WORLD_LAMBDA_ARN  = module.hello_world.function_arn
+    GET_LETTERS_LAMBDA_ARN  = module.get_letters.function_arn
   })
 
   destination_arn = "arn:aws:logs:${var.region}:${var.shared_infra_account_id}:destination:nhs-main-obs-firehose-logs"

infrastructure/terraform/components/api/module_lambda_get_letters.tf

@@ -0,0 +1,56 @@
+module "get_letters" {
+  source = "git::https://github.com/NHSDigital/nhs-notify-shared-modules.git//infrastructure/modules/lambda?ref=v2.0.10"
+
+  function_name = "get_letters"
+  description   = "Get paginated letter ids"
+
+  aws_account_id = var.aws_account_id
+  component      = var.component
+  environment    = var.environment
+  project        = var.project
+  region         = var.region
+  group          = var.group
+
+  log_retention_in_days = var.log_retention_in_days
+  kms_key_arn           = module.kms.key_arn
+
+  iam_policy_document = {
+    body = data.aws_iam_policy_document.get_letters_lambda.json
+  }
+
+  function_s3_bucket      = local.acct.s3_buckets["lambda_function_artefacts"]["id"]
+  function_code_base_path = local.aws_lambda_functions_dir_path
+  function_code_dir       = "api-handler/dist"
+  function_include_common = true
+  handler_function_name   = "getLetters"
+  runtime                 = "nodejs22.x"
+  memory                  = 128
+  timeout                 = 5
+  log_level               = var.log_level
+
+  force_lambda_code_deploy = var.force_lambda_code_deploy
+  enable_lambda_insights   = false
+
+  send_to_firehose          = true
+  log_destination_arn       = local.destination_arn
+  log_subscription_role_arn = local.acct.log_subscription_role_arn
+
+  lambda_env_vars = {
+  }
+}
+
+data "aws_iam_policy_document" "get_letters_lambda" {
+  statement {
+    sid    = "KMSPermissions"
+    effect = "Allow"
+
+    actions = [
+      "kms:Decrypt",
+      "kms:GenerateDataKey",
+    ]
+
+    resources = [
+      module.kms.key_arn, ## Requires shared kms module
+    ]
+  }
+}

infrastructure/terraform/components/api/module_lambda_hello_world.tf

@@ -22,7 +22,7 @@ module "hello_world" {
   function_code_base_path = local.aws_lambda_functions_dir_path
   function_code_dir       = "api-handler/dist"
   function_include_common = true
-  handler_function_name   = "handler"
+  handler_function_name   = "helloWorld"
   runtime                 = "nodejs22.x"
   memory                  = 128
   timeout                 = 5

infrastructure/terraform/components/api/resources/spec.tmpl.json

@@ -2,17 +2,17 @@
   "components": {
     "securitySchemes": {
       "LambdaAuthorizer": {
-        "type": "apiKey",
-        "name": "Authorization",
         "in": "header",
-        "x-amazon-apigateway-authtype": "custom",
+        "name": "Authorization",
+        "type": "apiKey",
         "x-amazon-apigateway-authorizer": {
-          "type": "request",
-          "authorizerUri": "arn:aws:apigateway:${AWS_REGION}:lambda:path/2015-03-31/functions/${AUTHORIZER_LAMBDA_ARN}/invocations",
           "authorizerCredentials": "${APIG_EXECUTION_ROLE_ARN}",
+          "authorizerResultTtlInSeconds": 0,
+          "authorizerUri": "arn:aws:apigateway:${AWS_REGION}:lambda:path/2015-03-31/functions/${AUTHORIZER_LAMBDA_ARN}/invocations",
           "identitySource": "method.request.header.Authorization",
-          "authorizerResultTtlInSeconds": 0
-        }
+          "type": "request"
+        },
+        "x-amazon-apigateway-authtype": "custom"
       }
     }
   },
@@ -25,13 +25,18 @@
   "paths": {
     "/": {
       "get": {
-        "summary": "Health check",
         "description": "Returns 200 OK if the API is up.",
         "responses": {
           "200": {
             "description": "OK"
           }
         },
+        "security": [
+          {
+            "LambdaAuthorizer": []
+          }
+        ],
+        "summary": "Health check",
         "x-amazon-apigateway-integration": {
           "contentHandling": "CONVERT_TO_TEXT",
           "credentials": "${APIG_EXECUTION_ROLE_ARN}",
@@ -45,12 +50,37 @@
           "timeoutInMillis": 29000,
           "type": "AWS_PROXY",
           "uri": "arn:aws:apigateway:${AWS_REGION}:lambda:path/2015-03-31/functions/${HELLO_WORLD_LAMBDA_ARN}/invocations"
+        }
+      }
+    },
+    "/letters": {
+      "get": {
+        "description": "Returns 200 OK with paginated letter ids.",
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
         },
         "security": [
           {
             "LambdaAuthorizer": []
           }
-        ]
+        ],
+        "summary": "Get letters",
+        "x-amazon-apigateway-integration": {
+          "contentHandling": "CONVERT_TO_TEXT",
+          "credentials": "${APIG_EXECUTION_ROLE_ARN}",
+          "httpMethod": "POST",
+          "passthroughBehavior": "WHEN_NO_TEMPLATES",
+          "responses": {
+            ".*": {
+              "statusCode": "200"
+            }
+          },
+          "timeoutInMillis": 29000,
+          "type": "AWS_PROXY",
+          "uri": "arn:aws:apigateway:${AWS_REGION}:lambda:path/2015-03-31/functions/${GET_LETTERS_LAMBDA_ARN}/invocations"
+        }
       }
     }
   }

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

@@ -0,0 +1,44 @@
+import { getLetters } from '../../index';
+import type { Context } from 'aws-lambda';
+import { mockDeep } from 'jest-mock-extended';
+
+describe('API Lambda handler', () => {
+  it('returns 200 OK with basic paginated resources', async () => {
+    const event = { path: '/letters' };
+    const context = mockDeep<Context>();
+    const callback = jest.fn();
+    const result = await getLetters(event, context, callback);
+
+    const expected = {
+      "links": {
+        "self": "/letters?page=1",
+        "first": "/letters?page=1",
+        "last": "/letters?page=1",
+        "next": "/letters?page=1",
+        "prev": "/letters?page=1"
+      },
+      "data": [
+        { "type": "letter", "id": "l1" },
+        { "type": "letter", "id": "l2" },
+        { "type": "letter", "id": "l3" }
+      ]
+    }
+
+    expect(result).toEqual({
+      statusCode: 200,
+      body: JSON.stringify(expected, null, 2),
+    });
+  });
+
+  it('returns 404 Not Found for an unknown path', async () => {
+    const event = { path: '/unknown' };
+    const context = mockDeep<Context>();
+    const callback = jest.fn();
+    const result = await getLetters(event, context, callback);
+
+    expect(result).toEqual({
+      statusCode: 404,
+      body: 'Not Found',
+    });
+  });
+});

lambdas/api-handler/src/__tests__/index.test.ts → lambdas/api-handler/src/handlers/__tests__/hello-world.test.ts

@@ -1,4 +1,4 @@
-import { handler } from '../index';
+import { helloWorld } from '../../index';
 import type { Context } from 'aws-lambda';
 import { mockDeep } from 'jest-mock-extended';
 
@@ -7,7 +7,7 @@ describe('API Lambda handler', () => {
     const event = { path: '/' };
     const context = mockDeep<Context>();
     const callback = jest.fn();
-    const result = await handler(event, context, callback);
+    const result = await helloWorld(event, context, callback);
 
     expect(result).toEqual({
       statusCode: 200,
@@ -19,7 +19,7 @@ describe('API Lambda handler', () => {
     const event = {}; // No path provided
     const context = mockDeep<Context>();
     const callback = jest.fn();
-    const result = await handler(event as any, context, callback);
+    const result = await helloWorld(event as any, context, callback);
 
     expect(result).toEqual({
       statusCode: 200,
@@ -31,7 +31,7 @@ describe('API Lambda handler', () => {
     const event = { path: '/unknown' };
     const context = mockDeep<Context>();
     const callback = jest.fn();
-    const result = await handler(event, context, callback);
+    const result = await helloWorld(event, context, callback);
 
     expect(result).toEqual({
       statusCode: 404,

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

@@ -0,0 +1,58 @@
+import { Handler, APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda';
+
+const storedLetters: string[] = ["l1", "l2", "l3"];
+
+export const getLetters: Handler = async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
+
+  if (event.path === '/letters') {
+
+    const response = createGetLettersResponse(event.path, storedLetters);
+
+    return {
+      statusCode: 200,
+      body: JSON.stringify(response, null, 2)
+    };
+  }
+
+  return {
+    statusCode: 404,
+    body: 'Not Found',
+  };
+};
+
+interface GetLettersLinks {
+  self: string;
+  first: string;
+  last: string;
+  next?: string;
+  prev?: string;
+}
+
+interface Resource {
+  type: string;
+  id: string;
+}
+
+interface GetLettersResponse {
+  links: GetLettersLinks;
+  data: Resource[];
+}
+
+function createGetLettersResponse(
+  baseUrl: string,
+  letters: string[]
+): GetLettersResponse {
+  return {
+    links: {
+      self: `${baseUrl}?page=1`,
+      first: `${baseUrl}?page=1`,
+      last: `${baseUrl}?page=1`,
+      next: `${baseUrl}?page=1`,
+      prev: `${baseUrl}?page=1`
+    },
+    data: letters.map((letterId) => ({
+      type: "letter",
+      id: letterId,
+    })),
+  };
+}

lambdas/api-handler/src/handlers/hello-world.ts

@@ -0,0 +1,18 @@
+// Replace me with the actual code for your Lambda function
+import { Handler, APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda';
+
+export const helloWorld: Handler = async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
+  const path = event.path || '/';
+
+  if (path === '/') {
+    return {
+      statusCode: 200,
+      body: 'Hello World',
+    };
+  }
+
+  return {
+    statusCode: 404,
+    body: 'Not Found',
+  };
+};

lambdas/api-handler/src/index.ts

@@ -1,18 +1,3 @@
-// Replace me with the actual code for your Lambda function
-import { Handler, APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda';
-
-export const handler: Handler = async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
-  const path = event.path || '/';
-
-  if (path === '/') {
-    return {
-      statusCode: 200,
-      body: 'Hello World',
-    };
-  }
-
-  return {
-    statusCode: 404,
-    body: 'Not Found',
-  };
-};
+// Export all handlers for ease of access
+export { getLetters } from './handlers/get-letters';
+export { helloWorld } from './handlers/hello-world';