Deploy Haskell binaries onto AWS Lambda
npm install serverless-haskell!Build status
Deploying Haskell code onto [AWS Lambda] using [Serverless].
* AWS account
* [Stack]
* [NPM]
* [Docker]
There are two ways to start, either via the stack template, or directly modifying a project. You may want to use the manual approach as the template specifies a specific stack resolver as it needs to hardcode the stack.yaml file.
In either case, you will want to have [Serverless] installed, eg. npm install -g serverless.
* Create a [Stack] package for your code:
``shell`
stack new mypackage https://raw.githubusercontent.com/seek-oss/serverless-haskell/master/serverless-haskell.hsfiles
* Update the resolver in the stack.yaml file. This is hardcoded as the resolver number is not known at template interpolation time. You should pick either the latest resolver, or one you have used before and have thus prebuilt many of the core packages for.
* Install the dependencies and build the project:
`shell`
cd mypackage
npm install
stack build
sls invoke local -f mypackage-func
This should invoke serverless locally and display output once everything has built.
* Create a [Stack] package for your code:
`shell`
stack new mypackage
LTS 10-17 are supported, older versions are likely to work too but untested.
* Initialise a Serverless project inside the Stack package directory and install
the serverless-haskell plugin:
`shell`
cd mypackage
npm init -y
npm install --save serverless serverless-haskell@x.y.z
The version of the NPM package to install must match the version of the
Haskell package.
* Create serverless.yml with the following contents:
`yaml
service: myservice
provider:
name: aws
runtime: haskell
functions:
myfunc:
handler: mypackage.mypackage-exe
# Here, mypackage is the Haskell package name and mypackage-exe 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 toserverless.yml
# , which points to the location where the Haskellmypackage
# package is defined. This prefix is not needed when theserverless.yml
# Stack project is defined at the same level as .
plugins:
- serverless-haskell
`
* Write your main function:
`haskell
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"
print evt
pure [1, 2, 3]
`
* Add aeson and serverless-haskell to package.yaml:
`yaml`
dependencies:
- base >= 4.7 && < 5
- aeson
- serverless-haskell
* Build and test locally using sls invoke local:
The serverless-haskell plugin will build the package using Stack. Note thatexport SLS_DEBUG=*
the first build can take a long time. Consider adding so
you can see what is happening.
`
export SLS_DEBUG=*
sls invoke local -f myfunc
* Use sls deploy to deploy the executable to AWS Lambda.
The serverless-haskell plugin will build the package using Stack, then upload
it to AWS together with a JavaScript wrapper to pass the input and output
from/to AWS Lambda.
`
export SLS_DEBUG=*
sls deploy
You can test the function and see the invocation results with:
`
sls invoke -f myfunc
``
This plugin supports handling API Gateway requests. Declare the HTTP events
normally in serverless.yml and use
AWSLambda.Events.APIGateway
in the handler to process them.
[Serverless Offline] can be used for local testing of API Gateway requests. You
must use --useDocker flag so that the native Haskell runtime works correctly.
When using [Serverless Offline], make sure that the project directory is
world-readable, otherwise the started Docker container will be unable to access
the handlers and all invocations will return HTTP status 502.
* Only AWS Lambda is supported at the moment. Other cloud providers would
require different JavaScript wrappers to be implemented.
See
AWSLambda
for documentation, including additional options to control the deployment.
master branch is the stable version. It is normally released to Hackage once
new changes are merged via Git tags.
The package is also maintained in Stackage LTS, provided the dependencies are
not blocking it.
* Haskell code is tested with Stack: stack test.eslint
* TypeScript code is linted with .
Integration test verifies that the project can build and deploy a complete
function to AWS, and it runs with expected functionality.
Integration test is only automatically run up to deployment due to the need for
an AWS account. To run manually:
* Ensure you have the required dependencies:
- curl
- [jq]
- [NPM]
-
-
- [Stack]
* Get an AWS account and add the access credentials into your shell environment.
* Run . The exit code indicates success../integration-test/run.sh --dry-run
* To verify just the packaging, without deployment, run
.stack.yaml
* By default, the integration test is run with the LTS specified in
. To specify a different series, use RESOLVER_SERIES=lts-9.--no-clean-dir
* To avoid creating a temporary directory for every run, specify
. This can speed up repeated test runs, but does not guarantee
the same results as a clean test.
* Ensure you are on the master branch../bumpversion major|minor|patch
* Ensure that all the changes are reflected in the changelog.
* Run the integration tests.
* Run . This will increment the version number,master`,
update the changelog, create and push the Git tag and the branch.
* If you have released an LTS version, merge the version branch into
taking care of the conflicts around version numbers and changelog, and release
the latest version as well.
[AWS Lambda]: https://aws.amazon.com/lambda/
[Docker]: https://www.docker.com/
[jq]: https://stedolan.github.io/jq/
[NPM]: https://www.npmjs.com/
[pkg-config]: https://www.freedesktop.org/wiki/Software/pkg-config/
[Serverless]: https://serverless.com/framework/
[Serverless Offline]: https://github.com/dherault/serverless-offline
[Stack]: https://haskellstack.org