Which Services Can Invoke Aws Lambda Functions

AWS Lambda Invocation Types

In this article, nosotros are going to see how triggered our Lambda functions, that means nosotros volition see AWS Lambda Invocation Types.

Subsequently that nosotros will map these Lambda Invocation Types with our course when developing Serverless East-commerce application. So AWS Lambda Invocation Types will be our Serverless Journey when developing our Serverless E-commerce application.

Pace by Step Design AWS Architectures westward/ Course

I accept just published a new course — AWS Serverless Microservices with Patterns & Best Practices.

In this class, we're going to larn how to Design and Develop AWS Serverless Event-driven Microservices with using AWS Lambda, AWS DynamoDB, AWS API Gateway, AWS EventBridge, AWS SQS, AWS CDK for IaC — Infrastructure equally Code tool and AWS CloudWatch for monitoring.

Source Code

Get the Source Lawmaking from Serverless Microservices GitHub — Clone or fork this repository, if you like don't forget the star. If y'all discover or ask anything you lot can directly open result on repository.

AWS Lambda Invocation Types

AWS Lambda functions is using everywhere for various use cases. Sometimes we want to invoke Lambda functions over HTTP and other times trigger a function based on different events. It is extremely useful to understand the different ways that we tin invoke Lambda functions.
Here are 3 unlike ways nosotros can invoke AWS Lambda function:

AWS Lambda has 3 Invocation Types;

Lambda Synchronous Invocation
Lambda Asynchronous Invocation
Lambda Result Source Mapping with Polling Invocation

https://aws.amazon.com/blogs/architecture/understanding-the-dissimilar-ways-to-invoke-lambda-functions/

Y'all can all invocation types in one paradigm.
Synchronous invocation is trigger by push button model and execute immediately and await response. nosotros tin say RequestResponse model.
Asynchronous invocation is trigger past event model and executes asynchronous don't look immediate response.
Result Source Mapping invocation is triggered by poll-based. That means lambda office receives multiple items.

Lets come across one by one and explain these invocation types.

Lambda Synchronous Invocation

This is one of the simple lambda invocation model. In this advice type, lambda functions execute immediately when yous perform the Lambda Invoke by API telephone call.
So when we perform a Lambda invoke an API call, we look for the office to process the function and return back to response. The response data includes the function response and boosted data which can be retrieved from DynamoDB or some other resources.

A common scenario for synchronous invocation is the API Gateway + Lambda integration:
You can see in the image of API Gateway — Lambda — DynamoDB that nosotros tin can perform CRUD operations for a particular DynamoDB table with exposing APIs from API Gateway.

The important thing; The Invocation-type flag should exist "RequestResponse". This instructs AWS to execute our Lambda part and wait for the response of function to complete.
When we perform a synchronous invocation, we are responsible for inspecting the response and determining if at that place was an mistake similar time out exceptions and decide to retry the invocation.

Nosotros can perform Synchronous RequestResponse invocation using the AWS CLI, SDKs and many other options.

Example of synchronous invocation using the AWS CLI:

          aws lambda invoke — part-name MyLambdaFunction — invocation-type RequestResponse — payload '{ "key": "value" }'

As you can see that when we specify the Invocation-type flag is RequestResponse. That means AWS execute our function and wait for the role to consummate. The of import part is nosotros are responsible for checking the response and determining whether it is an mistake and nosotros should retry the invoke.

There are many AWS services that tin trigger lambda function synchronously.
Here are some of them:

ELB (Application Load Balancer)
Amazon Cognito
Amazon Lex
Amazon Alexa
Amazon API Gateway
Amazon CloudFront (Lambda@Border)
Amazon Kinesis Data Firehose

Lambda Asynchronous Invocation

In this communication type, Lambda functions works with events and invoke by events and not respond immediately.

Basically we tin can invoke a lambda function asynchronously, afterwards that Lambda sends the event to a internal queue and returns a success response without whatsoever additional information. After that a dissever process reads events from the queue and runs our lambda office.

S3 + Lambda + DynamoDB

A common scenario for Asynchronous invocation is the S3 / SNS + Lambda + DynamoDB. You can see in the image of S3 / SNS + Lambda + DynamoDB.

In the diagram, Amazon S3 volition call the lambda asynchronous when a new object is written into the bucket. In order to invoke a function asynchronously, nosotros should set the invocation type parameter to Event.

Example of an asynchronous invokes using the CLI:

          aws lambda invoke — role-name MyLambdaFunction — invocation-type Event — payload '{ "key": "value" }'

When we specify the Invocation-type parameter value as Outcome if the function failed AWS will automatically retry the invoke twice.

By default AWS Lambda sets a retry policy for asynchronous invocation, your function will be invoked twice if there is an mistake.

In order to avoid upshot losses when using asynchronous lambda, e'er attach a dead-letter queue on the function in club to save events that weren't successfully processed.

Here is a list of services that invoke Lambda functions asynchronously:

S3
EventBridge
SNS
SES
CloudFormation
CloudWatch Logs
CloudWatch Events
CodeCommit
Pool Based Invokes

Lambda Event Source Mapping with Polling Invocation

Pool-Based invocation model allows usa to integrate with AWS Stream and Queue based services. These services don't invoke Lambda role directly. Lambda will poll from the AWS SQS or Kinesis streams, recollect records, and invoke functions.
AWS Lambda Effect Source Mapping manages the poller and performs Synchronous invokes of our function.

Data stream or queue are read in batches, the part receives multiple items when execute function. Batch sizes can configure according to service types and after that the event source mapping will ship data according to batch size. If the batch size is besides large to send in one event, it has to exist divide up, resulting in events with smaller numbers of items than the batch size.

SQS + Lambda

A common scenario for Event Source Mapping with Polling Invocation is the SQS + Lambda. You can meet in the image of SQS + Lambda

In the diagram, Amazon SQS has some queue records, this queue record tin can be added from other AWS Services like EventBridge, SNS and and so on.
Afterward that a lambda role poll events from AWS SQS and receive queue records with Result Source Mapping invocations. Lambda function retrieve queue records according to Batch Size property of polling configurations.

Another mutual scenario for Result Source Mapping with Polling Invocation is stream based processing. These are Kinesis and DynamoDB Streams that Lambda can poll stream records with Event Source Mapping invocations.

Here is a listing of services that invoke Lambda functions as event source mapping:

Amazon Kinesis
Amazon DynamoDB
Amazon Simple Queue Service

As you tin can see we have we have seen AWS Lambda Invocation Types.

Serverless E-Commerce Microservices with Lambda Invocation Types

If we map these Lambda Invocation Types with our microservices architecture when developing serverless e-commerce application, you can see the diagram beneath;

Serverless Event-driven E-commerce Microservices Architecture

And so AWS Lambda Invocation Types will be our Serverless Journeying when developing our serverless e-commerce awarding.

See details in the below captions.

AWS Serverless Microservices for Ecommerce Application Architecture

Here, you can detect the main overall Serverless Architecture for our application that we volition follow these steps and build tihs Serverless Eastward-Commerce Microservices Architecture.

This is the large moving-picture show of what nosotros are going to develop together for AWS Serverless Event-driven E-commerce Microservices application that is Step by Step Implementation together.

Serverless Upshot-driven E-commerce Microservices Architecture

We have followed the reference architecture above which is a real-world serverless e-commerce application and it includes;

REST API and Grime endpoints with using AWS Lambda, API Gateway
Information persistence with using AWS DynamoDB
Decouple microservices with events using AWS EventBridge
Message Queues for cantankerous-service communication using AWS SQS
Deject stack development with IaC using AWS CloudFormation CDK
Decouple microservices with events using AWS EventBridge
Message Queues for cross-service communication using AWS SQS
Cloud stack evolution with IaC using AWS CloudFormation CDK

Footstep by Step Pattern AWS Architectures w/ Grade

I accept but published a new course — AWS Serverless Microservices with Patterns & All-time Practices.

In this course, we're going to learn how to Design and Develop AWS Serverless Result-driven Microservices with using AWS Lambda, AWS DynamoDB, AWS API Gateway, AWS EventBridge, AWS SQS, AWS CDK for IaC — Infrastructure as Code tool and AWS CloudWatch for monitoring.

Source Lawmaking

Get the Source Code from Serverless Microservices GitHub — Clone or fork this repository, if you like don't forget the star. If you find or inquire anything you can straight open issue on repository.