Reworked the version handling of Apollo Federation. (#6839)

Author: michaelstaib

src/HotChocolate/ApolloFederation/src/ApolloFederation/Extensions/FederationVersionExtensions.cs

@@ -0,0 +1,81 @@
+using System.Collections.Generic;
+using HotChocolate.Types.Descriptors;
+using HotChocolate.Types.Descriptors.Definitions;
+
+namespace HotChocolate.ApolloFederation;
+
+internal static class FederationVersionExtensions
+{
+    private static readonly Dictionary<Uri, FederationVersion> _uriToVersion = new()
+    {
+        [new Uri(FederationVersionUrls.Federation20)] = FederationVersion.Federation20,
+        [new Uri(FederationVersionUrls.Federation21)] = FederationVersion.Federation21,
+        [new Uri(FederationVersionUrls.Federation22)] = FederationVersion.Federation22,
+        [new Uri(FederationVersionUrls.Federation23)] = FederationVersion.Federation23,
+        [new Uri(FederationVersionUrls.Federation24)] = FederationVersion.Federation24,
+        [new Uri(FederationVersionUrls.Federation25)] = FederationVersion.Federation25,
+    };
+    
+    private static readonly Dictionary<FederationVersion, Uri> _versionToUri = new()
+    {
+        [FederationVersion.Federation20] = new(FederationVersionUrls.Federation20),
+        [FederationVersion.Federation21] = new(FederationVersionUrls.Federation21),
+        [FederationVersion.Federation22] = new(FederationVersionUrls.Federation22),
+        [FederationVersion.Federation23] = new(FederationVersionUrls.Federation23),
+        [FederationVersion.Federation24] = new(FederationVersionUrls.Federation24),
+        [FederationVersion.Federation25] = new(FederationVersionUrls.Federation25),
+    };
+    
+    public static FederationVersion GetFederationVersion<T>(
+        this IDescriptor<T> descriptor)
+        where T : DefinitionBase
+    {
+        var contextData = descriptor.Extend().Context.ContextData;
+        if (contextData.TryGetValue(FederationContextData.FederationVersion, out var value) &&
+            value is FederationVersion version and > FederationVersion.Unknown)
+        {
+            return version;
+        }
+
+        // TODO : resources
+        throw new InvalidOperationException("The configuration state is invalid.");
+    }
+    
+    public static FederationVersion GetFederationVersion(
+        this IDescriptorContext context)
+    {
+        if (context.ContextData.TryGetValue(FederationContextData.FederationVersion, out var value) &&
+            value is FederationVersion version and > FederationVersion.Unknown)
+        {
+            return version;
+        }
+
+        // TODO : resources
+        throw new InvalidOperationException("The configuration state is invalid.");
+    }
+
+    public static Uri ToUrl(this FederationVersion version)
+    {
+        if(_versionToUri.TryGetValue(version, out var url))
+        {
+            return url;
+        }
+        
+        // TODO : resources
+        throw new ArgumentException("The federation version is not supported.", nameof(version));
+    }
+    
+    public static FederationVersion ToVersion(this Uri url)
+    {
+        if(_uriToVersion.TryGetValue(url, out var version))
+        {
+            return version;
+        }
+        
+        // TODO : resources
+        throw new ArgumentException("The federation url is not supported.", nameof(url));
+    }
+    
+    public static bool TryToVersion(this Uri url, out FederationVersion version)
+        => _uriToVersion.TryGetValue(url, out version);
+}

src/HotChocolate/ApolloFederation/src/ApolloFederation/Types/Directives/FederationContextData.cs renamed to src/HotChocolate/ApolloFederation/src/ApolloFederation/FederationContextData.cs

@@ -7,6 +7,7 @@ internal static class FederationContextData
     public const string ExternalSetter = "HotChocolate.ApolloFederation.ExternalSetter";
     public const string EntityResolver = "HotChocolate.ApolloFederation.EntityResolver";
     public const string FederationVersion = "HotChocolate.ApolloFederation.Version";
+    public const string ExportedDirectives = "HotChocolate.ApolloFederation.ExportedDirectives";
     public const string DataField = "data";
     public const string TypeField = "__type";
 }

src/HotChocolate/ApolloFederation/src/ApolloFederation/FederationTypeInterceptor.cs

@@ -39,9 +39,10 @@ internal sealed class FederationTypeInterceptor : TypeInterceptor
                 BindingFlags.Static | BindingFlags.Public)!;
 
     private readonly List<ObjectType> _entityTypes = new();
-    private readonly Dictionary<string, HashSet<string>> _imports = new();
+    private readonly Dictionary<Uri, HashSet<string>> _imports = new();
     private IDescriptorContext _context = default!;
     private ITypeInspector _typeInspector = default!;
+    private TypeRegistry _typeRegistry = default!;
     private ObjectType _queryType = default!;
     private ExtendedTypeDirectiveReference _keyDirectiveReference = default!;
     private SchemaTypeDefinition _schemaTypeDefinition = default!;
@@ -57,6 +58,7 @@ internal override void InitializeContext(
     {
         _typeInspector = context.TypeInspector;
         _context = context;
+        _typeRegistry = typeRegistry;
         _keyDirectiveReference = new ExtendedTypeDirectiveReference(_typeInspector.GetType(typeof(KeyDirective)));
         ModifyOptions(context, o => o.Mode = TagMode.ApolloFederation);
     }
@@ -102,7 +104,7 @@ public override IEnumerable<TypeReference> RegisterMoreTypes(
             yield return _typeInspector.GetTypeRef(typeof(LinkDirective));
         }
     }
-    
+
     public override void OnBeforeCompleteName(
         ITypeCompletionContext completionContext,
         DefinitionBase definition)
@@ -125,7 +127,7 @@ public override void OnAfterCompleteName(
 
         var hasRuntimeType = (IHasRuntimeType)definition;
         var type = hasRuntimeType.RuntimeType;
-        
+
         if (type != typeof(object) &&
             type.IsDefined(typeof(PackageAttribute)))
         {
@@ -134,6 +136,7 @@ public override void OnAfterCompleteName(
         }
 
         type = completionContext.Type.GetType();
+
         if (type.IsDefined(typeof(PackageAttribute)))
         {
             RegisterImport(type);
@@ -167,22 +170,105 @@ void RegisterImport(MemberInfo element)
     }
 
     public override void OnTypesCompletedName()
+    {
+        RegisterExportedDirectives();
+        RegisterImports();
+    }
+
+    private void RegisterImports()
     {
         if (_imports.Count == 0)
         {
             return;
         }
 
+        var version = _context.GetFederationVersion();
+        var federationTypes = new HashSet<string>();
+
+        foreach (var import in _imports)
+        {
+            if (!import.Key.TryToVersion(out var importVersion))
+            {
+                continue;
+            }
+
+            if (importVersion > version)
+            {
+                // todo: throw helper
+                throw new SchemaException(
+                    SchemaErrorBuilder.New()
+                        .SetMessage(
+                            "The following federation types were used and are not supported by " +
+                            "the current federation version: {0}",
+                            string.Join(", ", import.Value))
+                        .Build());
+            }
+
+            federationTypes.UnionWith(import.Value);
+        }
+
+        if (version == FederationVersion.Federation10)
+        {
+            return;
+        }
+
         var dependency = new TypeDependency(
             _typeInspector.GetTypeRef(typeof(LinkDirective)),
             TypeDependencyFulfilled.Completed);
         _schemaType.Dependencies.Add(dependency);
 
+        _schemaTypeDefinition
+            .GetLegacyDefinition()
+            .AddDirective(
+                new LinkDirective(version.ToUrl(), federationTypes),
+                _typeInspector);
+
         foreach (var import in _imports)
         {
+            if (import.Key.TryToVersion(out _))
+            {
+                continue;
+            }
+
             _schemaTypeDefinition
                 .GetLegacyDefinition()
-                .AddDirective(new LinkDirective(new Uri(import.Key), import.Value), _typeInspector);
+                .AddDirective(
+                    new LinkDirective(import.Key, import.Value),
+                    _typeInspector);
+        }
+    }
+
+    private void RegisterExportedDirectives()
+    {
+        if (!_context.ContextData.TryGetValue(ExportedDirectives, out var value) ||
+            value is not List<Type> exportedDirectives)
+        {
+            return;
+        }
+
+        var composeDirectives = new List<ComposeDirective>();
+        foreach (var exportedDirective in exportedDirectives)
+        {
+            var typeReference = _typeInspector.GetTypeRef(exportedDirective);
+            if (_typeRegistry.TryGetType(typeReference, out var exportedDirectiveType))
+            {
+                composeDirectives.Add(new ComposeDirective(exportedDirectiveType.Type.Name));
+            }
+        }
+
+        if (composeDirectives.Count > 0)
+        {
+            var dependency = new TypeDependency(
+                _typeInspector.GetTypeRef(typeof(ComposeDirective)),
+                TypeDependencyFulfilled.Completed);
+            _schemaType.Dependencies.Add(dependency);
+
+            foreach (var directive in composeDirectives)
+            {
+                _schemaTypeDefinition
+                    .GetLegacyDefinition()
+                    .AddDirective(directive, _typeInspector);
+            }
         }
     }
 

src/HotChocolate/ApolloFederation/src/ApolloFederation/FederationVersion.cs

@@ -13,6 +13,6 @@ public enum FederationVersion
     Federation23 = 2_3,
     Federation24 = 2_4,
     Federation25 = 2_5,
-    Federation26 = 2_6,
-    Latest = Federation26,
+    // Federation26 = 2_6,
+    Latest = Federation25,
 }

src/HotChocolate/ApolloFederation/src/ApolloFederation/FederationVersionExtensions.cs

@@ -104,11 +104,15 @@
     <Compile Update="Types\Directives\RequiresScopesDescriptorExtensions.cs">
       <DependentUpon>RequiresScopesDirective.cs</DependentUpon>
     </Compile>
-    <Compile Update="Types\Directives\FederationResources.Designer.cs">
+    <Compile Update="Properties\FederationResources.Designer.cs">
       <DesignTime>True</DesignTime>
       <AutoGen>True</AutoGen>
       <DependentUpon>FederationResources.resx</DependentUpon>
     </Compile>
+    <EmbeddedResource Update="Properties\FederationResources.resx">
+      <Generator>ResXFileCodeGenerator</Generator>
+      <LastGenOutput>FederationResources.Designer.cs</LastGenOutput>
+    </EmbeddedResource>
     <Compile Update="Types\Directives\RequiresScopesAttribute.cs">
       <DependentUpon>RequiresScopesDirective.cs</DependentUpon>
     </Compile>
@@ -119,15 +123,4 @@
     <None Include="$(MSBuildThisFileDirectory)..\MSBuild\HotChocolate.ApolloFederation.targets" Pack="true" PackagePath="build/HotChocolate.ApolloFederation.targets" Visible="false" />
   </ItemGroup>
 
-  <ItemGroup>
-    <Folder Include="Properties\" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <EmbeddedResource Update="Types\Directives\FederationResources.resx">
-      <Generator>ResXFileCodeGenerator</Generator>
-      <LastGenOutput>FederationResources.Designer.cs</LastGenOutput>
-    </EmbeddedResource>
-  </ItemGroup>
-
 </Project>

src/HotChocolate/ApolloFederation/src/ApolloFederation/HotChocolate.ApolloFederation.csproj

@@ -1,8 +1,7 @@
 using System.Reflection;
-using HotChocolate.ApolloFederation.Types;
 using HotChocolate.Types.Descriptors;
 
-namespace HotChocolate.ApolloFederation;
+namespace HotChocolate.ApolloFederation.Types;
 
 /// <summary>
 /// <code>