this is my favorite style, though always a pain

reflect derived types, then instantiate. No registration, just derive :)

.vscode/launch.json

@@ -15,7 +15,8 @@
             "cwd": "${workspaceFolder}",
             // For more information about the 'console' field, see https://aka.ms/VSCode-CS-LaunchJson-Console
             "console": "internalConsole",
-            "stopAtEntry": false
+            "stopAtEntry": false,
+            "requireExactSource": true
         },
         {
             "name": ".NET Core Attach",

Configuration.cs

@@ -7,7 +7,7 @@ namespace newsletter
         public List<Reporter> Reporters { get; set; }
         public class Reporter
         {
-            public string Type { get; set; }
+            public string ReporterClass { get; set; }
             public string Url { get; set; }
             public string Username { get; set; }
             public string Password { get; set; }

Program.cs

@@ -63,8 +63,41 @@ namespace newsletter
 
         static List<Task<Report>> CollectReporters(Configuration conf)
         {
-            //TODO
-            throw new NotImplementedException();
+            var toReturn = new List<Task<Report>>();
+
+            var reporterTypes = AppDomain.CurrentDomain.GetAssemblies()
+              .SelectMany(domainAssembly => domainAssembly.GetTypes())
+              .Where(type => type.IsSubclassOf(typeof(newsletter.Reporters.Reporter)) && !type.IsAbstract)
+              .ToList();
+            var skipPortionInName = "newsletter.Reporters.".Length;
+
+
+            foreach(var discoveredConfType in conf.Reporters.Select(r => r.ReporterClass))
+            {
+                Console.WriteLine($"{discoveredConfType} configuration type discovered");
+            }
+            foreach (var reporterType in reporterTypes)
+            {
+                Console.WriteLine($"{reporterType.ToString().Substring(skipPortionInName).ToLower()} reporter class discovered");
+                Func<Configuration.Reporter, bool> predicate = r => r.ReporterClass == reporterType.ToString().Substring(skipPortionInName).ToLower();
+                if (!conf.Reporters.Any(predicate))
+                {
+                    Console.WriteLine($"no configurations for it");
+                }
+                else
+                {
+                    var configurationsFor = conf.Reporters.Where(predicate);
+                    Console.WriteLine($"{configurationsFor.Count()} configurations for it");
+                    
+                    foreach (var confFor in configurationsFor)
+                    {
+                         var instance = (newsletter.Reporters.Reporter) Activator.CreateInstance(reporterType);
+                        toReturn.Add(instance.Report(confFor));
+                    }
+                }
+            }
+
+            return toReturn;
         }
 
         static async Task<List<Report>> CollectReports(List<Task<Report>> tasks)
@@ -81,6 +114,7 @@ namespace newsletter
         static HtmlDocument AssembleHTML(IEnumerable<HtmlNode> reportSections)
         {
             //TODO
+            Console.WriteLine($"assembling {reportSections.Count()} sections");
             throw new NotImplementedException();
         }
 

Reporters/Dummy.cs

@@ -6,7 +6,7 @@ namespace newsletter.Reporters
     public class Dummy : Reporter
     {
         #pragma warning disable CS1998
-        public async Task<Report> Report(Configuration.Reporter config)
+        public override async Task<Report> Report(Configuration.Reporter config)
         {
             return new Report()
             {

Reporters/Reporter.cs

@@ -2,8 +2,8 @@ using System.Threading.Tasks;
 
 namespace newsletter.Reporters
 {
-    public interface Reporter
+    public abstract class Reporter
     {
-        Task<Report> Report(Configuration.Reporter config);
+        public abstract Task<Report> Report(Configuration.Reporter config);
     }
 }