Create an Amplify frontend that calls Amazon API Gateway using Cognito

This pattern explains how to deploy an AWS SAM application that includes an AWS Amplify frontend, Cognito, API Gateway and Lambda Function. It also sets environmental variables to be used by Amplify and Lambda Function.

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: > Serverless Solution Cognito / Api Gateway / Lambda Function / Amplify Environmental Variables on Amplify Environmental Variables on Lambda Function #################### PARAMETERS ############################# Parameters: AmplifyFrontendRepository: Type: String Description: 'Amplify Frontend Repository in the format: https://<GitProviderDomain>/<user>/<repository>' Default: '' OauthToken: Type: String Description: 'Access token for git provider repository' NoEcho: true Default: '' ########################### RESOURCES ################################
Resources: ##################### API ####################### myAPI: Type: AWS::Serverless::Api Description: Main API Properties: StageName: dev Cors: AllowMethods: "'GET, OPTIONS'" AllowHeaders: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token'" AllowOrigin: "'*'" MaxAge: "'500'" Auth: AddDefaultAuthorizerToCorsPreflight: false DefaultAuthorizer: MyCognitoAuthorizer Authorizers: MyCognitoAuthorizer: UserPoolArn: !GetAtt rUserPool.Arn ##################### FUNCTIONS ################################ ################### LAMBDA ELASTICSEARCH ###################### myFunction: Type: AWS::Serverless::Function Properties: CodeUri: lambdaExample/ Handler: app.lambda_handler Runtime: python3.7 Events: EmyFunction: Type: Api Properties: Path: /lambdaExample Method: get RestApiId: Ref: myAPI Environment: Variables: cognito_region: !Ref AWS::Region user_pools_id: !Ref rUserPool user_pools_web_client_id: !Ref rAmplifyCognitoClient # INTEGRATION WITH FRONTEND ################################################################ ## COGNITO - USER POOL / USER POOL CLIENT rUserPool: Type: AWS::Cognito::UserPool Properties: AdminCreateUserConfig: AllowAdminCreateUserOnly: true AutoVerifiedAttributes: - email Schema: - AttributeDataType: String Mutable: true Name: given_name Required: true - AttributeDataType: String Mutable: true Name: family_name Required: true - AttributeDataType: String Mutable: false Name: email Required: true UsernameAttributes: - email UsernameConfiguration: CaseSensitive: false rAmplifyCognitoClient: Type: AWS::Cognito::UserPoolClient Properties: AccessTokenValidity: 1 AllowedOAuthFlows: - implicit AllowedOAuthFlowsUserPoolClient: true AllowedOAuthScopes: - email - openid - profile - aws.cognito.signin.user.admin CallbackURLs: - "http://localhost" EnableTokenRevocation: true ExplicitAuthFlows: - ALLOW_ADMIN_USER_PASSWORD_AUTH - ALLOW_CUSTOM_AUTH - ALLOW_USER_PASSWORD_AUTH - ALLOW_USER_SRP_AUTH - ALLOW_REFRESH_TOKEN_AUTH IdTokenValidity: 1 LogoutURLs: - "http://localhost" PreventUserExistenceErrors: ENABLED ReadAttributes: - given_name - family_name - email - email_verified RefreshTokenValidity: 1 SupportedIdentityProviders: - COGNITO TokenValidityUnits: AccessToken: hours IdToken: hours RefreshToken: days UserPoolId: !Ref rUserPool ################################################################# #################################################################
# AMPLIFY rAmplifyRole: Type: AWS::IAM::Role Properties: # RoleName: !Sub '${AWS::StackName}' AssumeRolePolicyDocument: Version: 2012-10-17 Statement: - Effect: Allow Principal: Service: - amplify.amazonaws.com Action: - sts:AssumeRole Policies: - PolicyName: Amplify PolicyDocument: Version: 2012-10-17 Statement: - Effect: Allow Action: - "amplify:*" Resource: "*" rAmplifyApp: Type: AWS::Amplify::App Properties: Name: !Sub '${AWS::StackName}' Description: Matching Tool CustomRules: - Source: '</^[^.]+$|\.(?!(css|gif|ico|jpg|js|png|txt|svg|woff|ttf)$)([^.]+$)/>' Target: '/index.html' Status: '200' EnvironmentVariables: # - Name: PROJECT_NAME # Value: !Ref pProjectName - Name: cognito_region Value: !Ref AWS::Region - Name: user_pools_id Value: !Ref rUserPool - Name: user_pools_web_client_id Value: !Ref rAmplifyCognitoClient - Name: APIURL Value: !Sub "https://${myAPI}.execute-api.${AWS::Region}.amazonaws.com/dev" Repository: !Ref AmplifyFrontendRepository OauthToken: !Ref OauthToken IAMServiceRole: !GetAtt rAmplifyRole.Arn rAmplifyBranch: Type: AWS::Amplify::Branch Properties: BranchName: 'main' AppId: !GetAtt rAmplifyApp.AppId Description: Branch EnableAutoBuild: true # OUTPUTS ################################################################# Outputs: CognitoRegion: Description: Cognito Region Value: !Ref AWS::Region Export: Name: CognitoRegion CognitoUserPool: Description: Cognito User Pool Value: !Ref rUserPool Export: Name: CognitoUserPool CognitoUserPoolClient: Description: Cognito User Pool Client Value: !Ref rAmplifyCognitoClient Export: Name: CognitoUserPoolClient APIurl: Description: API url Value: !Sub "https://${myAPI}.execute-api.${AWS::Region}.amazonaws.com/dev" Export: Name: APIurl

Integration of Amplify Frontend, Cognito, API Gateway, Lambda

This pattern explains how to deploy a SAM application that includes an AWS Amplify Frontend, Cognito, API Gateway and Lambda Function and set environmental variables to be used by Amplify and the Lambda function.

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/amplify-apigw-lambda.

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the AWS Pricing page for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

Requirements

• Create an AWS account if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
• AWS CLI installed and configured
• Git Installed
• AWS Serverless Application Model (AWS SAM) installed

Deployment Instructions

1. Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:

   git clone https://github.com/aws-samples/serverless-patterns
   

2. Change directory to the pattern directory:

   cd _patterns-model
   

3. From the command line, use AWS SAM to deploy the AWS resources for the pattern as specified in the template.yml file:

   sam deploy --guided
   

4. During the prompts:

   • Enter a stack name
   • Enter the desired AWS Region
   • Enter the Frontend Repository URL that will be hosted by AWS Amplify Frontend
   • Enter the OauthToken for you git provider
   • Allow SAM CLI to create IAM roles with the required permissions.

   Once you have run sam deploy --guided mode once and saved arguments to a configuration file (samconfig.toml), you can use sam deploy in future to use these defaults.

5. Note the outputs from the SAM deployment process. These contain the resource names and/or ARNs which are used for testing.

How it works

This template deploys a full-stack application where Amplify frontend application and Lambda Function will have as environmental variables Cognito Region, Cognito User Pool ID and Cognito User Pool Client ID allowing developer to quickly develop an application with Authentication on front and backend. Template set cognito as authorizer for API Gateway, requiring the frontend app to pass json web token (JWT) to call API

Testing

On AWS amplify Service, click on the app name (same of SAM stack name), click environment varaibles. You should be able to see 4 environmental variables created by the template.

On AWS Lambda Service, click Applications, click the application name (same of SAM stack name), click on Resource called myFunction, click configuration, click Environment variables. You should be able to see 4 environmental variables created by the template. Execute the lambda function and check the logs. You will see a result like: Cognito Region: us-east-1 Cognito User Pool Id: us-east-1_aYtONfZZZ Cognito User Pool Client ID: 1h2rrpldfqg8lhbgej2o5s2ZZZ

Cleanup

1. Delete the stack

   aws cloudformation delete-stack --stack-name STACK_NAME
   

2. Confirm the stack has been deleted

   aws cloudformation list-stacks --query "StackSummaries[?contains(StackName,'STACK_NAME')].StackStatus"