README file added

Author: anijitsao

README.md

@@ -1 +1,100 @@
-# simple-aws-sqs-lambda-microservices
+# simple-aws-sqs-lambda-microservices
+Simple [GraphQL](https://graphql.org/) APIs implementation using [Node JS](https://nodejs.org/en/docs/) and [AWS Lambda](https://aws.amazon.com/lambda/) with [Apollo Server](https://www.apollographql.com/docs/apollo-server/) and [MongoDB Atlas](https://www.mongodb.com/docs/atlas/). 
+
+This example illustrates how to deploy [GraphQL](https://graphql.org/) APIs using [NodeJS](https://nodejs.org/en/docs/) functions running on [AWS Lambda](https://aws.amazon.com/lambda/) using the traditional [Serverless](https://www.serverless.com/framework/docs/providers/aws/guide/intro) Framework. The deployed functions work with [MongoDB Atlas](https://www.mongodb.com/docs/atlas/).
+
+To work with [GraphQL](https://graphql.org/) features, i.e. **Type Definitions, Mutations, Queries, Resolvers** [Apollo Server](https://www.apollographql.com/docs/apollo-server/) is used.
+
+This Example works with [AWS HTTP API](https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop.html) events. 
+
+<!---
+For faster response with the APIs [Redis](https://redis.io/) *caching* is used.
+For *session tracking* [JSON Web Token (JWT)](https://jwt.io/) is used.
+-->
+
+All *logs* for the function is kept in [AWS Cloudwatch](https://aws.amazon.com/cloudwatch/) i.e *persistent*.
+
+To use the code in this example you **must** have an valid [AWS account](https://aws.amazon.com/account/) and necessary [AWS IAM](https://aws.amazon.com/iam/) roles and programmatic access to an user. You **must** have a [MongoDB Atlas](https://www.mongodb.com/docs/atlas/) account as well as an [AWS EC2](https://aws.amazon.com/ec2/) instance should be installed with [Redis](https://redis.io/).
+
+
+
+## Features
+1. [AWS Lambda](https://aws.amazon.com/lambda/) function using [NodeJS](https://nodejs.org/en/docs/)
+2. Function is using latest version of [AWS SDK JavaScript v3](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/welcome.html) with all **ES6+**  syntaxes like Promises, `async/await`
+
+<ol start="3">
+  <li>
+     Function are deployed using <a href="https://www.serverless.com/framework/docs/providers/aws/guide/intro">Serverless</a> Framework.
+  </li>  
+  <li>
+    <code>serverless.json</code> is used for deployment configuration instead of <code>serverless.yml</code>.
+  </li>  
+  <li>
+    All the deployment is created in <a href="https://aws.amazon.com/s3/">AWS S3</a> to store the <code>.zip</code> of the function code and <a href="https://aws.amazon.com/cloudformation/">AWS CloudFormation</a> Stack.
+  </li>  
+</ol>  
+
+
+<!---
+6. For **session tracking** [JWT](https://jwt.io/) is used.
+-->
+6. [AWS HTTP API](https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop.html) are using [AWS API GateWay](https://aws.amazon.com/api-gateway/)
+
+<ol start="7">
+  <li> All data is saved in <a href="https://www.mongodb.com/docs/atlas/">MongoDB Atlas</a> i.e. <i>persistent</i>
+  <!--- <li> <strong>Caching</strong> is used for faster response in the APIs. <a href="https://redis.io/">Redis</a> is used for that purpose</li> -->
+  <li> This APIs can also be consumed by any <b>Frontend Application</b>.</li> 
+  <li> To use <a href="https://graphql.org/">GraphQL</a> features <a href="https://www.apollographql.com/docs/apollo-server/">Apollo Server</a> is used
+  <li> For the <i>Schema</i> generation <b>Type Definitions</b> are added. <b>Queries</b> are used for the <i>Reading</i> operations while <b>Mutations</b> are added for <i>Mutable</i> operations.
+</ol>  
+
+
+
+11. [NPM](https://www.npmjs.com/) dependencies are used for various purposes.
+
+
+## Usage
+
+First clone the repo
+
+```bash
+$ git clone git@github.com:anijitsahu/simple-apollo-server-graphql-lambda.git
+```
+Install all the necessary dependencies by going inside the directory
+
+```bash
+$ cd simple-apollo-server-graphql-lambda
+$ npm install
+```
+
+
+### Deployment
+
+In order to deploy the example, you need to run the following command:
+
+```
+$ serverless deploy
+```
+
+### Invocation
+
+After successful deployment, you can invoke the deployed **functions / resolvers**. 
+
+However, to call using [GraphQL](https://graphql.org/) API you can use any *supported* Client like [Altair GraphQL Client](https://chrome.google.com/webstore/detail/altair-graphql-client/flnheeellpciglgpaodhkhmapeljopja?hl=en) with the `url` and *HTTP Verbs* as shown in Terminal after using `serverless deploy`.
+
+## API Listing
+
+API listing is given below, -
+
+**POST** /url-of-the-deployed-lambda/graphql have the following input JSON
+```javascript
+{
+  "itemPurchased": [
+    {
+      "itemName":"Madhur Sugar",
+      "qtyPurchased":"7"
+    }
+  ],
+  "storeName": "Grofers"
+}
+```