🔄 refactor: Sequential Event Ordering in Redis Streaming Mode (#11650)

* chore: linting image context file

* refactor: Event Emission with Async Handling for Redis Ordering

- Updated emitEvent and related functions to be async, ensuring proper event ordering in Redis mode.
- Refactored multiple handlers to await emitEvent calls, improving reliability for streaming deltas.
- Enhanced GenerationJobManager to await chunk emissions, critical for maintaining sequential event delivery.
- Added tests to verify that events are delivered in strict order when using Redis, addressing previous issues with out-of-order messages.

* refactor: Clear Pending Buffers and Timeouts in RedisEventTransport

- Enhanced the cleanup process in RedisEventTransport by ensuring that pending messages and flush timeouts are cleared when the last subscriber unsubscribes.
- Updated the destroy method to also clear pending messages and flush timeouts for all streams, improving resource management and preventing memory leaks.

* refactor: Update Event Emission to Async for Improved Ordering

- Refactored GenerationJobManager and RedisEventTransport to make emitDone and emitError methods async, ensuring proper event ordering in Redis mode.
- Updated all relevant calls to await these methods, enhancing reliability in event delivery.
- Adjusted tests to verify that events are processed in the correct sequence, addressing previous issues with out-of-order messages.

* refactor: Adjust RedisEventTransport for 0-Indexed Sequence Handling

- Updated sequence handling in RedisEventTransport to be 0-indexed, ensuring consistency across event emissions and buffer management.
- Modified integration tests to reflect the new sequence logic, improving the accuracy of event processing and delivery order.
- Enhanced comments for clarity on sequence management and terminal event handling.

* chore: Add Redis dump file to .gitignore

- Included dump.rdb in .gitignore to prevent accidental commits of Redis database dumps, enhancing repository cleanliness and security.

* test: Increase wait times in RedisEventTransport integration tests for CI stability

- Adjusted wait times for subscription establishment and event propagation from 100ms and 200ms to 500ms to improve reliability in CI environments.
- Enhanced code readability by formatting promise resolution lines for better clarity.

api/server/services/MCP.js

@@ -53,9 +53,9 @@ function isEmptyObjectSchema(jsonSchema) {
 function createRunStepDeltaEmitter({ res, stepId, toolCall, streamId = null }) {
   /**
    * @param {string} authURL - The URL to redirect the user for OAuth authentication.
-   * @returns {void}
+   * @returns {Promise<void>}
    */
-  return function (authURL) {
+  return async function (authURL) {
     /** @type {{ id: string; delta: AgentToolCallDelta }} */
     const data = {
       id: stepId,
@@ -68,7 +68,7 @@ function createRunStepDeltaEmitter({ res, stepId, toolCall, streamId = null }) {
     };
     const eventData = { event: GraphEvents.ON_RUN_STEP_DELTA, data };
     if (streamId) {
-      GenerationJobManager.emitChunk(streamId, eventData);
+      await GenerationJobManager.emitChunk(streamId, eventData);
     } else {
       sendEvent(res, eventData);
     }
@@ -83,9 +83,10 @@ function createRunStepDeltaEmitter({ res, stepId, toolCall, streamId = null }) {
  * @param {ToolCallChunk} params.toolCall - The tool call object containing tool information.
  * @param {number} [params.index]
  * @param {string | null} [params.streamId] - The stream ID for resumable mode.
+ * @returns {() => Promise<void>}
  */
 function createRunStepEmitter({ res, runId, stepId, toolCall, index, streamId = null }) {
-  return function () {
+  return async function () {
     /** @type {import('@librechat/agents').RunStep} */
     const data = {
       runId: runId ?? Constants.USE_PRELIM_RESPONSE_MESSAGE_ID,
@@ -99,7 +100,7 @@ function createRunStepEmitter({ res, runId, stepId, toolCall, index, streamId =
     };
     const eventData = { event: GraphEvents.ON_RUN_STEP, data };
     if (streamId) {
-      GenerationJobManager.emitChunk(streamId, eventData);
+      await GenerationJobManager.emitChunk(streamId, eventData);
     } else {
       sendEvent(res, eventData);
     }
@@ -147,7 +148,7 @@ function createOAuthEnd({ res, stepId, toolCall, streamId = null }) {
     };
     const eventData = { event: GraphEvents.ON_RUN_STEP_DELTA, data };
     if (streamId) {
-      GenerationJobManager.emitChunk(streamId, eventData);
+      await GenerationJobManager.emitChunk(streamId, eventData);
     } else {
       sendEvent(res, eventData);
     }