Add NullObject & FileNotFound exception handling for publishing telemetry data

NucuCar.Sensors/EnvironmentSensor/Sensor.cs

@@ -104,15 +104,25 @@ namespace NucuCar.Sensors.EnvironmentSensor
                 $"{_lastMeasurement.Temperature:N2} \u00B0C | {_lastMeasurement.Pressure:N2} hPa | {_lastMeasurement.Humidity:N2} %rH");
         }
 
+        public string GetIdentifier()
+        {
+            return nameof(EnvironmentSensor);
+        }
+
         public Dictionary<string, double> GetTelemetryData()
         {
-            return new Dictionary<string, double>
+            Dictionary<string, double> returnValue = null;
+            if (_lastMeasurement != null)
             {
-                ["temperature"] = _lastMeasurement.Temperature,
+                returnValue = new Dictionary<string, double>
-                ["humidity"] = _lastMeasurement.Humidity,
+                {
-                ["pressure"] = _lastMeasurement.Pressure,
+                    ["temperature"] = _lastMeasurement.Temperature,
-                ["voc"] = _lastMeasurement.VolatileOrganicCompound
+                    ["humidity"] = _lastMeasurement.Humidity,
-            };
+                    ["pressure"] = _lastMeasurement.Pressure,
+                    ["voc"] = _lastMeasurement.VolatileOrganicCompound
+                };
+            }
+            return returnValue;
         }
     }
 }

NucuCar.Sensors/Telemetry/ITelemetrySensor.cs

@@ -1,9 +1,11 @@
+using System;
 using System.Collections.Generic;
 
 namespace NucuCar.Sensors.Telemetry
 {
     public interface ITelemetrySensor
     {
+        string GetIdentifier();
         /* Dictionary containing the topic and the value */
         Dictionary<string, double> GetTelemetryData();
     }

NucuCar.Sensors/Telemetry/TelemetryService.cs

@@ -53,7 +53,7 @@ namespace NucuCar.Sensors.Telemetry
                 jwt = Jose.JWT.Encode(new Dictionary<string, object>()
                 {
                     ["iat"] = DateTime.UtcNow,
-                    ["exp"] = DateTime.UtcNow.AddMinutes(60),
+                    ["exp"] = DateTime.UtcNow.AddDays(60),
                     ["aud"] = ProjectId
                 }, rsa, Jose.JwsAlgorithm.RS256);
             }
@@ -74,17 +74,27 @@ namespace NucuCar.Sensors.Telemetry
 
         public async Task StartAsync()
         {
-            var options = new ManagedMqttClientOptionsBuilder()
-                .WithAutoReconnectDelay(TimeSpan.FromSeconds(5))
-                .WithClientOptions(new MqttClientOptionsBuilder()
-                    .WithClientId($"projects/{ProjectId}/locations/{Region}/registries/{RegistryId}/devices/{DeviceId}")
-                    .WithCredentials("unused", GetMqttPassword())
-                    .WithTcpServer("mqtt.googleapis.com")
-                    .WithTls().Build())
-                .Build();
-            
             _logger.LogInformation("Starting the MQTT client.");
+            ManagedMqttClientOptions options; 
+            try
+            {
+                options = new ManagedMqttClientOptionsBuilder()
+                    .WithAutoReconnectDelay(TimeSpan.FromSeconds(5))
+                    .WithClientOptions(new MqttClientOptionsBuilder()
+                        .WithClientId($"projects/{ProjectId}/locations/{Region}/registries/{RegistryId}/devices/{DeviceId}")
+                        .WithCredentials("unused", GetMqttPassword())
+                        .WithTcpServer("mqtt.googleapis.com")
+                        .WithTls().Build())
+                    .Build();
+            }
+            catch (IOException e)
+            {
+                _logger.LogCritical(e.Message);
+                throw;
+            }
+
             await _mqttClient.StartAsync(options);
+            _logger.LogInformation("Started the MQTT client!");
         }
 
         public async Task PublishDataAsync(CancellationToken cancellationToken)
@@ -92,6 +102,11 @@ namespace NucuCar.Sensors.Telemetry
             foreach (var sensor in _registeredSensors)
             {
                 var data = sensor.GetTelemetryData();
+                if (data == null)
+                {
+                    _logger.LogWarning($"Warning! Data for {sensor.GetIdentifier()} is null!");
+                    continue;
+                }
                 await UploadData(data, cancellationToken);
             }
         }

NucuCar.Sensors/appsettings.json

@@ -1,16 +1,16 @@
 {
   "Telemetry": {
     "Enabled": true,
-    "Interval": 5000,
+    "Interval": 3000,
     "ProjectId": "playground-239221",
     "DeviceId": "3087236321317137",
     "RegistryId": "Development",
     "Region": "europe-west1",
-    "RS256File": "Certificates\\key.key"
+    "RS256File": "/home/denis/Projects/RiderProjects/NucuCar/NucuCar.Sensors/Certificates/jwt.key"
   },
   "EnvironmentSensor": {
     "Enabled": true,
-    "Telemetry": false,
+    "Telemetry": true,
     "MeasurementInterval": 1000
   },
   "Logging": {