$0.0000002 / request
Every time you invoke a Lambda function, you save your pennies.
- Free-forever tier
- Pay per request
- Pay for just millis
Create a Lambda Function from AWS CLI
Don’t know how to setup AWS CLI? Follow this guide.
aws lambda create-function --function-name hello-fn --role
arn:aws:iam::acc_no:role /eg-role
From Servers to No Servers (Serverless)
AWS Lambda does need servers but AWS manages the scaling, patching, and upgradation of the servers.
Lambda Runtimes
- NodeJS
- Python
- Go
- Java
- .NET
- Amazon Linux
Lambda Cold Start
Just as it takes some time for a thermometer to take your temperature, an AWS Lambda instance takes a few seconds to launch.
To optimize, do these:
- Reserve concurrency
- Tree shaking
AWS spins up 2+ Lambda instances to handle website load
AWS Services You Can Use to Trigger a Lambda
DynamoDB
React to changes
SNS
Events Processing
S3
Resize Images
SQS
Batch Processing
API Gateway
REST APIs
More ways to trigger
- Function URL
- Step functions
- Event Bridge
- CloudFront
- AWS CLI
- AWS SDK
Environment Variables
- Just like your
.envfiles - Store key value pairs in AWS Lambda
- Encrypt them with AWS KMS
Lambda Role
Every AWS service needs an IAM role to perform any action on your behalf.
- Default Lambda role has access to all your CloudWatch logs
- To give your Lambda access to other AWS services like S3, DynamoDB, SNS, create a custom role and use that when creating a Lambda function.
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Lambda logs to CloudWatch
- Find error messages
- Get real time logs with live tail
- Set alarms for an specific event
- Setup Anomaly Detection with logs
- Monitor performance with Insights
Lambda Layers
- Used when abstraction is needed between multiple Lambda functions
- Needed for packages which relies on external binary files
- Helps to reduce deployment / upload time
- Increases cold start time [Only Disadvantage]
Lambda Versions
Keep your old Lambdas in multiple version, just like Git. Switch back to an older version anytime, anywhere.