This example shows a simple way to deploy a service to the Event Gateway. It uses the hosted version provided by Serverless, Inc. -- reach out if you'd like an invite!

This service will deploy three functions:

• createUser: an HTTP endpoint for creating and storing a User in a DynamoDB table;
• getUser: an HTTP endpoint for retrieving a User from DynamoDB; and
• addUserToCRM: a function that is triggered by a user.created event and stores new users in a CRM system.

The createUser function allows you to create a new User by sending a JSON payload to /users, and the getUser function lets you retrieve that User by making a GET request to /users/{id}.

In the createUser function, we're using the Event Gateway SDK to emit a custom event of user.created into the Event Gateway. You can then subscribe functions to react to this custom event. The addUserToCRM function is subscribed to this event as an example -- imagine a Marketing department that wants to store newly-created Users in a CRM.

Let's get started!

1. Clone this repository and install the packages:

   $ git clone https://github.com/serverless/event-gateway-getting-started.git $ cd event-gateway-getting-started $ npm install $ npm install -g serverless

2. Update the eventgateway section of the custom block in serverless.yml:

   # serverless.yml custom: eventgateway: url: <yourAppURL> # <-- Add your App URL, e.g. myorg-app.slsgateway.com accessKey: <yourAccessKey> # <-- Add your Access key

3. Deploy your service

   $ serverless deploy ... Service Information service: eg-quickstart stage: dev region: us-east-1 stack: eg-quickstart-dev api keys: None endpoints: None functions: getUser: eg-quickstart-dev-getUser createUser: eg-quickstart-dev-createUser addUserToCRM: eg-quickstart-dev-addUserToCRM Event Gateway Plugin EventGateway: Function "createUser" registered. (ID: eg-quickstart-dev-createUser) EventGateway: Function "getUser" registered. (ID: eg-quickstart-dev-getUser) EventGateway: Function "addUserToCRM" registered. (ID: eg-quickstart-dev-addUserToCRM) EventGateway: Function "createUser" subscribed to "http" event. EventGateway: Function "addUserToCRM" subscribed to "user.created" event. EventGateway: Function "getUser" subscribed to "http" event.

4. Create a new user by hitting the createUser endpoint:

   $ APP="<appURL>" $ curl -X POST -H "Content-Type: application/json" https://${APP}/users \ --data '{ 	"id": "10", 	"firstName": "Donald", 	"lastName": "Duck", 	"email": "donald.duck@disney.com"  }' {"id":10,"firstName":"Donald","lastName":"Duck","email":"donald.duck@disney.com"}

5. You can now retrieve your user by using the getUser endpoint:

   $ APP="<appURL>" $ curl -X GET https://${APP}/users/10 {"id":"10","email":"donald.duck@disney.com","firstName":"Donald","lastName":"Duck"}

6. In your createUser code, it emits a user.created event to the Event Gateway, which triggers the addUserToCRM function. You can check the logs for that function to see that it ran:

   $ sls logs -f addUserToCRM -t START RequestId: 0ccf992b-39dc-11e8-b35d-735763392802 Version: $LATEST 2018-04-06 20:49:50.917 (+00:00)	0ccf992b-39dc-11e8-b35d-735763392802 Received user.created event with user: { email: 'donald.duck@disney.com', firstName: 'Donald', id: '10', lastName: 'Duck' } END RequestId: 0ccf992b-39dc-11e8-b35d-735763392802 REPORT RequestId: 0ccf992b-39dc-11e8-b35d-735763392802 Duration: 5.15 ms	Billed Duration: 100 ms	Memory Size: 1024 MB	Max Memory Used: 32 MB

   Nice! We can see our logs from the triggered function.

7. If you'd like to test emitting events into the Gateway, you can use the sls gateway emit command:

   $ sls gateway emit --event "user.created" --data "$(cat event.json)" Event emitted: user.created Run `serverless logs -f <functionName>` to verify your subscribed function was triggered.

   Again, you can check your logs with sls logs -f addUserToCRM -t to check the behavior of your function.

Now that you know the basics of using the Event Gateway, let's cover some concepts:

• Events: Events are bits of data that indicate something happened. This could be an HTTP request ("a client requested the resource at path /users/15") or it could be a custom event emitted from your application ("a user was created with the following details...").

• Functions: Functions are bits of logic that operate on individual events. A function may be a Lambda function that reads the event and posts a message in Slack. It could also be a "connector" function that sends your event directly to another system, such as into Firehose for analytics or into SQS for transactional message processing.

• Subscriptions: Subscriptions tie functions and events together. Think "If this, then that" for data and compute. "If I get a user.created event, then execute my function to save a new user to our CRM."

• Space: Spaces are a logical unit of isolation within the Event Gateway. Your functions and subscriptions are registered within a particular space and may only interact with other elements in their space.

  With the hosted Event Gateway, you will create Apps. Each App receives a fully-qualified domain name to be used with the Event Gateway, such as https://myorg-dev.slsgateway.com. Each App maps to a Space within the Event Gateway and will be fully isolated from all other Apps.

• Event Gateway Repository
• Event Gateway plugin for the Serverless Framework
• Event Gateway SDK for interacting with the Event Gateway in your application code