Event Manager

Introduction

Aurras is a middleware that acts as an event processor and a low code workflow orchestration platform. Aurras is being pitched as a next-generation system for enabling decentralized push notification. This middleware solution listens to events from blockchain applications and propagates them to a registered pool of MQTT brokers. The broader architecture consist of parachain from which the middleware listens for the events.

The Event Manager as a core component of aurras system is composed of multiple actions including using a database to store trigger URLs and their respective auth, and Kafka provider, consumer, and producer. Once the event manager receives an event from the event feed, this data is produced to a topic. The feed action in the manager lets the user hook into the system. That is, once an event is indexed to a particular topic, it can invoke a particular action. While creating the workflow, users can choose the event trigger as feed and provide necessary parameters from which chain it should be listening to.

Architecture

Components

1. Event Sources
   Event Feeds sources events from numerous sources to aurras system. Events can come from different blockchains or IoT devices or external services for which workflow need to executed. Event Manager registers Event feeds after which the aurras system will be listening for events from the registered sources. Below are the available event sources

   • Substrate Event Feed

2. Event Manager (Core)
   Event manager is composed of multiple actions including using a database to store trigger URLs and their respective auths, and Kafka provider, consumer and producer. Once the event manager receives an event from the event feed, this data is produced to a topic. The feed action in the trigger manager lets the user hook into the system. That is, once an event is indexed to a particular topic, it can invoke a particular action. While creating the workflow, users can choose the event trigger as feed and provide necessary parameters from which chain it should be listening to and from which block it should start listening. Under the hood, a feed action is invoked with create lifecycle, which accepts the mandatory parameters the lifecycle, auth, trigger name, and other optional parameters of the event source. The feed action invokes the related actions of creating the entry in the database, adding to the Kafka consumer group, etc. The next component in the event trigger manager is a persistent connection to Kafka where it is used to produce and consume the stream of data. Once data is received in Kafka, the event trigger manager invokes the action to check the consumer groups for that particular topic and if found any, the trigger for the users under that particular group is invoked, which in turn invokes the workflow action.

3. Workflow Composer
   Workflow composer consists of an async Rust library to compose multiple triggers, deployment configuration generator, and whisk deployment tool. For creating the workflow, the only input is the configuration file which is a YAML file. The workflow composition is laid out in the YAML which in turn takes care of the deployment and composing the triggers. Once a workflow is deployed to a namespace it creates a specific topic unique workflow id in Kafka. Workflow configuration comprises the input URL of workflow tasks, primarily GitHub repo, the sequence of processing tasks, and argument structure. Arguments must match the task input parameters.

4. Web API Gateway and Backend Service
   This is the end user facing component to utilize the workflow. This component comprises of a backend application which is responsible for user registration, selecting the workflow, managing / creating workflow using friendly APIs, providing input parameters. API gateway / Machine gateway where the external world can connect to the Aurras system.

Prerequisites

1. Openwhisk
2. Openwhisk CLI

Components

Actions

• Event Register
• Event Receiver
• Event Processor
• Event Producer
• Kafka Provider
• Balance Filter
• Balance Notification Register
• Push Notification
• Substrate Event Processor
• User Login
• User Registration
• Workflow Invoker
• Workflow Management
• Workflow Registration

Installation

Assuming basic dependency such as git and yarn already installed.

1. Clone the repository

git clone https://github.com/HugoByte/aurras.git

2. Navigate to the cloned directory

cd aurras

3. Generate server token from https://console.firebase.google.com/project/<PROJECT_NAME>/settings/cloudmessaging and add as env FIREBASE_API_KEY

4. Deploy the actions using the deploy script. The script supports optional parameters which can be found here.

./deploy.sh

Usage

Generate Event Registration ID

./register_event_source.sh --name "Node Template Balance"

Testing

Run Unit test suites

Please fetch the Push Notification Token using examples/substrate-push-notification Image and add to TEST_DEVICE_TOKEN Environment Variable

To test push-notification action it is required to have a push notification token generated from the client and Firebase API Key in TEST_DEVICE_TOKEN and FIREBASE_API_KEY environment variable respectively

cargo test --all-features

Known Issues

• error: Invalid argument(s). Unable to get action '<ACTION_NAME>': The connection failed, or timed out. (HTTP status code 502)

  This can be due to openwhisk not started completely. Please see issue #18

License

Licensed under Apache-2.0