API Gateway

AWS- API Gateway Documentation 

Lambda:

AWS – Lambda documentation

Example API Gateway with Lambda

Step 1: Select Lambda service and Click on Create function button.

Step 2: Select the following properties

            Author from Scratch

            Function name: func1

            Runtime: Python 3.6

            Architecture x86_64

Click on Create function button.

Step 3: In the Code Source section you will find some code is written, you can replace it with API code with the code which you want to execute using API Gateway’s methods. I am using the default code.

Step 4: If you make the changes in the code then make sure that code is saved using File–>Save and then click on the Deploy button.

Step 5: Add trigger by clicking on Add Trigger button.

Step 6: Add API Gateway in the Trigger configuration

           Create API

           Rest API

           Security: IAM

Click on Add button

Step 7: Click on the function func1-API link.

Step 8: Select Any and Goto Action –> Delete method

Step 9: Action–>Create method

Step 10: Under func1 select the method as Get method.

            Integration Type: Lambda function

          Use Lambda Proxy Integer: select the check box

          Lambda function: func1

Click on save button.

Step 11: You will see the visual of GET method Execution

Step 12:  Select Get Method and Click on Action—>Deploy API

             Select Stage as default

           Click on the Deploy button.

Step 13: Select GET method and Click on the URL on RHS panel which will invoke GET method  of API.   

Lambda with S3 Example

Step 1: Create a DynomdbFullAccess Role and Assign to Lambda.

             AmazonDynamoDBFullAccess

Step 2: Create a Lambda function Func2 with Runtime as Python 3.6

           Write below code in the code window. This code is written in python using Boto Libray which insert  S3 object information in Dynamodb table.

import boto3

from uuid import uuid4

def lambda_handler(event, context):

    s3 = boto3.client(“s3”)

    dynamodb = boto3.resource(‘dynamodb’)

    for record in event[‘Records’]:

        bucket_name = record[‘s3’][‘bucket’][‘name’]

        object_key = record[‘s3’][‘object’][‘key’]

        size = record[‘s3’][‘object’].get(‘size’, -1)

        event_name = record [‘eventName’]

        event_time = record[‘eventTime’]

        dynamoTable = dynamodb.Table(‘newtable’)

        dynamoTable.put_item(

            Item={‘unique’: str(uuid4()), ‘Bucket’: bucket_name, ‘Object’: object_key,’Size’: size, ‘Event’: event_name, ‘EventTime’: event_time})

Step 3: File—> Save and Click on the Deploy button.

Step 4: Click on Configuration Tab and select Permission and click on Edit Role and attach the role which is created on Step1.

Step 4: Add Trigger by clicking on Add trigger button.

          Select S3 trigger

          Select bucket name

         Event Type: All objects create events

         Select acknowledgment for recursive invocation.

     Click on Add button

Step 5: Create a Dynamodb table newtable and partition key unique.

Step 6: Explore items in newtable and you will find no records for this table.

Step 7: Upload and file in S3 bucket.

Step 8: Explore items in the Dynamodb table. and you will find the metadata information of the uploaded file in the S3 bucket.