feat: Add aws-ruby-step-functions-express example (#639)

Author: Pigius

README.md

@@ -128,6 +128,7 @@ serverless install -u https://github.com/serverless/examples/tree/master/folder-
 | [Aws Ruby Step Functions Callback](https://github.com/serverless/examples/tree/master/aws-ruby-step-functions-with-callback) <br/> Ruby example that make usage of AWS Step Functions with callback pattern, AWS Lambda, DynamoDB, Amazon Comprehend, API Gateway, and Step Functions flows | ruby |
 | [Serverless Ruby Sqs Dynamodb](https://github.com/serverless/examples/tree/master/aws-ruby-sqs-with-dynamodb) <br/> A serverless ruby example that creates DynamoDB records with the usage of SQS, API Gateway, and AWS Lambda functions. | ruby |
 | [Aws Ruby Step Functions](https://github.com/serverless/examples/tree/master/aws-ruby-step-functions) <br/> Ruby example that make usage of AWS Step Functions with AWS Lambda, DynamoDB and Step Functions flows. | ruby |
+| [Aws Ruby Step Functions Express Workflow](https://github.com/serverless/examples/tree/master/aws-ruby-step-functions-express) <br/> Ruby example that make usage of AWS Step Functions Express Type with AWS Lambda, DynamoDB, Amazon SES, API Gateway, and Step Functions flows | ruby |
 | [Aws Rust Simple Http Endpoint](https://github.com/serverless/examples/tree/master/aws-rust-simple-http-endpoint) <br/> Example demonstrates how to setup a simple HTTP GET endpoint with rust | nodeJS |
 | [Azure Nodejs](https://github.com/serverless/examples/tree/master/azure-node-line-bot) <br/> Azure Functions sample for the Serverless framework | nodeJS |
 | [Azure Node Simple Http Endpoint](https://github.com/serverless/examples/tree/master/azure-node-simple-http-endpoint) <br/> An example of making http endpoints with the Azure Functions Serverless Framework plugin | nodeJS |

aws-ruby-step-functions-express/Gemfile

@@ -0,0 +1,3 @@
+source 'https://rubygems.org'
+
+gem 'aws-sdk-ses'

aws-ruby-step-functions-express/README.md

@@ -0,0 +1,207 @@
+<!--
+title: 'Ruby AWS Ruby Step Functions Express'
+description: 'Ruby example that make usage of AWS Step Functions Express Type with AWS Lambda, DynamoDB, Amazon SES, API Gateway, and Step Functions flows.'
+layout: Doc
+framework: v2
+platform: AWS
+language: Ruby
+authorLink: 'https://github.com/pigius'
+authorName: 'Daniel Aniszkiewicz'
+authorAvatar: 'https://avatars1.githubusercontent.com/u/8863200?s=200&v=4'
+-->
+# Serverless AWS Ruby Step Functions Express
+
+![diagram](./images/express-workflow-draw.png)
+
+
+This is an example of using `AWS Step Functions` `Express` Workflow Type. It uses `AWS Lambda`, `DynamoDB`, `Amazon SES`, `API Gateway` and `flows` from `Step Functions`.
+
+
+## Diagram
+
+![diagram](./images/stepfunctions_express_graph.png)
+
+It's a simple workflow, it adds the user to the database (`DynamoDB`) and if the save is successful, we send an email notification (`AWS Lambda` + `Amazon SES`). We also have error handling.
+
+![detailed-diagram](./images/express-diagram-visual.png)
+
+## Setup
+
+`npm install` to install all needed packages.
+
+## Deployment
+
+In order to deploy the service run:
+
+```bash
+sls deploy
+```
+
+for deploying with a specific `profile` (located in `~/.aws/credentials`) you can simply use the command:
+
+```bash
+AWS_PROFILE=YOUR_PROFILE_NAME sls deploy
+```
+
+for deploying to the specific stage, let's say `staging` do:
+
+```bash
+sls deploy --stage staging
+```
+
+The expected result should be similar to:
+
+```bash
+Serverless: Running "serverless" installed locally (in service node_modules)
+Serverless: Packaging service...
+Serverless: Excluding development dependencies...
+Serverless: Clearing previous build ruby layer build
+[ '2.2' ]
+Serverless: Installing gem using local bundler
+Serverless: Zipping the gemfiles to sls-examples/examples/aws-ruby-step-functions-express/.serverless/ruby_layer/gemLayer.zip
+Serverless: Configuring Layer and GEM_PATH to the functions
+✓ State machine "myStateMachine" definition is valid
+Serverless: Uploading CloudFormation file to S3...
+Serverless: Uploading artifacts...
+Serverless: Uploading service aws-ruby-step-functions.zip file to S3 (971.85 KB)...
+Serverless: Uploading service gemLayer.zip file to S3 (553.86 KB)...
+Serverless: Validating template...
+Serverless: Updating Stack...
+Serverless: Checking Stack update progress...
+................................
+Serverless: Stack update finished...
+Service Information
+service: aws-ruby-step-functions
+stage: dev
+region: eu-west-1
+stack: aws-ruby-step-functions-dev
+resources: 16
+api keys:
+  None
+endpoints:
+functions:
+  send-email: aws-ruby-step-functions-dev-send-email
+layers:
+  gem: arn:aws:lambda:your-region:XXXXXXXXXXX:layer:aws-ruby-step-functions-dev-ruby-bundle:2
+Serverless StepFunctions OutPuts
+endpoints:
+  POST - https://XXXXXXXXXXX.execute-api.your-region.amazonaws.com/dev/employees/add
+```
+
+
+## Prerequistes
+
+Make sure to validate `sender` and `recipient` emails within the `Amazon SES` (most likely for testing it, it will be one `email`):
+
+![verify-email](./images/verify-email.png)
+
+Later on within `serverless.yml` edit in `custom` section, both `sender` and `recipient`.
+
+## Usage
+
+There are two possible ways of invoking the example:
+
+## Via Api Gateway
+
+  After the deployment, grab the POST endpoint for this service. You can make a API call either by cURL or some tools like Postman.
+
+Use payload like:
+
+```json
+{ 
+  "id": "The name of the employee",
+  "jobTitle": "the name of the employee's position"
+}
+```
+As a response you will get:
+
+```json
+{
+    "executionArn": "arn:aws:states:your-region:XXXXXXXXXXX:express:add-employee-and-send-email-state-machine-dev:e9fcce40-0642-48cb-bd9a-4d3d9cea7bcc:da5ee796-5944-4426-9ca2-410a5003ceee",
+    "startDate": 1.62885382751E9
+}
+```
+
+![dynamo](./images/postman-express-step-functions.png)
+
+
+After it, you can then check the Dynamo database to see if a record has been created, and check the email.
+
+![dynamo](./images/dynamodb-results-express.png)
+
+![email](./images/email-express-step-functions.png)
+
+## Via AWS Dashboard
+
+After the deployment, go to the AWS Dashboard, and enter Step Functions page. You will see a newly created state machine.
+
+Open the state machine and click on `Start Execution`. You need to provide the input in the JSON schema.
+
+Example:
+
+``` JSON
+{
+ "id": "The name of the employee",
+ "jobTitle": "the name of the employee's position"
+}
+```
+
+Later on, simply start the excecution.
+
+After it, you can then check the Dynamo database to see if a record has been created, and check the email.
+
+
+Please keep in mind, that the `Express workflow` is different from the `Standard workflow`. Check the differences [here](https://docs.aws.amazon.com/step-functions/latest/dg/concepts-standard-vs-express.html). The main point here is the fact that you can't see all transitions between states. However, you can still use Workflow Studio.
+
+
+## Logs
+
+![logs](./images/metrics-express.png)
+
+
+By default, the logging is disabled. You can easily enabled it. The description is [here](https://www.serverless.com/plugins/serverless-step-functions#cloudwatch-logs).
+
+## Log retention
+
+The log retention is setup for 30 days. To change it simply change the value of this attribute in `serverless.yml` file:
+
+``` bash
+logRetentionInDays: 30
+```
+
+## Advanced configuration
+More options could be found in the plugin [repository](https://github.com/serverless-operations/serverless-step-functions).
+
+## Structure
+
+| Path                                          | Explanation                                                                                                                                                     |
+|-----------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `./src`                                       | All code for the project.                                                                                                                                       |
+| `./src/handlers/send-email`                   | Handler for lambda.                                                                                                                                             |
+| `./src/common/`                               | Space for common, reusable pieces of code.                                                                                                                      |
+| `./src/common/adapters/ses_adapter.rb`        | Adapter for the Amazon SES with the usage of AWS SDK for Ruby. Only used for sending emails.                                                                    |
+| `./src/common/services/send_email_service.rb` | The service object pattern is widely used within ruby/rails developers. A class that is responsible for doing only one thing. In our case is creating an email. |                                                                             |
+                                                                                                       
+## Serverless plugins
+
+For this example, there are two serverless plugins used:
+
+| Plugin                | Explanation                                                                                    |
+|-----------------------|------------------------------------------------------------------------------------------------|
+| [serverless-ruby-layer](https://www.npmjs.com/package/serverless-ruby-layer) | For bundling ruby gems from `Gemfile` and deploys them to the lambda layer.                      |
+| [serverless-step-functions](https://www.npmjs.com/package/serverless-step-functions)       | Serverless Framework plugin for AWS Step Functions. |
+
+## Ruby gems
+
+| Gem                | Explanation                                                                                                                    |
+|--------------------|--------------------------------------------------------------------------------------------------------------------------------|
+| `aws-sdk-ses` | It's a part of the AWS SDK for Ruby. Used for Amazon SES, in the case of this example - sending emails.          |
+
+## Remove service
+
+To remove the service do:
+
+```bash
+sls remove
+```
+And the stack will be removed from the AWS.