Random wanderings through Microsoft Azure esp. the IoT bits, AI on Micro controllers, .NET nanoFramework, .NET Core on *nix, and GHI Electronics TinyCLR
class Program
{
private static Model.ApplicationSettings _applicationSettings;
private static IMqttClient _client;
private static bool _publisherBusy = false;
static async Task Main()
{
Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} MQTTNet client starting");
try
{
// load the app settings into configuration
var configuration = new ConfigurationBuilder()
.AddJsonFile("appsettings.json", false, true)
.AddUserSecrets<Program>()
.Build();
_applicationSettings = configuration.GetSection("ApplicationSettings").Get<Model.ApplicationSettings>();
var mqttFactory = new MqttFactory();
using (_client = mqttFactory.CreateMqttClient())
{
// Certificate based authentication
List<X509Certificate2> certificates = new List<X509Certificate2>
{
new X509Certificate2(_applicationSettings.ClientCertificateFileName, _applicationSettings.ClientCertificatePassword)
};
var tlsOptions = new MqttClientTlsOptionsBuilder()
.WithClientCertificates(certificates)
.WithSslProtocols(System.Security.Authentication.SslProtocols.Tls12)
.UseTls(true)
.Build();
MqttClientOptions mqttClientOptions = new MqttClientOptionsBuilder()
.WithClientId(_applicationSettings.ClientId)
.WithTcpServer(_applicationSettings.Host, _applicationSettings.Port)
.WithCredentials(_applicationSettings.UserName, _applicationSettings.Password)
.WithCleanStart(_applicationSettings.CleanStart)
.WithTlsOptions(tlsOptions)
.Build();
var connectResult = await _client.ConnectAsync(mqttClientOptions);
if (connectResult.ResultCode != MqttClientConnectResultCode.Success)
{
throw new Exception($"Failed to connect: {connectResult.ReasonString}");
}
_client.ApplicationMessageReceivedAsync += OnApplicationMessageReceivedAsync;
Console.WriteLine($"Subscribed to Topic");
foreach (string topic in _applicationSettings.SubscribeTopics.Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
{
var subscribeResult = await _client.SubscribeAsync(topic, _applicationSettings.SubscribeQualityOfService);
Console.WriteLine($" {topic} Result:{subscribeResult.Items.First().ResultCode}");
}
}
//...
}
MQTTnet client console application output
The design of the MQTT protocol means that the hivemq-mqtt-client-dotnet and MQTTnet implementations are similar. Having used both I personally prefer the HiveMQ client library.
For one test deployment it took me an hour to generate the Root, Intermediate and a number of Devices certificates which was a waste of time. At this point I decided investigate writing some applications to simplify the process.
static void Main(string[] args)
{
var serviceProvider = new ServiceCollection()
.AddCertificateManager()
.BuildServiceProvider();
// load the app settings into configuration
var configuration = new ConfigurationBuilder()
.AddJsonFile("appsettings.json", false, true)
.AddUserSecrets<Program>()
.Build();
_applicationSettings = configuration.GetSection("ApplicationSettings").Get<Model.ApplicationSettings>();
//------
Console.WriteLine($"validFrom:{validFrom} ValidTo:{validTo}");
var serverRootCertificate = serviceProvider.GetService<CreateCertificatesClientServerAuth>();
var root = serverRootCertificate.NewRootCertificate(
new DistinguishedName {
CommonName = _applicationSettings.CommonName,
Organisation = _applicationSettings.Organisation,
OrganisationUnit = _applicationSettings.OrganisationUnit,
Locality = _applicationSettings.Locality,
StateProvince = _applicationSettings.StateProvince,
Country = _applicationSettings.Country
},
new ValidityPeriod {
ValidFrom = validFrom,
ValidTo = validTo,
},
_applicationSettings.PathLengthConstraint,
_applicationSettings.DnsName);
root.FriendlyName = _applicationSettings.FriendlyName;
Console.Write("PFX Password:");
string password = Console.ReadLine();
if ( String.IsNullOrEmpty(password))
{
Console.WriteLine("PFX Password invalid");
return;
}
var exportCertificate = serviceProvider.GetService<ImportExportCertificate>();
var rootCertificatePfxBytes = exportCertificate.ExportRootPfx(password, root);
File.WriteAllBytes(_applicationSettings.RootCertificateFilePath, rootCertificatePfxBytes);
Console.WriteLine($"Root certificate file:{_applicationSettings.RootCertificateFilePath}");
Console.WriteLine("press enter to exit");
Console.ReadLine();
}
The application’s configuration was split between application settings file(certificate file paths, validity periods, Organisation etc.) or entered at runtime ( certificate filenames, passwords etc.) The first application generates a Root Certificate using the distinguished name information from the application settings, plus file names and passwords entered by the user.
Root Certificate generation application output
The second application generates an Intermediate Certificate using the Root Certificate, the distinguished name information from the application settings, plus file names and passwords entered by the user.
static void Main(string[] args)
{
var serviceProvider = new ServiceCollection()
.AddCertificateManager()
.BuildServiceProvider();
// load the app settings into configuration
var configuration = new ConfigurationBuilder()
.AddJsonFile("appsettings.json", false, true)
.AddUserSecrets<Program>()
.Build();
_applicationSettings = configuration.GetSection("ApplicationSettings").Get<Model.ApplicationSettings>();
//------
Console.WriteLine($"validFrom:{validFrom} be after ValidTo:{validTo}");
Console.WriteLine($"Root Certificate file:{_applicationSettings.RootCertificateFilePath}");
Console.Write("Root Certificate Password:");
string rootPassword = Console.ReadLine();
if (String.IsNullOrEmpty(rootPassword))
{
Console.WriteLine("Fail");
return;
}
var rootCertificate = new X509Certificate2(_applicationSettings.RootCertificateFilePath, rootPassword);
var intermediateCertificateCreate = serviceProvider.GetService<CreateCertificatesClientServerAuth>();
var intermediateCertificate = intermediateCertificateCreate.NewIntermediateChainedCertificate(
new DistinguishedName
{
CommonName = _applicationSettings.CommonName,
Organisation = _applicationSettings.Organisation,
OrganisationUnit = _applicationSettings.OrganisationUnit,
Locality = _applicationSettings.Locality,
StateProvince = _applicationSettings.StateProvince,
Country = _applicationSettings.Country
},
new ValidityPeriod
{
ValidFrom = validFrom,
ValidTo = validTo,
},
_applicationSettings.PathLengthConstraint,
_applicationSettings.DnsName, rootCertificate);
intermediateCertificate.FriendlyName = _applicationSettings.FriendlyName;
Console.Write("Intermediate certificate Password:");
string intermediatePassword = Console.ReadLine();
if (String.IsNullOrEmpty(intermediatePassword))
{
Console.WriteLine("Fail");
return;
}
var importExportCertificate = serviceProvider.GetService<ImportExportCertificate>();
Console.WriteLine($"Intermediate PFX file:{_applicationSettings.IntermediateCertificatePfxFilePath}");
var intermediateCertificatePfxBtyes = importExportCertificate.ExportChainedCertificatePfx(intermediatePassword, intermediateCertificate, rootCertificate);
File.WriteAllBytes(_applicationSettings.IntermediateCertificatePfxFilePath, intermediateCertificatePfxBtyes);
Console.WriteLine($"Intermediate CER file:{_applicationSettings.IntermediateCertificateCerFilePath}");
var intermediateCertificatePemText = importExportCertificate.PemExportPublicKeyCertificate(intermediateCertificate);
File.WriteAllText(_applicationSettings.IntermediateCertificateCerFilePath, intermediateCertificatePemText);
Console.WriteLine("press enter to exit");
Console.ReadLine();
}
Uploading the Intermediate certificate to Azure Event Grid
The third application generates Device Certificates using the Intermediate Certificate, distinguished name information from the application settings, plus device id, file names and passwords entered by the user.
static void Main(string[] args)
{
var serviceProvider = new ServiceCollection()
.AddCertificateManager()
.BuildServiceProvider();
// load the app settings into configuration
var configuration = new ConfigurationBuilder()
.AddJsonFile("appsettings.json", false, true)
.AddUserSecrets<Program>()
.Build();
_applicationSettings = configuration.GetSection("ApplicationSettings").Get<Model.ApplicationSettings>();
//------
Console.WriteLine($"validFrom:{validFrom} ValidTo:{validTo}");
Console.WriteLine($"Intermediate PFX file:{_applicationSettings.IntermediateCertificateFilePath}");
Console.Write("Intermediate PFX Password:");
string intermediatePassword = Console.ReadLine();
if (String.IsNullOrEmpty(intermediatePassword))
{
Console.WriteLine("Intermediate PFX Password invalid");
return;
}
var intermediate = new X509Certificate2(_applicationSettings.IntermediateCertificateFilePath, intermediatePassword);
Console.Write("Device ID:");
string deviceId = Console.ReadLine();
if (String.IsNullOrEmpty(deviceId))
{
Console.WriteLine("Device ID invalid");
return;
}
var createClientServerAuthCerts = serviceProvider.GetService<CreateCertificatesClientServerAuth>();
var device = createClientServerAuthCerts.NewDeviceChainedCertificate(
new DistinguishedName
{
CommonName = deviceId,
Organisation = _applicationSettings.Organisation,
OrganisationUnit = _applicationSettings.OrganisationUnit,
Locality = _applicationSettings.Locality,
StateProvince = _applicationSettings.StateProvince,
Country = _applicationSettings.Country
},
new ValidityPeriod
{
ValidFrom = validFrom,
ValidTo = validTo,
},
deviceId, intermediate);
device.FriendlyName = deviceId;
Console.Write("Device PFX Password:");
string devicePassword = Console.ReadLine();
if (String.IsNullOrEmpty(devicePassword))
{
Console.WriteLine("Fail");
return;
}
var importExportCertificate = serviceProvider.GetService<ImportExportCertificate>();
string devicePfxPath = string.Format(_applicationSettings.DeviceCertificatePfxFilePath, deviceId);
Console.WriteLine($"Device PFX file:{devicePfxPath}");
var deviceCertificatePath = importExportCertificate.ExportChainedCertificatePfx(devicePassword, device, intermediate);
File.WriteAllBytes(devicePfxPath, deviceCertificatePath);
Console.WriteLine("press enter to exit");
Console.ReadLine();
}
Device Certificate generation application output
Uploading the Intermediate certificate to Azure Event Grid
Application Insights logging with message unpackingApplication Insights logging message payload
Then in the last log entry the decoded message payload
/*
Copyright ® 2020 Feb devMobile Software, All Rights Reserved
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE
Default URL for triggering event grid function in the local environment.
http://localhost:7071/runtime/webhooks/EventGrid?functionName=functionname
*/
namespace EventGridProcessorAzureIotHub
{
using System;
using System.IO;
using System.Reflection;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.EventGrid.Models;
using Microsoft.Azure.WebJobs.Extensions.EventGrid;
using log4net;
using log4net.Config;
using Newtonsoft.Json;
public static class Telemetry
{
[FunctionName("Telemetry")]
public static void Run([EventGridTrigger]Microsoft.Azure.EventGrid.Models.EventGridEvent eventGridEvent, ExecutionContext executionContext )//, TelemetryClient telemetryClient)
{
ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
var logRepository = LogManager.GetRepository(Assembly.GetEntryAssembly());
XmlConfigurator.Configure(logRepository, new FileInfo(Path.Combine(executionContext.FunctionAppDirectory, "log4net.config")));
log.Info($"eventGridEvent.Data-{eventGridEvent}");
log.Info($"eventGridEvent.Data.ToString()-{eventGridEvent.Data.ToString()}");
IotHubDeviceTelemetryEventData iOThubDeviceTelemetryEventData = (IotHubDeviceTelemetryEventData)JsonConvert.DeserializeObject(eventGridEvent.Data.ToString(), typeof(IotHubDeviceTelemetryEventData));
log.Info($"iOThubDeviceTelemetryEventData.Body.ToString()-{iOThubDeviceTelemetryEventData.Body.ToString()}");
byte[] base64EncodedBytes = System.Convert.FromBase64String(iOThubDeviceTelemetryEventData.Body.ToString());
log.Info($"System.Text.Encoding.UTF8.GetString(-{System.Text.Encoding.UTF8.GetString(base64EncodedBytes)}");
}
}
}
Overall it took roughly half a page of code (mainly generated by a tool) to unpack and log the contents of an Azure IoT Hub EventGrid payload to Application Insights.
I did notice that the .DeviceConnected and .DeviceDisconnected events did take a while to arrive. When I started the field gateway application on the Windows 10 IoT Core device I would get several DeviceTelemetry events before the DeviceConnected event arrived.
I was using Advanced Message Queueing Protocol (AMQP) so I modified the configuration file so I could try all the available options.
C# TransportType enumeration
namespace Microsoft.Azure.Devices.Client
{
//
// Summary:
// Transport types supported by DeviceClient - AMQP/TCP, HTTP 1.1, MQTT/TCP, AMQP/WS,
// MQTT/WS
public enum TransportType
{
//
// Summary:
// Advanced Message Queuing Protocol transport. Try Amqp over TCP first and fallback
// to Amqp over WebSocket if that fails
Amqp = 0,
//
// Summary:
// HyperText Transfer Protocol version 1 transport.
Http1 = 1,
//
// Summary:
// Advanced Message Queuing Protocol transport over WebSocket only.
Amqp_WebSocket_Only = 2,
//
// Summary:
// Advanced Message Queuing Protocol transport over native TCP only
Amqp_Tcp_Only = 3,
//
// Summary:
// Message Queuing Telemetry Transport. Try Mqtt over TCP first and fallback to
// Mqtt over WebSocket if that fails
Mqtt = 4,
//
// Summary:
// Message Queuing Telemetry Transport over Websocket only.
Mqtt_WebSocket_Only = 5,
//
// Summary:
// Message Queuing Telemetry Transport over native TCP only
Mqtt_Tcp_Only = 6
}
}
The first telemetry data arrived 00:57:18, the DeviceConnected arrived 01:01:28 so approximately a 4 minute delay, the DeviceDisconnected arrived within a minute of me shutting the device down.
The first telemetry data arrived 04:16:48, the DeviceConnected arrived 04:20:39 so approximately a 4 minute delay, the DeviceDisconnected arrived within a minute of me shutting the device down.
The first telemetry data arrived 04:05:36, DeviceConnected arrived 04:09:52 so approximately a 4 minute delay, the DeviceDisconnected arrived within a minute of me shutting the device down.
HTTP
I waited for 20 minutes and there wasn’t a DeviceConnected message which I sort of expected as HTTP is a connectionless protocol.
The first telemetry data arrived 01:11:33, the DeviceConnected arrived 01:11:25 so they arrived in order and within 10 seconds, the DeviceDisconnected arrived within a 15 seconds of me shutting the device down.
The first telemetry data arrived 04:42:15, the DeviceConnected arrived 04:42:06 so they arrived in order and within 10 seconds, the DeviceDisconnected arrived within a 20 seconds of me shutting device down.
The first telemetry data arrived 04:36:08, the DeviceConnected arrived 04:36:03 so they arrived in order and within 10 seconds, the DeviceDisconnected arrived within a 30 seconds of me shutting device down.
Summary
My LoRa sensors nodes are sending data roughly every minute which reduces the precision of the times.
It looks like for AMQP based messaging it can take 4-5 minutes for a Devices.DeviceConnected message to arrive, for based MQTT messaging it’s 5-10 seconds.
I have one an Azure IoT HubLoRa Telemetry Field Gateway running in my office and I wanted to process the data collected by the sensors around my property without using a Software as a Service(SaaS) Internet of Things (IoT) package.
Rather than lots of screen grabs of my configuration steps I figured people reading this series of posts would be able to figure the details out themselves.
I downloaded the JSON configuration file template from my Windows 10 device (which is created on first startup after installation) and configured the Azure IoT Hub connection string.
I then uploaded this to my Windows 10 IoT Core device and restarted the Azure IoT Hub Field gateway so it picked up the new settings.
I could then see on the device messages from sensor nodes being unpacked and uploaded to my Azure IoT Hub.
ETW logging on device
In the Azure IoT Hub metrics I graphed the number of devices connected and the number of telemetry messages sent and could see my device connect then start uploading telemetry.
Azure IoT Hub metrics
One of my customers uses Azure Event Grid for application integration and I wanted to explore using it in an IoT solution. The first step was to create an Event Grid Domain.
To confirm my event subscriptions were successful I previously found the “simplest” approach was to use an Azure storage queue endpoint. I had to create an Azure Storage Account with two Azure Storage Queues one for device connectivity (.DeviceConnected & .DeviceDisconnected) events and the other for device telemetry (.DeviceTelemetry) events.
I created a couple of other subscriptions so I could compare the different Event schemas (Event Grid Schema & Cloud Event Schema v1.0). At this stage I didn’t configure any Filters or Additional Features.
Azure IoT Hub Telemetry Event Metrics
I use Cerebrate Cerculean for monitoring and managing a couple of other customer projects so I used it to inspect the messages in the storage queues.
Without writing any code (I will script the configuration) I could upload sensor data to an Azure IoT Hub, subscribe to a selection of events the Azure IoT Hub publishes and then inspect them in an Azure Storage Queue.
I did notice that the .DeviceConnected and .DeviceDisconnected events did take a while to arrive. When I started the field gateway application on the device I would get several DeviceTelemetry events before the DeviceConnected event arrived.
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