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Chris Biscardi

Serverless Haskell with AWS Lambda and Serverless Framework

Using Serverless Haskell.

Suggested route to getting started is using stack and an hsfiles templatey

stack new mypackage https://raw.githubusercontent.com/seek-oss/serverless-haskell/master/serverless-haskell.hsfiles
shell
cd mypackage
npm install
stack build
# sls invoke local -f mypackage-func

The Stack project is split into src, app, and test.

➜ ls -R
app LICENSE package.yaml serverless.yml src test
ChangeLog.md package.json README.md Setup.hs stack.yaml
./app:
Main.hs
./src:
Lib.hs
./test:
Spec.hs

app/Main.hs is the program that runs our handler

app/Main.hs
hs
module Main where
import Lib
import qualified Data.Aeson as Aeson
import AWSLambda
main = lambdaMain handler
handler :: Aeson.Value -> IO [Int]
handler evt = do
putStrLn "This should go to logs"
someFunc
print evt
pure [1, 2, 3]

Extra

.hsfiles as of writing this post:

{-# START_FILE package.yaml #-}
name: {{name}}
version: 0.1.0
github: "{{github-username}}{{^github-username}}githubuser{{/github-username}}/{{name}}"
license: BSD3
author: "{{author-name}}{{^author-name}}Author name here{{/author-name}}"
maintainer: "{{author-email}}{{^author-email}}example@example.com{{/author-email}}"
copyright: "{{copyright}}{{^copyright}}{{year}}{{^year}}2018{{/year}} {{author-name}}{{^author-name}}Author name here{{/author-name}}{{/copyright}}"
extra-source-files:
- README.md
- ChangeLog.md
# Metadata used when publishing your package
# synopsis: Short description of your package
# category: {{category}}{{^category}}Web{{/category}}
# To avoid duplicated efforts in documentation and dealing with the
# complications of embedding Haddock markup inside cabal files, it is
# common to point users to the README.md file.
description: Please see the README on GitHub at <https://github.com/{{github-username}}{{^github-username}}githubuser{{/github-username}}/{{name}}#readme>
dependencies:
- base >= 4.7 && < 5
- serverless-haskell
- aeson
library:
source-dirs: src
executables:
{{name}}-exe:
main: Main.hs
source-dirs: app
ghc-options:
- -threaded
- -rtsopts
- -with-rtsopts=-N
dependencies:
- {{name}}
tests:
{{name}}-test:
main: Spec.hs
source-dirs: test
ghc-options:
- -threaded
- -rtsopts
- -with-rtsopts=-N
dependencies:
- {{name}}
{-# START_FILE Setup.hs #-}
import Distribution.Simple
main = defaultMain
{-# START_FILE test/Spec.hs #-}
main :: IO ()
main = putStrLn "Test suite not yet implemented"
{-# START_FILE src/Lib.hs #-}
module Lib
( someFunc
) where
someFunc :: IO ()
someFunc = putStrLn "Serverless is running your lambda function!"
{-# START_FILE app/Main.hs #-}
module Main where
import Lib
import qualified Data.Aeson as Aeson
import AWSLambda
main = lambdaMain handler
handler :: Aeson.Value -> IO [Int]
handler evt = do
putStrLn "This should go to logs"
someFunc
print evt
pure [1, 2, 3]
{-# START_FILE README.md #-}
# {{name}}
{-# START_FILE ChangeLog.md #-}
# Changelog for {{name}}
## Unreleased changes
{-# START_FILE LICENSE #-}
Copyright {{author-name}}{{^author-name}}Author name here{{/author-name}} (c) {{year}}{{^year}}2018{{/year}}
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials provided
with the distribution.
* Neither the name of {{author-name}}{{^author-name}}Author name here{{/author-name}} nor the names of other
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
{-# START_FILE .gitignore #-}
.stack-work/
node_modules/
.serverless/
{{name}}.cabal
{-# START_FILE serverless.yml #-}
service: {{name}}
provider:
name: aws
runtime: haskell
functions:
{{name}}-func:
handler: {{name}}.{{name}}-exe
# Here, mypackage is the Haskell package name and myfunc is the executable
# name as defined in the Cabal file. The handler field may be prefixed
# with a path of the form `dir1/.../dirn`, relative to `serverless.yml`,
# which points to the location where the Haskell package `mypackage` is
# defined. This prefix is not needed when the Stack project is defined at
# the same level as `serverless.yml`.
plugins:
- serverless-haskell
{-# START_FILE package.json #-}
{
"name": "{{name}}",
"version": "0.1.0",
"description": "",
"main": "index.js",
"directories": {
"test": "test"
},
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC",
"dependencies": {
"serverless": "^1.41.1",
"serverless-haskell": "^0.8.4"
}
}
{-# START_FILE stack.yaml #-}
# This file was automatically generated by 'stack init'
#
# Some commonly used options have been documented as comments in this file.
# For advanced use and comprehensive documentation of the format, please see:
# https://docs.haskellstack.org/en/stable/yaml_configuration/
# Resolver to choose a 'specific' stackage snapshot or a compiler version.
# A snapshot resolver dictates the compiler version and the set of packages
# to be used for project dependencies. For example:
#
# resolver: lts-3.5
# resolver: nightly-2015-09-21
# resolver: ghc-7.10.2
# resolver: ghcjs-0.1.0_ghc-7.10.2
#
# The location of a snapshot can be provided as a file or url. Stack assumes
# a snapshot provided as a file might change, whereas a url resource does not.
#
# resolver: ./custom-snapshot.yaml
# resolver: https://example.com/snapshots/2018-01-01.yaml
resolver: lts-12.19
# User packages to be built.
# Various formats can be used as shown in the example below.
#
# packages:
# - some-directory
# - https://example.com/foo/bar/baz-0.0.2.tar.gz
# - location:
# git: https://github.com/commercialhaskell/stack.git
# commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
# subdirs:
# - auto-update
# - wai
packages:
- .
# Dependency packages to be pulled from upstream that are not in the resolver
# using the same syntax as the packages field.
# (e.g., acme-missiles-0.3)
extra-deps:
- serverless-haskell-0.12.1
# Override default flag values for local packages and extra-deps
# flags: {}
# Extra package databases containing global packages
# extra-package-dbs: []
# Control whether we use the GHC we find on the path
# system-ghc: true
#
# Require a specific version of stack, using version ranges
# require-stack-version: -any # Default
# require-stack-version: ">=1.7"
#
# Override the architecture used by stack, especially useful on Windows
# arch: i386
# arch: x86_64
#
# Extra directories used by stack for building
# extra-include-dirs: [/path/to/dir]
# extra-lib-dirs: [/path/to/dir]
#
# Allow a newer minor version of GHC than the snapshot specifies
# compiler-check: newer-minor