TheLazy.Dev
Portfolio GitHub

Blog

aws |appsync |lambda |serverless

AWS AppSync ToDo APIs with AWS Lambda Resolvers using Serverless Framework

jaymitb

Jaymitkumar Bhoraniya

Posted on September 26, 2021

AWS AppSync ToDo APIs with AWS Lambda Resolvers using Serverless Framework

Implement basic ToDo APIs using AWS AppSync with AWS Lambda Resolvers by using Serverless Framework

Application Stack:
  • Serverless Framework
  • AWS AppSync
  • AWS Lambda
  • AWS DynamoDB
  • AWS IAM
  • NodeJs
  • GraphQL

Install NodeJs as per instruction given here

1. Install Serverless Framework 



npm install -g serverless
Enter fullscreen mode Exit fullscreen mode

2. Create basic NodeJs type template project using Serverless Framework 



serverless create --template aws-nodejs
Enter fullscreen mode Exit fullscreen mode

By default it will generate a folder structure like this:

  • handler.js
  • serverless.yml

Default serverless.yml will have below IaC code:



service: default-aws-nodejs
frameworkVersion: '2'
provider:
  name: aws
  runtime: nodejs12.x
  lambdaHashingVersion: 20201221

functions:
  hello:
    handler: handler.hello
Enter fullscreen mode Exit fullscreen mode

Default handler.js will have below NodeJs code:




'use strict';



module.exports.hello = async (event) => {

  return {

    statusCode: 200,

    body: JSON.stringify(

      {

        message: 'Go Serverless v1.0! Your function executed successfully!',

        input: event,

      },

      null,

      2

    ),

  };

};
Enter fullscreen mode Exit fullscreen mode



  1. Install required Serverless Framework Plugins

  • npm install serverless-appsync-plugin
  • npm install serverless-pseudo-parameters

4. Modify serverless.yml Infrastructure as code to provision needful AppSync, DynamoDb, Lambda resources, and relevant configuration 




service: appsync-todo-apis-demo

frameworkVersion: "2"



plugins:



    

  • serverless-appsync-plugin
    • 

  • serverless-pseudo-parameters
    • 




provider:

  name: aws

  runtime: nodejs12.x

  stage: dev

  region: ap-south-1

  lambdaHashingVersion: 20201221

  iam:

    role:

      statements:

        - Effect: "Allow"

          Action:


            - "dynamodb:PutItem"

            - "dynamodb:UpdateItem"

            - "dynamodb:DeleteItem"

            - "dynamodb:GetItem"

            - "dynamodb:Scan"

          Resource: "arn:aws:dynamodb:#{AWS::Region}:*:table/${self:custom.TODO_TABLE}"



custom:


  TODO_TABLE: todo-table



appSync:

    name: appsync-todo-apis-demo

    authenticationType: API_KEY

    mappingTemplates:


      - type: Mutation

        field: createTodo

        dataSource: createTodoFunction

        request: false

        response: false

      - type: Mutation

        field: updateTodo

        dataSource: updateTodoFunction

        request: false

        response: false

      - type: Mutation

        field: deleteTodo

        dataSource: deleteTodoFunction

        request: false

        response: false

      - type: Query

        field: getTodos

        dataSource: getTodosFunction

        request: false

        response: false


    dataSources:


      - type: AWS_LAMBDA

        name: createTodoFunction

        config:

          functionName: createTodo




  - type: AWS_LAMBDA
    name: updateTodoFunction
    config:
      functionName: updateTodo

  - type: AWS_LAMBDA
    name: deleteTodoFunction
    config:
      functionName: deleteTodo

  - type: AWS_LAMBDA
    name: getTodosFunction
    config:
      functionName: getTodos                     






    Enter fullscreen mode
    


    Exit fullscreen mode
    









functions: 

  getTodos:

    handler: functions/getTodos.handler

    environment:

      TODO_TABLE_NAME: !Ref TodoTable



createTodo:

    handler: functions/createTodo.handler

    environment:

      TODO_TABLE_NAME: !Ref TodoTable



updateTodo:

    handler: functions/updateTodo.handler

    environment:

      TODO_TABLE_NAME: !Ref TodoTable



deleteTodo:

    handler: functions/deleteTodo.handler

    environment:

      TODO_TABLE_NAME: !Ref TodoTable



resources:

  Resources:

    TodoTable:

      Type: "AWS::DynamoDB::Table"

      Properties:

        KeySchema:

          - AttributeName: id

            KeyType: HASH

        AttributeDefinitions:

          - AttributeName: id

            AttributeType: S

        BillingMode: PAY_PER_REQUEST

        TableName: ${self:custom.TODO_TABLE}
Enter fullscreen mode Exit fullscreen mode



  1. Create GraphQL Schema new file schema.graphql 





schema {

    query: Query

    mutation: Mutation

}



type Query {

    getTodos: [Get!]!

}



type Mutation {

    createTodo(id: ID!, name: String!, description: String!): Save

    updateTodo(id: ID!, name: String!, description: String!): Update

    deleteTodo(id: ID!): Delete

}



type Get {

    id: ID!

    name: String

    description: String 

}



type Save {

    id: ID!

    name: String

    description: String 

}



type Update {

    id: ID!

    name: String

    description: String 

}



type Delete {

    id: ID! 

}
Enter fullscreen mode Exit fullscreen mode



  1. Implement AWS Lambda Resolver CRUD handlers

Create new folder 'functions' with this files:

  • createTodo.js
  • deleteTodo.js
  • getTodos.js
  • updateTodo.js
6.1 createTodo.js handler 



const AWS = require('aws-sdk')

const dynamodb = new AWS.DynamoDB()



module.exports.handler = async (event) => {


    const id = event.arguments.id

    const name = event.arguments.name

    const description = event.arguments.description    




const params = {
    Item: {
        "id": {
            S: id
        },
        "name": {
            S: name
        },
        "description": {
            S: description
        }            
    },
    ReturnConsumedCapacity: "TOTAL",
    TableName: process.env.TODO_TABLE_NAME
}

return dynamodb.putItem(params).promise()
    .then(data => {            
        return {
            id,
            name,
            description
        }
    })
    .catch(err => {
        console.log(err)
    })






    Enter fullscreen mode
    


    Exit fullscreen mode
    









};
Enter fullscreen mode Exit fullscreen mode



6.2 deleteTodo.js handler




const AWS = require('aws-sdk')

const dynamodb = new AWS.DynamoDB()



module.exports.handler = async (event) => {

    const id = event.arguments.id




const params = {
  Key: {
      "id": {
          S: id
      }
  },
  TableName: process.env.TODO_TABLE_NAME
}


return dynamodb.deleteItem(params).promise()
    .then(data => {            
        return {
            id
        }
    })
    .catch(err => {
      console.log(err)
    })






    Enter fullscreen mode
    


    Exit fullscreen mode
    









};
Enter fullscreen mode Exit fullscreen mode



6.3 updateTodo.js handler




const AWS = require('aws-sdk')

const dynamodb = new AWS.DynamoDB()



module.exports.handler = async (event) => {

    const id = event.arguments.id

    const name = event.arguments.name

    const description = event.arguments.description




const params = {
  ExpressionAttributeNames: {
      "#n": "name",
      "#d": "description"          
  },
  ExpressionAttributeValues: {
      ":n": {
          S: name
      },
      ":d": {
          S: description
      }
  },
  Key: {
      "id": {
          S: id
      }
  },
  ReturnValues: "ALL_NEW",
  TableName: process.env.TODO_TABLE_NAME,
  UpdateExpression: "SET #n = :n, #d = :d"






    Enter fullscreen mode
    


    Exit fullscreen mode
    









}



return dynamodb.updateItem(params).promise()

      .then(data => {

          const body = data.Attributes

          return {

            id: body.id.S,

            name: body.name.S,

            description: body.description.S

          }

      })

      .catch(err => {

        console.log(err)

      })

};
Enter fullscreen mode Exit fullscreen mode



6.4 getTodos.js handler




const AWS = require('aws-sdk')

const dynamodb = new AWS.DynamoDB()



module.exports.handler = async (event) => {




const params = {        
    TableName: process.env.TODO_TABLE_NAME
}

return dynamodb.scan(params).promise()
    .then(data => {            
        const todoList = [];
        for (let i = 0; i < data.Items.length; i++) {
            todoList.push({
                id: data.Items[i].id.S,
                name: data.Items[i].name.S,
                description: data.Items[i].description.S
            });        
        }
        return todoList;            
    })
    .catch(err => {
        console.log(err)
    })






    Enter fullscreen mode
    


    Exit fullscreen mode
    









};
Enter fullscreen mode Exit fullscreen mode



  1. Create AWS IAM user with programmatic access and give needful permission that allows Serverless Framework to provision resources

The Serverless Framework needs access to your cloud provider account so that it can create and manage resources on your behalf.

During Creating AWS IAM user copy API Key & Secret.

8. Configure AWS Credentials for Serverless Framework Deployment 




serverless config credentials --provider aws --key xxxxx --secret xxxxx
Enter fullscreen mode Exit fullscreen mode



  1. Deploy using Serverless Framework 





serverless deploy
Enter fullscreen mode Exit fullscreen mode 



> serverless deploy

AppSync Plugin: GraphQl schema valid

Serverless: Packaging service...

Serverless: Excluding development dependencies...

Serverless: Creating Stack...

Serverless: Checking Stack create progress...

........

Serverless: Stack create finished...

Serverless: Uploading CloudFormation file to S3...

Serverless: Uploading artifacts...

Serverless: Uploading service appsync-todo-apis-demo.zip file to S3 (16.98 MB)...

Serverless: Validating template...

Serverless: Updating Stack...

Serverless: Checking Stack update progress...

..........................................................................................

Serverless: Stack update finished...

Service Information

service: appsync-todo-apis-demo


stage: dev

region: ap-south-1

stack: appsync-todo-apis-demo-dev

resources: 31

api keys:

  None

appsync api keys:

  xxxxxxxxxxxxxxx

endpoints:

  None

appsync endpoints:

  https://xxxxxxxxxxxxxxx.appsync-api.ap-south-1.amazonaws.com/graphql

functions:

  getTodos: appsync-todo-apis-demo-dev-getTodos

  createTodo: appsync-todo-apis-demo-dev-createTodo

  updateTodo: appsync-todo-apis-demo-dev-updateTodo

  deleteTodo: appsync-todo-apis-demo-dev-deleteTodo

layers:

  None
Enter fullscreen mode Exit fullscreen mode



  1. AWS AppSync APIs Verification Screenshots

AppSync API Verification - getTodos

getTodos API verification

AppSync API Verification - createTodo

createTodo API Verification

AppSync API Verification - deleteTodo

deleteTodo API Verification

11. Remove already provisioned resources 




serverless remove
Enter fullscreen mode Exit fullscreen mode




Relevant Resources Link

💖 💪 🙅 🚩
jaymitb
Jaymitkumar Bhoraniya

Posted on September 26, 2021

Join Our Newsletter. No Spam, Only the good stuff.

Sign up to receive the latest update from our blog.

Related

AWS AppSync: The Game-Changing Access Method For Environment Variables
aws AWS AppSync: The Game-Changing Access Method For Environment Variables

February 8, 2024

AWS AppSync ToDo APIs with AWS Lambda Resolvers using Serverless Framework
aws AWS AppSync ToDo APIs with AWS Lambda Resolvers using Serverless Framework

September 26, 2021