Random wanderings through Microsoft Azure esp. PaaS plumbing, the IoT bits, AI on Micro controllers, AI on Edge Devices, .NET nanoFramework, .NET Core on *nix and ML.NET+ONNX
Still couldn’t figure out why my code was failing so I turned up logging to 11 and noticed a couple of messages which didn’t make sense. The device was connecting than disconnecting which indicated a another problem. As part of the Message Queue Telemetry Transport(MQTT) specification there is a “feature” Last Will and Testament(LWT) which a client can configure so that the MQTT broker sends a message to a topic if the device disconnects unexpectedly.
I was looking at the code and noticed that LWT was being used and that the topic didn’t exist in my Azure Event Grid MQTT Broker namespace. When the LWT configuration was commented out the application worked.
Paying close attention to the logging I noticed the “Subscribing to ssl/mqtts” followed by “Subscribe request sent”
I checked the sample application and found that if the connect was successful the application would then try and subscribe to a topic that didn’t exist.
The same approach as the YoloV8.Detect.SecurityCamera.Stream sample is used because the image doesn’t have to be saved on the local filesystem.
Utralytics Pose Model marked-up image
To check the results, I put a breakpoint in the timer just after PoseAsync method is called and then used the Visual Studio 2022 Debugger QuickWatch functionality to inspect the contents of the PoseResult object.
namespace devMobile.IoT.myriotaAzureIoTConnector.myriota.UplinkWebhook.Models
{
public class UplinkPayloadWebDto
{
public string EndpointRef { get; set; }
public long Timestamp { get; set; }
public string Data { get; set; } // Embedded JSON ?
public string Id { get; set; }
public string CertificateUrl { get; set; }
public string Signature { get; set; }
}
}
The UplinkWebhook controller “automagically” deserialises the message, then in code the embedded JSON is deserialised and “unpacked”, finally the processed message is inserted into an Azure Storage queue.
For a couple of weeks Myriota Developer Toolkit has been sitting under my desk and today I got some time to setup a device, register it, then upload some data.
The first message sent shortly after I powered up the device had the latitude and longitude of Null Island
The Asset Tracker UserApplicationId is 65002 and the payload is similar to the Swarm Eval Kit. I created some message payloads (location of Christchurch Cathedral) for testing.
namespace PayloadFormatter // Additional namespace for shortening interface when usage in formatter code
{
using System.Collections.Generic;
using Newtonsoft.Json.Linq;
public interface IFormatterUplink
{
public JObject Evaluate(IDictionary<string, string> properties, uint organisationId, uint deviceId, byte deviceType, ushort userApplicationId, JObject payloadJson, string payloadText, byte[] payloadBytes);
}
public interface IFormatterDownlink
{
public byte[] Evaluate(IDictionary<string, string> properties, uint organisationId, uint deviceId, byte deviceType, ushort userApplicationId, JObject payloadJson, string payloadText, byte[] payloadBytes);
}
}
The definitions of the uplink & downlink payload formatter evaluator interfaces have been updated and shifted to a new project.
Visual Studio 2022 Solution with payloadformatter maintenance application
I built a console application to help with developing and debugging uplink or downlink formatters. The application has a number of command line parameters which specify the formatter to be used, UserApplicationId, OrganizationId, DeviceType etc.
public class CommandLineOptions
{
[Option('d', "Direction", Required = true, HelpText = "Test Uplink or DownLink formatter")]
public string Direction { get; set; }
[Option('p', "filename", HelpText = "Uplink or Downlink Payload file name")]
public string PayloadFilename { get; set; } = string.Empty;
[Option('o', "OrganisationId", Required = true, HelpText = "Organisation unique identifier")]
public uint OrganizationId { get; set; }
[Option('i', "DeviceId", Required = true, HelpText = "Device unique identitifer")]
public uint DeviceId { get; set; }
[Option('t', "DeviceType", Required = true, HelpText = "Device type number")]
public byte DeviceType { get; set; }
[Option('u', "UserApplicationId", Required = true, HelpText = "User Application Id")]
public ushort UserApplicationId { get; set; }
[Option('h', "SwarmHiveReceivedAtUtc", HelpText = "Swarm Hive received at time UTC")]
public DateTime? SwarmHiveReceivedAtUtc { get; set; }
[Option('w', "UplinkWebHookReceivedAtUtc", HelpText = "Webhook received at time UTC")]
public DateTime? UplinkWebHookReceivedAtUtc { get; set; }
[Option('s', "Status", HelpText = "Uplink local file system file name")]
public byte? Status { get; set; }
[Option('c', "Client", HelpText = "Uplink local file system file name")]
public string Client { get; set; }
}
The downlink formatter (similar approach for uplink) loads the sample file as an array of bytes, then tries to convert it to text, and finally to JSON. Then the formatter code is “compiled” and the executed with the file payload and command line parameters.
private static async Task DownlinkFormatterCore(CommandLineOptions options)
{
Dictionary<string, string> properties = new Dictionary<string, string>();
string formatterFolder = Path.Combine(Environment.CurrentDirectory, "downlink");
Console.WriteLine($"Downlink- uplinkFormatterFolder: {formatterFolder}");
string formatterFile = Path.Combine(formatterFolder, $"{options.UserApplicationId}.cs");
Console.WriteLine($"Downlink- UserApplicationId: {options.UserApplicationId}");
Console.WriteLine($"Downlink- Payload formatter file: {formatterFile}");
PayloadFormatter.IFormatterDownlink evalulator;
try
{
evalulator = CSScript.Evaluator.LoadFile<PayloadFormatter.IFormatterDownlink>(formatterFile);
}
catch (CSScriptLib.CompilerException cex)
{
Console.Write($"Loading or compiling file:{formatterFile} failed Exception:{cex}");
return;
}
string payloadFilename = Path.Combine(formatterFolder, options.PayloadFilename);
Console.WriteLine($"Downlink- payloadFilename:{payloadFilename}");
byte[] uplinkBytes;
try
{
uplinkBytes = File.ReadAllBytes(payloadFilename);
}
catch (DirectoryNotFoundException dex)
{
Console.WriteLine($"Uplink payload filename directory {formatterFolder} not found:{dex}");
return;
}
catch (FileNotFoundException fnfex)
{
Console.WriteLine($"Uplink payload filename {payloadFilename} not found:{fnfex}");
return;
}
catch (FormatException fex)
{
Console.WriteLine($"Uplink payload file invalid format {payloadFilename} not found:{fex}");
return;
}
// See if payload can be converted to a string
string uplinkText = string.Empty;
try
{
uplinkText = Encoding.UTF8.GetString(uplinkBytes);
}
catch (FormatException fex)
{
Console.WriteLine("Encoding.UTF8.GetString failed:{0}", fex.Message);
}
// See if payload can be converted to JSON
JObject uplinkJson;
try
{
uplinkJson = JObject.Parse(uplinkText);
}
catch (JsonReaderException jrex)
{
Console.WriteLine("JObject.Parse failed Exception:{1}", jrex);
uplinkJson = new JObject();
}
Console.WriteLine("Properties");
foreach (var property in properties)
{
Console.WriteLine($"{property.Key}:{property.Value}");
}
// Transform the byte and optional text and JSON payload
Byte[] payload;
try
{
payload = evalulator.Evaluate(properties, options.OrganizationId, options.DeviceId, options.DeviceType, options.UserApplicationId, uplinkJson, uplinkText, uplinkBytes);
}
catch (Exception ex)
{
Console.WriteLine($"evalulatorUplink.Evaluate failed Exception:{ex}");
return;
}
Console.WriteLine("Payload");
Console.WriteLine(Convert.ToBase64String(payload));
}
The sample JSON payload is what would be sent by Azure IoT Central to a device to configure the fan speed
Azure IoT Central M138 Breakout device template with the Fan Status command selected
{
"FanStatus": 2
}
If the downlink payload formatter is compiled and executes successfully the Base64 representation output is displayed
using System;
using System.Collections.Generic;
using Newtonsoft.Json.Linq;
public class FormatterDownlink : PayloadFormatter.IFormatterDownlink
{
public byte[] Evaluate(IDictionary<string, string> properties, uint organisationId, uint deviceId, byte deviceType, ushort userApplicationId, JObject payloadJson, string payloadText, byte[] payloadBytes)
{
byte? status = payloadJson.Value<byte?>("FanStatus");
if ( status.HasValue )
{
return new byte[] { status.Value };
}
return new byte[]{};
}
}
If the downlink payload formatter syntax is incorrect e.g. { status.Value ; }; an error message with the line and column is displayed.
using System;
using System.Collections.Generic;
using Newtonsoft.Json.Linq;
public class FormatterDownlink : PayloadFormatter.IFormatterDownlink
{
public byte[] Evaluate(IDictionary<string, string> properties, uint organisationId, uint deviceId, byte deviceType, ushort userApplicationId, JObject payloadJson, string payloadText, byte[] payloadBytes)
{
byte? status = payloadJson.Value<byte?>("FanStatus");
if ( status.HasValue )
{
return new byte[] { status.Value ; };
}
return new byte[]{};
}
}
If the downlink payload formatter syntax is correct but execution fails (in the example code division by zero) an error message is displayed.
using System;
using System.Collections.Generic;
using Newtonsoft.Json.Linq;
public class FormatterDownlink : PayloadFormatter.IFormatterDownlink
{
public byte[] Evaluate(IDictionary<string, string> properties, uint organisationId, uint deviceId, byte deviceType, ushort userApplicationId, JObject payloadJson, string payloadText, byte[] payloadBytes)
{
byte? status = payloadJson.Value<byte?>("FanStatus");
if ( status.HasValue )
{
int divideByZero = 10;
divideByZero = divideByZero / 0;
return new byte[] { status.Value };
}
return new byte[]{};
}
}
Swarm Space Bumble hive classes in Visual Studio 2022
My SwarmSpaceAzureIoTConnector project only needed to login, get a list of devices and send messages so all the additional functionality was never going to be used. The method to send a message didn’t work, the class used for the payload (UserMessage) appears to be wrong.
"post": {
"tags": [ "messages" ],
"summary": "POST user messages",
"description": "<p>This endpoint submits a JSON formatted UserMessage object for delivery to a Swarm device. A JSON object is returned with a newly assigned <code>packetId</code> and <code>status</code> of<code>OK</code> on success, or <code>ERROR</code> (with a description of the error) on failure.</p><p>The current user must have access to the <code>userApplicationId</code> and <code>device</code> given inside the UserMessage JSON. The device must also have the ability to receive messages from the Hive (\"two-way communication\") enabled. If these conditions are not met, a response with status code 403 (Forbidden) will be returned.</p><p>Note that the <code>data</code> field is the <b>Base64-encoded</b> version of the data to be sent. This allows the sending of binary, as well as text, data.</p>",
"operationId": "addApplicationMessage",
"requestBody": {
"content": { "application/json": { "schema": { "$ref": "#/components/schemas/UserMessage" } } },
"required": true
},
"responses": {
"401": {
"description": "Unauthorized",
"content": { "*/*": { "schema": { "$ref": "#/components/schemas/ApiError" } } }
},
"403": {
"description": "Forbidden",
"content": { "*/*": { "schema": { "$ref": "#/components/schemas/ApiError" } } }
},
"400": {
"description": "Bad Request",
"content": { "*/*": { "schema": { "$ref": "#/components/schemas/ApiError" } } }
},
"200": {
"description": "OK",
"content": { "application/json": { "schema": { "$ref": "#/components/schemas/PacketPostReturn" } } }
}
}
}
},
[System.CodeDom.Compiler.GeneratedCode("NJsonSchema", "13.17.0.0 (NJsonSchema v10.8.0.0 (Newtonsoft.Json v13.0.0.0))")]
public partial class UserMessage
{
/// <summary>
/// Swarm packet ID
/// </summary>
[Newtonsoft.Json.JsonProperty("packetId", Required = Newtonsoft.Json.Required.Always)]
public long PacketId { get; set; }
/// <summary>
/// Swarm message ID. There may be multiple messages for a single message ID. A message ID represents an intent to send a message, but there may be multiple Swarm packets that are required to fulfill that intent. For example, if a Hive -> device message fails to reach its destination, automatic retry attempts to send that message will have the same message ID.
/// </summary>
[Newtonsoft.Json.JsonProperty("messageId", Required = Newtonsoft.Json.Required.DisallowNull, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
public long MessageId { get; set; }
/// <summary>
/// Swarm device type
/// </summary>
[Newtonsoft.Json.JsonProperty("deviceType", Required = Newtonsoft.Json.Required.Always)]
public int DeviceType { get; set; }
/// <summary>
/// Swarm device ID
/// </summary>
[Newtonsoft.Json.JsonProperty("deviceId", Required = Newtonsoft.Json.Required.Always)]
public int DeviceId { get; set; }
/// <summary>
/// Swarm device name
/// </summary>
[Newtonsoft.Json.JsonProperty("deviceName", Required = Newtonsoft.Json.Required.DisallowNull, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
public string DeviceName { get; set; }
/// <summary>
/// Direction of message
/// </summary>
[Newtonsoft.Json.JsonProperty("direction", Required = Newtonsoft.Json.Required.Always)]
public int Direction { get; set; }
/// <summary>
/// Message data type, always = 6
/// </summary>
[Newtonsoft.Json.JsonProperty("dataType", Required = Newtonsoft.Json.Required.Always)]
public int DataType { get; set; }
/// <summary>
/// Application ID
/// </summary>
[Newtonsoft.Json.JsonProperty("userApplicationId", Required = Newtonsoft.Json.Required.Always)]
public int UserApplicationId { get; set; }
/// <summary>
/// Organization ID
/// </summary>
[Newtonsoft.Json.JsonProperty("organizationId", Required = Newtonsoft.Json.Required.Always)]
public int OrganizationId { get; set; }
/// <summary>
/// Length of data (in bytes) before base64 encoding
/// </summary>
[Newtonsoft.Json.JsonProperty("len", Required = Newtonsoft.Json.Required.DisallowNull, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
public int Len { get; set; }
/// <summary>
/// Base64 encoded data string
/// </summary>
[Newtonsoft.Json.JsonProperty("data", Required = Newtonsoft.Json.Required.Always)]
[System.ComponentModel.DataAnnotations.Required(AllowEmptyStrings = true)]
public byte[] Data { get; set; }
/// <summary>
/// Swarm packet ID of acknowledging packet from device
/// </summary>
[Newtonsoft.Json.JsonProperty("ackPacketId", Required = Newtonsoft.Json.Required.DisallowNull, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
public long AckPacketId { get; set; }
/// <summary>
/// Message status. Possible values:
/// <br/>0 = incoming message (from a device)
/// <br/>1 = outgoing message (to a device)
/// <br/>2 = incoming message, acknowledged as seen by customer. OR a outgoing message packet is on groundstation
/// <br/>3 = outgoing message, packet is on satellite
/// <br/>-1 = error
/// <br/>-3 = failed to deliver, retrying
/// <br/>-4 = failed to deliver, will not re-attempt
/// <br/>
/// </summary>
[Newtonsoft.Json.JsonProperty("status", Required = Newtonsoft.Json.Required.DisallowNull, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
public int Status { get; set; }
/// <summary>
/// Time that the message was received by the Hive
/// </summary>
[Newtonsoft.Json.JsonProperty("hiveRxTime", Required = Newtonsoft.Json.Required.Always)]
[System.ComponentModel.DataAnnotations.Required(AllowEmptyStrings = true)]
public System.DateTimeOffset HiveRxTime { get; set; }
private System.Collections.Generic.IDictionary<string, object> _additionalProperties;
[Newtonsoft.Json.JsonExtensionData]
public System.Collections.Generic.IDictionary<string, object> AdditionalProperties
{
get { return _additionalProperties ?? (_additionalProperties = new System.Collections.Generic.Dictionary<string, object>()); }
set { _additionalProperties = value; }
}
}
After several attempts I gave up and have rebuilt the required Bumble bee hive integration with RestSharp
public async Task SendAsync(uint organisationId, uint deviceId, byte deviceType, ushort userApplicationId, byte[] data, CancellationToken cancellationToken)
{
await TokenRefresh(cancellationToken);
_logger.LogInformation("SendAsync: OrganizationId:{0} DeviceType:{1} DeviceId:{2} UserApplicationId:{3} Data:{4} Enabled:{5}", organisationId, deviceType, deviceId, userApplicationId, Convert.ToBase64String(data), _bumblebeeHiveSettings.DownlinkEnabled);
Models.MessageSendRequest message = new Models.MessageSendRequest()
{
OrganizationId = (int)organisationId,
DeviceType = deviceType,
DeviceId = (int)deviceId,
UserApplicationId = userApplicationId,
Data = data,
};
RestClientOptions restClientOptions = new RestClientOptions()
{
BaseUrl = new Uri(_bumblebeeHiveSettings.BaseUrl),
ThrowOnAnyError = true,
};
using (RestClient client = new RestClient(restClientOptions))
{
RestRequest request = new RestRequest("api/v1/messages", Method.Post);
request.AddBody(message);
request.AddHeader("Authorization", $"bearer {_token}");
// To save the limited monthly allocation of mesages downlinks can be disabled
if (_bumblebeeHiveSettings.DownlinkEnabled)
{
var response = await client.PostAsync<Models.MessageSendResponse>(request, cancellationToken);
_logger.LogInformation("SendAsync-Result:{Status} PacketId:{PacketId}", response.Status, response.PacketId);
}
}
}
The application now has a StartUpService which loads the Azure DeviceClient cache (Lazy Cache) in the background as the application starts up. If an uplink message is received from a SwarmDevice before, it has been loaded by the FunctionsStartup the DeviceClient information is cached and another connection to the Azure IoT Hub is not established.
I’m looking at building a webby user interface where users an interactivity list, create, edit, delete formatters with syntax highlighter support, and the executing the formatter with sample payloads.
Swarm Space Azure IoT Connector Identity Translation Gateway Architecture
This approach uses most of the existing building blocks, and that’s it no more changes.
I initially tried building a cache loader with BackgroundService so that the DeviceClient cache would start loading as the application started but interdependencies became problem.
public partial class Connector
{
[Function("BumblebeeHiveCacheRefresh")]
public async Task<IActionResult> BumblebeeHiveCacheRefreshRun([HttpTrigger(AuthorizationLevel.Function, "get")] CancellationToken cancellationToken)
{
_logger.LogInformation("BumblebeeHiveCacheRefresh start");
await _swarmSpaceBumblebeeHive.Login(cancellationToken);
foreach (SwarmSpace.BumblebeeHiveClient.Device device in await _swarmSpaceBumblebeeHive.DeviceListAsync(cancellationToken))
{
_logger.LogInformation("BumblebeeHiveCacheRefresh DeviceId:{DeviceId} DeviceName:{DeviceName}", device.DeviceId, device.DeviceName);
Models.AzureIoTDeviceClientContext context = new Models.AzureIoTDeviceClientContext()
{
// TODO seems a bit odd getting this from application settings
OrganisationId = _applicationSettings.OrganisationId,
//UserApplicationId = device.UserApplicationId, deprecated
DeviceType = (byte)device.DeviceType,
DeviceId = (uint)device.DeviceId,
};
switch (_azureIoTSettings.ApplicationType)
{
case Models.ApplicationType.AzureIotHub:
switch (_azureIoTSettings.AzureIotHub.ConnectionType)
{
case Models.AzureIotHubConnectionType.DeviceConnectionString:
await _azureDeviceClientCache.GetOrAddAsync<DeviceClient>(device.DeviceId.ToString(), (ICacheEntry x) => AzureIoTHubDeviceConnectionStringConnectAsync(device.DeviceId.ToString(), context));
break;
case Models.AzureIotHubConnectionType.DeviceProvisioningService:
await _azureDeviceClientCache.GetOrAddAsync<DeviceClient>(device.DeviceId.ToString(), (ICacheEntry x) => AzureIoTHubDeviceProvisioningServiceConnectAsync(device.DeviceId.ToString(), context, _azureIoTSettings.AzureIotHub.DeviceProvisioningService));
break;
default:
_logger.LogError("Azure IoT Hub ConnectionType unknown {0}", _azureIoTSettings.AzureIotHub.ConnectionType);
throw new NotImplementedException("AzureIoT Hub unsupported ConnectionType");
}
break;
case Models.ApplicationType.AzureIoTCentral:
await _azureDeviceClientCache.GetOrAddAsync<DeviceClient>(device.DeviceId.ToString(), (ICacheEntry x) => AzureIoTHubDeviceProvisioningServiceConnectAsync(device.DeviceId.ToString(), context, _azureIoTSettings.AzureIoTCentral.DeviceProvisioningService));
break;
default:
_logger.LogError("AzureIoT application type unknown {0}", _azureIoTSettings.ApplicationType);
throw new NotImplementedException("AzureIoT unsupported ApplicationType");
}
}
_logger.LogInformation("BumblebeeHiveCacheRefresh finish");
return new OkResult();
}
}
In the short-term loading the cache with a call to an Azure HTTPTrigger Function works but may timeout issues. When I ran the connector with my 100’s of devices simulator the function timed out every so often.
There are now separate Data Transfer Objects(DTO) for the uplink and queue message payloads mainly, because the UplinkPayloadQueueDto has additional fields for the client (based on the x-api-key) and when the webhook was called.
public class UplinkPayloadQueueDto
{
public ulong PacketId { get; set; }
public byte DeviceType { get; set; }
public uint DeviceId { get; set; }
public ushort UserApplicationId { get; set; }
public uint OrganizationId { get; set; }
public string Data { get; set; } = string.Empty;
public byte Length { get; set; }
public int Status { get; set; }
public DateTime SwarmHiveReceivedAtUtc { get; set; }
public DateTime UplinkWebHookReceivedAtUtc { get; set; }
public string Client { get; set; } = string.Empty;
}
public class UplinkPayloadWebDto
{
public ulong PacketId { get; set; }
public byte DeviceType { get; set; }
public uint DeviceId { get; set; }
public ushort UserApplicationId { get; set; }
public uint OrganizationId { get; set; }
public string Data { get; set; } = string.Empty;
[Range(Constants.PayloadLengthMinimum, Constants.PayloadLengthMaximum)]
public byte Len { get; set; }
public int Status { get; set; }
public DateTime HiveRxTime { get; set; }
}
I did consider using AutoMapper to copy the values from the UplinkPayloadWebDto to the UplinkPayloadQueueDto but the additional complexity/configuration required for one mapping wasn’t worth it.
The UplinkController has a single POST method, which has a JSON payload(FromBody) and a single header (FromHeader) “x-api-key” which is to secure the method and identify the caller.
[HttpPost]
public async Task<IActionResult> Post([FromHeader(Name = "x-api-key")] string xApiKeyValue, [FromBody] Models.UplinkPayloadWebDto payloadWeb)
{
if (!_applicationSettings.XApiKeys.TryGetValue(xApiKeyValue, out string apiKeyName))
{
_logger.LogWarning("Authentication unsuccessful X-API-KEY value:{xApiKeyValue}", xApiKeyValue);
return this.Unauthorized("Unauthorized client");
}
_logger.LogInformation("Authentication successful X-API-KEY value:{apiKeyName}", apiKeyName);
// Could of used AutoMapper but didn't seem worth it for one place
Models.UplinkPayloadQueueDto payloadQueue = new()
{
PacketId = payloadWeb.PacketId,
DeviceType = payloadWeb.DeviceType,
DeviceId = payloadWeb.DeviceId,
UserApplicationId = payloadWeb.UserApplicationId,
OrganizationId = payloadWeb.OrganizationId,
Data = payloadWeb.Data,
Length = payloadWeb.Len,
Status = payloadWeb.Status,
SwarmHiveReceivedAtUtc = payloadWeb.HiveRxTime,
UplinkWebHookReceivedAtUtc = DateTime.UtcNow,
Client = apiKeyName,
};
_logger.LogInformation("SendAsync queue name:{QueueName}", _applicationSettings.QueueName);
QueueClient queueClient = _queueServiceClient.GetQueueClient(_applicationSettings.QueueName);
await queueClient.SendMessageAsync(Convert.ToBase64String(JsonSerializer.SerializeToUtf8Bytes(payloadQueue)));
return this.Ok();
}
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