Getting Started with Serverless and AWS

This is my first ever blog. I hope you find it valuable.

Setting up the Workstation

• Install Node.js - Download Node.js in my case - Windows Installer .msi 64-bit on workstation
• Install Serverless Download Serverless Getting Started on workstation - npm install -g serverless
• Root user or root equivalent user access in AWS

---

Create an IAM Role - AWS Service

Access key will enable serverless to connect with AWS

• Go to IAM -> Create users -> Add a user name: jayp1_serverless -> Select AWS access type -> Select AWS credential type -> Access key - Programmatic access

Description: > Access Key - Programmatic Access - Enables an access key ID and secret access key for the AWS API, CLI, SDK, and other development tools.

• Setup serverless configuration to connect with AWS serverless config credentials --provider aws --key <access-key> --secret <secret-key>

• Create a directory: mkdir aws_2022 && cd aws_2022 and initialize Serverless project serverless

• Choose AWS-Python-Starter

• Name it default

• Deploy - Yes
  

C:\Users\jp\Documents\aws_2022>serverless

Creating a new serverless project

? What do you want to make? AWS - Python - Starter
? What do you want to call this project? aws-python-project

✔ Project successfully created in aws-python-project folder

? Do you want to login/register to Serverless Dashboard? No

? Do you want to deploy now? (Y/n) y
? Do you want to deploy now? Yes

Deploying aws-python-project to stage dev (us-east-1)

× Stack aws-python-project-dev failed to deploy (78s)
Environment: win32, node 16.14.2, framework 3.12.0, plugin 6.2.1, SDK 4.3.2
Docs:        docs.serverless.com
Support:     forum.serverless.com
Bugs:        github.com/serverless/serverless/issues

Error:
CREATE_FAILED: IamRoleLambdaExecution (AWS::IAM::Role)
API: iam:GetRole User: arn:aws:iam::673040272970:user/jayp1_serverless is not authorized to perform: iam:GetRole on resource: role aws-python-project-dev-us-east-1-lambdaRole because no identity-based policy allows the iam:GetRole action

View the full error: https://us-east-1.console.aws.amazon.com/cloudformation/home?region=us-east-1#/stack/detail?stackId=arn%3Aaws%3Acloudformation%3Aus-east-1%3A673040272970%3Astack%2Faws-python-project-dev%2F6669ede0-c3c3-11ec-9584-0a8914e80a47

• Note the IamRole error , to fix is to update the role permissions by giving the access key user - jayp1_serverless.
• Go to IAM -> Users -> jayp1_serverless -> Add Permissions -> Choose Attach existing policy directly

Creating a new serverless project

? What do you want to make? AWS - Python - Starter
? What do you want to call this project? aws-python-project-2022

✔ Project successfully created in aws-python-project-2022 folder

? Do you want to login/register to Serverless Dashboard? No

? Do you want to deploy now? (Y/n) Y
? Do you want to deploy now? Yes

Deploying aws-python-project-2022 to stage dev (us-east-1)

✔ Service deployed to stack aws-python-project-2022-dev (111s)

functions:
  hello: aws-python-project-2022-dev-hello (1.7 kB)

What next?
Run these commands in the project directory:

serverless deploy    Deploy changes
serverless info      View deployed endpoints and resources
serverless invoke    Invoke deployed functions
serverless --help    Discover more commands

• Go to Lambda -> Functions -> aws-python-project-2022-dev-hello (filename-stage-function) - try to check in default region - N.Virginia

• Invoke lambda function on local workstation serverless invoke --function hello

C:\Users\jp\Documents\aws_2022>cd aws-python-project-2022

C:\Users\jp\Documents\aws_2022\aws-python-project-2022>serverless invoke --function hello
{
    "statusCode": 200,
    "body": "{\"message\": \"Go Serverless v3.0! Your function executed successfully!\", \"input\": {}}"
}

• Digging deep into folder stack of serverless project
  

• There are two concerned files for developer - handler.py and serverless.yml

  • handler.py contains a function hello which returns a json message.

import json


def hello(event, context):
    body = {
        "message": "Go Serverless v3.0! Your function executed successfully!",
        "input": event,
    }

    return {"statusCode": 200, "body": json.dumps(body)}

• serverless.yml is generated or created automatically while we create a serverless project. To understand serverless YML keywords Serverless Framework - AWS Lambda Guide

service: aws-python-project-2022

frameworkVersion: '3'

provider:
  name: aws
  runtime: python3.8

functions:
  hello:
    handler: handler.hello

• service - project configuration file
• provider : which cloud provider in our case its AWS
  • name : aws
  • runtime : python3.8

---

Deploying a new lambda function in desired region

Create a new lambda function getting_started in new handler file application.py which will be deployed in Mumbai region: ap-south-1

• Create a function - getting started in application.py

import json


def getting_started(event, context):
    body = {
        "message": "Go Serverless v3.0! Getting Started with Serverless \
             execution!",
        "event": event,
    }

    return {"statusCode": 200, "body": json.dumps(body)}

• Modify serverless.yml

service: aws-python-project-2022

frameworkVersion: '3'

provider:
  name: aws
  runtime: python3.8
  region: ap-south-1

functions:
  hello:
    handler: handler.hello
  getting_started:
    handler: application.getting_started

• Deploy changes on AWS serverless deploy

• Invoke getting_started on workstation serverless invoke --function getting_started

C:\Users\jp\Documents\aws_2022\aws-python-project-2022>serverless invoke --function getting_started
{
    "statusCode": 200,
    "body": "{\"message\": \"Go Serverless v3.0! Getting Started with Serverless              execution!\", \"event\": {}}"
}

---

API Gateway and AWS Lambda through Serverless Framework

• Event - Http - GET* Method will invoke getting_started function

• Setting up the APIs in API Gateway events under function and listing one such event -http with path: /data and method: GET
  

functions:
  hello:
    handler: handler.hello
  getting_started:
    handler: application.getting_started
    events:
      - http:
          path: /data
          method: GET

• Deploy the changes on AWS serverless deploy notice the endpoint

C:\Users\jp\Documents\aws_2022\aws-python-project-2022>serverless deploy

Deploying aws-python-project-2022 to stage dev (ap-south-1)

✔ Service deployed to stack aws-python-project-2022-dev (48s)

endpoint: GET - https://ni5xsk9f08.execute-api.ap-south-1.amazonaws.com/dev/data
functions:
  hello: aws-python-project-2022-dev-hello (2 kB)
  getting_started: aws-python-project-2022-dev-getting_started (2 kB)

Improve API performance – monitor it with the Serverless Dashboard: run "serverless"

• Checking the endpoint: https://ni5xsk9f08.execute-api.ap-south-1.amazonaws.com/dev/data

• Go to API Gateway -> Select Mumbai region -> APIs

• Check the invocation counts, error logs etc. in Monitor in Lambda console.