Implement TelemetryPublisherDisk

NucuCar.Domain/Services/ConnectionStringParser.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using DotNetty.Common;
+
+namespace NucuCar.Domain.Services
+{
+    /// <summary>
+    /// ConnectionStringParser is an utility service to parse and validate connection strings.
+    /// </summary>
+    public static class ConnectionStringParser
+    {
+        /// <summary>
+        /// Parse parses and validates a provided connection string.
+        /// </summary>
+        /// <param name="connectionString">The connection string to parse</param>
+        /// <returns>A dictionary object containing the values of the connection string.</returns>
+        /// <exception cref="ArgumentException"></exception>
+        public static Dictionary<string, string> Parse(string connectionString)
+        {
+            // TODO: Write tests for this.
+            var items = connectionString.Split(";");
+            var parsedConnectionString = new Dictionary<string, string>();
+            foreach (var item in items)
+            {
+                var keyValue = item.Split("=");
+                if (keyValue.Length != 2)
+                {
+                    throw new ArgumentException(
+                        $"Invalid argument for connection string, expected KEY=VALUE got {item}");
+                }
+
+                parsedConnectionString[keyValue[0]] = parsedConnectionString[keyValue[1]];
+            }
+
+            return parsedConnectionString;
+        }
+    }
+}

NucuCar.Domain/Telemetry/TelemetryPublisher.cs

@@ -11,13 +11,6 @@ namespace NucuCar.Domain.Telemetry
     /// </summary>
     public abstract class TelemetryPublisher : IDisposable
     {
-        /// <summary>
-        /// Parameter less constructor, mainly used for testing.
-        /// </summary>
-        public TelemetryPublisher()
-        {
-        }
-
         /// <summary>
         /// Raw connection string that is used to connect to the cloud service. Should be parsed if required.
         /// </summary>
@@ -40,15 +33,10 @@ namespace NucuCar.Domain.Telemetry
         protected readonly ILogger Logger;
 
         /// <summary>
-        /// Constructor for <see cref="TelemetryPublisher"/>.
+        /// Parameter less constructor, mainly used for testing.
         /// </summary>
-        /// <param name="opts">TelemetryPublisher options, see: <see cref="TelemetryPublisherBuilderOptions"/></param>
+        public TelemetryPublisher()
-        protected TelemetryPublisher(TelemetryPublisherBuilderOptions opts)
         {
-            ConnectionString = opts.ConnectionString;
-            TelemetrySource = opts.TelemetrySource;
-            Logger = opts.Logger;
-            RegisteredTelemeters = new List<ITelemeter>(5);
         }
 
         /// <summary>
@@ -88,5 +76,47 @@ namespace NucuCar.Domain.Telemetry
             RegisteredTelemeters.Remove(t);
             return true;
         }
+
+        /// <summary>
+        /// Constructor for <see cref="TelemetryPublisher"/>.
+        /// </summary>
+        /// <param name="opts">TelemetryPublisher options, see: <see cref="TelemetryPublisherBuilderOptions"/></param>
+        protected TelemetryPublisher(TelemetryPublisherBuilderOptions opts)
+        {
+            ConnectionString = opts.ConnectionString;
+            TelemetrySource = opts.TelemetrySource;
+            Logger = opts.Logger;
+            RegisteredTelemeters = new List<ITelemeter>(5);
+        }
+
+        /// <summary>
+        /// Iterates through the registered telemeters and returns the telemetry data as dictionary.
+        /// It also adds metadata information such as: source and timestamp.
+        /// </summary>
+        /// <returns>A dictionary containing all telemetry data.</returns>
+        protected Dictionary<string, object> GetTelemetry()
+        {
+            var data = new List<Dictionary<string, object>>();
+            foreach (var telemeter in RegisteredTelemeters)
+            {
+                var telemetryData = telemeter.GetTelemetryData();
+                if (telemetryData == null)
+                {
+                    Logger?.LogWarning($"Warning! Data for {telemeter.GetIdentifier()} is null!");
+                    continue;
+                }
+
+                telemetryData["_id"] = telemeter.GetIdentifier();
+                data.Add(telemetryData);
+            }
+
+            var metadata = new Dictionary<string, object>
+            {
+                ["source"] = TelemetrySource ?? nameof(TelemetryPublisher),
+                ["timestamp"] = DateTime.Now,
+                ["data"] = data.ToArray()
+            };
+            return metadata;
+        }
     }
 }

NucuCar.Domain/Telemetry/TelemetryPublisherAzure.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
@@ -25,7 +24,7 @@ namespace NucuCar.Domain.Telemetry
                 throw;
             }
 
-            Logger?.LogDebug("Started the AzureTelemetryPublisher!");
+            Logger?.LogDebug("Initialized the AzureTelemetryPublisher!");
         }
 
         /// <summary>
@@ -83,31 +82,6 @@ namespace NucuCar.Domain.Telemetry
             await PublishToCloudAsync(message, cancellationToken);
         }
 
-        private Dictionary<string, object> GetTelemetry()
-        {
-            var data = new List<Dictionary<string, object>>();
-            foreach (var telemeter in RegisteredTelemeters)
-            {
-                var telemetryData = telemeter.GetTelemetryData();
-                if (telemetryData == null)
-                {
-                    Logger?.LogWarning($"Warning! Data for {telemeter.GetIdentifier()} is null!");
-                    continue;
-                }
-
-                telemetryData["_id"] = telemeter.GetIdentifier();
-                data.Add(telemetryData);
-            }
-
-            var metadata = new Dictionary<string, object>
-            {
-                ["source"] = TelemetrySource ?? nameof(TelemetryPublisherAzure),
-                ["timestamp"] = DateTime.Now,
-                ["data"] = data.ToArray()
-            };
-            return metadata;
-        }
-
         private async Task PublishToCloudAsync(Message message, CancellationToken cancellationToken, int maxRetries = 3)
         {
             var retry = 0;

NucuCar.Domain/Telemetry/TelemetryPublisherDisk.cs

@@ -0,0 +1,55 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using Newtonsoft.Json;
+using NucuCar.Domain.Services;
+
+namespace NucuCar.Domain.Telemetry
+{
+    /// <summary>
+    /// The TelemetryPublisherDisk is used to publish telemetry data to a file residing on the disk.
+    /// </summary>
+    public class TelemetryPublisherDisk : TelemetryPublisher
+    {
+        private readonly FileStream _fileStream;
+
+        /// <summary>
+        /// Constructs an instance of <see cref="TelemetryPublisherDisk"/>.
+        /// <remarks>
+        ///    The connection string must contain the following options:
+        ///     Filename (required) - The path of the filename in which to log telemetry data.
+        ///     BufferSize (optional) - The buffer size for the async writer. Default: 4096
+        /// </remarks>
+        /// </summary>
+        /// <param name="opts"></param>
+        public TelemetryPublisherDisk(TelemetryPublisherBuilderOptions opts) : base(opts)
+        {
+            var connectionStringParams = ConnectionStringParser.Parse(opts.ConnectionString);
+            var fileName = connectionStringParams.GetValueOrDefault("Filename");
+            var bufferSize = connectionStringParams.GetValueOrDefault("BufferSize", "4096");
+
+            _fileStream = new FileStream(fileName, FileMode.Append, FileAccess.Write,
+                FileShare.None, int.Parse(bufferSize), true);
+            Logger?.LogDebug("Initialized the TelemetryPublisherDisk!");
+        }
+
+        public override async Task PublishAsync(CancellationToken cancellationToken)
+        {
+            var data = GetTelemetry();
+            var messageString = JsonConvert.SerializeObject(data);
+            Logger?.LogDebug($"Telemetry message: {messageString}");
+            var encodedText = Encoding.Unicode.GetBytes(messageString);
+
+            await _fileStream.WriteAsync(encodedText, (int) _fileStream.Length,
+                encodedText.Length, cancellationToken);
+        }
+
+        public override void Dispose()
+        {
+            _fileStream.Close();
+        }
+    }
+}