feat: Remove Component from public (#6403)

Signed-off-by: tzulingk@nvidia.com <tzulingk@nvidia.com>

lib/runtime/src/component.rs

@@ -47,6 +47,7 @@ use async_nats::{
     rustls::quic,
     service::{Service, ServiceExt},
 };
+use dashmap::DashMap;
 use derive_builder::Builder;
 use derive_getters::Getters;
 use educe::Educe;
@@ -425,6 +426,13 @@ pub struct Namespace {
     /// This hierarchy's own metrics registry
     #[builder(default = "crate::MetricsRegistry::new()")]
     metrics_registry: crate::MetricsRegistry,
+
+    /// Cache for components to avoid duplicate registrations and metrics collisions.
+    /// When the same component is requested multiple times, we return the cached instance
+    /// to ensure all endpoints share the same Component and MetricsRegistry.
+    /// Uses DashMap for lock-free reads and automatic handling of concurrent inserts.
+    #[builder(default = "Arc::new(DashMap::new())")]
+    component_cache: Arc<DashMap<String, Component>>,
 }
 
 impl DistributedRuntimeProvider for Namespace {
@@ -469,14 +477,34 @@ impl Namespace {
     }
 
     /// Create a [`Component`] in the namespace who's endpoints can be discovered with etcd
+    ///
+    /// Components are cached by name to ensure that multiple calls with the same name
+    /// return the same Component instance. This prevents duplicate metrics registrations
+    /// and ensures all endpoints share the same Component's MetricsRegistry.
     pub fn component(&self, name: impl Into<String>) -> anyhow::Result<Component> {
+        let name = name.into();
+
+        // Fast path: Check if component exists in cache
+        // DashMap provides lock-free reads via internal sharding
+        if let Some(cached) = self.component_cache.get(&name) {
+            return Ok(cached.value().clone());
+        }
+
+        // Slow path: Create new component
         let component = ComponentBuilder::from_runtime(self.runtime.clone())
-            .name(name)
+            .name(&name)
             .namespace(self.clone())
             .build()?;
+
         // Attach component registry so scrapes traverse separate registries (avoids collisions).
         self.get_metrics_registry()
             .add_child_registry(component.get_metrics_registry());
+
+        // Cache the component for future calls
+        // DashMap handles race conditions internally - if another thread
+        // inserted the same key concurrently, we just use our created component
+        self.component_cache.insert(name, component.clone());
+
         Ok(component)
     }
 

tests/router/test_router_e2e_with_trtllm.py

@@ -407,7 +407,7 @@ def test_router_decisions_trtllm_attention_dp(
 
         # Get runtime and create endpoint
         runtime = get_runtime(request_plane=request_plane)
-        # Use the namespace from the vLLM workers
+        # Use the namespace from the TRT-LLM workers
         endpoint = runtime.endpoint(f"{trtllm_workers.namespace}.tensorrt_llm.generate")
 
         _test_router_decisions(