[Rust Frontend][gRPC] Add LoRA lifecycle control (#52840)

Co-authored-by: Bugen Zhao <i@bugenzhao.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Signed-off-by: Connor Carpenter <connorc@nvidia.com>
Signed-off-by: Bugen Zhao <i@bugenzhao.com>

rust/src/engine-core-client/src/protocol/lora.rs

@@ -2,6 +2,7 @@
 // SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 use serde_tuple::{Deserialize_tuple, Serialize_tuple};
+use thiserror::Error;
 
 use crate::protocol::OpaqueValue;
 
@@ -24,6 +25,16 @@ pub struct LoraRequest {
     pub is_3d_lora_weight: bool,
 }
 
+#[derive(Debug, Error, PartialEq, Eq)]
+pub enum LoraRequestError {
+    #[error("lora_name must not be empty")]
+    EmptyName,
+    #[error("lora_int_id must be nonzero")]
+    ZeroId,
+    #[error("lora_path must not be empty")]
+    EmptyPath,
+}
+
 impl LoraRequest {
     pub fn new(
         lora_name: String,
@@ -31,8 +42,18 @@ impl LoraRequest {
         lora_path: String,
         load_inplace: bool,
         is_3d_lora_weight: bool,
-    ) -> Self {
-        Self {
+    ) -> Result<Self, LoraRequestError> {
+        if lora_name.trim().is_empty() {
+            return Err(LoraRequestError::EmptyName);
+        }
+        if lora_int_id == 0 {
+            return Err(LoraRequestError::ZeroId);
+        }
+        if lora_path.trim().is_empty() {
+            return Err(LoraRequestError::EmptyPath);
+        }
+
+        Ok(Self {
             lora_name,
             lora_int_id,
             lora_path,
@@ -40,6 +61,6 @@ impl LoraRequest {
             tensorizer_config_dict: None,
             load_inplace,
             is_3d_lora_weight,
-        }
+        })
     }
 }