(cake-buildGH-2904) Frosting cake.config&tool config support

* Frosting utilize CakeConfigurationProvider, enables config
    * Frosting IServiceCollection.UseToolPath
    * cake.config file
    * environment variables
    * command line arguments
* Tools path should be resolved using configuration
* fixes cake-build#2904

src/Cake.Core/Configuration/CakeConfigurationProvider.cs

@@ -4,6 +4,8 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
 using Cake.Core.Configuration.Parser;
 using Cake.Core.IO;
 
@@ -43,18 +45,40 @@ public CakeConfigurationProvider(IFileSystem fileSystem, ICakeEnvironment enviro
         /// <param name="arguments">The arguments.</param>
         /// <returns>The created configuration.</returns>
         public ICakeConfiguration CreateConfiguration(DirectoryPath path, IDictionary<string, string> arguments)
+            => CreateConfiguration(path, Enumerable.Empty<KeyValuePair<string, string>>(), arguments);
+
+        /// <summary>
+        /// Creates a configuration from the provided arguments.
+        /// </summary>
+        /// <param name="path">The directory to look for the configuration file.</param>
+        /// <param name="baseConfiguration">The initial base configuration.</param>
+        /// <param name="arguments">The arguments.</param>
+        /// <returns>The created configuration.</returns>
+        public ICakeConfiguration CreateConfiguration(DirectoryPath path, IEnumerable<KeyValuePair<string, string>> baseConfiguration, IDictionary<string, string> arguments)
         {
             if (path == null)
             {
                 throw new ArgumentNullException(nameof(path));
             }
+
+            if (baseConfiguration == null)
+            {
+                throw new ArgumentNullException(nameof(baseConfiguration));
+            }
+
             if (arguments == null)
             {
                 throw new ArgumentNullException(nameof(arguments));
             }
 
             var result = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
 
+            // Add base configuration.
+            foreach (var kv in baseConfiguration)
+            {
+                result[KeyNormalizer.Normalize(kv.Key)] = kv.Value;
+            }
+
             // Get all environment variables.
             foreach (var variable in _environment.GetEnvironmentVariables())
             {

src/Cake.Frosting/Extensions/ServiceCollectionExtensions.cs

@@ -178,5 +178,16 @@ public static IServiceCollection UseCakeSetting(this IServiceCollection services
             services.AddSingleton(new FrostingConfigurationValue(key, value));
             return services;
         }
+
+        /// <summary>
+        /// Sets the tool path configuration to the specified value.
+        /// </summary>
+        /// <param name="services">The service collection.</param>
+        /// <param name="toolPath">The tool path value.</param>
+        /// <returns>The same <see cref="IServiceCollection"/> instance so that multiple calls can be chained.</returns>
+        public static IServiceCollection UseToolPath(this IServiceCollection services, DirectoryPath toolPath)
+        {
+            return services.UseCakeSetting("paths_tools", toolPath.FullPath);
+        }
     }
 }

src/Cake.Frosting/Internal/Commands/DefaultCommand.cs

@@ -28,6 +28,7 @@ public override int Execute(CommandContext context, DefaultCommandSettings setti
             // Register arguments
             var arguments = new CakeArguments(context.Remaining.Parsed);
             _services.AddSingleton<ICakeArguments>(arguments);
+            _services.AddSingleton(context.Remaining);
 
             var provider = _services.BuildServiceProvider();
 

src/Cake.Frosting/Internal/FrostingConfiguration.cs

@@ -4,32 +4,47 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
+using Cake.Core;
 using Cake.Core.Configuration;
+using Cake.Core.IO;
+using Spectre.Console.Cli;
 
 namespace Cake.Frosting.Internal
 {
     internal sealed class FrostingConfiguration : ICakeConfiguration
     {
-        private readonly Dictionary<string, string> _lookup;
+        private readonly ICakeConfiguration _cakeConfiguration;
 
-        public FrostingConfiguration(IEnumerable<FrostingConfigurationValue> values)
+        public FrostingConfiguration(IEnumerable<FrostingConfigurationValue> values, IFileSystem fileSystem, ICakeEnvironment environment, IRemainingArguments remainingArguments)
         {
             if (values is null)
             {
                 throw new ArgumentNullException(nameof(values));
             }
 
-            _lookup = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+            if (fileSystem is null)
+            {
+                throw new ArgumentNullException(nameof(fileSystem));
+            }
+
+            if (environment is null)
+            {
+                throw new ArgumentNullException(nameof(environment));
+            }
+
+            var baseConfiguration = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
             foreach (var value in values)
             {
-                _lookup[value.Key] = value.Value;
+                baseConfiguration[value.Key] = value.Value;
             }
-        }
 
-        public string GetValue(string key)
-        {
-            _lookup.TryGetValue(key, out var value);
-            return value;
+            var provider = new CakeConfigurationProvider(fileSystem, environment);
+            var args = remainingArguments.Parsed.ToDictionary(x => x.Key, x => x.FirstOrDefault() ?? string.Empty);
+
+            _cakeConfiguration = provider.CreateConfiguration(environment.WorkingDirectory, baseConfiguration, args);
         }
+
+        public string GetValue(string key) => _cakeConfiguration.GetValue(key);
     }
 }

tests/integration/Cake.Frosting/build/Build.csproj

@@ -6,7 +6,7 @@
     <PackAsTool>true</PackAsTool>
 
     <!-- Make sure start same folder .NET Core CLI and Visual Studio -->
-    <RunWorkingDirectory>$(MSBuildProjectDirectory)</RunWorkingDirectory>
+    <RunWorkingDirectory>$(MSBuildProjectDirectory)\..</RunWorkingDirectory>
   </PropertyGroup>
 
   <ItemGroup>

tests/integration/Cake.Frosting/build/Program.cs

@@ -13,6 +13,7 @@ public void Configure(IServiceCollection services)
     {
         services.UseContext<Context>();
         services.UseLifetime<Lifetime>();
+        services.UseTool(new System.Uri("nuget:?package=xunit.runner.console"));
         services.UseWorkingDirectory("..");
     }
 }

tests/integration/Cake.Frosting/cake.config

@@ -0,0 +1,2 @@
+[Paths]
+Tools=../tools/frostingtools