On the Microsoft Azure public cloud, Azure Functions is a serverless computing solution. Serverless computing, in general, and Azure Functions, in particular, are intended to speed up and simplify application development. Both Azure IoT Central and Azure IoT Hub solution accelerators use Azure IoT Hub as their fundamental Azure PaaS. IoT Hub allows millions of IoT devices to communicate with a cloud solution in a reliable and secure manner.
Various Functions of Azure IoT Hub are:
Scaling
A single EventProcessorHost instance supports each instance of an event-triggered function. Only one Event Processor Host instance may acquire a lease on a particular partition, thanks to the trigger (driven by Event Hubs). It is not necessary to create new function instances: Function 0 can handle all 1,000 events before the scaling logic of the Function kicks in. Function 0 processes all 1,000 messages in this scenario.
A new function app instance is generated if the Functions scaling logic finds that Function 0 has more messages than it can process. This new function has an EventProcessorHost object attached to it. When the underlying Event Hubs detect a new host instance attempting to read messages, the partitions are load-balanced between the host instances. For example, Function 0 may be assigned to partitions 0-4 and Function 1 to partitions 5-9.
If the Functions scaling logic finds that both Function 0 and Function 1 have more messages to process than they can handle, more Functions N function app instances are launched. Apps are developed until the number of event hub partitions N exceeds the number of apps. Event Hubs load balances the partitions in our example, this time across the instances Function 0…Functions 9.
N instances become bigger than the number of event hub divisions when scaling happens. This approach is used to guarantee that EventProcessorHost instances are accessible to get locks on partitions when additional instances become available. When the function instance executes, you are only charged for the resources needed. Checkpoints are added to the corresponding storage account once all functions have been completed (with or without faults). When check-pointing is successful, all 1,000 messages are lost forever.
Annotations and attributes
Use the EventHubTriggerAttribute property in C# class libraries. The event hub name, consumer group, and the name of an app setting that includes the connection string are sent to the attribute’s function Object() { [native code] }. See the trigger setup section for further details on these options. App settings are saved in the local.settings.json file while developing locally.
Connections
The connection attribute is a reference to the app’s environment setup, which determines how it should connect to Event Hubs. It may state:
The name of a connection string-containing application setting. The name of a common prefix that may be used by several applications to define an identity-based relationship. The exact match is utilized if the specified value is both an exact match for a single parameter and a prefix match for additional settings.
Connection string
Click the Connection Information button for the namespace, not the event hub itself, to get this connection string. Not the event hub itself, but an Event Hubs namespace must be used in the connection string.
To activate the function, the connection string must have at least “read” permissions when used for triggers. To transmit messages to the event stream, the connection string must have “send” permissions when used for output bindings. This connection string should be saved in an application setting with a name that matches the value supplied by the binding configuration’s connection property.
Connections based on identity
Instead of utilizing a connection string with a secret, you may have the app utilize an Azure Active Directory identity if you’re using version 5.x or above of the extension. To do this, create settings with a common prefix that corresponds to the connection attribute in the trigger and binding setup.
To personalize the connection, further attributes can be specified. For identity-based links, see Common characteristics.
Identity-based connections employ a managed identity when hosted in the Azure Functions service. The system-assigned identity is used by default, however, the credential and clientID attributes can be used to provide a user-assigned identity. Your developer identity is used instead in other scenarios, such as local development, however, this may be adjusted.
Give the identity authorization
Permissions to conduct the required actions must be granted to whichever identity is being used. You’ll need to assign a role to grant those rights in Azure RBAC, either using built-in or custom roles.
You’ll need to construct a role assignment that gives you runtime access to your event hub. The role assignment must cover an Event Hub’s namespace rather than the event hub itself. Management positions such as Owner are insufficient. The table below lists the built-in roles that are suggested for routine use of the Event Hubs extension. Depending on the code you write, your application may require extra permissions.
Relationship Between MQTT and Azure IoT Hub
In recent years, MQTT has become one of the most popular protocols for IoT applications. Because of its publish and subscribe strategy, MQTT’s adaptability allows it to support a wide range of use cases and IoT project designs. Because the broker controls all connections, the system’s publishers and subscribers don’t even need to be aware of each other’s existence.
The protocol facilitates the implementation of large-scale projects, possibly connecting millions of IoT devices in a single system. Because MQTT is bidirectional, you can transmit messages to a large number of devices simultaneously.
Conclusion
Azure IoT Hub has a lot of features. All of the main functions are discussed in the article. Microsoft’s Azure IoT Hub is a cloud-based Internet of Things connection. It’s a fully managed cloud service that allows millions of IoT devices to communicate with a solution back end in a dependable and secure manner. Telemetry data from your devices to the cloud inform you of the status of your assets.
