AWS Lambda

Getting started with Lambda:

  • Create a function using Lambda function and then invoke it
  • You can create Lambda function using Lambda console, or Code Editor IDE on Lambda Console or using command line tools, AWS SDK’s. For AWS CLI you get access to Lambda API
  • You can deploy code to Lambda using a zip file or container image.
  1. Create a Lambda function with default function code
    • On Lambda console, choose create function
    • Give all information such as name and language parameters
    • Finally create function and then invoke it after configure test events and by clicking on TEST
    • Lastly check the execution Results.
  2. Create a Lambda function as a container image
    • Create a Project Directory lets assume cd /opt ( We are working on EC2 instance here)
    • Create a node.js function or any language which ever suits you
    • Create a Dockerfile
    • Install software’s : sudo apt update npm awscli
    • Create Package.json for dependencies by running npm init command
    • Finally Build your Docker image , Push it to ECR and then finally create Lambda function using container images.
  3. Create Lambda function using AWS CLI * It uses Boto3 to connect with Lambda API & you need to have access to create role
    • aws lambda create-function –function-name func1 –zip-file fileb:// –handler index.handler –runtime nodejs12.x \ –role arn:aws:iam:::role/lambda-ex
Lambda componentsWorking
FunctionIt gets invoked to run your code. It process events
QualifierSpecific Version of code or configuration
Execution EnvironmentIt manages process and resource that are required for lambda
DeploymentsContainer Based or Zip
RuntimeIt is Language specific like python, node.js
Extension To integrate with other AWS services
EventIts required by function to process the data
Trigger Which Invokes Lambda

Features of Lambda:

  1. Programming Model: Provides runtime for languages that it supports and can easily switch between frameworks
  2. Scaling: As per Requests it auto scales
  3. Concurrency Methods: It can help in defining the right number of requests as required.
  4. Asynchronous Invocation: Lambda function queues the event and return response right away else in case of synchronous invocation it waits for a response.
  5. Based on container rich tool as well. You can use docker commands to work with Lambda.

Permissions In Lambda:

Here we have created a very simple diagram to explain if AWS service wants to connect with Lambda or vice versa , have a look here.

Resource Based Policy : For Any user , group or any other Accounts want to access Lambda function you need Resource Based Policy

Lambda Execution role: For Lambda function to access other AWS services you need this role and by default there are permission boundary which prevents you to openly access everything( Modify according to need)