Merge initial development

README.md

@@ -1,2 +1,31 @@
-# ETL-Abstractions
-Interfaces and base classes for creating ETLs
+# Wolfgang.Etl.Abstractions
+
+This package contains interfaces and base classes for building ETLs using a specific design pattern
+
+The ETL design pattern is a common approach in data processing that involves three main stages:
+- **Extract**: Retrieving data from various sources.
+- **Transform**: Processing and transforming the extracted data into a desired format.
+- **Load**: Storing the transformed data into a target system.
+
+The abstractions in this package provide a way to define and implement these stages 
+in a flexible and reusable manner. Each stage can be implemented with or without 
+support for cancellation and progress reporting, allowing for greater control 
+over the ETL process.
+
+To build an ETL using this package, you would typically need to create 5 classes:
+- One class for each of the three stages: Extract, Transform, and Load.
+- One class representing the source data.
+- One class representing the target data.
+- One class that acts as the ETL orchestrator, coordinating the execution of the three stages.
+
+The design uses lazy loading and lazy evaluation to ensure that data is processed only when needed.
+This allows for efficient memory usage and can handle large datasets without loading everything into memory at once.
+
+The process uses a pull method rather than a push method to move data through the pipeline.
+The process starts when the ETL orchestrator calls the `LoadAsyc` method of the `Loader` class. 
+The loader will start enumerating through the list of items passed into its `LoadAsync` method.
+This will intern trigger the `TransformAsync` method of the `Transformer` class, which will process each item 
+and yield the transformed results. The process of transformation will also trigger the `ExtractAsync` method of the `Extractor` class,
+which will retrieve the necessary data from the source.
+
+For more information check out the [documentation](https://github.com/Chris-Wolfgang/ETL-Abstractions/wiki)

Wolfgang.Etl.Abstractions.sln

@@ -0,0 +1,167 @@
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+Microsoft Visual Studio Solution File, Format Version 12.00
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examples/Net4.8/Example1-BasicETL/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8" />
+    </startup>
+</configuration>

examples/Net4.8/Example1-BasicETL/ETL/ConsoleLoader.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Wolfgang.Etl.Abstractions;
+
+namespace Example1_BasicETL.ETL
+{
+    internal class ConsoleLoader : ILoadAsync<string>
+    {
+        public async Task LoadAsync(IAsyncEnumerable<string> items)
+        {
+            Console.WriteLine($"{ConsoleColors.Green}Loading{ConsoleColors.Reset} data to console asynchronously...\n");
+
+            await foreach (var item in items)
+            {
+                Console.WriteLine($"Loading item: {item}\n");
+                await Task.Delay(50); // Simulate some delay for loading
+            }
+
+            Console.WriteLine($"{ConsoleColors.Green}Loading{ConsoleColors.Reset} completed.\n");
+        }
+    }
+}

examples/Net4.8/Example1-BasicETL/ETL/FibonacciExtractor.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Wolfgang.Etl.Abstractions;
+
+namespace Example1_BasicETL.ETL
+{
+    internal class FibonacciExtractor : IExtractAsync<int>
+    {
+        public async IAsyncEnumerable<int> ExtractAsync()
+        {
+            Console.WriteLine($"{ConsoleColors.Green}Extracting{ConsoleColors.Reset} Fibonacci numbers asynchronously...\n");
+
+            var current = 1;
+            var previous = 0;
+            for (var x = 0; x < 10; ++x)
+            {
+                Console.WriteLine($"Extracting Fibonacci number {x + 1}: {current}");
+                yield return current;
+                var temp = current;
+                current += previous;
+                previous = temp;
+                await Task.Yield(); // Simulate asynchronous operation
+            }
+
+            Console.WriteLine($"{ConsoleColors.Green}Extraction{ConsoleColors.Reset} completed.\n");
+        }
+    }
+}

examples/Net4.8/Example1-BasicETL/ETL/IntToStringTransformer.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Wolfgang.Etl.Abstractions;
+
+namespace Example1_BasicETL.ETL
+{
+    internal class IntToStringTransformer : ITransformAsync<int, string>
+    {
+        public async IAsyncEnumerable<string> TransformAsync(IAsyncEnumerable<int> items)
+        {
+            Console.WriteLine($"{ConsoleColors.Green}Transforming{ConsoleColors.Reset} integers to strings asynchronously...\n");
+
+            await foreach (var item in items)
+            {
+                Console.WriteLine($"Transforming integer {item} to string.");
+                await Task.Delay(50); // Simulate some delay for transformation
+                yield return item.ToString();
+            }
+
+            Console.WriteLine($"{ConsoleColors.Green}Transformation{ConsoleColors.Reset} completed.\n");
+        }
+    }
+}