[router] Add remove worker api (#2380)

.github/workflows/pr-test-rust.yml

@@ -57,7 +57,7 @@ jobs:
           cd rust
           pip install setuptools-rust wheel build
           python3 -m build
-          pip install dist/*.whl
+          pip install --force-reinstall dist/*.whl
       - name: Run e2e test
         run: |
           cd rust/py_test

rust/py_test/test_launch_server.py

@@ -114,17 +114,12 @@ def popen_launch_server(
     raise TimeoutError("Server failed to start within the timeout period.")
 
 
-class TestEvalAccuracyMini(unittest.TestCase):
+class TestLaunchServer(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.model = DEFAULT_MODEL_NAME_FOR_TEST
         cls.base_url = DEFAULT_URL_FOR_TEST
-        cls.process = popen_launch_router(
-            cls.model,
-            cls.base_url,
-            dp_size=1,
-            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
-        )
+        cls.process = None
         cls.other_process = []
 
     @classmethod
@@ -134,6 +129,14 @@ class TestEvalAccuracyMini(unittest.TestCase):
             kill_process_tree(process.pid)
 
     def test_mmlu(self):
+        # DP size = 2
+        TestLaunchServer.process = popen_launch_router(
+            self.model,
+            self.base_url,
+            dp_size=2,
+            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
+        )
+
         args = SimpleNamespace(
             base_url=self.base_url,
             model=self.model,
@@ -150,14 +153,21 @@ class TestEvalAccuracyMini(unittest.TestCase):
         msg = f"MMLU test {'passed' if passed else 'failed'} with score {score:.3f} (threshold: {THRESHOLD})"
         self.assertGreaterEqual(score, THRESHOLD, msg)
 
-    def test_add_worker(self):
+    def test_add_and_remove_worker(self):
+        # DP size = 1
+        TestLaunchServer.process = popen_launch_router(
+            self.model,
+            self.base_url,
+            dp_size=1,
+            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
+        )
         # 1. start a worker, and wait until it is healthy
         port = find_available_port()
         worker_url = f"http://127.0.0.1:{port}"
         worker_process = popen_launch_server(
             self.model, worker_url, DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH
         )
-        self.other_process.append(worker_process)
+        TestLaunchServer.other_process.append(worker_process)
         # 2. use /add_worker api to add it the the router
         with requests.Session() as session:
             response = session.post(f"{self.base_url}/add_worker?url={worker_url}")
@@ -179,6 +189,20 @@ class TestEvalAccuracyMini(unittest.TestCase):
         msg = f"MMLU test {'passed' if passed else 'failed'} with score {score:.3f} (threshold: {THRESHOLD})"
         self.assertGreaterEqual(score, THRESHOLD, msg)
 
+        # 4. use /remove_worker api to remove it from the router
+        with requests.Session() as session:
+            response = session.post(f"{self.base_url}/remove_worker?url={worker_url}")
+            print(f"status code: {response.status_code}, response: {response.text}")
+            self.assertEqual(response.status_code, 200)
+
+        # 5. run mmlu again
+        metrics = run_eval(args)
+        score = metrics["score"]
+        THRESHOLD = 0.65
+        passed = score >= THRESHOLD
+        msg = f"MMLU test {'passed' if passed else 'failed'} with score {score:.3f} (threshold: {THRESHOLD})"
+        self.assertGreaterEqual(score, THRESHOLD, msg)
+
 
 if __name__ == "__main__":
     unittest.main()

rust/src/router.rs

@@ -396,4 +396,23 @@ impl Router {
             }
         }
     }
+
+    pub fn remove_worker(&self, worker_url: String) {
+        match self {
+            Router::RoundRobin { worker_urls, .. }
+            | Router::Random { worker_urls }
+            | Router::CacheAware { worker_urls, .. } => {
+                let mut urls = worker_urls.write().unwrap();
+                let index = urls.iter().position(|url| url == &worker_url).unwrap();
+                urls.remove(index);
+                info!("Removed worker: {}", worker_url);
+            }
+        }
+
+        // if cache aware, remove the worker from the tree
+        if let Router::CacheAware { tree, .. } = self {
+            tree.lock().unwrap().remove_tenant(&worker_url);
+            info!("Removed worker from tree: {}", worker_url);
+        }
+    }
 }

rust/src/server.rs

@@ -145,6 +145,19 @@ async fn add_worker(
     HttpResponse::Ok().finish()
 }
 
+#[post("/remove_worker")]
+async fn remove_worker(
+    query: web::Query<HashMap<String, String>>,
+    data: web::Data<AppState>,
+) -> impl Responder {
+    let worker_url = match query.get("url") {
+        Some(url) => url.to_string(),
+        None => return HttpResponse::BadRequest().finish(),
+    };
+    data.router.remove_worker(worker_url);
+    HttpResponse::Ok().finish()
+}
+
 pub struct ServerConfig {
     pub host: String,
     pub port: u16,
@@ -201,6 +214,7 @@ pub async fn startup(config: ServerConfig) -> std::io::Result<()> {
             .service(health_generate)
             .service(get_server_info)
             .service(add_worker)
+            .service(remove_worker)
     })
     .bind((config.host, config.port))?
     .run()