At the moment Im simulating device where every 30 seconds I send telemetry data to IoT hub. Here is simple code:

s_deviceClient = DeviceClient.Create(s_iotHubUri, new DeviceAuthenticationWithRegistrySymmetricKey(s_myDeviceId, s_deviceKey), TransportType.Mqtt);

using var cts = new CancellationTokenSource();
var messages = SendDeviceToCloudMessagesAsync(cts.Token);
await s_deviceClient.CloseAsync(cts.Token);
await messages;
cts.Cancel();

And function to send message:

string combinedString = fileStrings[0]   fileStrings[1];
var telemetryDataString = converter.SerializeObject(combinedString);

using var message = new Message(Encoding.UTF8.GetBytes(telemetryDataString))
    {
     ContentEncoding = "utf-8",
     ContentType = "application/json",
    };

await s_deviceClient.SendEventAsync(message);
await Task.Delay(interval);

Everything works fine and I created .exe file that was running without problems. But computer where code is running tends to shut-off from time to time which is problematic. So I tried to move this to Azure Time Trigger Function. While in logs everything looks ok, messages aren't actually posted to IoT hub. I tried to find solution but have not been able to find anything. Is it possible to send messages as device with azure function?

CodePudding user response：

You seem to be closing your DeviceClient before you start using it to send messages. Try the following:

public async Task Do()
{
    // Using statement will dispose your client after you're done with it.
    // No need to close it manually.
    using(var client = DeviceClient.Create(s_iotHubUri, new DeviceAuthenticationWithRegistrySymmetricKey(s_myDeviceId, s_deviceKey), TransportType.Mqtt))
    {
        // Send messages, await for completion.
        await SendDeviceToCloudMessagesAsync(client);
    }
}

private async Task SendDeviceToCloudMessagesAsync(DeviceClient client)
{
    string combinedString = fileStrings[0]   fileStrings[1];
    var telemetryDataString = converter.SerializeObject(combinedString);

    using var message = new Message(Encoding.UTF8.GetBytes(telemetryDataString))
    {
        ContentEncoding = "utf-8",
        ContentType = "application/json",
    };

    await client.SendEventAsync(message);
    await Task.Delay(interval);
}