Creation Time Utc

[Hinton]

• OS and version used: Windows 10

• SDK version used: 1.6.2

Description of the issue:

The C# SDK supports setting a CreationTimeUtc property on the Microsoft.Azure.Devices.Client.Message class, which afterwards shows up in the Event Hub endpoint of the IoT Hub as iothub-creation-time-utc.

I've been unable to find any references to this property in the IoT Hub documentation or in the other SDKs (C, Node.js). Is this an official supported property, and the best practice for sending the timestamp of the message?

Code sample exhibiting the issue:

using (DeviceClient iotClient = DeviceClient.Create(config.IoTHub, auth))
{
    var message = new Message(Encoding.ASCII.GetBytes("{}"));
    message.CreationTimeUtc = DateTime.UtcNow;
    await iotClient.SendEventAsync(message);
}

[CIPop]

@tameraw @pierreca @jspaith Is this property supported / planned on the Node and C SDKs? If not, is there a workaround?

Is this an official supported property, and the best practice for sending the timestamp of the message?

@yzhong94 @simonporter PTAL

[pierreca]

Doesn't look like the Node SDK supports it. is this something we should add to the backlog?

[yzhong94]

@Hinton Can you give some details on your use case for setting CreationTimeUtc? Do you need it for downstream processing or for debugging?

[Hinton]

@yzhong94 In our use case, the IoT device may be offline for some periods, during which we continue to collect telemetry data. Once the device gets connectivity to Azure IoT Hub we stream up the collected telemetry. This requires us to also send the timestamp of when the telemetry was collected.

So it's primarily for downstream processing but could also be useful for debugging.

[CIPop]

@Hinton please use the support options or equivalents in the C and NodeJS repos to track this request.

@dominicbetts / @yzhong94 please add the following system property documentation within https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-devguide-messages-construct :
https://github.com/Azure/azure-iot-sdk-csharp/blob/cd93e75fd8914b6247f23eb6a5cfd7aea459676f/iothub/device/src/MessageSystemPropertyNames.cs

[dominicbetts]

@CIPop - I've merged the doc change -it'll be published later today. I don't have permission to close this issue - can you do it? Thanks

[CIPop]

Thanks @dominicbetts !