In the Azure IOT Hub Client telemetry sample there are two calls you can make that are commented out:
// Set Message property
/*(void)IoTHubMessage_SetMessageId(message_handle, "MSG_ID");
(void)IoTHubMessage_SetCorrelationId(message_handle, "CORE_ID");
...
*/
https://github.com/Azure/azure-iot-sdk-c/blob/master/iothub_client/samples/iothub_ll_telemetry_sample/iothub_ll_telemetry_sample.c
I understand I can pass strings into these calls in a certain format.
But what is their use case in Azure?
What should go into these fields to best help the user process the telemetry in Azure IoT Hub?
This page tells me the format of message id, not much guidance:
https://learn.microsoft.com/en-us/azure/iot-hub/iot-hub-devguide-messages-construct
IoT Hub is one of the first Azure services to support distributed tracing. As more Azure services support distributed tracing, you'll be able trace IoT messages throughout the Azure services involved in your solution.
Enabling distributed tracing for IoT Hub gives you the ability to:
Precisely monitor the flow of each message through IoT Hub using trace context. This trace context includes correlation IDs that allow you to correlate events from one component with events from another component. It can be applied for a subset or all IoT device messages using device twin.
Automatically log the trace context to Azure Monitor diagnostic logs.
Measure and understand message flow and latency from devices to IoT Hub and routing endpoints.
Start considering how you want to implement distributed tracing for the non-Azure services in your IoT solution.
here you can find more.
Related
I have an Azure IoT device connected to an Azure IoT Hub. The device sends 6 - 7 messages per minute. By looking at the D2C message metrics, I found an outlier, that states that at a specific time, the count of the D2C message was zero (see picture). As the messages are routed to a storage, I can check the storage to see if there are messages missing at that specific time, but the data saved in the storage shows that every message was received correctly at that time. Does any one know how that comes or if the metrics are not that reliable generally? If that's the case, what is the best practice to monitor the IoT Hub message transfer?
IoT Hub D2C Message Metrics
EnqueuedTimeUtc in the storage
For precisely monitor the flow of each message through IoT Hub you will need to Trace Azure IoT device-to-cloud messages with distributed tracing (currently in preview)
This trace context includes correlation IDs that allow you to correlate events from one component with events from another component
Automatically log the trace context to Azure Monitor Logs.
Measure and understand message flow and latency from devices to IoT Hub and routing endpoints.
Ref: https://learn.microsoft.com/en-us/azure/iot-hub/iot-hub-distributed-tracing
Right now, on IoT Hub there is an information that limit for messages per day 8000. I would like to ask you about any patterns which are being used in Azure.
I am curious if I am able to hit to Azure with some service outside Messages in order to prevent it from being overloaded by big amount of data, or save some confidentiality for this service.
For example, I would like to store some data from given service to Messages that are not being confidential and other data by using some WebSocket or any Rest protocol. I think that there are some patterns that serve that scenarios.
Does anyone has experience with that kind of situation?
Not everything needs to go through IoT Hub. IoT Hub is great for two way communication to/from IoT devices. You could also look at Event Hubs for ingestion from devices that don't need two way comms. We have a write up on the differences here Connecting IoT Devices to Azure: IoT Hub and Event Hubs.
In my case I have 1000+ of devices that stores activity inside. I need to send a http get request to this device to get those data in csv or json format and save it in a storage hosted on azure.
Cab IOT hub require data using get request and can it be scheduled to read daily/weekly?
What other azure services would you suggest to facilitated this scheduled reads?
You have not mentioned which the Azure IoT Hub scale tier is used. Basically there are two price groups such as Basic and Standard with a significant different cost and capabilities. The Basic tier offers only services for one-way communications between the devices and Azure IoT Hub.
Based on that, the following scenarios can be used for your business case:
1. Basic Tier (non event-driven solution)
The device pushs periodicaly a telementry and non-telemetry messages based on the needs to the Azure IoT Hub, where the non-telemetry messages are routed to the Azure Function via the Service Bus Queue/Topic. Responsibility for this non-telemetry pipe is to persist a real device state in the database. Note, that the 6M messages will cost only $50/month. The back-end application can any time to query this database for devices state.
2. Standard Tier (event-driven solution) In this scenario you can use a Device Twin of the Azure IoT Hub to enable storing a real-device state in the cloud-backend (described by #HelenLo). The device can be triggered by C2D message, changing a desired property, invoking a method or based on the device edge trigger to the action for updating a state (reported properties).
The Azure IoT Hub has a capabilities to run your scheduled jobs for multiple devices.
In this solution, the back-end application can call any time a job for ExportDevicesAsync to the blob storage, see more details here. Note, that the 6M messages will cost $250/month.
As you can see the above each scenario needs to build a different device logic model based on the communications capabilities between the devices and Azure IoT Hub and back. Note, there are some limitations for these communications, see more details here.
You can consider using Device Twin of IoT Hub
https://learn.microsoft.com/en-us/azure/iot-hub/iot-hub-devguide-device-twins
Use device twins to:
Store device-specific metadata in the cloud. For example, the deployment location of a vending machine.
Report current state information such as available capabilities and conditions from your device app. For example, a device is connected to your IoT hub over cellular or WiFi.
Synchronize the state of long-running workflows between device app and back-end app. For example, when the solution back end specifies the new firmware version to install, and the device app reports the various stages of the update process.
Query your device metadata, configuration, or state.
IoT Hub provides you with the ability to connect your devices over various protocols. Preferred protocols are messaging protocols, such as MQTT or AMQP, but HTTPS is also supported. Using IoT hub, you do not request data from the device, though. The device will send the data to the IoT Hub. You have to options to implement that with IoT Hub:
The device connects to the IoT Hub whenever it has some data to be sent, and pushes the data up to IoT Hub
The device does not send any data on its own, but stays always or at least regularly connected to IoT Hub. You then can send a cloud to device message over IoT Hub to the device, requesting the data to be sent. The device then sends the data the same way it would in the first option.
When the data then has been sent to IoT Hub, you need to push it somewhere where it is persistently stored - IoT Hub only keeps messages for 1 day by default. Options for this are:
Create a blob storage account and push to that directly from IoT Hub using a custom endpoint This would probably be the easiest and cheapest. Dependening on how you need to access your data, a blob might not be the best option, though
Create a function app, create a function with an EventHubTrigger, connect it to IoT Hub and let the function process incoming data by outputting it into any kind of data sink, such as SQL, CosmosDB, Table Storage...
in our usecase, we receive messages on Azure IoT Hub, and would like to route the data to different Event Hubs or Service Bus topics.
IoT Hub routes and endpoints are no option, because the data is binary data (protobuf), and there are only 10 different endpoints possible (we need more).
Our requierements are:
Splitting the message
Transform the data (maybe json)
Routing to different endpoints based on the payload (different parts of message could be routed to different endpoints)
(optional) enrich the data with additional payload
I see different options:
Azure Stream Analytics
Azure Functions
Spark or Flink
Do it yourself (write an Application and run it in Service Fabric or Kubernets)
Which techology would you recommend?
Regards,
Markus
There is also another option for your scenario such as using an Azure Event Grid. In this case, the telemetry data from the Azure IoT Hub are pushed to the Event Grid via its custom topic endpoint. Note, that there is a limit for the event message such as 64KB, see more details here.
The Event Grid allows to subscribe unlimited number of the Event Hubs, more details about the Event Grid are here and here.
Based on the above, the following screen snippet shows your another option for routing a small telemetry data to more than 10 Event Hubs, basically to any kind of subscriber.
I would like to get some recommendation, for designing a routing of IoT messages in Azure.
I have following scenario:
Senors sending messages to Azure IoT Hub in Google Protobuf format. Depending of the type of a message, I want to route the message to different applications inside a service fabric.
My current approach is to use a service fabric application to receive all messages from the IoT hub, parse the protobuf message, send the message depending on their type (attribute inside the protobuf) to an type-specific Azure event hub. Now the applications fetches the messages from their "own" event hub and process the messages.
I'm not sure if this is the best approach. I don't like the fact, to have one event hub for each type of message. Service Bus Topics are probably not an option, because I have a lot of messages (~30k per second).
Do I realy need a event hub, to decoupling this process, or does it make sense, to send the messages from the "routing application" direct to the different "type applications"?
What do you think?
Regards,
Markus
If you really need high performance you should take a look at IoT Hub and Event Hubs. Azure Event Hubs is a highly scalable data streaming platform and event ingestion service capable of receiving and processing millions of events per second. Event Hubs can process and store events, data, or telemetry produced by distributed software and devices. Data sent to an event hub can be transformed and stored using any real-time analytics provider or batching/storage adapters.
In other hand if you need only 30k messages per second you can go with Premium Messaging.
Comparison of Azure IoT Hub and Azure Event Hubs
Premium Messaging: How fast is it?
What is Event Hubs?