Namespace override with ROS2_NAMESPACE environment variable

rcl/src/rcl/node.c

@@ -54,6 +54,7 @@ extern "C"
 #include "./context_impl.h"
 
 const char * const RCL_DISABLE_LOANED_MESSAGES_ENV_VAR = "ROS_DISABLE_LOANED_MESSAGES";
+const char * const RCL_NAMESPACE_ENV_VAR = "ROS_NAMESPACE";
 
 struct rcl_node_impl_s
 {
@@ -121,13 +122,27 @@ rcl_node_init(
   rcl_context_t * context,
   const rcl_node_options_t * options)
 {
+
   const rmw_guard_condition_t * rmw_graph_guard_condition = NULL;
   rcl_guard_condition_options_t graph_guard_condition_options =
     rcl_guard_condition_get_default_options();
   rcl_ret_t ret;
   rcl_ret_t fail_ret = RCL_RET_ERROR;
   char * remapped_node_name = NULL;
 
+  const char * env_error_str = NULL;
+  const char * env_val = NULL;
+  env_error_str = rcutils_get_env(RCL_NAMESPACE_ENV_VAR, &env_val);
+  if (NULL != env_error_str) {
+    RCL_SET_ERROR_MSG_WITH_FORMAT_STRING(
+      "Error getting env var: '" RCUTILS_STRINGIFY(RCL_NAMESPACE_ENV_VAR) "': %s\n",
+      env_error_str);
+    return RCL_RET_ERROR;
+  }
+  if (NULL != env_val && 0 != strlen(env_val)) {
+    namespace_ = env_val;
+  }
+
   // Check options and allocator first, so allocator can be used for errors.
   RCL_CHECK_ARGUMENT_FOR_NULL(options, RCL_RET_INVALID_ARGUMENT);
   const rcl_allocator_t * allocator = &options->allocator;

rcl/test/rcl/test_node.cpp

@@ -1043,3 +1043,45 @@ TEST_F(CLASSNAME(TestNodeFixture, RMW_IMPLEMENTATION), test_rcl_get_disable_loan
     EXPECT_FALSE(disable_loaned_message);
   }
 }
+
+/* Tests node namespace override
+ */
+TEST_F(CLASSNAME(TestNodeFixture, RMW_IMPLEMENTATION), test_rcl_node_namespace_override) {
+  {
+    const char * expected_namespace = "/bar/foo";
+    ASSERT_TRUE(rcutils_set_env("ROS2_NAMESPACE", expected_namespace));
+
+    osrf_testing_tools_cpp::memory_tools::enable_monitoring_in_all_threads();
+    rcl_ret_t ret;
+    // Initialize rcl with rcl_init().
+    rcl_init_options_t init_options = rcl_get_zero_initialized_init_options();
+    ret = rcl_init_options_init(&init_options, rcl_get_default_allocator());
+    ASSERT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
+    OSRF_TESTING_TOOLS_CPP_SCOPE_EXIT(
+    {
+      EXPECT_EQ(RCL_RET_OK, rcl_init_options_fini(&init_options)) << rcl_get_error_string().str;
+    });
+    EXPECT_EQ(RCL_RET_OK, rcl_init_options_set_domain_id(&init_options, 42));
+    const char * name = "test_rcl_node_namespace_override";
+    const char * namespace_ = "/ns";
+    rcl_node_options_t default_options = rcl_node_get_default_options();
+    rcl_context_t context = rcl_get_zero_initialized_context();
+    ret = rcl_init(0, nullptr, &init_options, &context);
+    ASSERT_EQ(RCL_RET_OK, ret);
+    // Create a normal node.
+    rcl_node_t node = rcl_get_zero_initialized_node();
+    ret = rcl_node_init(&node, name, namespace_, &context, &default_options);
+    ASSERT_EQ(RCL_RET_OK, ret);
+
+    // Check that the node namespace is overridden
+    ASSERT_STREQ(expected_namespace, rcl_node_get_namespace(&node));
+
+    OSRF_TESTING_TOOLS_CPP_SCOPE_EXIT(
+    {
+      osrf_testing_tools_cpp::memory_tools::disable_monitoring_in_all_threads();
+      ASSERT_EQ(RCL_RET_OK, rcl_node_fini(&node));
+      ASSERT_EQ(RCL_RET_OK, rcl_shutdown(&context));
+      ASSERT_EQ(RCL_RET_OK, rcl_context_fini(&context));
+    });
+  }
+}