[model-gateway] grpc to leverage event type (#14450)

Co-authored-by: Chang Su <chang.s.su@oracle.com>

sgl-router/src/protocols/event_types.rs

@@ -81,6 +81,56 @@ impl fmt::Display for FunctionCallEvent {
     }
 }
 
+/// Content part streaming events
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum ContentPartEvent {
+    Added,
+    Done,
+}
+
+impl ContentPartEvent {
+    pub const ADDED: &'static str = "response.content_part.added";
+    pub const DONE: &'static str = "response.content_part.done";
+
+    pub const fn as_str(&self) -> &'static str {
+        match self {
+            Self::Added => Self::ADDED,
+            Self::Done => Self::DONE,
+        }
+    }
+}
+
+impl fmt::Display for ContentPartEvent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+/// Output text streaming events
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum OutputTextEvent {
+    Delta,
+    Done,
+}
+
+impl OutputTextEvent {
+    pub const DELTA: &'static str = "response.output_text.delta";
+    pub const DONE: &'static str = "response.output_text.done";
+
+    pub const fn as_str(&self) -> &'static str {
+        match self {
+            Self::Delta => Self::DELTA,
+            Self::Done => Self::DONE,
+        }
+    }
+}
+
+impl fmt::Display for OutputTextEvent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
 // ============================================================================
 // MCP Events
 // ============================================================================
@@ -92,6 +142,7 @@ pub enum McpEvent {
     CallArgumentsDone,
     CallInProgress,
     CallCompleted,
+    CallFailed,
     ListToolsInProgress,
     ListToolsCompleted,
 }
@@ -101,6 +152,7 @@ impl McpEvent {
     pub const CALL_ARGUMENTS_DONE: &'static str = "response.mcp_call_arguments.done";
     pub const CALL_IN_PROGRESS: &'static str = "response.mcp_call.in_progress";
     pub const CALL_COMPLETED: &'static str = "response.mcp_call.completed";
+    pub const CALL_FAILED: &'static str = "response.mcp_call.failed";
     pub const LIST_TOOLS_IN_PROGRESS: &'static str = "response.mcp_list_tools.in_progress";
     pub const LIST_TOOLS_COMPLETED: &'static str = "response.mcp_list_tools.completed";
 
@@ -110,6 +162,7 @@ impl McpEvent {
             Self::CallArgumentsDone => Self::CALL_ARGUMENTS_DONE,
             Self::CallInProgress => Self::CALL_IN_PROGRESS,
             Self::CallCompleted => Self::CALL_COMPLETED,
+            Self::CallFailed => Self::CALL_FAILED,
             Self::ListToolsInProgress => Self::LIST_TOOLS_IN_PROGRESS,
             Self::ListToolsCompleted => Self::LIST_TOOLS_COMPLETED,
         }

sgl-router/src/routers/grpc/common/responses/streaming.rs

@@ -14,6 +14,10 @@ use crate::{
     protocols::{
         chat::ChatCompletionStreamResponse,
         common::{Usage, UsageInfo},
+        event_types::{
+            ContentPartEvent, FunctionCallEvent, McpEvent, OutputItemEvent, OutputTextEvent,
+            ResponseEvent,
+        },
         responses::{
             ResponseOutputItem, ResponseStatus, ResponsesRequest, ResponsesResponse, ResponsesUsage,
         },
@@ -159,7 +163,7 @@ impl ResponseStreamEventEmitter {
     pub fn emit_created(&mut self) -> serde_json::Value {
         self.has_emitted_created = true;
         json!({
-            "type": "response.created",
+            "type": ResponseEvent::CREATED,
             "sequence_number": self.next_sequence(),
             "response": {
                 "id": self.response_id,
@@ -175,7 +179,7 @@ impl ResponseStreamEventEmitter {
     pub fn emit_in_progress(&mut self) -> serde_json::Value {
         self.has_emitted_in_progress = true;
         json!({
-            "type": "response.in_progress",
+            "type": ResponseEvent::IN_PROGRESS,
             "sequence_number": self.next_sequence(),
             "response": {
                 "id": self.response_id,
@@ -193,7 +197,7 @@ impl ResponseStreamEventEmitter {
     ) -> serde_json::Value {
         self.has_emitted_content_part_added = true;
         json!({
-            "type": "response.content_part.added",
+            "type": ContentPartEvent::ADDED,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -214,7 +218,7 @@ impl ResponseStreamEventEmitter {
     ) -> serde_json::Value {
         self.accumulated_text.push_str(delta);
         json!({
-            "type": "response.output_text.delta",
+            "type": OutputTextEvent::DELTA,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -230,7 +234,7 @@ impl ResponseStreamEventEmitter {
         content_index: usize,
     ) -> serde_json::Value {
         json!({
-            "type": "response.output_text.done",
+            "type": OutputTextEvent::DONE,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -246,7 +250,7 @@ impl ResponseStreamEventEmitter {
         content_index: usize,
     ) -> serde_json::Value {
         json!({
-            "type": "response.content_part.done",
+            "type": ContentPartEvent::DONE,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -336,7 +340,7 @@ impl ResponseStreamEventEmitter {
         }
 
         json!({
-            "type": "response.completed",
+            "type": ResponseEvent::COMPLETED,
             "sequence_number": self.next_sequence(),
             "response": response_obj
         })
@@ -359,7 +363,7 @@ impl ResponseStreamEventEmitter {
 
     pub fn emit_mcp_list_tools_in_progress(&mut self, output_index: usize) -> serde_json::Value {
         json!({
-            "type": "response.mcp_list_tools.in_progress",
+            "type": McpEvent::LIST_TOOLS_IN_PROGRESS,
             "sequence_number": self.next_sequence(),
             "output_index": output_index
         })
@@ -382,7 +386,7 @@ impl ResponseStreamEventEmitter {
             .collect();
 
         json!({
-            "type": "response.mcp_list_tools.completed",
+            "type": McpEvent::LIST_TOOLS_COMPLETED,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "tools": tool_items
@@ -395,7 +399,7 @@ impl ResponseStreamEventEmitter {
         item_id: &str,
     ) -> serde_json::Value {
         json!({
-            "type": "response.mcp_call.in_progress",
+            "type": McpEvent::CALL_IN_PROGRESS,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id
@@ -415,7 +419,7 @@ impl ResponseStreamEventEmitter {
             .push_str(delta);
 
         json!({
-            "type": "response.mcp_call_arguments.delta",
+            "type": McpEvent::CALL_ARGUMENTS_DELTA,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -430,7 +434,7 @@ impl ResponseStreamEventEmitter {
         arguments: &str,
     ) -> serde_json::Value {
         json!({
-            "type": "response.mcp_call_arguments.done",
+            "type": McpEvent::CALL_ARGUMENTS_DONE,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -444,7 +448,7 @@ impl ResponseStreamEventEmitter {
         item_id: &str,
     ) -> serde_json::Value {
         json!({
-            "type": "response.mcp_call.completed",
+            "type": McpEvent::CALL_COMPLETED,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id
@@ -458,7 +462,7 @@ impl ResponseStreamEventEmitter {
         error: &str,
     ) -> serde_json::Value {
         json!({
-            "type": "response.mcp_call.failed",
+            "type": McpEvent::CALL_FAILED,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -477,7 +481,7 @@ impl ResponseStreamEventEmitter {
         delta: &str,
     ) -> serde_json::Value {
         json!({
-            "type": "response.function_call_arguments.delta",
+            "type": FunctionCallEvent::ARGUMENTS_DELTA,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -492,7 +496,7 @@ impl ResponseStreamEventEmitter {
         arguments: &str,
     ) -> serde_json::Value {
         json!({
-            "type": "response.function_call_arguments.done",
+            "type": FunctionCallEvent::ARGUMENTS_DONE,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item_id": item_id,
@@ -511,7 +515,7 @@ impl ResponseStreamEventEmitter {
         item: &serde_json::Value,
     ) -> serde_json::Value {
         json!({
-            "type": "response.output_item.added",
+            "type": OutputItemEvent::ADDED,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item": item
@@ -528,7 +532,7 @@ impl ResponseStreamEventEmitter {
         self.store_output_item_data(output_index, item.clone());
 
         json!({
-            "type": "response.output_item.done",
+            "type": OutputItemEvent::DONE,
             "sequence_number": self.next_sequence(),
             "output_index": output_index,
             "item": item