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adamnfish/lazio

AWS Lambda template for Scala backed by ZIO
Source code at GitHub null
adamnfish/lazio.json
{
  "createdAt": "2019-08-05T14:06:13Z",
  "defaultBranch": "master",
  "description": "AWS Lambda template for Scala backed by ZIO",
  "fullName": "adamnfish/lazio",
  "homepage": null,
  "language": "Scala",
  "name": "lazio",
  "pushedAt": "2023-12-21T15:03:08Z",
  "stargazersCount": 1,
  "topics": [],
  "updatedAt": "2025-03-20T23:09:09Z",
  "url": "https://github.com/adamnfish/lazio"
}

[!WARNING] This was a prototype that never materialised, and has been archived

Lazio

Section titled “Lazio”

Easily write Scala AWS Lambda functions using ZIO.

Lazio Core

Section titled “Lazio Core”

This provides a ZIO wrapper around AWS Lambda handlers as well as some helpful utilities. Using this library you can proide a ZIO program and have its execution handled for you.

  • [Core Lazio clas for HTTP integrations]!(lazio-core/src/main/scala/com/adamnfish/lazio/LazioAPIGatewayProxy.scala)
  • [ZIO wrapper aruond AWS Scala SDK v1.x API calls]!(lazio-core/src/main/scala/com/adamnfish/lazio/ZioAwsSdk.scala)

The ZIO wrapper requires a ZIO program with the following type:

ZIO[Environment, Nothing, ApiGatewayProxyResponse]

For more information on ZIO and the types it expects, take a look at ZIO’s documentation

Environment is the ZIO environment required by your program. You can think of the environment as your application’s dependencies.

The second type parameter is Nothing to indicate that all errors should have been handled. This parameter is used by ZIO to represent the errors that this program can produce during its execution. Since there are no values of type Nothing, we are indicating that it cannot fail. This means that the program you provide must always return an ApiGatewayProxyResponse. Practically, this means you should handle any errors encountered during the program’s execution and make sure that an appropriate HTTP response is returned (e.g. an HTTP 5xx).

The final type parameter is [ApiGatewayProxyResponse]!(lazio-core/src/main/scala/com/adamnfish/lazio/model/models.scala), which represents an HTTP response. It is comprised of an HTTP status code, a body, and a Map containing HTTP headers. A value of this type will be returned at the end of the program’s execution and this is what will be sent back to the client by Lazio.

Example Lambda

Section titled “Example Lambda”

This project shows a simple example of how to use Lazio to create a Lambda function. The program itself is a trivial example that uses ZIO’s Console to print to the console, and echoes some request details back to the client.

The example also contains a CDK program that can be used to create the Lambda function in an AWS account, behind API Gateway. The API Gateway integration puts the Lambda function behind a public URL.

  • [Example ZIO Lambda program]!(example/lambda/src/main/scala/com/adamnfish/lazio/Lambda.scala)
  • [CDK program for creating the example in AWS]!(example/lambda/cdk/index.ts)

Important note: using the provided CDK program to create the Lambda function in an AWS account will incur costs!

Example Dev Server

Section titled “Example Dev Server”

The dev server allows you to execute your Lambda function locally. It mimics the API Gateway integration so that you can use HTTP requests locally to invoke the Lambda function in the same way you would do in Production when the Lambda function is deployed.

You can run the dev server by selecting the exampleDevServer project from the sbt shell and using sbt’s run command.

sbt:lazio> project exampleDevServer
  ...
sbt:example-dev-server> run
  ...

When the server is running you can stop it and return to the sbt shell using ctrl+d.