Add backend name to telemetry (#2962)

* feat: Add backend name to telemetry

backends/trtllm/src/looper.rs

@@ -340,4 +340,8 @@ impl Backend for TensorRtLlmBackendV2 {
     async fn health(&self, _: bool) -> bool {
         true
     }
+
+    fn name(&self) -> &'static str {
+        "TensorRT-LLM"
+    }
 }

backends/v2/src/backend.rs

@@ -108,6 +108,10 @@ impl Backend for BackendV2 {
     fn start_health(&self) -> bool {
         true
     }
+
+    fn name(&self) -> &'static str {
+        "tgi-v2"
+    }
 }
 
 /// Batching logic

backends/v3/src/backend.rs

@@ -115,6 +115,10 @@ impl Backend for BackendV3 {
     fn start_health(&self) -> bool {
         true
     }
+
+    fn name(&self) -> &'static str {
+        "tgi-v3"
+    }
 }
 
 /// Batching logic

router/src/infer/mod.rs

@@ -40,6 +40,8 @@ pub trait Backend {
     fn start_health(&self) -> bool {
         false
     }
+
+    fn name(&self) -> &'static str;
 }
 
 /// Inference struct

router/src/server.rs

@@ -1898,6 +1898,7 @@ pub async fn run(
                 disable_grammar_support,
                 max_client_batch_size,
                 usage_stats_level,
+                backend.name(),
             );
             Some(usage_stats::UserAgent::new(reduced_args))
         }

router/src/usage_stats.rs

@@ -97,6 +97,7 @@ pub struct Args {
     disable_grammar_support: bool,
     max_client_batch_size: usize,
     usage_stats_level: UsageStatsLevel,
+    backend_name: &'static str,
 }
 
 impl Args {
@@ -120,6 +121,7 @@ impl Args {
         disable_grammar_support: bool,
         max_client_batch_size: usize,
         usage_stats_level: UsageStatsLevel,
+        backend_name: &'static str,
     ) -> Self {
         Self {
             model_config,
@@ -140,6 +142,7 @@ impl Args {
             disable_grammar_support,
             max_client_batch_size,
             usage_stats_level,
+            backend_name,
         }
     }
 }