Add entity-scoped GraphQL subscription support

schemas/dab.draft.schema.json

@@ -1348,6 +1348,27 @@
                       "$ref": "#/$defs/boolean-or-string",
                       "description": "Allow enabling/disabling GraphQL requests for this specific entity.",
                       "default": true
+                    },
+                    "subscription": {
+                      "type": "object",
+                      "additionalProperties": false,
+                      "description": "GraphQL subscription configuration for this entity.",
+                      "properties": {
+                        "enabled": {
+                          "$ref": "#/$defs/boolean-or-string",
+                          "description": "Allow enabling/disabling GraphQL subscriptions for this specific entity.",
+                          "default": true
+                        },
+                        "events": {
+                          "type": "array",
+                          "description": "GraphQL subscription events to generate for this entity.",
+                          "items": {
+                            "type": "string",
+                            "enum": ["created", "updated", "deleted"]
+                          },
+                          "uniqueItems": true
+                        }
+                      }
                     }
                   },
                   "anyOf": [
@@ -1359,6 +1380,9 @@
                     },
                     {
                       "required": ["enabled"]
+                    },
+                    {
+                      "required": ["subscription"]
                     }
                   ]
                 }

src/Cli/Commands/EntityOptions.cs

@@ -38,6 +38,8 @@ public EntityOptions(
             IEnumerable<bool>? fieldsPrimaryKeyCollection,
             string? mcpDmlTools = null,
             string? mcpCustomTool = null,
+            string? graphQLSubscriptionEnabled = null,
+            string? graphQLSubscriptionEvents = null,
             string? config = null
         )
             : base(config)
@@ -69,6 +71,8 @@ public EntityOptions(
             FieldsPrimaryKeyCollection = fieldsPrimaryKeyCollection;
             McpDmlTools = mcpDmlTools;
             McpCustomTool = mcpCustomTool;
+            GraphQLSubscriptionEnabled = graphQLSubscriptionEnabled;
+            GraphQLSubscriptionEvents = graphQLSubscriptionEvents;
         }
 
         // Entity is required but we have made required as false to have custom error message (more user friendly), if not provided.
@@ -96,6 +100,12 @@ public EntityOptions(
         [Option("graphql.operation", Required = false, HelpText = "GraphQL operation to be supported for stored procedure. Valid operations are: [query, mutation]")]
         public string? GraphQLOperationForStoredProcedure { get; }
 
+        [Option("graphql.subscription.enabled", Required = false, HelpText = "Enable or disable GraphQL subscriptions for the entity.")]
+        public string? GraphQLSubscriptionEnabled { get; }
+
+        [Option("graphql.subscription.events", Required = false, HelpText = "GraphQL subscription events for the entity as a comma separated list. Valid events are: [created, updated, deleted]")]
+        public string? GraphQLSubscriptionEvents { get; }
+
         [Option("fields.include", Required = false, Separator = ',', HelpText = "Fields that are allowed access to permission.")]
         public IEnumerable<string>? FieldsToInclude { get; }
 

src/Cli/ConfigGenerator.cs

@@ -3361,7 +3361,32 @@ private static EntityGraphQLOptions ConstructUpdatedGraphQLDetails(Entity entity
                 graphQLOperation = GraphQLOperation.Mutation;
             }
 
-            return graphQLType with { Operation = graphQLOperation };
+            EntityGraphQLSubscriptionOptions? subscription = graphQLType.Subscription;
+
+            if (options.GraphQLSubscriptionEnabled is not null || options.GraphQLSubscriptionEvents is not null)
+            {
+                bool enabled = subscription?.Enabled ?? true;
+                GraphQLSubscriptionEvent[] events = subscription?.Events ?? Array.Empty<GraphQLSubscriptionEvent>();
+
+                if (options.GraphQLSubscriptionEnabled is not null)
+                {
+                    enabled = bool.Parse(options.GraphQLSubscriptionEnabled);
+                }
+
+                if (options.GraphQLSubscriptionEvents is not null)
+                {
+                    events = string.IsNullOrWhiteSpace(options.GraphQLSubscriptionEvents)
+                        ? Array.Empty<GraphQLSubscriptionEvent>()
+                        : options.GraphQLSubscriptionEvents
+                            .Split(',', StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries)
+                            .Select(value => Enum.Parse<GraphQLSubscriptionEvent>(value, ignoreCase: true))
+                            .ToArray();
+                }
+
+                subscription = new EntityGraphQLSubscriptionOptions(enabled, events);
+            }
+
+            return graphQLType with { Operation = graphQLOperation, Subscription = subscription };
         }
 
         /// <summary>

src/Config/Converters/EntityGraphQLOptionsConverterFactory.cs

@@ -52,12 +52,13 @@ public EntityGraphQLOptionsConverter(DeserializationVariableReplacementSettings?
                 string plural = string.Empty;
                 bool enabled = true;
                 GraphQLOperation? operation = null;
+                EntityGraphQLSubscriptionOptions? subscription = null;
 
                 while (reader.Read())
                 {
                     if (reader.TokenType is JsonTokenType.EndObject)
                     {
-                        return new EntityGraphQLOptions(singular, plural, enabled, operation);
+                        return new EntityGraphQLOptions(singular, plural, enabled, operation, subscription);
                     }
 
                     string? property = reader.GetString();
@@ -117,6 +118,9 @@ public EntityGraphQLOptionsConverter(DeserializationVariableReplacementSettings?
                                 operation = Enum.Parse<GraphQLOperation>(op, ignoreCase: true);
                             }
 
+                            break;
+                        case "subscription":
+                            subscription = JsonSerializer.Deserialize<EntityGraphQLSubscriptionOptions>(ref reader, options);
                             break;
                     }
                 }
@@ -157,6 +161,12 @@ public override void Write(Utf8JsonWriter writer, EntityGraphQLOptions value, Js
                 writer.WriteNull("operation");
             }
 
+            if (value.Subscription is not null)
+            {
+                writer.WritePropertyName("subscription");
+                JsonSerializer.Serialize(writer, value.Subscription, options);
+            }
+
             writer.WriteStartObject("type");
             writer.WriteString("singular", value.Singular);
             writer.WriteString("plural", value.Plural);

src/Config/ObjectModel/EntityGraphQLOptions.cs

@@ -10,5 +10,6 @@ namespace Azure.DataApiBuilder.Config.ObjectModel;
 /// <param name="Plural">The pluralisation of the entity. If none is provided a pluralisation of the Singular property is used.</param>
 /// <param name="Enabled">Indicates if GraphQL is enabled for the entity.</param>
 /// <param name="Operation">When the entity maps to a stored procedure, this represents the GraphQL operation to use, otherwise it will be null.</param>
+/// <param name="Subscription">GraphQL subscription settings for the entity.</param>
 /// <seealso cref="https://engdic.org/singular-and-plural-noun-rules-definitions-examples"/>
-public record EntityGraphQLOptions(string Singular, string Plural, bool Enabled = true, GraphQLOperation? Operation = null);
+public record EntityGraphQLOptions(string Singular, string Plural, bool Enabled = true, GraphQLOperation? Operation = null, EntityGraphQLSubscriptionOptions? Subscription = null);

src/Config/ObjectModel/EntityGraphQLSubscriptionOptions.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace Azure.DataApiBuilder.Config.ObjectModel;
+
+/// <summary>
+/// Describes GraphQL subscription settings specific to an entity.
+/// </summary>
+/// <param name="Enabled">Indicates if GraphQL subscriptions are enabled for the entity.</param>
+/// <param name="Events">The enabled subscription events.</param>
+public record EntityGraphQLSubscriptionOptions(bool Enabled = true, GraphQLSubscriptionEvent[]? Events = null)
+{
+    public GraphQLSubscriptionEvent[] Events { get; init; } = Events ?? Array.Empty<GraphQLSubscriptionEvent>();
+}

src/Config/ObjectModel/GraphQLSubscriptionEvent.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace Azure.DataApiBuilder.Config.ObjectModel;
+
+/// <summary>
+/// GraphQL subscription events supported by DAB.
+/// </summary>
+public enum GraphQLSubscriptionEvent
+{
+    Created,
+    Updated,
+    Deleted
+}

src/Core/Azure.DataApiBuilder.Core.csproj

@@ -28,6 +28,7 @@
     <PackageReference Include="HotChocolate" />
     <PackageReference Include="HotChocolate.AspNetCore" />
     <PackageReference Include="HotChocolate.AspNetCore.Authorization" />
+    <PackageReference Include="HotChocolate.Subscriptions.InMemory" />
     <PackageReference Include="HotChocolate.Types.NodaTime" />
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" />
     <PackageReference Include="Microsoft.IdentityModel.Validators" />

src/Core/Configurations/RuntimeConfigValidator.cs

@@ -983,6 +983,11 @@ public void ValidateEntityConfiguration(RuntimeConfig runtimeConfig)
             {
                 ValidateNameRequirements(entity.GraphQL.Singular);
                 ValidateNameRequirements(entity.GraphQL.Plural);
+
+                if (entity.GraphQL.Subscription is { Enabled: true, Events.Length: 0 })
+                {
+                    _logger.LogWarning("Entity {entityName} has GraphQL subscriptions enabled but no subscription events configured.", entityName);
+                }
             }
         }
     }

src/Core/Resolvers/Factories/MutationEngineFactory.cs

@@ -7,6 +7,7 @@
 using Azure.DataApiBuilder.Config.ObjectModel;
 using Azure.DataApiBuilder.Core.Configurations;
 using Azure.DataApiBuilder.Core.Models;
+using Azure.DataApiBuilder.Core.Services;
 using Azure.DataApiBuilder.Core.Services.MetadataProviders;
 using Azure.DataApiBuilder.Service.Exceptions;
 using Microsoft.AspNetCore.Http;
@@ -29,6 +30,7 @@ public class MutationEngineFactory : IMutationEngineFactory
         private readonly IHttpContextAccessor _httpContextAccessor;
         private readonly IAuthorizationResolver _authorizationResolver;
         private readonly GQLFilterParser _gQLFilterParser;
+        private readonly IGraphQLSubscriptionEventPublisher _subscriptionEventPublisher;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="MutationEngineFactory"/> class.
@@ -49,6 +51,7 @@ public MutationEngineFactory(RuntimeConfigProvider runtimeConfigProvider,
             IHttpContextAccessor httpContextAccessor,
             IAuthorizationResolver authorizationResolver,
             GQLFilterParser gQLFilterParser,
+            IGraphQLSubscriptionEventPublisher subscriptionEventPublisher,
             HotReloadEventHandler<HotReloadEventArgs>? handler)
 
         {
@@ -61,6 +64,7 @@ public MutationEngineFactory(RuntimeConfigProvider runtimeConfigProvider,
             _queryEngineFactory = queryEngineFactory;
             _runtimeConfigProvider = runtimeConfigProvider;
             _gQLFilterParser = gQLFilterParser;
+            _subscriptionEventPublisher = subscriptionEventPublisher;
             _mutationEngines = new Dictionary<DatabaseType, IMutationEngine>();
             ConfigureMutationEngines();
         }
@@ -78,7 +82,8 @@ private void ConfigureMutationEngines()
                     _authorizationResolver,
                     _gQLFilterParser,
                     _httpContextAccessor,
-                    _runtimeConfigProvider);
+                    _runtimeConfigProvider,
+                    _subscriptionEventPublisher);
                 _mutationEngines.Add(DatabaseType.MySQL, mutationEngine);
                 _mutationEngines.Add(DatabaseType.MSSQL, mutationEngine);
                 _mutationEngines.Add(DatabaseType.PostgreSQL, mutationEngine);