feat: return error on invalid config (#291)

Author: kavinvalli

ai-gateway/src/utils/validate_config.rs

@@ -16,6 +16,7 @@ use crate::{
         api::ApiError, internal::InternalError,
         invalid_req::InvalidRequestError,
     },
+    types::json::Json,
 };
 
 #[derive(Debug, Clone)]
@@ -79,6 +80,7 @@ where
 #[derive(Serialize)]
 pub struct ValidateRouterConfigResponse {
     pub valid: bool,
+    pub error: Option<String>,
 }
 
 impl<S, ReqBody> Service<Request<ReqBody>> for ValidateRouterConfig<S, ReqBody>
@@ -125,22 +127,20 @@ where
                         }
                     };
 
-                let valid = config.validate().is_ok();
-                let response_body =
-                    serde_json::to_vec(&ValidateRouterConfigResponse { valid })
-                        .expect(
-                            "can always serialize a \
-                             ValidateRouterConfigResponse",
-                        );
-
-                Ok(http::Response::builder()
-                    .status(http::StatusCode::OK)
-                    .header(http::header::CONTENT_TYPE, "application/json")
-                    .body(axum_core::body::Body::from(response_body))
-                    .expect(
-                        "serialized ValidateRouterConfigResponse is always a \
-                         valid axum body",
-                    ))
+                let validate_result = config.validate();
+                if let Err(e) = validate_result {
+                    let body = Json(ValidateRouterConfigResponse {
+                        valid: false,
+                        error: Some(e.to_string()),
+                    });
+                    return Ok(body.into_response());
+                } else {
+                    let body = Json(ValidateRouterConfigResponse {
+                        valid: true,
+                        error: None,
+                    });
+                    return Ok(body.into_response());
+                }
             };
             Either::Left(Box::pin(fut))
         } else {