[router] remove worker url requirement (#13172)

sgl-router/py_src/sglang_router/router_args.py

@@ -677,12 +677,9 @@ class RouterArgs:
     def _validate_router_args(self):
         # Validate configuration based on mode
         if self.pd_disaggregation:
-            # Validate PD configuration - skip URL requirements if using service discovery
-            if not self.service_discovery:
-                if not self.prefill_urls:
-                    raise ValueError("PD disaggregation mode requires --prefill")
-                if not self.decode_urls:
-                    raise ValueError("PD disaggregation mode requires --decode")
+            # Allow empty URLs even without service discovery to support dynamic worker addition
+            # URLs will be validated separately if provided
+            pass
 
             # Warn about policy usage in PD mode
             if self.prefill_policy and self.decode_policy and self.policy:

sgl-router/py_test/unit/test_router_config.py

@@ -53,8 +53,8 @@ class TestRouterConfigValidation:
         assert args.decode_urls == ["http://decode1:8001", "http://decode2:8001"]
         assert args.policy == "cache_aware"
 
-    def test_pd_config_without_urls_raises_error(self):
-        """Test that PD mode without URLs raises validation error."""
+    def test_pd_config_without_urls_allowed(self):
+        """Test that PD mode without URLs is now allowed (URLs are optional)."""
         args = RouterArgs(
             pd_disaggregation=True,
             prefill_urls=[],
@@ -62,11 +62,14 @@ class TestRouterConfigValidation:
             service_discovery=False,
         )
 
-        # This should raise an error when trying to launch
-        with pytest.raises(
-            ValueError, match="PD disaggregation mode requires --prefill"
-        ):
+        # Should not raise validation error - URLs are now optional
+        with patch("sglang_router.launch_router.Router") as router_mod:
+            mock_router_instance = MagicMock()
+            router_mod.from_args = MagicMock(return_value=mock_router_instance)
+
+            # This should succeed without raising an error
             launch_router(args)
+            router_mod.from_args.assert_called_once()
 
     def test_pd_config_with_service_discovery_allows_empty_urls(self):
         """Test that PD mode with service discovery allows empty URLs."""

sgl-router/py_test/unit/test_startup_sequence.py

@@ -464,7 +464,7 @@ class TestStartupValidation:
 
     def test_pd_mode_validation_during_startup(self):
         """Test PD mode validation during startup."""
-        # PD mode without URLs should fail
+        # PD mode without URLs is now allowed (URLs are optional)
         args = RouterArgs(
             pd_disaggregation=True,
             prefill_urls=[],
@@ -472,10 +472,14 @@ class TestStartupValidation:
             service_discovery=False,
         )
 
-        with pytest.raises(
-            ValueError, match="PD disaggregation mode requires --prefill"
-        ):
+        # Should not raise validation error - URLs are now optional
+        with patch("sglang_router.launch_router.Router") as router_mod:
+            mock_router_instance = MagicMock()
+            router_mod.from_args = MagicMock(return_value=mock_router_instance)
+
+            # This should succeed without raising an error
             launch_router(args)
+            router_mod.from_args.assert_called_once()
 
     def test_pd_mode_with_service_discovery_validation(self):
         """Test PD mode with service discovery validation during startup."""

sgl-router/py_test/unit/test_validation.py

@@ -400,9 +400,9 @@ class TestConfigurationValidation:
 class TestLaunchValidation:
     """Test launch-time validation logic."""
 
-    def test_pd_mode_requires_urls(self):
-        """Test that PD mode requires prefill and decode URLs."""
-        # PD mode without URLs should fail
+    def test_pd_mode_allows_empty_urls(self):
+        """Test that PD mode now allows empty URLs (URLs are optional)."""
+        # PD mode without URLs is now allowed
         args = RouterArgs(
             pd_disaggregation=True,
             prefill_urls=[],
@@ -410,10 +410,14 @@ class TestLaunchValidation:
             service_discovery=False,
         )
 
-        with pytest.raises(
-            ValueError, match="PD disaggregation mode requires --prefill"
-        ):
+        # Should not raise validation error - URLs are now optional
+        with patch("sglang_router.launch_router.Router") as router_mod:
+            mock_router_instance = MagicMock()
+            router_mod.from_args = MagicMock(return_value=mock_router_instance)
+
+            # This should succeed without raising an error
             launch_router(args)
+            router_mod.from_args.assert_called_once()
 
     def test_pd_mode_with_service_discovery_allows_empty_urls(self):
         """Test that PD mode with service discovery allows empty URLs."""

sgl-router/src/config/validation.rs

@@ -6,9 +6,7 @@ pub struct ConfigValidator;
 
 impl ConfigValidator {
     pub fn validate(config: &RouterConfig) -> ConfigResult<()> {
-        let has_service_discovery = config.discovery.as_ref().is_some_and(|d| d.enabled);
-
-        Self::validate_mode(&config.mode, has_service_discovery)?;
+        Self::validate_mode(&config.mode)?;
         Self::validate_policy(&config.policy)?;
         Self::validate_server_settings(config)?;
 
@@ -89,7 +87,7 @@ impl ConfigValidator {
         Ok(())
     }
 
-    fn validate_mode(mode: &RoutingMode, has_service_discovery: bool) -> ConfigResult<()> {
+    fn validate_mode(mode: &RoutingMode) -> ConfigResult<()> {
         match mode {
             RoutingMode::Regular { worker_urls } => {
                 if !worker_urls.is_empty() {
@@ -103,19 +101,8 @@ impl ConfigValidator {
                 prefill_policy,
                 decode_policy,
             } => {
-                if !has_service_discovery {
-                    if prefill_urls.is_empty() {
-                        return Err(ConfigError::ValidationFailed {
-                            reason: "PD mode requires at least one prefill worker URL".to_string(),
-                        });
-                    }
-                    if decode_urls.is_empty() {
-                        return Err(ConfigError::ValidationFailed {
-                            reason: "PD mode requires at least one decode worker URL".to_string(),
-                        });
-                    }
-                }
-
+                // Allow empty URLs even without service discovery to support dynamic worker addition
+                // URLs will be validated if provided
                 if !prefill_urls.is_empty() {
                     let prefill_url_strings: Vec<String> =
                         prefill_urls.iter().map(|(url, _)| url.clone()).collect();
@@ -145,12 +132,11 @@ impl ConfigValidator {
                 }
             }
             RoutingMode::OpenAI { worker_urls } => {
-                if worker_urls.is_empty() {
-                    return Err(ConfigError::ValidationFailed {
-                        reason: "OpenAI mode requires at least one --worker-urls entry".to_string(),
-                    });
+                // Allow empty URLs to support dynamic worker addition
+                // URLs will be validated if provided
+                if !worker_urls.is_empty() {
+                    Self::validate_urls(worker_urls)?;
                 }
-                Self::validate_urls(worker_urls)?;
             }
         }
         Ok(())
@@ -888,6 +874,45 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_validate_empty_urls_allowed_without_service_discovery() {
+        // Test that empty URLs are now allowed in PD mode
+        let config = RouterConfig::new(
+            RoutingMode::PrefillDecode {
+                prefill_urls: vec![],
+                decode_urls: vec![],
+                prefill_policy: None,
+                decode_policy: None,
+            },
+            PolicyConfig::Random,
+        );
+
+        // Should pass validation even with empty URLs
+        assert!(ConfigValidator::validate(&config).is_ok());
+
+        // Test that empty URLs are allowed in Regular mode
+        let config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec![],
+            },
+            PolicyConfig::Random,
+        );
+
+        // Should pass validation even with empty URLs
+        assert!(ConfigValidator::validate(&config).is_ok());
+
+        // Test that empty URLs are allowed in OpenAI mode
+        let config = RouterConfig::new(
+            RoutingMode::OpenAI {
+                worker_urls: vec![],
+            },
+            PolicyConfig::Random,
+        );
+
+        // Should pass validation even with empty URLs
+        assert!(ConfigValidator::validate(&config).is_ok());
+    }
+
     #[test]
     fn test_validate_grpc_requires_tokenizer() {
         let mut config = RouterConfig::new(

sgl-router/src/main.rs

@@ -478,12 +478,7 @@ impl CliArgs {
         } else if self.pd_disaggregation {
             let decode_urls = self.decode.clone();
 
-            if !self.service_discovery && (prefill_urls.is_empty() || decode_urls.is_empty()) {
-                return Err(ConfigError::ValidationFailed {
-                    reason: "PD disaggregation mode requires --prefill and --decode URLs when not using service discovery".to_string(),
-                });
-            }
-
+            // Allow empty URLs to support dynamic worker addition
             RoutingMode::PrefillDecode {
                 prefill_urls,
                 decode_urls,
@@ -491,12 +486,7 @@ impl CliArgs {
                 decode_policy: self.decode_policy.as_ref().map(|p| self.parse_policy(p)),
             }
         } else {
-            if !self.service_discovery && self.worker_urls.is_empty() {
-                return Err(ConfigError::ValidationFailed {
-                    reason: "Regular mode requires --worker-urls when not using service discovery"
-                        .to_string(),
-                });
-            }
+            // Allow empty URLs to support dynamic worker addition
             RoutingMode::Regular {
                 worker_urls: self.worker_urls.clone(),
             }