refactor: improve serve responses (#455)

Argcfile.sh

@@ -28,18 +28,23 @@ test-without-config() {
 # @arg clients+[`_choice_client`]
 test-clients() {
     for c in "${argc_clients[@]}"; do
-        echo "### $c streaming"
+        echo "### $c stream"
         aichat -m "$c" 1 + 2 = ?
-        echo "### $c non-streaming"
+        echo "### $c non-stream"
         aichat -m "$c" -S 1 + 2 = ?
     done
 }
 
 # @cmd Test proxy server
-# @option --model=default
+# @option -m --model=default
+# @flag -S --no-stream
 # @arg text~
 test-server() {
-    argc generic-chat \
+    args=()
+    if [[ -n "$argc_no_stream" ]]; then
+        args+=("-S")
+    fi
+    argc generic-chat "${args[@]}" \
     --api-base http://localhost:8000/v1 \
     --model $argc_model \
     "$@"

src/serve.rs

@@ -30,6 +30,7 @@ use tokio_graceful::Shutdown;
 use tokio_stream::wrappers::UnboundedReceiverStream;
 
 const DEFAULT_ADDRESS: &str = "127.0.0.1:8000";
+const DEFAULT_MODEL_NAME: &str = "default";
 
 type AppResponse = Response<BoxBody<Bytes, Infallible>>;
 
@@ -145,8 +146,17 @@ impl Server {
             ..Default::default()
         };
         let config = Arc::new(RwLock::new(config));
-        if model != "default" && model != self.model.id() {
-            config.write().set_model(&model)?;
+
+        let (model_name, change) = if model == DEFAULT_MODEL_NAME {
+            (self.model.id(), true)
+        } else if self.model.id() == model {
+            (model, false)
+        } else {
+            (model, true)
+        };
+
+        if change {
+            config.write().set_model(&model_name)?;
         }
 
         let mut client = init_client(&config)?;
@@ -198,6 +208,7 @@ impl Server {
                         if let Err(err) = ret {
                             send_first_event(&tx, Some(format!("{err:?}")), &mut is_first)
                         }
+                        let _ = tx.send(ResEvent::Done);
                     }
                 }
             });
@@ -208,16 +219,23 @@ impl Server {
                 bail!("{err}");
             }
 
-            let shared: Arc<(String, i64)> = Arc::new((completion_id, created));
+            let shared: Arc<(String, String, i64)> = Arc::new((completion_id, model_name, created));
             let stream = UnboundedReceiverStream::new(rx);
             let stream = stream.filter_map(move |res_event| {
                 let shared = shared.clone();
                 async move {
+                    let (completion_id, model, created) = shared.as_ref();
                     match res_event {
-                        ResEvent::Text(text) => {
-                            Some(Ok(create_frame(&shared.0, shared.1, &text, false)))
+                        ResEvent::Text(text) => Some(Ok(create_frame(
+                            completion_id,
+                            model,
+                            *created,
+                            &text,
+                            false,
+                        ))),
+                        ResEvent::Done => {
+                            Some(Ok(create_frame(completion_id, model, *created, "", true)))
                         }
-                        ResEvent::Done => Some(Ok(create_frame(&shared.0, shared.1, "", true))),
                         _ => None,
                     }
                 }
@@ -290,7 +308,7 @@ fn set_cors_header(res: &mut AppResponse) {
     );
 }
 
-fn create_frame(id: &str, created: i64, content: &str, done: bool) -> Frame<Bytes> {
+fn create_frame(id: &str, model: &str, created: i64, content: &str, done: bool) -> Frame<Bytes> {
     let (delta, finish_reason) = if done {
         (json!({}), "stop".into())
     } else {
@@ -301,11 +319,11 @@ fn create_frame(id: &str, created: i64, content: &str, done: bool) -> Frame<Byte
         };
         (delta, Value::Null)
     };
-    let mut value = json!({
+    let value = json!({
         "id": id,
         "object": "chat.completion.chunk",
         "created": created,
-        "model": "gpt-3.5-turbo",
+        "model": model,
         "choices": [
             {
                 "index": 0,
@@ -315,11 +333,6 @@ fn create_frame(id: &str, created: i64, content: &str, done: bool) -> Frame<Byte
         ],
     });
     let output = if done {
-        value["usage"] = json!({
-            "prompt_tokens": 0,
-            "completion_tokens": 0,
-            "total_tokens": 0,
-        });
         format!("data: {value}\n\ndata: [DONE]\n\n")
     } else {
         format!("data: {value}\n\n")