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
   

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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
   ●
   

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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
   

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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
   

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5. Haskell library
   lambdaMain ::
   (Aeson.FromJSON event, Aeson.ToJSON res)
   => (event -> IO res) -- ^ Function to process the event
   -> IO ()
   

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6. Event types
   Types for dealing with common Lambda events
   So far
   ● SNS
   ● S3
   ● Kinesis
   ● APIGateway
   Plan to add more.
   

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7. Alternative events
   ● Compose handlers for different types of events
   

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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
   

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9. Examples
   

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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
    

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