Serverless Haskell

Slides from a talk on Serverless Haskell at the Melbourne Haskell Users Group meetup, 22nd February 2018

Transcript

1. Serverless Haskell Alexey Kotlyarov & David Overton
2. Motivation • AWS Lambda and the Serverless Framework make it easy to write small functions and deploy them to the cloud… • … but not in Haskell • Aim: to make it as easy to do serverless programming in Haskell as it is in NodeJS or Python •
3. What we did • Serverless Haskell • Developed over a 3 day Hackathon at SEEK in December 2017 • Consists of ◦ A Serverless plugin ◦ A Haskell library
4. Serverless plugin • Provides a NodeJS wrapper that spawns your Haskell executable • Hooks up pipes for input, output and logging • At the moment it will spawn a new exe on each invocation • Future plan: keep the exe running so that it can handle multiple invocations
5. Haskell library lambdaMain :: (Aeson.FromJSON event, Aeson.ToJSON res) => (event -> IO res) -- ^ Function to process the event -> IO ()
6. Event types Types for dealing with common Lambda events So far • SNS • S3 • Kinesis • APIGateway Plan to add more.
7. Alternative events • Compose handlers for different types of events
8. Embedded events • Some event types (e.g. SNS, APIGateway) have stringified JSON or Base64 embedded within string values in the JSON • TextValue and Embedded
9. Examples
10. Conclusion • We have several Lambdas at SEEK using this • GitHub https://github.com/seek-oss/serverless-haskell • Also on npm, hackage and stackage • Future extensions: ◦ Allow more than one Lambda invocation ◦ Allow multiple functions per project ◦ Expand the supported event types • We would love to get more users • Pull requests invited