(GH-71) Sources can have explicit priority order

When a priority order is specified, sources will order explicitly by
that order, lowest number above zero will have the highest priority and
so on, then any items with a priority of 0 will be evaluated in
configuration file order.

src/chocolatey/infrastructure.app/builders/ConfigurationBuilder.cs

@@ -73,7 +73,15 @@ private static void set_file_configuration(ChocolateyConfiguration config, IFile
 
             var configFileSettings = xmlService.deserialize<ConfigFileSettings>(globalConfigPath);
             var sources = new StringBuilder();
-            foreach (var source in configFileSettings.Sources.Where(s => !s.Disabled).or_empty_list_if_null())
+
+            var defaultSourcesInOrder = configFileSettings.Sources.Where(s => !s.Disabled).or_empty_list_if_null().ToList();
+            if (configFileSettings.Sources.Any(s => s.Priority > 0))
+            {
+                defaultSourcesInOrder = configFileSettings.Sources.Where(s => !s.Disabled && s.Priority != 0).OrderBy(s => s.Priority).or_empty_list_if_null().ToList();
+                defaultSourcesInOrder.AddRange(configFileSettings.Sources.Where(s => !s.Disabled && s.Priority == 0 ).or_empty_list_if_null().ToList());
+            }
+
+            foreach (var source in defaultSourcesInOrder)
             {
                 sources.AppendFormat("{0};", source.Value);
             }
@@ -120,7 +128,8 @@ private static void set_machine_sources(ChocolateyConfiguration config, ConfigFi
                         Key = source.Value,
                         Name = source.Id,
                         Username = source.UserName,
-                        EncryptedPassword = source.Password
+                        EncryptedPassword = source.Password,
+                        Priority = source.Priority
                     });
             }
         }

src/chocolatey/infrastructure.app/commands/ChocolateySourceCommand.cs

@@ -53,7 +53,10 @@ public void configure_argument_parser(OptionSet optionSet, ChocolateyConfigurati
                      option => configuration.SourceCommand.Username = option.remove_surrounding_quotes())
                 .Add("p=|password=",
                      "Password - the user's password to the source. Encrypted in chocolatey.config file.",
-                     option => configuration.SourceCommand.Password = option.remove_surrounding_quotes())
+                     option => configuration.SourceCommand.Password = option.remove_surrounding_quotes())  
+                .Add("priority=",
+                     "Priority - The priority order of this source as compared to other sources, lower is better. Defaults to 0 (no priority). All priorities above 0 will be evaluated first, then zero-based values will be evaluated in config file order.",
+                     option => configuration.SourceCommand.Priority = int.Parse(option.remove_surrounding_quotes()))
                 ;
         }
 

src/chocolatey/infrastructure.app/configuration/ChocolateyConfiguration.cs

@@ -355,6 +355,7 @@ public sealed class SourcesCommandConfiguration
         public SourceCommandType Command { get; set; }
         public string Username { get; set; }
         public string Password { get; set; }
+        public int Priority { get; set; }
     }
 
     [Serializable]
@@ -364,6 +365,7 @@ public sealed class MachineSourceConfiguration
         public string Key { get; set; }
         public string Username { get; set; }
         public string EncryptedPassword { get; set; }
+        public int Priority { get; set; }
     }
 
     [Serializable]

src/chocolatey/infrastructure.app/configuration/ConfigFileSourceSetting.cs

@@ -38,6 +38,9 @@ public sealed class ConfigFileSourceSetting
         public string UserName { get; set; }
 
         [XmlAttribute(AttributeName = "password")]
-        public string Password { get; set; }
+        public string Password { get; set; }   
+
+        [XmlAttribute(AttributeName = "priority")]
+        public int Priority { get; set; }
     }
 }

src/chocolatey/infrastructure.app/services/ChocolateyConfigSettingsService.cs

@@ -19,6 +19,7 @@ namespace chocolatey.infrastructure.app.services
     using System.Linq;
     using configuration;
     using infrastructure.services;
+    using logging;
     using nuget;
 
     internal class ChocolateyConfigSettingsService : IChocolateyConfigSettingsService
@@ -47,7 +48,12 @@ public void source_list(ChocolateyConfiguration configuration)
         {
             foreach (var source in configFileSettings.Sources)
             {
-                this.Log().Info(() => "{0}{1} - {2}".format_with(source.Id, source.Disabled ? " [Disabled]" : string.Empty, source.Value));
+                this.Log().Info(() => "{0}{1} - {2} {3}| Priority {4}.".format_with(
+                    source.Id, 
+                    source.Disabled ? " [Disabled]" : string.Empty, 
+                    source.Value,
+                    string.IsNullOrWhiteSpace(source.UserName) ? string.Empty : "(Authenticated)", 
+                    source.Priority));
             }
         }
 
@@ -56,17 +62,18 @@ public void source_add(ChocolateyConfiguration configuration)
             var source = configFileSettings.Sources.FirstOrDefault(p => p.Id.is_equal_to(configuration.SourceCommand.Name));
             if (source == null)
             {
-                configFileSettings.Sources.Add(new ConfigFileSourceSetting
-                    {
-                        Id = configuration.SourceCommand.Name,
-                        Value = configuration.Sources,
-                        UserName = configuration.SourceCommand.Username,
-                        Password = NugetEncryptionUtility.EncryptString(configuration.SourceCommand.Password),
-                    });
+                source = new ConfigFileSourceSetting
+                {
+                    Id = configuration.SourceCommand.Name,
+                    Value = configuration.Sources,
+                    UserName = configuration.SourceCommand.Username,
+                    Password = NugetEncryptionUtility.EncryptString(configuration.SourceCommand.Password),
+                    Priority = configuration.SourceCommand.Priority
+                };
+                configFileSettings.Sources.Add(source);
 
                 _xmlService.serialize(configFileSettings, ApplicationParameters.GlobalConfigFileLocation);
-
-                this.Log().Warn(() => "Added {0} - {1}".format_with(configuration.SourceCommand.Name, configuration.Sources));
+                this.Log().Warn(() => "Added {0} - {1} (Priority {2})".format_with(source.Id, source.Value, source.Priority));
             }
             else
             {