How to set device's twin properties without Etag?

Question

I am using the API:

RegistryManager.UpdateTwinAsync(string deviceId, Twin twinPatch, string etag);

However, it need to call device's twin first:

Twin twin= await _registryManager.GetTwinAsync(deviceId);
var etag = twin.Etag

So I need to 2 I/O call, that decreases application performance.

Is there any way to set device's twin without getting Etag first?

Thanks,

In the case of device twin at the service-facing side such as tags and desired properties, the REST PATCH can be used, see more details: https://learn.microsoft.com/en-us/rest/api/iothub/service/updatetwin In the case of initialize a device, I do recommend to use registryManager.ImportDevicesAsync job method. Note, that the runtime owner of the device twin reported properties is a device-facing endpoint. — Roman Kiss, Oct 08 '18 at 06:19

score 1 · Answer 1 · answered Oct 08 '18 at 01:38

1

You could use DeviceClient's UpdateReportedPropertiesAsync or, if you want to serialize you data yourself, SendEventAsync(Message message).

DeviceClient is in Microsoft.Azure.Devices.Client library.

Also, you can cache the etag to improve performance (but that depends on how you app works).

answered Oct 08 '18 at 01:38

tymtam

Thank for your information! however, I want to use RegistryManager class to update properties. – Phat Huynh Oct 08 '18 at 02:04
1

Then you will need to supply the `etag` :) – tymtam Oct 08 '18 at 02:11
have you tried using `*` as an ETag value? just bear in mind that the ETag is there to avoid losing data, so make sure that's what you really want. – Devis L. Nov 06 '18 at 02:29

1 Answers1