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README.md

README.md

Learn Step Functions

This is a workshop to learn how to develop and deploy AWS Step Functions. You can find some tutorials I've written here.

Pre-requisites

Serverless framework

We're going to use the serverless framework to deploy and test the step functions. The serverless framework is a NodeJS library, so first we'll need to install NodeJs. Go to the [NodeJS] website and install it in your favourite OS.

Once we have NodeJS install, we can install the serverless framework. To do that, open a terminal window and type npm install serverless -g. That will install the framework. To check that the installation finished successfully, type sls -v to see the installed version of the framework. At the time of writting, you should see 1.16.1

You'll need to install the plugin for step functions. To do that, create your working folder and, inside it type npm install --save serverless-step-functions

.Net Core

You can download the last version of the SDK, but we'll need to target netcoreapp1.0. So, go to the official website and follow the instructions for your favourite OS.

Javascript

If you've followed the steps to install the serverless framework, you should be in a good position to develop using Javascript.

Python

Download and install the latest version of Python from the official website. Take a look here for extra help.

VSCode

I'm going to use VSCode in this workshop (you can use whatever editor you'd like). If you don't have VSCode installed, go to the official website and follow the instructions for you favourite OS.

There are a couple of extensions that will make our live easier. For F# development, download the ionide extension. For C# development, download the C# extension.

AWS

You'll need an AWS account to follow the workshop. You can get one for free here. Once you have the account, you'll need to setup an account so that the serverless framework can interact with AWS. Please, follow the steps explained here. My preferred option is to set up an AWS profile. It's a good idea that you give access from the console to that user, so you can connect to it and see the step function running.

Creating the first function

Create a simple Step Function called rpg with an state called Attack of type Pass.

Deploy the Step Function and test it.

Check the Step Function in the AWS console.

step 1

Check the Step 1 branch to see the final solution.

A parallel execution

Create a parallel state called CalculateMultipliers with two branches. The first branch should have a state of type Pass called AttackMultiplier and the second branch should have a state of type Pass called DefenseMultiplier.

Create the step that collects the result of the paralles execution and name it Result.

Link the state created in the previous step to the parallel one.

Deploy and test the Step Function.

Check the Step Function in the AWS console.

step 2

Check the Step 2 branch to see the solution.

Choices

Rename the Result state to CalculateAttackResult. Change its type to Choice and create two choices, one for a number greater than 0 and the other for a number less or equal to 0 (use any variable you want depending on what you want to pass to the function).

Link the first choice to an state of type Fail named Alive and link the second choice to an state of type Succeed named Dead.

Deploy and test the function.

Check the Step Function in the AWS console.

step 3

Check the Step 3 branch for the final solution.

Our first lambda

Create a Lambda using C#, call it AttackMultiplierLambda. The lambda will receive a JSON like this:

{ "Attack":{ "Player":{ "Level":10, "Live":50 }, "Strength":10 }, "Defense":{ "Player":{ "Level":8, "Live":20 }, "Strength": 30 } }

Create the classes that will allow us to receive this input (and return it).

Change the code to generate a number between 0 and 2 (0, 1 or 2) and multiply the strength of the attack to it. Return the whole object.

Deploy the function and test it.

Check the Step 4 branch for the final solution.

Defense multiplier in Python

Create a Lambda using Python.

Change the code to generate a number between 0 and 2 (0, 1 or 2) and multiply the strength of the defense to it. Return the whole object.

Deploy the function and test it.

Check the Step 5 branch for the final solution.

Calculate result in JS

Create a Lambda using NodeJS.

Change the code to calculate the result of the attack, i.e. substract the result of the substraction of the strength of the defense to the strength of the attack, to the player's live.

Return the result (the whole object).

Deploy and test the Lambda.

Check the Step 6 branch for the final solution.

Joining all together

Modify the serverles.yml file in the root folder to replace the actual states of CalculateAttackMultiplier, CalculateDefenseMultiplier and CalculateResult with the recently created Lambdas.

Deploy the Step Function and test it.

Check the Step 7 branch for the final solution.

Calling the Step Function.

Create an HTTP endpoint in your Step Function to be able to call it (POST).

Deploy the Step Function and test it via curl or postman.

Install the aws-sdk package via npm or yarn. Create a Lambda that calls the Step Function. Get the arn of the step function via environment variable.

Edit the serverles.yml file to export the arn of the Step Function. Pass it to the Lambda Function via environment variable. Add an HTTP handler to the Lambda.

Grant permissions to the service to be able to execute a Step Function.

Check the Step 8 branch for the final solution.