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Serverless Framework - What should you know?

zero-friction serverless development - Having looked at an overview of what a serverless architecture in our previous post, the next step would be to build one. And having to learn to many things before actually building a serveless application would cause friction. Hence I chose the Serverless Framework which requires you to know about yml/json. Hence I picked this for my serverless journey.

Getting Started

  • Install Serverless Framework.
  • Create a project based on serverless template.
  • Verify the resources created in CloudFormation Stack.

Install Serverless Framework

npm install -g serverless

Create a serverless project with node js template

Let us use the Nodejs template of serverless framework to create the new project.

sls create --template aws-nodejs --path serverless-demo


The following simple snippet deployed an AWS Lambda to your account

service: serverless-demo
frameworkVersion: '2'

  name: aws
  runtime: nodejs12.x
  lambdaHashingVersion: 20201221

    handler: handler.hello


Assuming AWS_PROFILE is set in the path in the terminal, let us go ahead and deploy the project created without making any changes.

serverless deploy


It will package and deploy the resources in the AWS Account as shown in the logs below.

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 file to S3 (390 B)…
Serverless: Validating template…
Serverless: Updating Stack…
Serverless: Checking Stack update progress…
Serverless: Stack update finished…
Service Information
service: serverless-demo
stage: dev
region: us-east-1
stack: serverless-demo-dev
resources: 6
api keys:
 hello: serverless-demo-dev-hello

The log summary shows that, it had created,

  • default environment as dev (stage) variable.
  • default region : us-east-1
  • Cloudformation stack is named serverless-demo-dev (service name + stage name defined in serverless.yml)
  • Six AWS resources. We will look into the CloudFormation stack to see what were all the AWS resources created.
  • Created a lambda function named serverless-demo-dev-hello. ( service name defined in serverless.yml + stage in serverless.yml + function name defined in serverless.yml). This is the default name generated for the lambda function but can be overridden.

CloudFormation Stack

While looking into the CloudFormation stack, following are the AWS resources created.

  • AWS::Lambda::Function — serverless-demo-dev-hello
  • AWS::Lambda::Version — arn:aws:lambda:us-east-1:AccountID:function:serverless-demo-dev-hello:1
  • AWS::Logs::LogGroup — /aws/lambda/serverless-demo-dev-hello
  • AWS::IAM::Role — IamRoleLambdaExecution
  • AWS::S3::Bucket — S3 Bucket for our package
  • AWS::S3::BucketPolicy — S3 Bucket Policy
  • Any serverless projects deployed would create an S3 Bucket and a Bucket Policy attached to the bucket that has the cloudformation template and the package deployed containing the code for the lambda functions.
  • In this serverless project, a lambda function and an IAM role attached to the lambda function to CreateLogStream, CreateLogGroup and PutLogEvents’, a log group where the lambda’s log events will be traced were created.

Demo Project - High Level Overview

The high-level architecture would look like as below, Serverless Framework