λ# - Favorinus (v0.6.0.1) - 2019-06-11

Favorinus had extensive knowledge, combined with great oratorical powers, that raised him to eminence both in Athens and in Rome. He lived on close terms with Plutarch, with Herodes Atticus, to whom he bequeathed his library in Rome, with Demetrius the Cynic, Cornelius Fronto, Aulus Gellius, and with the emperor Hadrian. (Wikipedia)

What's New

This release focuses on API Gateway, both for REST APIs and WebSockets. After building the Lambda functions, λ# analyzes the compiled assemblies to enhance the API Gateway rout definitions in CloudFormation. For example, λ# will extract the JSON schema from the target methods to create request validation rules for API Gateway. This enables API Gateway to block requests before they reach the Lambda function. In addition, λ# allows checks if the target method returns a response. If not, API Gateway will be configured to invoke the Lambda function asynchronously, providing much faster response times.

In addition, there is a new documentation site that covers all aspects of λ#, including the base classes, modules, and syntax.

BREAKING CHANGES

The following change may impact modules created with previous releases.

λ# Tool

  • The git-sha is now prefixed with DIRTY- if the git checkout contains modified or untracked files.

λ# Assemblies

The λ# dependencies were updated to Amazon.Lambda.Core v1.1.0 and Amazon.Lambda.Serialization.Json v1.5.0. All projects need their dependencies updated to reflect this change. Otherwise, a compilation error will occur.

The LambdaSharp.dll assembly was refactored for consistency. Classes are now organized into the following namespaces:

  • LambdaSharp: Common base classes, such as ALambdaFunction and LambdaConfig.
  • LambdaSharp.ApiGateway: Classes relating to ALambdaApiGatewayFunction.
  • LambdaSharp.ConfigSource: Classes for reading configuration information. Usually not required.
  • LambdaSharp.CustomResource: Classes relating to ALambdaCustomResourceFunction<TProperties,TAttributes>.
  • LambdaSharp.ErrorReports: Classes for generating error reports. Usually not required.
  • LambdaSharp.Exceptions: Classes for throwing exceptions. Usually not required.
  • LambdaSharp.Finalizer: Classes relating to ALambdaFinalizerFunction.
  • LambdaSharp.Logger: Classes for basic logging. Usually not required.
  • LambdaSharp.Schedule: Classes relating to ALambdaScheduleFunction.
  • LambdaSharp.SimpleNotificationService: Classes relating to ALambdaTopicFunction.
  • LambdaSharp.SimpleQueueService: Classes relating to [ALambdaQueueFunction](xref:LambdaSharp.SimpleQueueService.ALambdaQueueFunction1).

Other functional changes include:

  • The RequestId property in ALambdaFunction was replaced by the more generic CurrentContext property. Old code needs to be updated to use CurrentContext.AwsRequestId instead.
  • The ILambdaContext context parameter was removed in favor of the CurrentContext property.
  • Methods starting with HandleXYZ were renamed to ProcessXYZ for consistency.

New λ# Module Features

API Gateway .NET

The Api event-source now supports specifying a target invocation method using the Invoke attribute. At compile time, λ# CLI verifies that the target method exists in the compiled assembly. In addition, λ# generates the request/response JSON schema models for the method and uses them to configure API Gateway. If the method has either void or Task as return type, λ# will configure the lambda function as an asynchronous invocation in API Gateway. Note, for this behavior to take effect, the Lambda function must derive from ALambdaApiGatewayFunction.

- Function: MyFunction
  Memory: 256
  Timeout: 30
  Sources:

    - Api: POST:/items
      Invoke: AddItem

The target method can now be implemented in a straightforward way, without requiring deserializing or validation.

public AddItemResponse AddItem(AddItemRequest request) {

    // add new item to list
    var item = new Item {
        Id = Guid.NewGuid().ToString("N"),
        Value = request.Value
    };
    _items.Add(item);

    // respond with new item ID
    return new AddItemResponse {
        Id = item.Id
    };
}

WebSockets .NET

A new WebSocket event-source is now supported. Similar to the Api event-source, WebSocket supports specifying a target invocation method using the Invoke attribute. At compile time, λ# CLI verifies that the target method exists in the compiled assembly. In addition, λ# generates the request/response JSON schema models for the method and uses them to configure API Gateway v2. If the method has either void or Task as return type, λ# will configure the lambda function as an asynchronous invocation in API Gateway v2. Otherwise, it will be configured for bidirectional communication. Note, for this behavior to take effect, the Lambda function must derive from ALambdaApiGatewayFunction.

- Function: MessageFunction
  Memory: 256
  Timeout: 30
  Sources:

    - WebSocket: send
      Invoke: SendMessageAsync

The target method can now be implemented in a straightforward way, without requiring deserializing or validation. The method uses the WebSocketClient property, which is inherited from the base class. The WebSocketClient returns the IAmazonApiGatewayManagementApi instance when ALambdaApiGatewayFunction was instantiated with a WebSocket URL.

public Task SendMessageAsync(Message request) {

    // echo message back
    return WebSocketClient.PostToConnectionAsync(new PostToConnectionRequest {
        ConnectionId = CurrentRequest.RequestContext.ConnectionId,
        Data = SerializeJson(new Message {
            From = request.From,
            Text = request.Text
        }).ToStream()
    });
}

API Gateway CloudWatch Log

The API Gateway CloudWatch log is now created--and therefore, deleted--by CloudFormation.

New λ# CLI Features

Build Command

The --module-version option was added to allow overriding the version of the module being compiled. This capability is useful in build pipelines where a script needs to set the current version number.

In addition, the captured git-sha is now prepended with DIRTY- when there are uncommitted/untracked changes when the module is built.

Publish Command

The --force-publish option was modified to publish all assets even even when the checksums match.

Deploy Command

All CloudFormation stacks are now tagged with LambdaSharp:DeployedBy to capture the identity of who deployed the stack.

New Command

The new module, new function, and new resource commands will now prompt for the name and type when omitted.

The new resource command now also inserts a documentation link with the newly added resource declaration. In addition, if the exact resource name cannot be found, the new resource command will show partial matches.

- Resource: MyTopic
  Description: TO-DO - update resource description
  Type: AWS::SNS::Topic
  Properties:
    # Documentation: http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-sns-topic.html
    DisplayName: String
    KmsMasterKeyId: String
    Subscription:
      - Endpoint: String # Required
        Protocol: String # Required
    TopicName: String

Util Command

The util create-invoke-methods-schema was added to help generate JSON schema from compiled methods to be used with ALambdaApiGatewayFunction.

List Command

The output of the list command was enhanced to show the module name and version.

lash list --tier Sandbox

Output:

LambdaSharp CLI (v0.6) - List deployed LambdaSharp modules

Found 2 modules for deployment tier 'Default'

NAME                 MODULE                   STATUS             DATE
LambdaSharp-Core     LambdaSharp.Core:0.6     UPDATE_COMPLETE    2019-04-05 10:36:49
LambdaSharp-S3-IO    LambdaSharp.S3.IO:0.6    UPDATE_COMPLETE    2019-04-05 10:37:19

Done (finished: 4/5/2019 3:36:10 PM; duration: 00:00:01.4137682)

Init Command

The init command was improved to detect previous versions of a deployment tier and prompt for perform an upgrade operation, similar to the config command.

New λ# Assembly Features

This release adds ALambdaQueueFunction<T> as base class for processing messages from SQS queues.

The ALambdaApiGatewayFunction was also enhanced to provide support for target methods invocations.

Fixes

(v0.6.0.1) - 2019-06-11

Updated Documentation

New Features

  • X-Ray Tracing now works for API Gateway V1 and Nested Modules.
  • Updated CloudFormation spec to 3.3.0.
  • Colorized warning and errors in console output.
  • Added ALambdaFunction.RunTask() and ALambdaFunction.AddPendingTask(Task) to queue background operations that must complete before the Lambda invocation finishes.
  • Added HttpClient with X-Ray tracing instrumentation to ALambdaFunction base class.
  • ALambdaFunction now unrolls AggregateException instances and reports errors individually.
  • lash util delete-orphan-logs replaces delete-orphan-lambda-logs, which now also delete orphaned API Gateway V1/V2 CloudWatch logs

Fixes

  • Fixed an issue with setting the correct IAM role for the API Gateway account.
  • Various bug fixes to generating the proper JSON schema for API Gateway endpoints and routes.
  • lash publish now warns if version already exists instead of reporting an error.