[router] Allow empty worker list for sglang.launch_router (#2979)

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

@@ -40,7 +40,7 @@ jobs:
           cd sgl-router/
           cargo test
 
-  e2e-rust:
+  e2e-python:
     if: github.repository == 'sgl-project/sglang' || github.event_name == 'pull_request'
     runs-on: 2-gpu-runner
     steps:
@@ -65,7 +65,7 @@ jobs:
           python3 run_suite.py
 
   finish:
-    needs: [unit-test-rust, e2e-rust]
+    needs: [unit-test-rust, e2e-python]
     runs-on: ubuntu-latest
     steps:
       - name: Finish

scripts/ci_install_rust.sh

 #!/bin/bash
 set -euxo pipefail
 
-# these are required for actix
-apt-get update
-apt-get install -y libssl-dev pkg-config
+# Check if sudo is available
+if command -v sudo >/dev/null 2>&1; then
+    sudo apt-get update
+    sudo apt-get install -y libssl-dev pkg-config
+else
+    apt-get update
+    apt-get install -y libssl-dev pkg-config
+fi
 
 # Install rustup (Rust installer and version manager)
 curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y

sgl-router/README.md

@@ -67,6 +67,16 @@ $ pip install -e .
 
 **Note:** When modifying Rust code, you must rebuild the wheel for changes to take effect.
 
+### Troubleshooting
+
+1. If rust analyzer is not working in VSCode, set `rust-analyzer.linkedProjects` to the absolute path of `Cargo.toml` in your repo. For example:
+
+```json
+{
+  "rust-analyzer.linkedProjects":  ["/workspaces/sglang/sgl-router/Cargo.toml"]
+}
+```
+
 ### CI/CD Setup
 
 The continuous integration pipeline consists of three main steps:

sgl-router/py_src/sglang_router/launch_router.py

@@ -27,7 +27,7 @@ def setup_logger():
 @dataclasses.dataclass
 class RouterArgs:
     # Worker configuration
-    worker_urls: List[str]
+    worker_urls: List[str] = dataclasses.field(default_factory=list)
     host: str = "127.0.0.1"
     port: int = 30000
 
@@ -141,8 +141,9 @@ class RouterArgs:
             use_router_prefix: If True, look for arguments with 'router-' prefix
         """
         prefix = "router_" if use_router_prefix else ""
+        worker_urls = args.worker_urls if args.worker_urls is not None else []
         return cls(
-            worker_urls=args.worker_urls,
+            worker_urls=worker_urls,
             host=args.host,
             port=args.port,
             policy=getattr(args, f"{prefix}policy"),
@@ -237,7 +238,6 @@ Examples:
 
 
 def main() -> None:
-    logger = setup_logger()
     router_args = parse_router_args(sys.argv[1:])
     router = launch_router(router_args)
 

sgl-router/py_src/sglang_router/launch_server.py

@@ -23,7 +23,7 @@ def setup_logger():
     logger.setLevel(logging.INFO)
 
     formatter = logging.Formatter(
-        "[Router (Python)] %(asctime)s - %(levelname)s - %(message)s",
+        "[Router (Python)] %(asctime)s - %(levelname)s - %(message)s - %(filename)s:%(lineno)d",
         datefmt="%Y-%m-%d %H:%M:%S",
     )
 

sgl-router/py_src/sglang_router/version.py

-__version__ = "0.1.1"
+__version__ = "0.1.2"

sgl-router/py_test/test_launch_router.py

@@ -22,11 +22,9 @@ def terminate_process(process: multiprocessing.Process, timeout: float = 1.0) ->
 
 
 class TestLaunchRouter(unittest.TestCase):
-    def test_launch_router_no_exception(self):
-
-        # Create SimpleNamespace with default arguments
-        args = SimpleNamespace(
-            worker_urls=["http://localhost:8000"],
+    def setUp(self):
+        """Set up default arguments for router tests."""
+        self.default_args = SimpleNamespace(
             host="127.0.0.1",
             port=30000,
             policy="cache_aware",
@@ -39,6 +37,15 @@ class TestLaunchRouter(unittest.TestCase):
             verbose=False,
         )
 
+    def create_router_args(self, **kwargs):
+        """Create router arguments by updating default args with provided kwargs."""
+        args_dict = vars(self.default_args).copy()
+        args_dict.update(kwargs)
+        return SimpleNamespace(**args_dict)
+
+    def run_router_process(self, args):
+        """Run router in a separate process and verify it starts successfully."""
+
         def run_router():
             try:
                 from sglang_router.launch_router import launch_router
@@ -51,7 +58,6 @@ class TestLaunchRouter(unittest.TestCase):
                 print(e)
                 return 1
 
-        # Start router in separate process
         process = multiprocessing.Process(target=run_router)
         try:
             process.start()
@@ -62,6 +68,14 @@ class TestLaunchRouter(unittest.TestCase):
         finally:
             terminate_process(process)
 
+    def test_launch_router_common(self):
+        args = self.create_router_args(worker_urls=["http://localhost:8000"])
+        self.run_router_process(args)
+
+    def test_launch_router_with_empty_worker_urls(self):
+        args = self.create_router_args(worker_urls=[])
+        self.run_router_process(args)
+
 
 if __name__ == "__main__":
     unittest.main()

sgl-router/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "sglang-router"
-version = "0.1.1"
+version = "0.1.2"
 description = "SGLang router is a standalone module implemented in Rust to achieve data parallelism across SGLang instances."
 authors = [{name = "Byron Hsu", email = "byronhsu1230@gmail.com"}]
 requires-python = ">=3.8"