Add function for getting clients by node (#459)

* Add graph test for service clients

There were tests for publishers, subscriptions, and services, but not clients.

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Add function for getting clients by node

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Update service client graph test

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Fix doc sentence

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Update docs

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

rcl/include/rcl/graph.h

@@ -135,7 +135,7 @@ rcl_get_subscriber_names_and_types_by_node(
   const char * node_namespace,
   rcl_names_and_types_t * topic_names_and_types);
 
-/// Return a list of service names and types for associated with a node.
+/// Return a list of service names and types associated with a node.
 /**
  * The `node` parameter must point to a valid node.
  *
@@ -148,7 +148,7 @@ rcl_get_subscriber_names_and_types_by_node(
  * \see rcl_get_publisher_names_and_types_by_node for details on the `no_demangle` parameter.
  *
  * The returned names are not automatically remapped by this function.
- * Attempting to create clients or services using names returned by this function may not
+ * Attempting to create service clients using names returned by this function may not
  * result in the desired service name being used depending on the remap rules in use.
  *
  * <hr>
@@ -180,6 +180,51 @@ rcl_get_service_names_and_types_by_node(
   const char * node_namespace,
   rcl_names_and_types_t * service_names_and_types);
 
+/// Return a list of service client names and types associated with a node.
+/**
+ * The `node` parameter must point to a valid node.
+ *
+ * The `service_names_and_types` parameter must be allocated and zero initialized.
+ * This function allocates memory for the returned list of names and types and so it is the
+ * callers responsibility to pass `service_names_and_types` to rcl_names_and_types_fini()
+ * when it is no longer needed.
+ * Failing to do so will result in leaked memory.
+ *
+ * \see rcl_get_publisher_names_and_types_by_node for details on the `no_demangle` parameter.
+ *
+ * The returned names are not automatically remapped by this function.
+ * Attempting to create service servers using names returned by this function may not
+ * result in the desired service name being used depending on the remap rules in use.
+ *
+ * <hr>
+ * Attribute          | Adherence
+ * ------------------ | -------------
+ * Allocates Memory   | Yes
+ * Thread-Safe        | No
+ * Uses Atomics       | No
+ * Lock-Free          | Maybe [1]
+ * <i>[1] implementation may need to protect the data structure with a lock</i>
+ *
+ * \param[in] node the handle to the node being used to query the ROS graph
+ * \param[in] allocator allocator to be used when allocating space for strings
+ * \param[in] node_name the node name of the services to return
+ * \param[in] node_namespace the node namespace of the services to return
+ * \param[out] service_names_and_types list of service client names and their types
+ * \return `RCL_RET_OK` if the query was successful, or
+ * \return `RCL_RET_NODE_INVALID` if the node is invalid, or
+ * \return `RCL_RET_INVALID_ARGUMENT` if any arguments are invalid, or
+ * \return `RCL_RET_ERROR` if an unspecified error occurs.
+ */
+RCL_PUBLIC
+RCL_WARN_UNUSED
+rcl_ret_t
+rcl_get_client_names_and_types_by_node(
+  const rcl_node_t * node,
+  rcl_allocator_t * allocator,
+  const char * node_name,
+  const char * node_namespace,
+  rcl_names_and_types_t * service_names_and_types);
+
 /// Return a list of topic names and their types.
 /**
  * The `node` parameter must point to a valid node.

rcl/src/rcl/graph.c

@@ -142,6 +142,42 @@ rcl_get_service_names_and_types_by_node(
   return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
 }
 
+rcl_ret_t
+rcl_get_client_names_and_types_by_node(
+  const rcl_node_t * node,
+  rcl_allocator_t * allocator,
+  const char * node_name,
+  const char * node_namespace,
+  rcl_names_and_types_t * service_names_and_types)
+{
+  if (!rcl_node_is_valid(node)) {
+    return RCL_RET_NODE_INVALID;
+  }
+  RCL_CHECK_ALLOCATOR_WITH_MSG(allocator, "invalid allocator", return RCL_RET_INVALID_ARGUMENT);
+  RCL_CHECK_ARGUMENT_FOR_NULL(node_name, RCL_RET_INVALID_ARGUMENT);
+  RCL_CHECK_ARGUMENT_FOR_NULL(node_namespace, RCL_RET_INVALID_ARGUMENT);
+  RCL_CHECK_ARGUMENT_FOR_NULL(service_names_and_types, RCL_RET_INVALID_ARGUMENT);
+
+  const char * valid_namespace = "/";
+  if (strlen(node_namespace) > 0) {
+    valid_namespace = node_namespace;
+  }
+  rmw_ret_t rmw_ret;
+  rmw_ret = rmw_names_and_types_check_zero(service_names_and_types);
+  if (rmw_ret != RMW_RET_OK) {
+    return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
+  }
+  rcutils_allocator_t rcutils_allocator = *allocator;
+  rmw_ret = rmw_get_client_names_and_types_by_node(
+    rcl_node_get_rmw_handle(node),
+    &rcutils_allocator,
+    node_name,
+    valid_namespace,
+    service_names_and_types
+  );
+  return rcl_convert_rmw_ret_to_rcl_ret(rmw_ret);
+}
+
 rcl_ret_t
 rcl_get_topic_names_and_types(
   const rcl_node_t * node,

rcl/test/rcl/test_graph.cpp

@@ -516,6 +516,78 @@ TEST_F(
   rcl_reset_error();
 }
 
+/* Test the rcl_get_client_names_and_types_by_node function.
+ *
+ * This does not test content of the response.
+ */
+TEST_F(
+  CLASSNAME(TestGraphFixture, RMW_IMPLEMENTATION),
+  test_rcl_get_client_names_and_types_by_node
+) {
+  rcl_ret_t ret;
+  rcl_allocator_t allocator = rcl_get_default_allocator();
+  rcl_allocator_t zero_allocator = static_cast<rcl_allocator_t>(
+    rcutils_get_zero_initialized_allocator());
+  rcl_node_t zero_node = rcl_get_zero_initialized_node();
+  const char * unknown_node_name = "/test_rcl_get_client_names_and_types_by_node";
+  rcl_names_and_types_t nat = rcl_get_zero_initialized_names_and_types();
+  // invalid node
+  ret = rcl_get_client_names_and_types_by_node(
+    nullptr, &allocator, this->test_graph_node_name, "", &nat);
+  EXPECT_EQ(RCL_RET_NODE_INVALID, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  ret = rcl_get_client_names_and_types_by_node(
+    &zero_node, &allocator, this->test_graph_node_name, "", &nat);
+  EXPECT_EQ(RCL_RET_NODE_INVALID, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  ret = rcl_get_client_names_and_types_by_node(
+    this->old_node_ptr, &allocator, this->test_graph_node_name, "", &nat);
+  EXPECT_EQ(RCL_RET_NODE_INVALID, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  // invalid allocator
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, nullptr, this->test_graph_node_name, "", &nat);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &zero_allocator, this->test_graph_node_name, "", &nat);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  // invalid names
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &allocator, nullptr, "", &nat);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &allocator, this->test_graph_node_name, nullptr, &nat);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  // test valid strings with invalid node names
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &allocator, "", "", &nat);
+  EXPECT_EQ(RCL_RET_ERROR, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &allocator, "_InvalidNodeName", "", &nat);
+  EXPECT_EQ(RCL_RET_ERROR, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  // invalid names and types
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &allocator, this->test_graph_node_name, "", nullptr);
+  EXPECT_EQ(RCL_RET_INVALID_ARGUMENT, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  // unknown node name
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &allocator, unknown_node_name, "", &nat);
+  EXPECT_EQ(RCL_RET_ERROR, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+  // valid call
+  ret = rcl_get_client_names_and_types_by_node(
+    this->node_ptr, &allocator, this->test_graph_node_name, "", &nat);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
+  rcl_reset_error();
+}
+
 /* Test the rcl_count_publishers function.
  *
  * This does not test content of the response.
@@ -728,6 +800,7 @@ struct expected_node_state
   size_t publishers;
   size_t subscribers;
   size_t services;
+  size_t clients;
 };
 
 /**
@@ -740,7 +813,7 @@ public:
   std::string topic_name = "/test_node_info_functions__";
   rcl_node_t * remote_node_ptr;
   rcl_allocator_t allocator = rcl_get_default_allocator();
-  GetTopicsFunc sub_func, pub_func, service_func;
+  GetTopicsFunc sub_func, pub_func, service_func, client_func;
   rcl_context_t * remote_context_ptr;
 
   void SetUp() override
@@ -787,6 +860,12 @@ public:
         std::placeholders::_2,
         "/",
         std::placeholders::_3);
+    client_func = std::bind(rcl_get_client_names_and_types_by_node,
+        std::placeholders::_1,
+        &this->allocator,
+        std::placeholders::_2,
+        "/",
+        std::placeholders::_3);
     WaitForAllNodesAlive();
   }
 
@@ -858,6 +937,9 @@ public:
         RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Checking services from node");
         expect_topics_types(node, service_func, node_state.services,
           test_graph_node_name, is_expect, is_success);
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Checking clients from node");
+        expect_topics_types(node, client_func, node_state.clients,
+          test_graph_node_name, is_expect, is_success);
         RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Checking publishers from node");
         expect_topics_types(node, pub_func, node_state.publishers,
           test_graph_node_name, is_expect, is_success);
@@ -871,6 +953,9 @@ public:
         RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Checking services from remote node");
         expect_topics_types(node, service_func, remote_node_state.services,
           this->remote_node_name, is_expect, is_success);
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Checking clients from remote node");
+        expect_topics_types(node, client_func, remote_node_state.clients,
+          this->remote_node_name, is_expect, is_success);
         if (!is_success) {
           ret = rcl_wait_set_clear(wait_set_ptr);
           ASSERT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
@@ -917,19 +1002,19 @@ TEST_F(NodeGraphMultiNodeFixture, test_node_info_subscriptions)
   EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
   rcl_reset_error();
 
-  VerifySubsystemCount(expected_node_state{1, 1, 0}, expected_node_state{1, 1, 0});
+  VerifySubsystemCount(expected_node_state{1, 1, 0, 0}, expected_node_state{1, 1, 0, 0});
 
   // Destroy the node's subscriber
   ret = rcl_subscription_fini(&sub, this->node_ptr);
   EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
   rcl_reset_error();
-  VerifySubsystemCount(expected_node_state{1, 0, 0}, expected_node_state{1, 1, 0});
+  VerifySubsystemCount(expected_node_state{1, 0, 0, 0}, expected_node_state{1, 1, 0, 0});
 
   // Destroy the remote node's subdscriber
   ret = rcl_subscription_fini(&sub2, this->remote_node_ptr);
   EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
   rcl_reset_error();
-  VerifySubsystemCount(expected_node_state{1, 0, 0}, expected_node_state{1, 0, 0});
+  VerifySubsystemCount(expected_node_state{1, 0, 0, 0}, expected_node_state{1, 0, 0, 0});
 }
 
 TEST_F(NodeGraphMultiNodeFixture, test_node_info_publishers)
@@ -942,14 +1027,14 @@ TEST_F(NodeGraphMultiNodeFixture, test_node_info_publishers)
   ret = rcl_publisher_init(&pub, this->node_ptr, ts, this->topic_name.c_str(), &pub_ops);
   EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
   rcl_reset_error();
-  VerifySubsystemCount(expected_node_state{2, 0, 0}, expected_node_state{1, 0, 0});
+  VerifySubsystemCount(expected_node_state{2, 0, 0, 0}, expected_node_state{1, 0, 0, 0});
 
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Destroyed publisher");
   // Destroy the publisher.
   ret = rcl_publisher_fini(&pub, this->node_ptr);
   EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
   rcl_reset_error();
-  VerifySubsystemCount(expected_node_state{1, 0, 0}, expected_node_state{1, 0, 0});
+  VerifySubsystemCount(expected_node_state{1, 0, 0, 0}, expected_node_state{1, 0, 0, 0});
 }
 
 TEST_F(NodeGraphMultiNodeFixture, test_node_info_services)
@@ -961,12 +1046,29 @@ TEST_F(NodeGraphMultiNodeFixture, test_node_info_services)
   auto ts1 = ROSIDL_GET_SRV_TYPE_SUPPORT(test_msgs, srv, BasicTypes);
   ret = rcl_service_init(&service, this->node_ptr, ts1, service_name, &service_options);
   ASSERT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
-  VerifySubsystemCount(expected_node_state{1, 0, 1}, expected_node_state{1, 0, 0});
+  VerifySubsystemCount(expected_node_state{1, 0, 1, 0}, expected_node_state{1, 0, 0, 0});
 
   // Destroy service.
   ret = rcl_service_fini(&service, this->node_ptr);
   EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
-  VerifySubsystemCount(expected_node_state{1, 0, 0}, expected_node_state{1, 0, 0});
+  VerifySubsystemCount(expected_node_state{1, 0, 0, 0}, expected_node_state{1, 0, 0, 0});
+}
+
+TEST_F(NodeGraphMultiNodeFixture, test_node_info_clients)
+{
+  rcl_ret_t ret;
+  const char * service_name = "test_service";
+  rcl_client_t client = rcl_get_zero_initialized_client();
+  rcl_client_options_t client_options = rcl_client_get_default_options();
+  auto ts = ROSIDL_GET_SRV_TYPE_SUPPORT(test_msgs, srv, BasicTypes);
+  ret = rcl_client_init(&client, this->node_ptr, ts, service_name, &client_options);
+  ASSERT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
+  VerifySubsystemCount(expected_node_state{1, 0, 0, 1}, expected_node_state{1, 0, 0, 0});
+
+  // Destroy client
+  ret = rcl_client_fini(&client, this->node_ptr);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string().str;
+  VerifySubsystemCount(expected_node_state{1, 0, 0, 0}, expected_node_state{1, 0, 0, 0});
 }
 
 /*