Routing over gRPC: VRP server + compiled C++/Cython client

cpp/CMakeLists.txt

@@ -427,6 +427,23 @@ if (NOT SKIP_GRPC_BUILD)
     set(PROTO_PATH_MANUAL "${CMAKE_CURRENT_SOURCE_DIR}/src/grpc")
     set(PROTO_PATH_GEN "${CMAKE_CURRENT_SOURCE_DIR}/src/grpc/codegen/generated")
 
+    # Routing solution proto (leaf; no imports). Embedded structurally by the
+    # generated data proto and by cuopt_remote.proto, so it is generated first.
+    set(ROUTING_SOLUTION_PROTO_FILE "${PROTO_PATH_MANUAL}/cuopt_routing_solution.proto")
+    set(ROUTING_SOLUTION_PROTO_SRCS "${CMAKE_CURRENT_BINARY_DIR}/cuopt_routing_solution.pb.cc")
+    set(ROUTING_SOLUTION_PROTO_HDRS "${CMAKE_CURRENT_BINARY_DIR}/cuopt_routing_solution.pb.h")
+
+    add_custom_command(
+            OUTPUT "${ROUTING_SOLUTION_PROTO_SRCS}" "${ROUTING_SOLUTION_PROTO_HDRS}"
+            COMMAND ${_PROTOBUF_PROTOC}
+            ARGS --cpp_out ${CMAKE_CURRENT_BINARY_DIR}
+            --proto_path ${PROTO_PATH_MANUAL}
+            ${ROUTING_SOLUTION_PROTO_FILE}
+            DEPENDS ${ROUTING_SOLUTION_PROTO_FILE}
+            COMMENT "Generating C++ code from cuopt_routing_solution.proto"
+            VERBATIM
+    )
+
     # Generate C++ code from cuopt_remote_data.proto (auto-generated data definitions)
     set(DATA_PROTO_FILE "${PROTO_PATH_GEN}/cuopt_remote_data.proto")
     set(DATA_PROTO_SRCS "${CMAKE_CURRENT_BINARY_DIR}/cuopt_remote_data.pb.cc")
@@ -437,8 +454,9 @@ if (NOT SKIP_GRPC_BUILD)
             COMMAND ${_PROTOBUF_PROTOC}
             ARGS --cpp_out ${CMAKE_CURRENT_BINARY_DIR}
             --proto_path ${PROTO_PATH_GEN}
+            --proto_path ${PROTO_PATH_MANUAL}
             ${DATA_PROTO_FILE}
-            DEPENDS ${DATA_PROTO_FILE}
+            DEPENDS ${DATA_PROTO_FILE} ${ROUTING_SOLUTION_PROTO_FILE}
             COMMENT "Generating C++ code from cuopt_remote_data.proto"
             VERBATIM
     )
@@ -455,7 +473,7 @@ if (NOT SKIP_GRPC_BUILD)
             --proto_path ${PROTO_PATH_MANUAL}
             --proto_path ${PROTO_PATH_GEN}
             ${PROTO_FILE}
-            DEPENDS ${PROTO_FILE} ${DATA_PROTO_FILE}
+            DEPENDS ${PROTO_FILE} ${DATA_PROTO_FILE} ${ROUTING_SOLUTION_PROTO_FILE}
             COMMENT "Generating C++ code from cuopt_remote.proto"
             VERBATIM
     )
@@ -467,6 +485,23 @@ if (NOT SKIP_GRPC_BUILD)
     set(GRPC_SERVICE_SRCS "${CMAKE_CURRENT_BINARY_DIR}/cuopt_remote_service.grpc.pb.cc")
     set(GRPC_SERVICE_HDRS "${CMAKE_CURRENT_BINARY_DIR}/cuopt_remote_service.grpc.pb.h")
 
+    # Routing proto (standalone VRP messages; imported by service proto)
+    set(ROUTING_PROTO_FILE "${PROTO_PATH_MANUAL}/cuopt_routing.proto")
+    set(ROUTING_PROTO_SRCS "${CMAKE_CURRENT_BINARY_DIR}/cuopt_routing.pb.cc")
+    set(ROUTING_PROTO_HDRS "${CMAKE_CURRENT_BINARY_DIR}/cuopt_routing.pb.h")
+
+    add_custom_command(
+            OUTPUT "${ROUTING_PROTO_SRCS}" "${ROUTING_PROTO_HDRS}"
+            COMMAND ${_PROTOBUF_PROTOC}
+            ARGS --cpp_out ${CMAKE_CURRENT_BINARY_DIR}
+            --proto_path ${PROTO_PATH_MANUAL}
+            --proto_path ${PROTO_PATH_GEN}
+            ${ROUTING_PROTO_FILE}
+            DEPENDS ${ROUTING_PROTO_FILE} ${PROTO_FILE} ${DATA_PROTO_FILE} ${ROUTING_SOLUTION_PROTO_FILE}
+            COMMENT "Generating C++ code from cuopt_routing.proto"
+            VERBATIM
+    )
+
     add_custom_command(
             OUTPUT "${GRPC_PROTO_SRCS}" "${GRPC_PROTO_HDRS}" "${GRPC_SERVICE_SRCS}" "${GRPC_SERVICE_HDRS}"
             COMMAND ${_PROTOBUF_PROTOC}
@@ -476,7 +511,7 @@ if (NOT SKIP_GRPC_BUILD)
             --proto_path ${PROTO_PATH_MANUAL}
             --proto_path ${PROTO_PATH_GEN}
             ${GRPC_PROTO_FILE}
-            DEPENDS ${GRPC_PROTO_FILE} ${PROTO_FILE} ${DATA_PROTO_FILE}
+            DEPENDS ${GRPC_PROTO_FILE} ${PROTO_FILE} ${DATA_PROTO_FILE} ${ROUTING_PROTO_FILE} ${ROUTING_SOLUTION_PROTO_FILE}
             COMMENT "Generating gRPC C++ code from cuopt_remote_service.proto"
             VERBATIM
     )
@@ -526,14 +561,17 @@ endif ()
 if (NOT SKIP_GRPC_BUILD)
     # Add gRPC mapper files and generated protobuf sources
     set(GRPC_INFRA_FILES
+            ${ROUTING_SOLUTION_PROTO_SRCS}
             ${DATA_PROTO_SRCS}
             ${PROTO_SRCS}
+            ${ROUTING_PROTO_SRCS}
             ${GRPC_PROTO_SRCS}
             ${GRPC_SERVICE_SRCS}
             src/grpc/grpc_problem_mapper.cpp
             src/grpc/grpc_solution_mapper.cpp
             src/grpc/grpc_settings_mapper.cpp
             src/grpc/grpc_service_mapper.cpp
+            src/grpc/grpc_routing_problem_mapper.cpp
             src/grpc/client/grpc_client.cpp
             src/grpc/client/grpc_client_env.cpp
             src/grpc/client/cython_grpc_client.cpp

cpp/include/cuopt/grpc/cython_grpc_client.hpp

@@ -6,6 +6,7 @@
 #pragma once
 
 #include <cuopt/mathematical_optimization/utilities/cython_solve.hpp>
+#include <cuopt/routing/cpu_routing_problem.hpp>
 
 #include <cstddef>
 #include <cstdint>
@@ -22,6 +23,11 @@ class data_model_view_t;
 }  // namespace io
 }  // namespace cuopt::mathematical_optimization
 
+namespace cuopt::routing {
+template <typename i_t, typename f_t>
+class solver_settings_t;
+}  // namespace cuopt::routing
+
 namespace cuopt::cython {
 
 /** Mirrors cuopt::mathematical_optimization::job_status_t for the Python bindings. */
@@ -56,6 +62,13 @@ struct grpc_result_outcome_t {
   std::unique_ptr<solver_ret_t> solution;
 };
 
+struct grpc_vrp_result_outcome_t {
+  bool not_ready = false;
+  bool success   = false;
+  std::string error_message;
+  cuopt::routing::cpu_routing_solution_t solution;
+};
+
 struct grpc_logs_result_t {
   bool success = false;
   std::string error_message;
@@ -136,6 +149,17 @@ class grpc_python_client_t {
    */
   grpc_result_outcome_t result(const std::string& job_id, bool is_mip);
 
+  /**
+   * @brief Submit a VRP problem (unary only). Reuse status/wait/delete/result_vrp.
+   */
+  grpc_submit_result_t submit_vrp(cuopt::routing::cpu_routing_problem_t* problem,
+                                  cuopt::routing::solver_settings_t<int, float>* settings);
+
+  /**
+   * @brief Fetch and parse a completed VRP job's routing solution.
+   */
+  grpc_vrp_result_outcome_t result_vrp(const std::string& job_id);
+
   /**
    * @brief Block until the job completes, collecting all solver log lines.
    */

cpp/include/cuopt/routing/cpu_routing_problem.hpp

@@ -0,0 +1,149 @@
+/* clang-format off */
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+/* clang-format on */
+
+#pragma once
+
+#include <cuopt/routing/data_model_view.hpp>
+#include <cuopt/routing/routing_structures.hpp>
+
+#include <cstdint>
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace raft {
+class handle_t;
+}
+
+namespace cuopt {
+namespace routing {
+
+/**
+ * @brief Host-memory owning routing problem (gRPC / remote-execution analog of
+ * data_model_view_t). Owns all arrays in std::vector and can materialize a
+ * device-backed data_model_view_t via to_device().
+ */
+struct cpu_cost_matrix_t {
+  uint8_t vehicle_type = 0;
+  std::vector<float> matrix;  // num_locations x num_locations, row-major
+};
+
+struct cpu_capacity_dimension_t {
+  std::string name;
+  std::vector<int32_t> demand;    // per-order
+  std::vector<int32_t> capacity;  // per-vehicle
+};
+
+struct cpu_vehicle_break_t {
+  int32_t earliest = 0;
+  int32_t latest   = 0;
+  int32_t duration = 0;
+  std::vector<int32_t> locations;
+};
+
+struct cpu_uniform_break_t {
+  std::vector<int32_t> earliest;
+  std::vector<int32_t> latest;
+  std::vector<int32_t> duration;
+};
+
+struct cpu_initial_solution_t {
+  std::vector<int32_t> vehicle_ids;
+  std::vector<int32_t> routes;
+  std::vector<int32_t> types;  // node_type_t values
+  std::vector<int32_t> sol_offsets;
+};
+
+class cpu_routing_problem_t {
+ public:
+  int32_t num_locations = 0;
+  int32_t fleet_size    = 0;
+  int32_t num_orders    = -1;  // -1 => same as num_locations
+
+  std::vector<cpu_cost_matrix_t> cost_matrices;
+  std::vector<cpu_cost_matrix_t> transit_time_matrices;
+
+  std::vector<int32_t> vehicle_start_locations;
+  std::vector<int32_t> vehicle_return_locations;
+  std::vector<int32_t> vehicle_tw_earliest;
+  std::vector<int32_t> vehicle_tw_latest;
+  std::vector<uint8_t> vehicle_types;
+  std::vector<uint8_t> drop_return_trips;  // 0/1 (avoid vector<bool>)
+  std::vector<uint8_t> skip_first_trips;   // 0/1
+  std::vector<float> vehicle_max_costs;
+  std::vector<float> vehicle_max_times;
+  std::vector<float> vehicle_fixed_costs;
+
+  std::vector<int32_t> order_locations;
+  std::vector<int32_t> order_tw_earliest;
+  std::vector<int32_t> order_tw_latest;
+  std::vector<float> order_prizes;
+  // vehicle_id -> service times; use -1 for the default (all vehicles)
+  std::map<int32_t, std::vector<int32_t>> order_service_times;
+
+  std::vector<int32_t> pickup_indices;
+  std::vector<int32_t> delivery_indices;
+
+  std::vector<cpu_capacity_dimension_t> capacity_dimensions;
+
+  std::vector<int32_t> break_locations;
+  std::vector<cpu_uniform_break_t> uniform_breaks;
+  std::map<int32_t, std::vector<cpu_vehicle_break_t>> vehicle_breaks;
+
+  std::map<int32_t, std::vector<int32_t>> vehicle_order_match;
+  std::map<int32_t, std::vector<int32_t>> order_vehicle_match;
+  std::map<int32_t, std::vector<int32_t>> order_precedence;
+
+  std::vector<int32_t> objectives;  // objective_t enum values
+  std::vector<float> objective_weights;
+  int32_t min_vehicles = 0;
+
+  cpu_initial_solution_t initial_solutions;
+
+  /** Opaque owner of device buffers backing the returned data_model_view_t. */
+  struct device_data_t;
+
+  /** Deleter so unique_ptr can destroy incomplete device_data_t outside the .cu TU. */
+  struct device_data_deleter {
+    void operator()(device_data_t* p) const;
+  };
+
+  using device_data_ptr = std::unique_ptr<device_data_t, device_data_deleter>;
+
+  /**
+   * @brief Copy host data to the GPU and return a non-owning data_model_view_t.
+   * The returned device_data_t must outlive the view.
+   */
+  std::pair<data_model_view_t<int, float>, device_data_ptr> to_device(raft::handle_t* handle) const;
+};
+
+/**
+ * @brief Host-memory routing solution (remote-execution analog of the parsed
+ * RoutingSolution proto). Populated on the client from the server's response.
+ */
+struct cpu_routing_solution_t {
+  std::vector<int32_t> route;
+  std::vector<double> arrival_stamp;
+  std::vector<int32_t> truck_id;
+  std::vector<int32_t> locations;
+  std::vector<int32_t> node_types;
+  std::vector<int32_t> unserviced_nodes;
+  std::vector<int32_t> accepted;
+
+  int32_t vehicle_count        = 0;
+  double total_objective_value = 0.0;
+  std::map<int32_t, double> objective_values;
+
+  int32_t status = 0;  // cuopt.remote.RoutingSolutionStatus (0 == SUCCESS)
+  std::string status_message;
+  std::string error_message;
+};
+
+}  // namespace routing
+}  // namespace cuopt

cpp/src/grpc/client/cython_grpc_client.cpp

@@ -151,6 +151,49 @@ grpc_submit_result_t grpc_python_client_t::submit(
   return out;
 }
 
+grpc_submit_result_t grpc_python_client_t::submit_vrp(
+  cuopt::routing::cpu_routing_problem_t* problem,
+  cuopt::routing::solver_settings_t<int, float>* settings)
+{
+  grpc_submit_result_t out;
+  if (problem == nullptr || settings == nullptr) {
+    out.error_message = "problem and settings must not be null";
+    return out;
+  }
+  auto sub          = impl_->client.submit_vrp(*problem, *settings);
+  out.success       = sub.success;
+  out.error_message = sub.error_message;
+  out.job_id        = sub.job_id;
+  out.is_mip        = false;
+  return out;
+}
+
+grpc_vrp_result_outcome_t grpc_python_client_t::result_vrp(const std::string& job_id)
+{
+  grpc_vrp_result_outcome_t out;
+
+  // Mirror result(): surface a structured "still running" signal instead of a
+  // generic GetResult failure when a caller polls result_vrp on an in-flight job.
+  auto st = status(job_id);
+  if (!st.success) {
+    out.error_message = st.error_message;
+    return out;
+  }
+  if (is_in_flight(st.status)) {
+    out.not_ready = true;
+    return out;
+  }
+
+  auto remote = impl_->client.get_vrp_result(job_id);
+  if (!remote.success) {
+    out.error_message = remote.error_message;
+    return out;
+  }
+  out.success  = true;
+  out.solution = std::move(remote.solution);
+  return out;
+}
+
 grpc_status_result_t grpc_python_client_t::status(const std::string& job_id)
 {
   return map_status_result(impl_->client.check_status(job_id));