JavaScript SDK for CloudEvents

The CloudEvents SDK for JavaScript.

Status

This SDK is still considered a work in progress.

This SDK current supports the following versions of CloudEvents:

• v1.0

Checkout the changelog to see what's going on!

Installation

This CloudEvents SDK requires nodejs 6.11+

Nodejs

npm install cloudevents-sdk

Specification Support

These are the supported specifications by this version.

Specifications	v0.3	v1.0
CloudEvents	yes	yes
HTTP Transport Binding - Structured	yes	yes
HTTP Transport Binding - Binary	yes	yes
JSON Event Format	yes	yes

What we can do

What	v0.3	v1.0
Create events	yes	yes
Emit Structured events over HTTP	yes	yes
Emit Binary events over HTTP	yes	yes
JSON Event Format	yes	yes
Receive Structured events over HTTP	yes	yes
Receive Binary events over HTTP	yes	yes

How to use

Usage

const v1 = require("cloudevents-sdk/v1");

/*
 * Creating an event
 */
let myevent = v1.event()
  .type("com.github.pull.create")
  .source("urn:event:from:myapi/resource/123");

Formatting

const v1 = require("cloudevents-sdk/v1");

/*
 * Creating an event
 */
let myevent = v1.event()
  .type("com.github.pull.create")
  .source("urn:event:from:myapi/resource/123");

/*
 * Format the payload and return it
 */
let formatted = myevent.format();

Emitting

const v1 = require("cloudevents-sdk/v1");

/*
 * Creating an event
 */
let myevent = v1.event()
  .type("com.github.pull.create")
  .source("urn:event:from:myapi/resource/123");

// The binding configuration using POST
let config = {
  method: "POST",
  url   : "https://myserver.com"
};

// The binding instance
let binding = new v1.StructuredHTTPEmitter(config);

// Emit the event using Promise
binding.emit(myevent)
  .then(response => {
    // Treat the response
    console.log(response.data);

  }).catch(err => {
    // Deal with errors
    console.error(err);
  });

Receiving Events

You can choose any framework for port binding. But, use the StructuredHTTPReceiver or BinaryHTTPReceiver to process the HTTP Payload and HTTP Headers, extracting the CloudEvents.

😃 Checkout the full working example: here.

// some parts were removed //

const v1 = require("cloudevents-sdk/v1");

const receiver = new v1.StructuredHTTPReceiver();

// some parts were removed //

app.post("/", (req, res) => {
  try {
    let myevent = receiver.parse(req.body, req.headers);

    // TODO use the event

    res.status(201).send("Event Accepted");

  } catch(err) {
    // TODO deal with errors
    console.error(err);
    res.status(415)
          .header("Content-Type", "application/json")
          .send(JSON.stringify(err));
  }
});

Unit Testing

The unit test checks the result of formatted payload and the constraints.

npm test

The API

CloudEvent class

/*
 * Format the payload and return an Object.
 */
Object CloudEvent.format()

/*
 * Format the payload as String.
 */
String CloudEvent.toString()

Formatter classes

Every formatter class must implement these methods to work properly.

/*
 * Format the CloudEvent payload argument and return an Object.
 */
Object Formatter.format(Object)

/*
 * Format the CloudEvent payload as String.
 */
String Formatter.toString(Object)

Parser classes

Every Parser class must implement these methods to work properly.

/*
 * The default constructor with Parser as decorator
 */
Parser(Parser)

/*
 * Try to parse the payload to some event format
 */
Object Parser.parse(payload)

Spec classes

Every Spec class must implement these methods to work properly.

/*
 * The constructor must receives the CloudEvent type.
 */
Spec(CloudEvent)

/*
 * Checks the spec constraints, throwing an error if do not pass.
 * @throws Error when it is an invalid event
 */
Spec.check()

/*
 * Checks if the argument pass through the spec constraints
 * @throws Error when it is an invalid event
 */
Spec.check(Object)

Binding classes

Every Binding class must implement these methods to work properly.

Emitter Binding

Following we have the signature for the binding to emit CloudEvents.

/*
 * The constructor must receives the map of configurations.
 */
Binding(config)

/*
 * Emits the event using an instance of CloudEvent.
 */
Binding.emit(cloudEvent)

Receiver Binding

Following we have the signature for the binding to receive CloudEvents.

/*
 * The constructor must receives the map of configurations.
 */
Receiver(config)

/*
 * Checks if some Object and a Map of headers
 * follows the binding definition, throwing an error if did not follow
 */
Receiver.check(Object, Map)

/*
 * Checks and parse as CloudEvent
 */
CloudEvent Receiver.parse(Object, Map)

Versioning

• x.M.p: where x relates to spec version, M relates to minor and p relates to fixes. See semver

Community

• There are bi-weekly calls immediately following the Serverless/CloudEvents call at 9am PT (US Pacific). Which means they will typically start at 10am PT, but if the other call ends early then the SDK call will start early as well. See the CloudEvents meeting minutes to determine which week will have the call.
• Slack: #cloudeventssdk channel under CNCF's Slack workspace.
• Email: https://lists.cncf.io/g/cncf-cloudevents-sdk
• Contact for additional information: Fabio José (@fabiojose on slack).