{"id":79821,"date":"2018-07-20T20:27:48","date_gmt":"2018-07-20T20:27:48","guid":{"rendered":"https:\/\/www.red-gate.com\/simple-talk\/?p=79821"},"modified":"2021-07-29T19:44:12","modified_gmt":"2021-07-29T19:44:12","slug":"aws-step-function-serverless-applications","status":"publish","type":"post","link":"https:\/\/www.red-gate.com\/simple-talk\/cloud\/aws\/aws-step-function-serverless-applications\/","title":{"rendered":"AWS Step Function Serverless Applications"},"content":{"rendered":"

I am a C# developer in an AWS world. I have been doing C# work in the Microsoft space for over 10 years. I was given a chance to work with colleagues who are redesigning an existing application into C# .NET Core within the Amazon Web Services (AWS) space. I am here to explain some of what I have learned.<\/p>\n

I want to talk to you about the structure of AWS Serverless Application (.NET Core) Step Function. (Serverless is crazy, right? Just wait.) This article begins by describing the \u2018Hello world\u2019 Visual Studio template AWS generates for you. Then, it steps through changing the project files to show how to add more functionality. It shows how to leverage an existing C# logic\/assembly into an AWS Lambda and how that Lambda could be treated as a microservice.<\/p>\n

Serverless means you do not have to think about managing a server. Wiki has a good definition<\/a>.<\/p>\n

Installing VS Components<\/h2>\n

To follow along with this article, you must have an AWS account and install the AWS Toolkit for Visual Studio. I\u2019m using Visual Studio Community 2017. Visit AWS<\/a> on Amazon to create an AWS account.<\/p>\n

You can find the latest AWS Toolkit in the Extension and Updates (Tools => Extensions and Updates \u2026) . Within the dialog window, select online the section and search for AWS Toolkit. You will see here that I have it installed:<\/p>\n

<\/p>\n

Or visit Visual Studio Marketplace and search for AWS Toolkit. For Visual Studio 2017 it is located here<\/a>. For Visual Studio 2013\/2015, it is located here<\/a>. You can download the AWS SDK for .NET here<\/a>.<\/p>\n

The AWS Toolkit installs an AWS Explorer window.<\/p>\n

<\/p>\n

When you choose an AWS template for the first time, Visual Studio will ask you for account information such as your AWS access key, your AWS secret, and in what region you want to work for creating your default profile. As you can see, I chose to use the US West region.<\/p>\n

Navigating AWS<\/h2>\n

I will be referencing the AWS Console<\/a> throughout this article. In the upper right hand corner, you will see a button Sign in to the Console<\/em>. Clicking that button takes you to a login screen. After authenticating, you finally end up on the AWS dashboard. In this dashboard you will see several services listed.<\/p>\n

<\/p>\n

This article will visit the consoles for Lambda<\/em>, Step Functions<\/em>, CloudFormation<\/em>, and S3<\/em> as you follow along. The top banner of the console website has a dropdown called Services<\/em>. Chose that dropdown for ease of navigating between console screens.<\/p>\n

<\/p>\n

Setting up Account Privileges<\/h2>\n

To see what your account privileges are when you created your account, you can go to the IAM console for drilling down to the details. There are a couple of tasks you may want to complete. I created a new Group called Develop <\/em>within the Groups <\/em>section.<\/p>\n

<\/p>\n

You will have to assign a name and permissions as you walk through the wizard. I gave Develop the AdministratorAccess <\/em>policy,<\/em> and I assigned myself to that group.<\/p>\n

To create a group, click the Create New Group<\/em> button to start the Create New Group Wizard<\/em>.<\/p>\n

<\/p>\n

Set the Group Name<\/em> to something that will help you remember what it does.<\/p>\n

<\/p>\n

Click the Next Step<\/em> button to advance to Attach Policy<\/em>.<\/p>\n

<\/p>\n

For the demo, select AdminstratorAccess<\/em> before clicking the Next Step button for reviewing your actions.<\/p>\n

<\/p>\n

After reviewing the group name and the policies, select the Create Group<\/em> button.<\/p>\n

<\/p>\n

Then, on the Groups<\/em> tab and add your account to the group by selecting the Add User<\/em> to Group button. You will be able to select a user. <\/p>\n

This article doesn\u2019t dive too deep into the Identity and Access Management (IAM) since that could be the topic of a future article.<\/p>\n

Creating the VS Project<\/h2>\n

Create a Visual Studio solution\/project by choosing AWS Serverless Application (.NET Core)<\/em> within the New Project<\/em> UI.<\/p>\n

<\/p>\n

On the next screen choose Step Functions Hello World <\/em>and click Finish<\/em>.<\/p>\n

<\/p>\n

The C# solution created will look something like the following:<\/p>\n

\"Screen<\/p>\n

Basically, the GeraldsLambdaApp<\/em> is an AWS Step Functions project similar to a workflow that calls Lambdas. Lambdas are like functions that run as Micro Services. It\u2019s time to dissect the project.<\/p>\n

Since I\u2019m a developer I must look at the code. The State.cs<\/em> file contains the State<\/strong> class which is a vanilla data transfer object.<\/p>\n

<\/p>\n

There is nothing earth shattering in the StepFunctionTasks.cs;<\/em> it contains two methods that take in the State<\/strong> class and an ILambdaContext<\/strong> object.<\/p>\n

<\/p>\n

The .NET Core dependencies are pretty straightforward.<\/p>\n

<\/p>\n

Now onto the AWS files.<\/p>\n

Take note of the following AWS files because they are instrumental for deploying to AWS via Visual Studio:<\/p>\n