feat: proxy rerank api (#851)

src/serve.rs

@@ -56,6 +56,7 @@ pub async fn run(config: GlobalConfig, addr: Option<String>) -> Result<()> {
     let stop_server = server.run(listener).await?;
     println!("Chat Completions API: http://{addr}/v1/chat/completions");
     println!("Embeddings API:       http://{addr}/v1/embeddings");
+    println!("Rerank API:           http://{addr}/v1/rerank");
     println!("LLM Playground:       http://{addr}/playground");
     println!("LLM Arena:            http://{addr}/arena?num=2");
     shutdown_signal().await;
@@ -158,6 +159,8 @@ impl Server {
             self.chat_completions(req).await
         } else if path == "/v1/embeddings" {
             self.embeddings(req).await
+        } else if path == "/v1/rerank" {
+            self.rerank(req).await
         } else if path == "/v1/models" {
             self.list_models()
         } else if path == "/v1/roles" {
@@ -498,6 +501,57 @@ impl Server {
             .body(Full::new(Bytes::from(output.to_string())).boxed())?;
         Ok(res)
     }
+
+    async fn rerank(&self, req: hyper::Request<Incoming>) -> Result<AppResponse> {
+        let req_body = req.collect().await?.to_bytes();
+        let req_body: Value = serde_json::from_slice(&req_body)
+            .map_err(|err| anyhow!("Invalid request json, {err}"))?;
+
+        debug!("rerank request: {req_body}");
+        let req_body = serde_json::from_value(req_body)
+            .map_err(|err| anyhow!("Invalid request body, {err}"))?;
+
+        let RerankReqBody {
+            model: reranker_model_id,
+            documents,
+            query,
+            top_n,
+        } = req_body;
+
+        let top_n = top_n.unwrap_or(documents.len());
+
+        let config = Arc::new(RwLock::new(self.config.clone()));
+
+        let reranker_model = Model::retrieve_embedding(&config.read(), &reranker_model_id)?;
+
+        let client = init_client(&config, Some(reranker_model))?;
+        let data = client
+            .rerank(RerankData {
+                query,
+                documents: documents.clone(),
+                top_n,
+            })
+            .await?;
+
+        let results: Vec<_> = data
+            .into_iter()
+            .map(|v| {
+                json!({
+                    "index": v.index,
+                    "relevance_score": v.relevance_score,
+                    "document": documents.get(v.index).map(|v| json!(v)).unwrap_or_default(),
+                })
+            })
+            .collect();
+        let output = json!({
+            "id": uuid::Uuid::new_v4().to_string(),
+            "results": results,
+        });
+        let res = Response::builder()
+            .header("Content-Type", "application/json")
+            .body(Full::new(Bytes::from(output.to_string())).boxed())?;
+        Ok(res)
+    }
 }
 
 #[derive(Debug, Deserialize)]
@@ -520,8 +574,8 @@ struct ChatCompletionsReqBody {
 
 #[derive(Debug, Deserialize)]
 struct EmbeddingsReqBody {
-    pub input: EmbeddingsReqBodyInput,
-    pub model: String,
+    input: EmbeddingsReqBodyInput,
+    model: String,
 }
 
 #[derive(Debug, Deserialize)]
@@ -531,6 +585,14 @@ enum EmbeddingsReqBodyInput {
     Multiple(Vec<String>),
 }
 
+#[derive(Debug, Deserialize)]
+struct RerankReqBody {
+    documents: Vec<String>,
+    query: String,
+    model: String,
+    top_n: Option<usize>,
+}
+
 #[derive(Debug)]
 enum ResEvent {
     First(Option<String>),