update api wrapper signature for easier testing in apps

Author: manwaring

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html)
 
+## [1.0.7]  (2019-09-04)
+
+### Changed
+
+- Update the api wrapper signature for easier testing in applications
+
 ## [1.0.1]  (2019-09-04)
 
 ### Fixed
@@ -32,5 +38,6 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/),
 - Update older libraries
 - Now publish from Git tags instead of master pushes
 
+[1.0.7]: https://github.com/manwaring/lambda-wrapper/compare/v1.0.1...v1.0.7
 [1.0.1]: https://github.com/manwaring/lambda-wrapper/compare/v1.0.0...v1.0.1
 [1.0.0]: https://github.com/manwaring/lambda-wrapper/compare/v0.3.8...v1.0.0

__mocks__/@iopipe/iopipe.ts

@@ -1,13 +1,14 @@
 {
   "name": "@manwaring/lambda-wrapper",
   "description": "A lambda handler wrapper to abstract common functionality and provide useful defaults",
-  "version": "1.0.6",
+  "version": "1.0.7",
   "scripts": {
     "publish-please-dry-run": "publish-please --dry-run",
     "publish-please": "publish-please",
     "prepublishOnly": "publish-please guard && npm run build",
     "build": "rimraf dist && tsc -p ./tsconfig.build.json",
     "test": "jest --coverage",
+    "watch-tests": "jest --watch",
     "codecov": "codecov -f coverage/*.json"
   },
   "dependencies": {

__mocks__/epsagon.ts

@@ -5,7 +5,9 @@ describe('API responses', () => {
   const metrics = new Metrics('API Gateway');
   const callback = jest.fn((err, result) => (err ? new Error(err) : result));
 
-  beforeEach(() => jest.resetAllMocks());
+  beforeEach(() => {
+    jest.resetAllMocks();
+  });
 
   it('Handles success response', () => {
     const success = successWrapper(metrics, callback);

package-lock.json

@@ -9,7 +9,20 @@ describe('API wrapper', () => {
     queryStringParameters: { name: 'a test' },
     headers: { 'content-type': 'application/json', 'Test-Request': 'true' }
   });
-  const context = {};
+  const context = {
+    callbackWaitsForEmptyEventLoop: false,
+    functionName: 'function-name',
+    functionVersion: '$LATEST',
+    invokedFunctionArn: 'arn:',
+    memoryLimitInMB: 128,
+    awsRequestId: 'request',
+    logGroupName: 'group',
+    logStreamName: 'stream',
+    getRemainingTimeInMillis: () => 2,
+    done: () => {},
+    fail: () => {},
+    succeed: () => {}
+  };
   const callback = jest.fn((err, result) => (err ? new Error(err) : result));
 
   it('Has expected properties and response functions', () => {
@@ -39,7 +52,6 @@ describe('API wrapper', () => {
       expect(error).toBeInstanceOf(Function);
       success('success');
     }
-    // @ts-ignore
     api(mockHandler)(requestEvent, context, callback);
   });
 });

package.json

@@ -5,12 +5,13 @@ import { successWrapper, invalidWrapper, errorWrapper, redirectWrapper } from '.
 
 const metrics = new Metrics('API Gateway');
 
-export function api<T extends Function>(fn: T): T {
-  return <any>function(event: APIGatewayEvent, context: Context, callback: Callback) {
-    // const responses = new Responses(metrics, callback).getResponses();
+export function api(
+  custom: (props: ApiSignature) => any
+): (event: APIGatewayEvent, context: Context, callback: Callback) => any {
+  return function handler(event: APIGatewayEvent, context: Context, callback: Callback) {
     const { body, path, query, auth, headers, testRequest } = new Request(event).getProperties();
 
-    const signature: ApiSignature = {
+    const signature = {
       event,
       body,
       path,
@@ -23,7 +24,7 @@ export function api<T extends Function>(fn: T): T {
       error: errorWrapper(metrics, callback),
       redirect: redirectWrapper(metrics, callback)
     };
-    return fn(signature);
+    return custom(signature);
   };
 }
 

src/api/responses.test.ts

@@ -1,21 +1,23 @@
-import { isRunningInAwsLambdaEnvironment } from './environment';
+import { isRunningInAwsLambdaEnvironment, EXPECTED_ENV_VARS } from './environment';
+
+export const FULL_LAMBDA_RUNTIME = {
+  _HANDLER: 'index.handler',
+  AWS_REGION: 'us-east-1',
+  AWS_EXECUTION_ENV: 'AWS_Lambda_nodejs10.x',
+  AWS_LAMBDA_FUNCTION_NAME: 'sample-function-name',
+  AWS_LAMBDA_FUNCTION_MEMORY_SIZE: '128',
+  AWS_LAMBDA_FUNCTION_VERSION: '$LATEST',
+  LAMBDA_TASK_ROOT: '/var/task',
+  LAMBDA_RUNTIME_DIR: '/var/runtime'
+};
 
 describe('Runtime environment determination', () => {
   const ORIGINAL_ENVS = process.env;
-  const FULL_LAMBDA_RUNTIME = {
-    _HANDLER: 'index.handler',
-    AWS_REGION: 'us-east-1',
-    AWS_EXECUTION_ENV: 'AWS_Lambda_nodejs10.x',
-    AWS_LAMBDA_FUNCTION_NAME: 'sample-function-name',
-    AWS_LAMBDA_FUNCTION_MEMORY_SIZE: '128',
-    AWS_LAMBDA_FUNCTION_VERSION: '$LATEST',
-    LAMBDA_TASK_ROOT: '/var/task',
-    LAMBDA_RUNTIME_DIR: '/var/runtime'
-  };
 
   beforeEach(() => {
     jest.resetModules();
     process.env = { ...ORIGINAL_ENVS };
+    console.debug = jest.fn();
   });
 
   it('Default environment is recognized as not AWS Lambda runtime', () => {
@@ -29,9 +31,21 @@ describe('Runtime environment determination', () => {
 
   it('Partially modified environment is not recognized as AWS Lambda runtime', () => {
     // Delete a random property from the lambda runtime object
-    const keys = Object.keys(FULL_LAMBDA_RUNTIME);
-    delete FULL_LAMBDA_RUNTIME[keys[(Math.random() * keys.length) << 0]];
     process.env = { ...ORIGINAL_ENVS, ...FULL_LAMBDA_RUNTIME };
+    const varToRemove = EXPECTED_ENV_VARS[(Math.random() * EXPECTED_ENV_VARS.length) << 0];
+    delete process.env[varToRemove];
+    expect(isRunningInAwsLambdaEnvironment()).toBe(false);
+  });
+
+  it('Logs about why not recognized as AWS Lambda runtime given proper DEBUG flag', () => {
+    // Delete a random property from the lambda runtime object
+    process.env = { ...ORIGINAL_ENVS, ...FULL_LAMBDA_RUNTIME, ...{ DEBUG: 'true' } };
+    const varToRemove = EXPECTED_ENV_VARS[(Math.random() * EXPECTED_ENV_VARS.length) << 0];
+    delete process.env[varToRemove];
     expect(isRunningInAwsLambdaEnvironment()).toBe(false);
+    expect(console.debug).toHaveBeenCalledWith(
+      'Code is not running in an AWS Lambda Environment, missing the following environment variables:',
+      [varToRemove]
+    );
   });
 });

src/api/wrapper.test.ts

@@ -1,22 +1,21 @@
+export const EXPECTED_ENV_VARS = [
+  '_HANDLER',
+  'AWS_REGION',
+  'AWS_EXECUTION_ENV',
+  'AWS_LAMBDA_FUNCTION_NAME',
+  'AWS_LAMBDA_FUNCTION_MEMORY_SIZE',
+  'AWS_LAMBDA_FUNCTION_VERSION',
+  'LAMBDA_TASK_ROOT',
+  'LAMBDA_RUNTIME_DIR'
+];
+
 export function isRunningInAwsLambdaEnvironment(): boolean {
-  const {
-    _HANDLER,
-    AWS_REGION,
-    AWS_EXECUTION_ENV,
-    AWS_LAMBDA_FUNCTION_NAME,
-    AWS_LAMBDA_FUNCTION_MEMORY_SIZE,
-    AWS_LAMBDA_FUNCTION_VERSION,
-    LAMBDA_TASK_ROOT,
-    LAMBDA_RUNTIME_DIR
-  } = process.env;
-  return (
-    !!_HANDLER &&
-    !!AWS_REGION &&
-    !!AWS_EXECUTION_ENV &&
-    !!AWS_LAMBDA_FUNCTION_NAME &&
-    !!AWS_LAMBDA_FUNCTION_MEMORY_SIZE &&
-    !!AWS_LAMBDA_FUNCTION_VERSION &&
-    !!LAMBDA_TASK_ROOT &&
-    !!LAMBDA_RUNTIME_DIR
-  );
+  const missingEnvVars = EXPECTED_ENV_VARS.filter(expected => !process.env[expected]);
+  if (missingEnvVars.length > 0 && process.env.DEBUG) {
+    console.debug(
+      'Code is not running in an AWS Lambda Environment, missing the following environment variables:',
+      missingEnvVars
+    );
+  }
+  return missingEnvVars.length === 0;
 }