sglangv0.5.2 & support Qwen3-Next-80B-A3B-Instruct

sgl-router/src/config/mod.rs

@@ -0,0 +1,28 @@
+pub mod types;
+pub mod validation;
+
+pub use types::*;
+pub use validation::*;
+
+/// Configuration errors
+#[derive(Debug, thiserror::Error)]
+pub enum ConfigError {
+    #[error("Validation failed: {reason}")]
+    ValidationFailed { reason: String },
+
+    #[error("Invalid value for field '{field}': {value} - {reason}")]
+    InvalidValue {
+        field: String,
+        value: String,
+        reason: String,
+    },
+
+    #[error("Incompatible configuration: {reason}")]
+    IncompatibleConfig { reason: String },
+
+    #[error("Missing required field: {field}")]
+    MissingRequired { field: String },
+}
+
+/// Result type for configuration operations
+pub type ConfigResult<T> = Result<T, ConfigError>;

sgl-router/src/config/validation.rs

@@ -0,0 +1,776 @@
+use super::*;
+
+/// Configuration validator
+pub struct ConfigValidator;
+
+impl ConfigValidator {
+    /// Validate a complete router configuration
+    pub fn validate(config: &RouterConfig) -> ConfigResult<()> {
+        // Check if service discovery is enabled
+        let has_service_discovery = config.discovery.as_ref().is_some_and(|d| d.enabled);
+
+        Self::validate_mode(&config.mode, has_service_discovery)?;
+        Self::validate_policy(&config.policy)?;
+        Self::validate_server_settings(config)?;
+
+        if let Some(discovery) = &config.discovery {
+            Self::validate_discovery(discovery, &config.mode)?;
+        }
+
+        if let Some(metrics) = &config.metrics {
+            Self::validate_metrics(metrics)?;
+        }
+
+        Self::validate_compatibility(config)?;
+
+        // Validate effective retry/CB configs (respect disable flags)
+        let retry_cfg = config.effective_retry_config();
+        let cb_cfg = config.effective_circuit_breaker_config();
+        Self::validate_retry(&retry_cfg)?;
+        Self::validate_circuit_breaker(&cb_cfg)?;
+
+        Ok(())
+    }
+
+    /// Validate routing mode configuration
+    fn validate_mode(mode: &RoutingMode, has_service_discovery: bool) -> ConfigResult<()> {
+        match mode {
+            RoutingMode::Regular { worker_urls } => {
+                // Validate URLs if any are provided
+                if !worker_urls.is_empty() {
+                    Self::validate_urls(worker_urls)?;
+                }
+                // Note: We allow empty worker URLs even without service discovery
+                // to let the router start and fail at runtime when routing requests.
+                // This matches legacy behavior and test expectations.
+            }
+            RoutingMode::PrefillDecode {
+                prefill_urls,
+                decode_urls,
+                prefill_policy,
+                decode_policy,
+            } => {
+                // Only require URLs if service discovery is disabled
+                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(),
+                        });
+                    }
+                }
+
+                // Validate URLs if any are provided
+                if !prefill_urls.is_empty() {
+                    let prefill_url_strings: Vec<String> =
+                        prefill_urls.iter().map(|(url, _)| url.clone()).collect();
+                    Self::validate_urls(&prefill_url_strings)?;
+                }
+                if !decode_urls.is_empty() {
+                    Self::validate_urls(decode_urls)?;
+                }
+
+                // Validate bootstrap ports
+                for (_url, port) in prefill_urls {
+                    if let Some(port) = port {
+                        if *port == 0 {
+                            return Err(ConfigError::InvalidValue {
+                                field: "bootstrap_port".to_string(),
+                                value: port.to_string(),
+                                reason: "Port must be between 1 and 65535".to_string(),
+                            });
+                        }
+                    }
+                }
+
+                // Validate optional prefill and decode policies
+                if let Some(p_policy) = prefill_policy {
+                    Self::validate_policy(p_policy)?;
+                }
+                if let Some(d_policy) = decode_policy {
+                    Self::validate_policy(d_policy)?;
+                }
+            }
+            RoutingMode::OpenAI { worker_urls } => {
+                // Require exactly one worker URL for OpenAI router
+                if worker_urls.len() != 1 {
+                    return Err(ConfigError::ValidationFailed {
+                        reason: "OpenAI mode requires exactly one --worker-urls entry".to_string(),
+                    });
+                }
+                // Validate URL format
+                if let Err(e) = url::Url::parse(&worker_urls[0]) {
+                    return Err(ConfigError::ValidationFailed {
+                        reason: format!("Invalid OpenAI worker URL '{}': {}", &worker_urls[0], e),
+                    });
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// Validate policy configuration
+    fn validate_policy(policy: &PolicyConfig) -> ConfigResult<()> {
+        match policy {
+            PolicyConfig::Random | PolicyConfig::RoundRobin => {
+                // No specific validation needed
+            }
+            PolicyConfig::CacheAware {
+                cache_threshold,
+                balance_abs_threshold: _,
+                balance_rel_threshold,
+                eviction_interval_secs,
+                max_tree_size,
+            } => {
+                if !(0.0..=1.0).contains(cache_threshold) {
+                    return Err(ConfigError::InvalidValue {
+                        field: "cache_threshold".to_string(),
+                        value: cache_threshold.to_string(),
+                        reason: "Must be between 0.0 and 1.0".to_string(),
+                    });
+                }
+
+                if *balance_rel_threshold < 1.0 {
+                    return Err(ConfigError::InvalidValue {
+                        field: "balance_rel_threshold".to_string(),
+                        value: balance_rel_threshold.to_string(),
+                        reason: "Must be >= 1.0".to_string(),
+                    });
+                }
+
+                if *eviction_interval_secs == 0 {
+                    return Err(ConfigError::InvalidValue {
+                        field: "eviction_interval_secs".to_string(),
+                        value: eviction_interval_secs.to_string(),
+                        reason: "Must be > 0".to_string(),
+                    });
+                }
+
+                if *max_tree_size == 0 {
+                    return Err(ConfigError::InvalidValue {
+                        field: "max_tree_size".to_string(),
+                        value: max_tree_size.to_string(),
+                        reason: "Must be > 0".to_string(),
+                    });
+                }
+            }
+            PolicyConfig::PowerOfTwo {
+                load_check_interval_secs,
+            } => {
+                if *load_check_interval_secs == 0 {
+                    return Err(ConfigError::InvalidValue {
+                        field: "load_check_interval_secs".to_string(),
+                        value: load_check_interval_secs.to_string(),
+                        reason: "Must be > 0".to_string(),
+                    });
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// Validate server configuration
+    fn validate_server_settings(config: &RouterConfig) -> ConfigResult<()> {
+        if config.port == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "port".to_string(),
+                value: config.port.to_string(),
+                reason: "Port must be > 0".to_string(),
+            });
+        }
+
+        if config.max_payload_size == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "max_payload_size".to_string(),
+                value: config.max_payload_size.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+
+        if config.request_timeout_secs == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "request_timeout_secs".to_string(),
+                value: config.request_timeout_secs.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+
+        if config.worker_startup_timeout_secs == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "worker_startup_timeout_secs".to_string(),
+                value: config.worker_startup_timeout_secs.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+
+        if config.worker_startup_check_interval_secs == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "worker_startup_check_interval_secs".to_string(),
+                value: config.worker_startup_check_interval_secs.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+
+        Ok(())
+    }
+
+    /// Validate service discovery configuration
+    fn validate_discovery(discovery: &DiscoveryConfig, mode: &RoutingMode) -> ConfigResult<()> {
+        if !discovery.enabled {
+            return Ok(()); // No validation needed if disabled
+        }
+
+        if discovery.port == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "discovery.port".to_string(),
+                value: discovery.port.to_string(),
+                reason: "Port must be > 0".to_string(),
+            });
+        }
+
+        if discovery.check_interval_secs == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "discovery.check_interval_secs".to_string(),
+                value: discovery.check_interval_secs.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+
+        // Validate selectors based on mode
+        match mode {
+            RoutingMode::Regular { .. } => {
+                if discovery.selector.is_empty() {
+                    return Err(ConfigError::ValidationFailed {
+                        reason: "Regular mode with service discovery requires a non-empty selector"
+                            .to_string(),
+                    });
+                }
+            }
+            RoutingMode::PrefillDecode { .. } => {
+                if discovery.prefill_selector.is_empty() && discovery.decode_selector.is_empty() {
+                    return Err(ConfigError::ValidationFailed {
+                        reason: "PD mode with service discovery requires at least one non-empty selector (prefill or decode)".to_string(),
+                    });
+                }
+            }
+            RoutingMode::OpenAI { .. } => {
+                // OpenAI mode doesn't use service discovery
+                return Err(ConfigError::ValidationFailed {
+                    reason: "OpenAI mode does not support service discovery".to_string(),
+                });
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Validate metrics configuration
+    fn validate_metrics(metrics: &MetricsConfig) -> ConfigResult<()> {
+        if metrics.port == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "metrics.port".to_string(),
+                value: metrics.port.to_string(),
+                reason: "Port must be > 0".to_string(),
+            });
+        }
+
+        if metrics.host.is_empty() {
+            return Err(ConfigError::InvalidValue {
+                field: "metrics.host".to_string(),
+                value: metrics.host.clone(),
+                reason: "Host cannot be empty".to_string(),
+            });
+        }
+
+        Ok(())
+    }
+
+    /// Validate retry configuration
+    fn validate_retry(retry: &RetryConfig) -> ConfigResult<()> {
+        if retry.max_retries < 1 {
+            return Err(ConfigError::InvalidValue {
+                field: "retry.max_retries".to_string(),
+                value: retry.max_retries.to_string(),
+                reason: "Must be >= 1 (set to 1 to effectively disable retries)".to_string(),
+            });
+        }
+        if retry.initial_backoff_ms == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "retry.initial_backoff_ms".to_string(),
+                value: retry.initial_backoff_ms.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+        if retry.max_backoff_ms < retry.initial_backoff_ms {
+            return Err(ConfigError::InvalidValue {
+                field: "retry.max_backoff_ms".to_string(),
+                value: retry.max_backoff_ms.to_string(),
+                reason: "Must be >= initial_backoff_ms".to_string(),
+            });
+        }
+        if retry.backoff_multiplier < 1.0 {
+            return Err(ConfigError::InvalidValue {
+                field: "retry.backoff_multiplier".to_string(),
+                value: retry.backoff_multiplier.to_string(),
+                reason: "Must be >= 1.0".to_string(),
+            });
+        }
+        if !(0.0..=1.0).contains(&retry.jitter_factor) {
+            return Err(ConfigError::InvalidValue {
+                field: "retry.jitter_factor".to_string(),
+                value: retry.jitter_factor.to_string(),
+                reason: "Must be between 0.0 and 1.0".to_string(),
+            });
+        }
+        Ok(())
+    }
+
+    /// Validate circuit breaker configuration
+    fn validate_circuit_breaker(cb: &CircuitBreakerConfig) -> ConfigResult<()> {
+        if cb.failure_threshold < 1 {
+            return Err(ConfigError::InvalidValue {
+                field: "circuit_breaker.failure_threshold".to_string(),
+                value: cb.failure_threshold.to_string(),
+                reason: "Must be >= 1 (set to u32::MAX to effectively disable CB)".to_string(),
+            });
+        }
+        if cb.success_threshold < 1 {
+            return Err(ConfigError::InvalidValue {
+                field: "circuit_breaker.success_threshold".to_string(),
+                value: cb.success_threshold.to_string(),
+                reason: "Must be >= 1".to_string(),
+            });
+        }
+        if cb.timeout_duration_secs == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "circuit_breaker.timeout_duration_secs".to_string(),
+                value: cb.timeout_duration_secs.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+        if cb.window_duration_secs == 0 {
+            return Err(ConfigError::InvalidValue {
+                field: "circuit_breaker.window_duration_secs".to_string(),
+                value: cb.window_duration_secs.to_string(),
+                reason: "Must be > 0".to_string(),
+            });
+        }
+        Ok(())
+    }
+
+    /// Validate compatibility between different configuration sections
+    fn validate_compatibility(config: &RouterConfig) -> ConfigResult<()> {
+        // IGW mode is independent - skip other compatibility checks when enabled
+        if config.enable_igw {
+            return Ok(());
+        }
+
+        // Validate gRPC connection mode requires tokenizer configuration
+        if config.connection_mode == ConnectionMode::Grpc
+            && config.tokenizer_path.is_none()
+            && config.model_path.is_none()
+        {
+            return Err(ConfigError::ValidationFailed {
+                reason: "gRPC connection mode requires either --tokenizer-path or --model-path to be specified".to_string(),
+            });
+        }
+
+        // All policies are now supported for both router types thanks to the unified trait design
+        // No mode/policy restrictions needed anymore
+
+        // Check if service discovery is enabled for worker count validation
+        let has_service_discovery = config.discovery.as_ref().is_some_and(|d| d.enabled);
+
+        // Only validate worker counts if service discovery is disabled
+        if !has_service_discovery {
+            // Check if power-of-two policy makes sense with insufficient workers
+            if let PolicyConfig::PowerOfTwo { .. } = &config.policy {
+                let worker_count = config.mode.worker_count();
+                if worker_count < 2 {
+                    return Err(ConfigError::IncompatibleConfig {
+                        reason: "Power-of-two policy requires at least 2 workers".to_string(),
+                    });
+                }
+            }
+
+            // For PD mode, validate that policies have sufficient workers
+            if let RoutingMode::PrefillDecode {
+                prefill_urls,
+                decode_urls,
+                prefill_policy,
+                decode_policy,
+            } = &config.mode
+            {
+                // Check power-of-two for prefill
+                if let Some(PolicyConfig::PowerOfTwo { .. }) = prefill_policy {
+                    if prefill_urls.len() < 2 {
+                        return Err(ConfigError::IncompatibleConfig {
+                            reason: "Power-of-two policy for prefill requires at least 2 prefill workers".to_string(),
+                        });
+                    }
+                }
+
+                // Check power-of-two for decode
+                if let Some(PolicyConfig::PowerOfTwo { .. }) = decode_policy {
+                    if decode_urls.len() < 2 {
+                        return Err(ConfigError::IncompatibleConfig {
+                            reason:
+                                "Power-of-two policy for decode requires at least 2 decode workers"
+                                    .to_string(),
+                        });
+                    }
+                }
+            }
+        }
+
+        // Service discovery is conflict with dp_aware routing for now
+        // since it's not fully supported yet
+        if has_service_discovery && config.dp_aware {
+            return Err(ConfigError::IncompatibleConfig {
+                reason: "DP-aware routing is not compatible with service discovery".to_string(),
+            });
+        }
+
+        Ok(())
+    }
+
+    /// Validate URL format
+    fn validate_urls(urls: &[String]) -> ConfigResult<()> {
+        for url in urls {
+            if url.is_empty() {
+                return Err(ConfigError::InvalidValue {
+                    field: "worker_url".to_string(),
+                    value: url.clone(),
+                    reason: "URL cannot be empty".to_string(),
+                });
+            }
+
+            if !url.starts_with("http://")
+                && !url.starts_with("https://")
+                && !url.starts_with("grpc://")
+            {
+                return Err(ConfigError::InvalidValue {
+                    field: "worker_url".to_string(),
+                    value: url.clone(),
+                    reason: "URL must start with http://, https://, or grpc://".to_string(),
+                });
+            }
+
+            // Basic URL validation
+            match ::url::Url::parse(url) {
+                Ok(parsed) => {
+                    // Additional validation
+                    if parsed.host_str().is_none() {
+                        return Err(ConfigError::InvalidValue {
+                            field: "worker_url".to_string(),
+                            value: url.clone(),
+                            reason: "URL must have a valid host".to_string(),
+                        });
+                    }
+                }
+                Err(e) => {
+                    return Err(ConfigError::InvalidValue {
+                        field: "worker_url".to_string(),
+                        value: url.clone(),
+                        reason: format!("Invalid URL format: {}", e),
+                    });
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_validate_regular_mode() {
+        let config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec!["http://worker:8000".to_string()],
+            },
+            PolicyConfig::Random,
+        );
+
+        assert!(ConfigValidator::validate(&config).is_ok());
+    }
+
+    #[test]
+    fn test_validate_empty_worker_urls() {
+        let config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec![],
+            },
+            PolicyConfig::Random,
+        );
+
+        // Empty worker URLs are now allowed to match legacy behavior
+        assert!(ConfigValidator::validate(&config).is_ok());
+    }
+
+    #[test]
+    fn test_validate_empty_worker_urls_with_service_discovery() {
+        let mut config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec![],
+            },
+            PolicyConfig::Random,
+        );
+
+        // Enable service discovery
+        config.discovery = Some(DiscoveryConfig {
+            enabled: true,
+            selector: vec![("app".to_string(), "test".to_string())]
+                .into_iter()
+                .collect(),
+            ..Default::default()
+        });
+
+        // Should pass validation since service discovery is enabled
+        assert!(ConfigValidator::validate(&config).is_ok());
+    }
+
+    #[test]
+    fn test_validate_invalid_urls() {
+        let config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec!["invalid-url".to_string()],
+            },
+            PolicyConfig::Random,
+        );
+
+        assert!(ConfigValidator::validate(&config).is_err());
+    }
+
+    #[test]
+    fn test_validate_cache_aware_thresholds() {
+        let config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec![
+                    "http://worker1:8000".to_string(),
+                    "http://worker2:8000".to_string(),
+                ],
+            },
+            PolicyConfig::CacheAware {
+                cache_threshold: 1.5, // Invalid: > 1.0
+                balance_abs_threshold: 32,
+                balance_rel_threshold: 1.1,
+                eviction_interval_secs: 60,
+                max_tree_size: 1000,
+            },
+        );
+
+        assert!(ConfigValidator::validate(&config).is_err());
+    }
+
+    #[test]
+    fn test_validate_cache_aware_single_worker() {
+        // Cache-aware with single worker should be allowed (even if not optimal)
+        let config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec!["http://worker1:8000".to_string()],
+            },
+            PolicyConfig::CacheAware {
+                cache_threshold: 0.5,
+                balance_abs_threshold: 32,
+                balance_rel_threshold: 1.1,
+                eviction_interval_secs: 60,
+                max_tree_size: 1000,
+            },
+        );
+
+        assert!(ConfigValidator::validate(&config).is_ok());
+    }
+
+    #[test]
+    fn test_validate_pd_mode() {
+        let config = RouterConfig::new(
+            RoutingMode::PrefillDecode {
+                prefill_urls: vec![("http://prefill:8000".to_string(), Some(8081))],
+                decode_urls: vec!["http://decode:8000".to_string()],
+                prefill_policy: None,
+                decode_policy: None,
+            },
+            PolicyConfig::Random,
+        );
+
+        assert!(ConfigValidator::validate(&config).is_ok());
+    }
+
+    #[test]
+    fn test_validate_roundrobin_with_pd_mode() {
+        // RoundRobin with PD mode is now supported
+        let config = RouterConfig::new(
+            RoutingMode::PrefillDecode {
+                prefill_urls: vec![("http://prefill:8000".to_string(), None)],
+                decode_urls: vec!["http://decode:8000".to_string()],
+                prefill_policy: None,
+                decode_policy: None,
+            },
+            PolicyConfig::RoundRobin,
+        );
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_validate_cache_aware_with_pd_mode() {
+        // CacheAware with PD mode is now supported
+        let config = RouterConfig::new(
+            RoutingMode::PrefillDecode {
+                prefill_urls: vec![("http://prefill:8000".to_string(), None)],
+                decode_urls: vec!["http://decode:8000".to_string()],
+                prefill_policy: None,
+                decode_policy: None,
+            },
+            PolicyConfig::CacheAware {
+                cache_threshold: 0.5,
+                balance_abs_threshold: 32,
+                balance_rel_threshold: 1.1,
+                eviction_interval_secs: 60,
+                max_tree_size: 1000,
+            },
+        );
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_validate_power_of_two_with_regular_mode() {
+        // PowerOfTwo with Regular mode is now supported
+        let config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec![
+                    "http://worker1:8000".to_string(),
+                    "http://worker2:8000".to_string(),
+                ],
+            },
+            PolicyConfig::PowerOfTwo {
+                load_check_interval_secs: 60,
+            },
+        );
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_validate_pd_mode_with_separate_policies() {
+        // Test PD mode with different policies for prefill and decode
+        let config = RouterConfig::new(
+            RoutingMode::PrefillDecode {
+                prefill_urls: vec![
+                    ("http://prefill1:8000".to_string(), None),
+                    ("http://prefill2:8000".to_string(), None),
+                ],
+                decode_urls: vec![
+                    "http://decode1:8000".to_string(),
+                    "http://decode2:8000".to_string(),
+                ],
+                prefill_policy: Some(PolicyConfig::CacheAware {
+                    cache_threshold: 0.5,
+                    balance_abs_threshold: 32,
+                    balance_rel_threshold: 1.1,
+                    eviction_interval_secs: 60,
+                    max_tree_size: 1000,
+                }),
+                decode_policy: Some(PolicyConfig::PowerOfTwo {
+                    load_check_interval_secs: 60,
+                }),
+            },
+            PolicyConfig::Random, // Main policy as fallback
+        );
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_validate_pd_mode_power_of_two_insufficient_workers() {
+        // Test that power-of-two policy requires at least 2 workers
+        let config = RouterConfig::new(
+            RoutingMode::PrefillDecode {
+                prefill_urls: vec![("http://prefill1:8000".to_string(), None)], // Only 1 prefill
+                decode_urls: vec![
+                    "http://decode1:8000".to_string(),
+                    "http://decode2:8000".to_string(),
+                ],
+                prefill_policy: Some(PolicyConfig::PowerOfTwo {
+                    load_check_interval_secs: 60,
+                }), // Requires 2+ workers
+                decode_policy: None,
+            },
+            PolicyConfig::Random,
+        );
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_err());
+        if let Err(e) = result {
+            assert!(e.to_string().contains("prefill requires at least 2"));
+        }
+    }
+
+    #[test]
+    fn test_validate_grpc_requires_tokenizer() {
+        // Test that gRPC connection mode requires tokenizer configuration
+        let mut config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec!["grpc://worker:50051".to_string()],
+            },
+            PolicyConfig::Random,
+        );
+
+        // Set connection mode to gRPC without tokenizer config
+        config.connection_mode = ConnectionMode::Grpc;
+        config.tokenizer_path = None;
+        config.model_path = None;
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_err());
+        if let Err(e) = result {
+            assert!(e.to_string().contains("gRPC connection mode requires"));
+        }
+    }
+
+    #[test]
+    fn test_validate_grpc_with_model_path() {
+        // Test that gRPC works with model_path
+        let mut config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec!["grpc://worker:50051".to_string()],
+            },
+            PolicyConfig::Random,
+        );
+
+        config.connection_mode = ConnectionMode::Grpc;
+        config.model_path = Some("meta-llama/Llama-3-8B".to_string());
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_validate_grpc_with_tokenizer_path() {
+        // Test that gRPC works with tokenizer_path
+        let mut config = RouterConfig::new(
+            RoutingMode::Regular {
+                worker_urls: vec!["grpc://worker:50051".to_string()],
+            },
+            PolicyConfig::Random,
+        );
+
+        config.connection_mode = ConnectionMode::Grpc;
+        config.tokenizer_path = Some("/path/to/tokenizer.json".to_string());
+
+        let result = ConfigValidator::validate(&config);
+        assert!(result.is_ok());
+    }
+}