Weather API demo

Status

• REST integration:

  • a REST API exposed via the API Gateway allows to query weather events.
  • a CLI client app queries this REST endpoint
  • API keys are configured to limit traffic (usage/quotas)
  • authentication is based on mutual TLS

• websocket integration:

  • a websocket endpoint is exposed on the API Gateway
  • the on-connect lambda keeps track of the currently connected websocket clients
  • the ws-push lambda is notified when events are added to DynamoDB and forwards them to all currently connected websocket clients
  • a CLI websocket client streams weather events from the websocket endpoint and prints them

• both the REST and websocket endpoints are exposed on a custom DNS domain

• a data generator lambda, triggered every minute, adds random weather events to DynamoDB

TODO (maybe)

• handle SIGINT correcty in ws socket client
• add Webocket security: API key? Or first request a temp token through REST, then pass it in the connect ws phase
• add OpenAPI spec to REST endpoint

References

Go AWS SDK

• AWS GO SDK v2 https://aws.github.io/aws-sdk-go-v2/docs/making-requests/

• Go lambda handler https://docs.aws.amazon.com/lambda/latest/dg/golang-handler.html

• Lambda events for each kind of integration https://github.com/aws/aws-lambda-go/tree/main/events

Go DynamoDB SDK

• API client, operations, and parameter types for Amazon DynamoDB https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/dynamodb#Client

• Types and functions to create Amazon DynamoDB Expression strings, ExpressionAttributeNames maps, and ExpressionAttributeValues maps https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/feature/dynamodb/expression#hdr-Using_the_Package

• Marshal slices, maps, structs, and scalar values to and from the AttributeValue type https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue

• AWS GO SDK examples https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/go

Security

• API Gateways usage plans and API keys https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-api-usage-plans.html

• Blog on mutual TLS using the API Gateway https://aws.amazon.com/blogs/compute/introducing-mutual-tls-authentication-for-amazon-api-gateway/