Add entity-scoped GraphQL subscription support

[Copilot]

Why make this change?

• DAB needs entity-scoped GraphQL subscriptions for created, updated, and deleted events over the existing GraphQL endpoint. Subscriptions should stay invisible unless an entity configures subscription events, use process-local Hot Chocolate WebSockets, and publish only DAB-originated writes.

What is this change?

• Entity configuration + CLI

  • Adds entity-level entities.<name>.graphql.subscription.enabled and entities.<name>.graphql.subscription.events.
  • Supports config merge behavior through existing JSON merge/deserialization paths.
  • Updates schema validation for entity subscription config, including stored-procedure rejection and JSON schema defaults for empty event lists.
  • Adds CLI support for dab update <entity> --graphql.subscription.events and --graphql.subscription.enabled, with validation errors for invalid values.

• GraphQL schema

  • Adds SubscriptionEvent and entity event types only when entity events are configured and eligible.
  • Generates event fields such as actorCreated, actorUpdated, actorDeleted.
  • Omits fields when no role has the matching write permission.
  • Omits Cosmos subscription fields until Cosmos write-event publishing support exists.
  • Uses the SubscriptionEvent interface as the explicit resolver marker for generated event payloads.
  • Keeps subscription schema generation compatible with the latest main Hot Chocolate 16 stable updates.
  • Resolves subscription metadata scalar fields through the normal leaf resolver so UUID and DateTime payload fields use the expected Hot Chocolate runtime types.

• Runtime publishing

  • Keeps subscription schema fields absent unless an entity enables eligible events, while registering process-local subscription infrastructure so late-configured and hot-reloaded subscription settings can become active.
  • Enables WebSocket middleware for late configuration, while dynamically rejecting WebSocket upgrades when no eligible subscription field exists.
  • Publishes SQL DAB write events from GraphQL, REST, and MCP mutation paths.
  • Handles compound GraphQL mutations and multiple-create results by emitting one event per affected record.
  • Delete payloads publish primary-key data only, ignore non-key GraphQL arguments, and do not publish for no-op deletes.
  • Logs publish failures without converting already-committed writes into API errors.

• Telemetry

  • Logs subscription creation, closure, WebSocket connection lifecycle, and event publication details.
  • Adds active subscription metric: active_graphql_subscriptions.
  • Increments active subscription counts only after successful subscription setup.
  • Includes eventId in payloads and publish telemetry.
  • Avoids logging full GraphQL documents, connection init payloads, authorization tokens, or record payload values.

"entities": {
  "Actor": {
    "graphql": {
      "subscription": {
        "events": [ "created", "updated", "deleted" ]
      }
    }
  }
}

How was this tested?

• Integration Tests
• Unit Tests
• Solution Build
• CodeQL Security Scan final rerun
• Code Review Validation
• Independent GPT-5.5 spec/code review

Final CodeQL validation was attempted after the latest spec-follow-up changes, but the validation tool hit its time limit before completing.

Sample Request(s)

subscription {
  actorUpdated {
    eventId
    utcDateTime
    actorRole
    record {
      Id
      Name
    }
  }
}

dab update Actor --graphql.subscription.events "created,updated,deleted"
dab update Actor --graphql.subscription.enabled false

[Copilot]

Pull request overview

Adds entity-scoped GraphQL subscription support to DAB (schema generation + in-process Hot Chocolate WebSocket subscriptions) and publishes DAB-originated write events from GraphQL/REST paths, with config/CLI/schema updates and unit tests.

Changes:

• Introduces per-entity GraphQL subscription configuration (graphql.subscription.enabled / graphql.subscription.events) across config object model, CLI, and JSON schema validation.
• Generates GraphQL Subscription fields and event payload types conditionally (based on configured events + role write permissions).
• Publishes created/updated/deleted events from mutation paths and tracks active subscriptions via metrics/telemetry.

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/Service/Startup.cs	Registers subscription publisher, enables Hot Chocolate in-memory subscriptions, and enables WebSockets middleware.
src/Service/Azure.DataApiBuilder.Service.csproj	Adds HotChocolate in-memory subscriptions package reference.
src/Service.Tests/UnitTests/SerializationDeserializationTests.cs	Adds config merge/deserialization coverage for entity subscription options.
src/Service.Tests/UnitTests/GraphQLSubscriptionEventTests.cs	Adds unit tests for extracting per-record publish payloads from mutation results.
src/Service.Tests/GraphQLBuilder/SubscriptionBuilderTests.cs	Adds tests for subscription SDL generation and permission-based field omission.
src/Service.GraphQLBuilder/Subscriptions/SubscriptionBuilder.cs	Implements subscription SDL generation (event interface, event types, subscription fields).
src/Directory.Packages.props	Central package version for HotChocolate.Subscriptions.InMemory.
src/Core/Telemetry/TelemetryMetricsHelper.cs	Adds an active GraphQL subscriptions UpDownCounter metric.
src/Core/Services/ResolverTypeInterceptor.cs	Wires subscription resolvers and adds special pure-resolver handling for event payload types.
src/Core/Services/GraphQLSubscriptionEventPublisher.cs	Adds event publish/subscribe abstraction using Hot Chocolate topics + telemetry/logging.
src/Core/Services/GraphQLSchemaCreator.cs	Adds subscription document generation and injects publisher/logger into ExecutionHelper.
src/Core/Services/ExecutionHelper.cs	Adds subscription subscribe resolver, event payload resolvers, and subscription metric tracking.
src/Core/Resolvers/SqlMutationEngine.cs	Publishes subscription events after successful mutations (GraphQL + REST paths).
src/Core/Resolvers/Factories/MutationEngineFactory.cs	Injects subscription publisher into mutation engines.
src/Core/Configurations/RuntimeConfigValidator.cs	Warns when subscriptions are enabled but no events are configured.
src/Core/Azure.DataApiBuilder.Core.csproj	Adds HotChocolate in-memory subscriptions package reference.
src/Config/ObjectModel/GraphQLSubscriptionEvent.cs	Adds enum for supported subscription event kinds.
src/Config/ObjectModel/EntityGraphQLSubscriptionOptions.cs	Adds per-entity subscription options model.
src/Config/ObjectModel/EntityGraphQLOptions.cs	Extends entity GraphQL options to include subscription settings.
src/Config/Converters/EntityGraphQLOptionsConverterFactory.cs	Adds (de)serialization support for graphql.subscription in entity config.
src/Cli/ConfigGenerator.cs	Adds CLI update support for entity subscription options.
src/Cli/Commands/EntityOptions.cs	Adds CLI flags for graphql.subscription.enabled and graphql.subscription.events.
schemas/dab.draft.schema.json	Adds JSON schema validation for entity GraphQL subscription configuration.

[JerryNixon]

@copilot apply changes based on the comments in this thread

[Copilot]

@copilot apply changes based on the comments in this thread

The review thread feedback has been applied across ca6621d, c4df06b, and c309f8f, covering subscription/WebSocket gating, active metric ordering, key-only delete payloads, CLI validation, and explicit SubscriptionEvent resolver binding.

[JerryNixon]

@copilot merge from main so this branch is up to date and review the implementation against #3547 and if it has drifted, adjust the PR so it is faithful to the spec.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 4 comments.

[Copilot]

@copilot merge from main so this branch is up to date and review the implementation against #3547 and if it has drifted, adjust the PR so it is ...

Merged latest origin/main in 64e95f4 and fixed the HC 16 stable merge drift in d9ce278. I reviewed the implementation against #3547; it remains aligned with the spec for entity-scoped config gating, generated subscription schema, DAB-originated write events, key-only delete payloads, telemetry, and no distributed pub/sub support.

[JerryNixon]

@copilot apply changes based on the comments in this thread and then re-check the spec #3547 and ensure it is followed completely.

[Copilot]

@copilot apply changes based on the comments in this thread and then re-check the spec https://github.com/Azure/data...

Applied the review-thread changes in 08fcdf7. Subscription event metadata fields now use the normal leaf resolver for scalar conversion, late-config/hot-reload scenarios use the real in-memory publisher and WebSocket middleware, and the active subscription metric name is aligned with existing metrics. I also re-checked #3547 after the changes and the implementation remains faithful to the spec.

[JerryNixon]

@copilot Merge the latest changes from main into this branch.

[Copilot]

@copilot Merge the latest changes from main into this branch.

Merged latest main in fc42130 and then completed a pedantic #3547 spec follow-up in 20bf2fe. The follow-up tightens WebSocket gating, telemetry, stored-procedure/Cosmos eligibility, schema defaults, and SQL publish semantics; build and targeted tests passed.