Create & Deploy an AWS State Machine with a .NET Core Lambda using AWS SAM

This article explains how to create & deploy an AWS State Machine with a .NET Core Lambda using AWS SAM.

Prerequisites

Latest AWS CLI. This guide uses v2.0.19.
Latest SAM CLI. This guide uses v0.39.0.
VS Code with AWS Toolkit. This guide uses VS Code v1.45.1 with AWS Toolkit v1.10.0.
Latest .NET Core SDK. This guide uses v3.1.300.

Step 1 — Create SAM App

In VS Code:

Select .NET Core:

Select Hello World:

Select a folder:

Name the app:

The app is created & the template is displayed:

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  Sample SAM Template for sam-app

# More info about Globals: https://github.com/awslabs/serverless-application-model/blob/master/docs/globals.rst
Globals:
  Function:
    Timeout: 10

Resources:
  HelloWorldFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: ./src/HelloWorld/
      Handler: HelloWorld::HelloWorld.Function::FunctionHandler
      Runtime: dotnetcore2.1
      Environment: # More info about Env Vars: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#environment-object
        Variables:
          PARAM1: VALUE
      Events:
        HelloWorld:
          Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
          Properties:
            Path: /hello
            Method: get

Outputs:
  # ServerlessRestApi is an implicit API created out of Events key under Serverless::Function
  # Find out more about other implicit resources you can reference within SAM
  # https://github.com/awslabs/serverless-application-model/blob/master/docs/internals/generated_resources.rst#api
  HelloWorldApi:
    Description: "API Gateway endpoint URL for Prod stage for Hello World function"
    Value: !Sub "https://${ServerlessRestApi}.execute-api.${AWS::Region}.amazonaws.com/Prod/hello/"
  HelloWorldFunction:
    Description: "Hello World Lambda Function ARN"
    Value: !GetAtt HelloWorldFunction.Arn
  HelloWorldFunctionIamRole:
    Description: "Implicit IAM Role created for Hello World function"
    Value: !GetAtt HelloWorldFunctionRole.Arn

Delete the highlighted lines above.

Step 2 — Add State Machine

Add the following between lines 11 & 12 in the template:

  StateMachine:
    Type: AWS::Serverless::StateMachine
    Properties:
      Definition:
        StartAt: HelloWorldLambdaState
        States:
          HelloWorldLambdaState:
            Type: Task
            Resource: !GetAtt HelloWorldFunction.Arn
            End: true
      Policies:
      - LambdaInvokePolicy:
          FunctionName: !Ref HelloWorldFunction

Step 3 — Deploy SAM App

In VS Code:

Select template:

Select region:

Provide an S3 bucket:

Name the CloudFormation stack:

Wait for deployment:

Starting SAM Application deployment...
Building SAM Application...
Packaging SAM Application to S3 Bucket: sam-app-code-c6ba893e
Deploying SAM Application to CloudFormation Stack: sam-app-stack
Successfully deployed SAM Application to CloudFormation Stack: sam-app-stack

Step 4 — Test State Machine

Open the state machine in AWS console & start execution:

In a few seconds, the execution completes & output is displayed: