generic approach to package dependencies for Lambda

steps involved

1. create funtion
2. create terraform - to create s3 bucket, create lambda role, zip the source code and upload the function
3. test terraform
4. create api gateway
5. integrate the api gateway with lambda funtion

• terraform init
• terraform appy
• terraform destroy (run destroy when you are ready to clean up resources)

- aws lambda invoke --region=us-west-1 --function-name=hello response.json

• cat response.json

- terraform apply
- aws lambda invoke --region=us-west-1 --function-name=hello response.json
- cat response.json

• https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/apigatewayv2_api

• create api gateway - api-gateway.tf
• integrate the api gateway with lambda funtion - hello-api-gateway.tf

- curl "https://<id>.execute-api.us-west-1.amazonaws.com/dev/hello?Name=Vito%20Croleone"
note: %20 represents a space in URL - as space is assigned number 32 which is 20 in hexadecimal

-curl -X POST \
-H "Content-Type: application/json" \
-d '{"name":"Vito Corleone"}' \
"https://<id>.execute-api.us-west-1.amazonaws.com/dev/hello"

• 1. s3 bucket
• 2. api gateway and routes GET and POST
• 3. cloudwatch logs

How to move dependencies into AWS lambda environment? Lets consider an eg: Reading a new file in an S3 bucket using aws sdk libs steps involved:

• 1.create a node project and add external dependencies (npm init)
• 2. grant access to this function to read a file in a new S3 bucket
• 3. create lambda funtion using terraform - s3-lambda.tf
• 4. simple wrapper around terraform to deploy from local
• 5. make the script executable - chmod +x terraform.sh
• 6. finally run the script - ./terraform.sh to test from local
• 7. invoke this new s3 function and provide a json payload with the bucket name and the object

Test running terraform apply and check the outputs.

hello_base_url = "https://<id>.execute-api.us-west-1.amazonaws.com/dev"
test_s3_bucket = "<bucket-name>"

TEST invoking lambda using AWS CLI

 aws lambda invoke --region=us-west-1  --function-name=s3 \
 --cli-binary-format raw-in-base64-out \
 --payload '{"bucket":"test-<your>-<name>","object":"hello.json"}' \
 response.json

'{"bucket":"test-literate-silkworm","object":"hello.json"}'