Responding to Device Events

In the ever-expanding world of IoT, where devices are becoming increasingly interconnected and intelligent, efficient communication between these devices and systems is paramount. This chapter delves deep into the fundamental concepts of Event Grid, a powerful service that plays a pivotal role in orchestrating the flow of information within IoT ecosystems. From understanding Event Grid’s core principles to mastering the art of subscribing to and responding to events, we embark on a journey that equips you with the knowledge and skills needed to manage and monitor IoT events effectively.

Our exploration begins with understanding Event Grid fundamentals, where we lay the groundwork for comprehending this essential service’s architecture and components. We delve into the inner workings of Event Grid, discussing its role in facilitating seamless communication between IoT devices and the cloud.

Next, we transition to exploring common IoT events...

Event Grid versus Event Hubs

The difference between an event grid and an event hub can be confusing. Event Grid and Event Hubs are both event-driven services in Azure, but they serve different purposes and have distinct characteristics. Here are the key differences between Event Grid and Event Hubs:

• Purpose and use cases:
  • Event Grid: Event Grid is a fully managed event routing service that simplifies event-driven programming and enables you to build applications that respond to events from various Azure services and custom sources. It is designed for distributing events to multiple subscribers in near real time. Event Grid is well suited for scenarios where you want to react to events and trigger specific actions, such as sending notifications, updating data, or triggering workflows based on events.
  • Event Hubs: Event Hubs is a highly scalable data streaming platform and event ingestion service that is primarily used for ingesting, collecting, and processing large volumes of data...

Understanding Event Grid fundamentals

In the realm of IoT and event-driven architectures (EDAs), understanding the core principles of Event Grid is essential. Event Grid serves as the backbone for managing and orchestrating events within an ecosystem of interconnected devices and services. This section provides a comprehensive overview of Event Grid’s fundamentals, including its architecture, key components, and how it enables seamless communication between IoT devices and cloud services.

Event Grid architecture

Event Grid operates on a publish-subscribe (pub-sub) model, allowing for the decoupling of event producers and consumers. This architecture ensures that events generated by IoT devices can be efficiently delivered to interested parties without these devices needing to be aware of who or what is consuming their data. Here are the key components of Event Grid’s architecture:

• Event publishers: These are the sources of events, which can be IoT devices...

Exploring common IoT events

In an IoT environment, a wide range of events can be sent to an event grid to enable real-time communication, data processing, and automation. Here are some common IoT events that are typically sent to an event grid:

• Sensor data updates: This is one of the most common types of IoT events. It includes data from various sensors such as temperature, humidity, light, motion, and more. These updates can trigger actions such as alerts, data storage, or analytics.
• Device status changes: Events indicating changes in the status of IoT devices, such as device startup, shutdown, reboot, or connectivity status changes. These events can help in monitoring and managing the health of IoT devices.
• Alarm and alert events: IoT devices often generate events when certain thresholds or conditions are met. For example, a smoke detector might send an event when it detects smoke, or a security camera might trigger an event when it detects motion.
• Device firmware...

Sending IoT events to Event Grid

One thing to remember is that Event Grid is used for any type of event-based processing in Azure. It can facilitate events from many different Azure services. Some common services are storage, functions, and web applications.

Azure IoT Hub seamlessly integrates with Azure Event Grid, allowing you to effortlessly dispatch event notifications to various services and initiate subsequent workflows. By configuring your business applications to actively monitor IoT Hub events, you can respond to pivotal occurrences with utmost reliability, scalability, and security. For instance, envision the creation of an application that automatically updates a database, generates a work ticket, and dispatches email notifications whenever a new IoT device is registered within your IoT hub.

To set up an event, navigate to the service providing the event (in our case, IoT Hub) and select the Events option in the menu:

Figure 12.2 – Setting...

Responding to events

The next step is to define an endpoint, which is the event handler that is responsible for processing an event. Currently, you can select quite a few handlers depending on how you plan on reacting to the event, as seen here:

Figure 12.3 – Selecting an endpoint

You can also put filtering on your events. Filtering events from an Azure IoT hub can be a valuable tool for managing and processing IoT data efficiently. Here are some reasons why you might want to use filtering for IoT Hub events:

• Reducing data volume: IoT devices can generate a massive amount of data, and not all of it may be relevant to your specific use case. Filtering allows you to discard or route only the events that meet certain criteria, reducing the volume of data that needs to be processed and stored. This can help save on data storage costs and processing resources.
• Selective routing: Filtering enables you to route specific types of IoT events to different...

Subscribing and responding to IoT Hub events

Responding to IoT Hub events typically involves creating event handlers or subscribers that can process events generated by IoT devices and take appropriate actions. Here is some guidance on how to respond to IoT Hub events:

• Create event handlers:
  • Decide how you want to respond to IoT Hub events. Common response actions include storing data, sending alerts, performing analytics, or triggering downstream processes.
  • Choose Azure services or custom applications that will act as event handlers or subscribers for IoT Hub events. Some common choices include Azure Functions, Azure Logic Apps, Azure Stream Analytics (ASA), and custom applications.
• Azure Functions:
  • If you’re using Azure Functions as your event handler, create a new Azure function or use an existing one.
  • Configure an Event Hubs trigger or IoT Hub trigger in your Azure function to listen for events from your IoT hub.
  • Implement the desired processing logic in your Azure...

Lab – monitoring device connection and disconnection with Event Grid

In this lab, we will create an automated email when a device connects or disconnects from an IoT hub:

1. In a new resource group, create an IoT hub.
2. On the menu for the IoT hub, select the Events option.

   On the Events page, you can see some examples of event consumers:

Figure 12.6 – Natively supported event handlers

3. Select the Logic Apps option. This will open the Logic Apps Designer page with a connection to the Event Grid service:

Figure 12.7 – Creating a logic app to respond to the event

4. Sign in to the Event Grid service. Select the Continue button after signing in.
5. Select Microsoft.Devices.IoTHubs as the resource type and select Microsoft.Devices.DevicesConnected as the event type. Enter a value (of your choice) for the Subscription name:

Figure 12.8 – Filling out the necessary...

Summary

In this chapter, we embarked on a journey through the intricacies of Event Grid, focusing on its pivotal role in managing IoT events effectively. We began by establishing a solid foundation in the fundamentals of Event Grid, gaining insight into its architecture, key components, and the seamless communication it facilitates between IoT devices and cloud services.

Next, we delved into the rich use cases of common IoT events, uncovering the diverse range of events that populate the IoT landscape. These events, from sensor data updates to device status changes, form the lifeblood of IoT systems and lay the groundwork for responsive, intelligent applications.

Our exploration continued as we ventured into subscribing to events. Here, we learned how to create event subscriptions, configure event filters, and choose the appropriate delivery methods to ensure that IoT events are routed precisely where they are needed. With this knowledge, you’re now equipped to fine-tune...