refactor init to allow for non-global init (#587)

* refactor init to allow for non-global init

Signed-off-by: William Woodall <william@osrfoundation.org>

* Update rclcpp/include/rclcpp/utilities.hpp

Co-Authored-By: wjwwood <william+github@osrfoundation.org>

* Update rclcpp/include/rclcpp/utilities.hpp

Co-Authored-By: wjwwood <william+github@osrfoundation.org>

* Update rclcpp/include/rclcpp/utilities.hpp

Co-Authored-By: wjwwood <william+github@osrfoundation.org>

* Update rclcpp/src/rclcpp/utilities.cpp

Co-Authored-By: wjwwood <william+github@osrfoundation.org>

* refactor state into context objects and fix signal handling

Signed-off-by: William Woodall <william@osrfoundation.org>

* avoid nullptr access in error messages

Signed-off-by: William Woodall <william@osrfoundation.org>

* avoid exception in publish after shutdown was called

Signed-off-by: William Woodall <william@osrfoundation.org>

* fix missing and unused headers

Signed-off-by: William Woodall <william@osrfoundation.org>

* cpplint

Signed-off-by: William Woodall <william@osrfoundation.org>

* fixes found during testing

Signed-off-by: William Woodall <william@osrfoundation.org>

* address bug found in review comment

Signed-off-by: William Woodall <william@osrfoundation.org>

* fixes and warnings fixed during testing

Signed-off-by: William Woodall <william@osrfoundation.org>

* addressing review comments

Signed-off-by: William Woodall <william@osrfoundation.org>

* ensure new ExecutorArgs are used everywhere

rclcpp/CMakeLists.txt

@@ -40,6 +40,7 @@ set(${PROJECT_NAME}_SRCS
   src/rclcpp/executors/multi_threaded_executor.cpp
   src/rclcpp/executors/single_threaded_executor.cpp
   src/rclcpp/graph_listener.cpp
+  src/rclcpp/init_options.cpp
   src/rclcpp/intra_process_manager.cpp
   src/rclcpp/intra_process_manager_impl.cpp
   src/rclcpp/logger.cpp

rclcpp/include/rclcpp/client.hpp

@@ -110,6 +110,7 @@ protected:
 
   rclcpp::node_interfaces::NodeGraphInterface::WeakPtr node_graph_;
   std::shared_ptr<rcl_node_t> node_handle_;
+  std::shared_ptr<rclcpp::Context> context_;
 
   std::shared_ptr<rcl_client_t> client_handle_;
 };
@@ -171,13 +172,13 @@ public:
   }
 
   std::shared_ptr<void>
-  create_response()
+  create_response() override
   {
     return std::shared_ptr<void>(new typename ServiceT::Response());
   }
 
   std::shared_ptr<rmw_request_id_t>
-  create_request_header()
+  create_request_header() override
   {
     // TODO(wjwwood): This should probably use rmw_request_id's allocator.
     //                (since it is a C type)
@@ -187,7 +188,7 @@ public:
   void
   handle_response(
     std::shared_ptr<rmw_request_id_t> request_header,
-    std::shared_ptr<void> response)
+    std::shared_ptr<void> response) override
   {
     std::unique_lock<std::mutex> lock(pending_requests_mutex_);
     auto typed_response = std::static_pointer_cast<typename ServiceT::Response>(response);

rclcpp/include/rclcpp/context.hpp

@@ -15,34 +15,208 @@
 #ifndef RCLCPP__CONTEXT_HPP_
 #define RCLCPP__CONTEXT_HPP_
 
-#include <iostream>
+#include <functional>
 #include <memory>
 #include <mutex>
+#include <string>
 #include <typeindex>
 #include <typeinfo>
 #include <unordered_map>
 #include <utility>
+#include <vector>
 
+#include "rcl/context.h"
+#include "rclcpp/init_options.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/visibility_control.hpp"
-#include "rmw/rmw.h"
 
 namespace rclcpp
 {
 
-class Context
+/// Thrown when init is called on an already initialized context.
+class ContextAlreadyInitialized : public std::runtime_error
+{
+public:
+  ContextAlreadyInitialized()
+  : std::runtime_error("context is already initialized") {}
+};
+
+/// Context which encapsulates shared state between nodes and other similar entities.
+/**
+ * A context also represents the lifecycle between init and shutdown of rclcpp.
+ * It is often used in conjunction with rclcpp::init, or rclcpp::init_local,
+ * and rclcpp::shutdown.
+ */
+class Context : public std::enable_shared_from_this<Context>
 {
 public:
   RCLCPP_SMART_PTR_DEFINITIONS(Context)
 
+  /// Default constructor, after which the Context is still not "initialized".
+  /**
+   * Every context which is constructed is added to a global vector of contexts,
+   * which is used by the signal handler to conditionally shutdown each context
+   * on SIGINT.
+   * See the shutdown_on_sigint option in the InitOptions class.
+   */
   RCLCPP_PUBLIC
   Context();
 
+  RCLCPP_PUBLIC
+  virtual
+  ~Context();
+
+  /// Initialize the context, and the underlying elements like the rcl context.
+  /**
+   * This method must be called before passing this context to things like the
+   * constructor of Node.
+   * It must also be called before trying to shutdown the context.
+   *
+   * Note that this function does not setup any signal handlers, so if you want
+   * it to be shutdown by the signal handler, then you need to either install
+   * them manually with rclcpp::install_signal_handers() or use rclcpp::init().
+   * In addition to installing the signal handlers, the shutdown_on_sigint
+   * of the InitOptions needs to be `true` for this context to be shutdown by
+   * the signal handler, otherwise it will be passed over.
+   *
+   * After calling this method, shutdown() can be called to invalidate the
+   * context for derived entities, e.g. nodes, guard conditions, etc.
+   * However, the underlying rcl context is not finalized until this Context's
+   * destructor is called or this function is called again.
+   * Allowing this class to go out of scope and get destructed or calling this
+   * function a second time while derived entities are still using the context
+   * is undefined behavior and should be avoided.
+   * It's a good idea to not reuse context objects and instead create a new one
+   * each time you need to shutdown and init again.
+   * This allows derived entities to hold on to shard pointers to the first
+   * context object until they are done.
+   *
+   * This function is thread-safe.
+   *
+   * \param[in] argc number of arguments
+   * \param[in] argv argument array which may contain arguments intended for ROS
+   * \param[in] init_options initialization options for rclcpp and underlying layers
+   * \throw ContextAlreadyInitialized if called if init is called more than once
+   */
+  RCLCPP_PUBLIC
+  virtual
+  void
+  init(
+    int argc,
+    char const * const argv[],
+    const rclcpp::InitOptions & init_options = rclcpp::InitOptions());
+
+  /// Return true if the context is valid, otherwise false.
+  /**
+   * The context is valid if it has been initialized but not shutdown.
+   *
+   * This function is thread-safe.
+   * This function is lock free so long as pointers and uint64_t atomics are
+   * lock free.
+   *
+   * \return true if valid, otherwise false
+   */
+  RCLCPP_PUBLIC
+  bool
+  is_valid() const;
+
+  /// Return the init options used during init.
+  RCLCPP_PUBLIC
+  const rclcpp::InitOptions &
+  get_init_options() const;
+
+  /// Return a copy of the init options used during init.
+  RCLCPP_PUBLIC
+  rclcpp::InitOptions
+  get_init_options();
+
+  /// Return the shutdown reason, or empty string if not shutdown.
+  /**
+   * This function is thread-safe.
+   */
+  RCLCPP_PUBLIC
+  std::string
+  shutdown_reason();
+
+  /// Shutdown the context, making it uninitialized and therefore invalid for derived entities.
+  /**
+   * Several things happen when the context is shutdown, in this order:
+   *
+   * - acquires a lock to prevent race conditions with init, on_shutdown, etc.
+   * - if the context is not initialized, return false
+   * - rcl_shutdown() is called on the internal rcl_context_t instance
+   * - the shutdown reason is set
+   * - each on_shutdown callback is called, in the order that they were added
+   * - if notify_all is true, rclcpp::notify_all is called to unblock some ROS functions
+   *
+   * The underlying rcl context is not finalized by this function.
+   *
+   * This function is thread-safe.
+   *
+   * \param[in] reason the description of why shutdown happened
+   * \param[in] notify_all if true, then rclcpp::notify_all will be called
+   * \return true if shutdown was successful, false if context was already shutdown
+   * \throw various exceptions derived from RCLErrorBase, if rcl_shutdown fails
+   */
+  RCLCPP_PUBLIC
+  virtual
+  bool
+  shutdown(const std::string & reason, bool notify_all = true);
+
+  using OnShutdownCallback = std::function<void ()>;
+
+  /// Add a on_shutdown callback to be called when shutdown is called for this context.
+  /**
+   * These callbacks will be called in the order they are added as the second
+   * to last step in shutdown().
+   *
+   * These callbacks may be run in the signal handler as the signal handler
+   * may call shutdown() on this context.
+   * Also, shutdown() may be called from the destructor of this function.
+   * Therefore, it is not safe to throw exceptions from these callbacks.
+   * Instead, log errors or use some other mechanism to indicate an error has
+   * occurred.
+   *
+   * On shutdown callbacks may be registered before init and after shutdown,
+   * and persist on repeated init's.
+   *
+   * \param[in] callback the on shutdown callback to be registered
+   * \return the callback passed, for convenience when storing a passed lambda
+   */
+  RCLCPP_PUBLIC
+  virtual
+  OnShutdownCallback
+  on_shutdown(OnShutdownCallback callback);
+
+  /// Return the shutdown callbacks as const.
+  /**
+   * Using the returned reference is not thread-safe with calls that modify
+   * the list of "on shutdown" callbacks, i.e. on_shutdown().
+   */
+  RCLCPP_PUBLIC
+  const std::vector<OnShutdownCallback> &
+  get_on_shutdown_callbacks() const;
+
+  /// Return the shutdown callbacks.
+  /**
+   * Using the returned reference is not thread-safe with calls that modify
+   * the list of "on shutdown" callbacks, i.e. on_shutdown().
+   */
+  RCLCPP_PUBLIC
+  std::vector<OnShutdownCallback> &
+  get_on_shutdown_callbacks();
+
+  /// Return the internal rcl context.
+  RCLCPP_PUBLIC
+  std::shared_ptr<rcl_context_t>
+  get_rcl_context();
+
+  /// Return a singleton instance for the SubContext type, constructing one if necessary.
   template<typename SubContext, typename ... Args>
   std::shared_ptr<SubContext>
   get_sub_context(Args && ... args)
   {
-    std::lock_guard<std::mutex> lock(mutex_);
+    std::lock_guard<std::recursive_mutex> lock(sub_contexts_mutex_);
 
     std::type_index type_i(typeid(SubContext));
     std::shared_ptr<SubContext> sub_context;
@@ -62,13 +236,41 @@ public:
     return sub_context;
   }
 
+protected:
+  // Called by constructor and destructor to clean up by finalizing the
+  // shutdown rcl context and preparing for a new init cycle.
+  RCLCPP_PUBLIC
+  virtual
+  void
+  clean_up();
+
 private:
   RCLCPP_DISABLE_COPY(Context)
 
+  // This mutex is recursive so that the destructor can ensure atomicity
+  // between is_initialized and shutdown.
+  std::recursive_mutex init_mutex_;
+  std::shared_ptr<rcl_context_t> rcl_context_;
+  rclcpp::InitOptions init_options_;
+  std::string shutdown_reason_;
+
   std::unordered_map<std::type_index, std::shared_ptr<void>> sub_contexts_;
-  std::mutex mutex_;
+  // This mutex is recursive so that the constructor of a sub context may
+  // attempt to acquire another sub context.
+  std::recursive_mutex sub_contexts_mutex_;
+
+  std::vector<OnShutdownCallback> on_shutdown_callbacks_;
+  std::mutex on_shutdown_callbacks_mutex_;
 };
 
+/// Return a copy of the list of context shared pointers.
+/**
+ * This function is thread-safe.
+ */
+RCLCPP_PUBLIC
+std::vector<Context::SharedPtr>
+get_contexts();
+
 }  // namespace rclcpp
 
 #endif  // RCLCPP__CONTEXT_HPP_

rclcpp/include/rclcpp/executor.hpp

@@ -28,9 +28,10 @@
 #include "rcl/guard_condition.h"
 #include "rcl/wait.h"
 
-#include "rclcpp/node_interfaces/node_base_interface.hpp"
+#include "rclcpp/contexts/default_context.hpp"
 #include "rclcpp/memory_strategies.hpp"
 #include "rclcpp/memory_strategy.hpp"
+#include "rclcpp/node_interfaces/node_base_interface.hpp"
 #include "rclcpp/utilities.hpp"
 #include "rclcpp/visibility_control.hpp"
 
@@ -65,16 +66,20 @@ to_string(const FutureReturnCode & future_return_code);
  */
 struct ExecutorArgs
 {
+  ExecutorArgs()
+  : memory_strategy(memory_strategies::create_default_strategy()),
+    context(rclcpp::contexts::default_context::get_global_default_context()),
+    max_conditions(0)
+  {}
+
   memory_strategy::MemoryStrategy::SharedPtr memory_strategy;
-  size_t max_conditions = 0;
+  std::shared_ptr<rclcpp::Context> context;
+  size_t max_conditions;
 };
 
 static inline ExecutorArgs create_default_executor_arguments()
 {
-  ExecutorArgs args;
-  args.memory_strategy = memory_strategies::create_default_strategy();
-  args.max_conditions = 0;
-  return args;
+  return ExecutorArgs();
 }
 
 /// Coordinate the order and timing of available communication tasks.
@@ -95,7 +100,7 @@ public:
   /// Default constructor.
   // \param[in] ms The memory strategy to be used with this executor.
   RCLCPP_PUBLIC
-  explicit Executor(const ExecutorArgs & args = create_default_executor_arguments());
+  explicit Executor(const ExecutorArgs & args = ExecutorArgs());
 
   /// Default destructor.
   RCLCPP_PUBLIC
@@ -237,7 +242,7 @@ public:
     }
     std::chrono::nanoseconds timeout_left = timeout_ns;
 
-    while (rclcpp::ok()) {
+    while (rclcpp::ok(this->context_)) {
       // Do one item of work.
       spin_once(timeout_left);
       // Check if the future is set, return SUCCESS if it is.
@@ -353,6 +358,9 @@ protected:
   /// The memory strategy: an interface for handling user-defined memory allocation strategies.
   memory_strategy::MemoryStrategy::SharedPtr memory_strategy_;
 
+  /// The context associated with this executor.
+  std::shared_ptr<rclcpp::Context> context_;
+
 private:
   RCLCPP_DISABLE_COPY(Executor)
 

rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp

@@ -51,7 +51,7 @@ public:
    */
   RCLCPP_PUBLIC
   MultiThreadedExecutor(
-    const executor::ExecutorArgs & args = rclcpp::executor::create_default_executor_arguments(),
+    const executor::ExecutorArgs & args = executor::ExecutorArgs(),
     size_t number_of_threads = 0,
     bool yield_before_execute = false);
 

rclcpp/include/rclcpp/executors/single_threaded_executor.hpp

@@ -45,7 +45,7 @@ public:
   /// Default constructor. See the default constructor for Executor.
   RCLCPP_PUBLIC
   SingleThreadedExecutor(
-    const executor::ExecutorArgs & args = rclcpp::executor::create_default_executor_arguments());
+    const executor::ExecutorArgs & args = executor::ExecutorArgs());
 
   /// Default destrcutor.
   RCLCPP_PUBLIC

rclcpp/include/rclcpp/graph_listener.hpp

@@ -23,6 +23,7 @@
 
 #include "rcl/guard_condition.h"
 #include "rcl/wait.h"
+#include "rclcpp/context.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/node_interfaces/node_graph_interface.hpp"
 #include "rclcpp/visibility_control.hpp"
@@ -62,7 +63,7 @@ class GraphListener : public std::enable_shared_from_this<GraphListener>
 {
 public:
   RCLCPP_PUBLIC
-  GraphListener();
+  explicit GraphListener(std::shared_ptr<rclcpp::Context> parent_context);
 
   RCLCPP_PUBLIC
   virtual ~GraphListener();
@@ -164,6 +165,7 @@ private:
   std::vector<rclcpp::node_interfaces::NodeGraphInterface *> node_graph_interfaces_;
 
   rcl_guard_condition_t interrupt_guard_condition_ = rcl_get_zero_initialized_guard_condition();
+  std::shared_ptr<rcl_context_t> interrupt_guard_condition_context_;
   rcl_guard_condition_t * shutdown_guard_condition_;
   rcl_wait_set_t wait_set_ = rcl_get_zero_initialized_wait_set();
 };

rclcpp/include/rclcpp/init_options.hpp

@@ -0,0 +1,69 @@
+// Copyright 2018 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__INIT_OPTIONS_HPP_
+#define RCLCPP__INIT_OPTIONS_HPP_
+
+#include <memory>
+
+#include "rcl/init_options.h"
+#include "rclcpp/visibility_control.hpp"
+
+namespace rclcpp
+{
+
+/// Encapsulation of options for initializing rclcpp.
+class InitOptions
+{
+public:
+  /// If true, the context will be shutdown on SIGINT by the signal handler (if it was installed).
+  bool shutdown_on_sigint = true;
+
+  /// Constructor which allows you to specify the allocator used within the init options.
+  RCLCPP_PUBLIC
+  explicit InitOptions(rcl_allocator_t allocator = rcl_get_default_allocator());
+
+  /// Constructor which is initialized by an existing init_options.
+  RCLCPP_PUBLIC
+  explicit InitOptions(const rcl_init_options_t & init_options);
+
+  /// Copy constructor.
+  RCLCPP_PUBLIC
+  InitOptions(const InitOptions & other);
+
+  /// Assignment operator.
+  RCLCPP_PUBLIC
+  InitOptions &
+  operator=(const InitOptions & other);
+
+  RCLCPP_PUBLIC
+  virtual
+  ~InitOptions();
+
+  /// Return the rcl init options.
+  RCLCPP_PUBLIC
+  const rcl_init_options_t *
+  get_rcl_init_options() const;
+
+protected:
+  void
+  finalize_init_options();
+
+private:
+  std::unique_ptr<rcl_init_options_t> init_options_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__INIT_OPTIONS_HPP_

rclcpp/include/rclcpp/logger.hpp

@@ -20,6 +20,8 @@
 
 #include "rclcpp/visibility_control.hpp"
 
+#include "rcl/node.h"
+
 /**
  * \def RCLCPP_LOGGING_ENABLED
  * When this define evaluates to true (default), logger factory functions will
@@ -60,6 +62,18 @@ RCLCPP_PUBLIC
 Logger
 get_logger(const std::string & name);
 
+/// Return a named logger using an rcl_node_t.
+/**
+ * This is a convenience function that does error checking and returns the node
+ * logger name, or "rclcpp" if it is unable to get the node name.
+ *
+ * \param[in] node the rcl node from which to get the logger name
+ * \return a logger based on the node name, or "rclcpp" if there's an error
+ */
+RCLCPP_PUBLIC
+Logger
+get_node_logger(const rcl_node_t * node);
+
 class Logger
 {
 private:

rclcpp/include/rclcpp/node.hpp

@@ -428,6 +428,11 @@ public:
   rclcpp::node_interfaces::NodeGraphInterface::SharedPtr
   get_node_graph_interface();
 
+  /// Return the Node's internal NodeLoggingInterface implementation.
+  RCLCPP_PUBLIC
+  rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr
+  get_node_logging_interface();
+
   /// Return the Node's internal NodeTimersInterface implementation.
   RCLCPP_PUBLIC
   rclcpp::node_interfaces::NodeTimersInterface::SharedPtr

rclcpp/include/rclcpp/node_impl.hpp

@@ -160,7 +160,8 @@ Node::create_wall_timer(
 {
   auto timer = rclcpp::WallTimer<CallbackT>::make_shared(
     std::chrono::duration_cast<std::chrono::nanoseconds>(period),
-    std::move(callback));
+    std::move(callback),
+    this->node_base_->get_context());
   node_timers_->add_timer(timer, group);
   return timer;
 }

rclcpp/include/rclcpp/node_interfaces/node_clock.hpp

@@ -41,7 +41,8 @@ public:
     rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base,
     rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics,
     rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph,
-    rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services);
+    rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services,
+    rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging);
 
   RCLCPP_PUBLIC
   virtual
@@ -60,6 +61,7 @@ private:
   rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics_;
   rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_;
   rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services_;
+  rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging_;
 
   rclcpp::Clock::SharedPtr ros_clock_;
   rclcpp::TimeSource time_source_;

rclcpp/include/rclcpp/publisher.hpp

@@ -205,6 +205,16 @@ public:
       ipm.publisher_id = intra_process_publisher_id_;
       ipm.message_sequence = message_seq;
       auto status = rcl_publish(&intra_process_publisher_handle_, &ipm);
+      if (RCL_RET_PUBLISHER_INVALID == status) {
+        rcl_reset_error();  // next call will reset error message if not context
+        if (rcl_publisher_is_valid_except_context(&intra_process_publisher_handle_)) {
+          rcl_context_t * context = rcl_publisher_get_context(&intra_process_publisher_handle_);
+          if (nullptr != context && !rcl_context_is_valid(context)) {
+            // publisher is invalid due to context being shutdown
+            return;
+          }
+        }
+      }
       if (RCL_RET_OK != status) {
         rclcpp::exceptions::throw_from_rcl_error(status, "failed to publish intra process message");
       }
@@ -305,6 +315,16 @@ protected:
   do_inter_process_publish(const MessageT * msg)
   {
     auto status = rcl_publish(&publisher_handle_, msg);
+    if (RCL_RET_PUBLISHER_INVALID == status) {
+      rcl_reset_error();  // next call will reset error message if not context
+      if (rcl_publisher_is_valid_except_context(&publisher_handle_)) {
+        rcl_context_t * context = rcl_publisher_get_context(&publisher_handle_);
+        if (nullptr != context && !rcl_context_is_valid(context)) {
+          // publisher is invalid due to context being shutdown
+          return;
+        }
+      }
+    }
     if (RCL_RET_OK != status) {
       rclcpp::exceptions::throw_from_rcl_error(status, "failed to publish message");
     }

rclcpp/include/rclcpp/service.hpp

@@ -119,7 +119,7 @@ public:
         if (handle) {
           if (rcl_service_fini(service, handle.get()) != RCL_RET_OK) {
             RCLCPP_ERROR(
-              rclcpp::get_logger(rcl_node_get_logger_name(handle.get())).get_child("rclcpp"),
+              rclcpp::get_node_logger(handle.get()).get_child("rclcpp"),
               "Error in destruction of rcl service handle: %s",
               rcl_get_error_string().str);
             rcl_reset_error();

rclcpp/include/rclcpp/time_source.hpp

@@ -47,10 +47,11 @@ public:
 
   RCLCPP_PUBLIC
   void attachNode(
-    const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface,
-    const rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics_interface,
-    const rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_interface,
-    const rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services_interface);
+    rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface,
+    rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics_interface,
+    rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_interface,
+    rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services_interface,
+    rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging_interface);
 
   RCLCPP_PUBLIC
   void detachNode();
@@ -74,6 +75,10 @@ private:
   rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics_;
   rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_;
   rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services_;
+  rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging_;
+
+  // Store (and update on node attach) logger for logging.
+  Logger logger_;
 
   // The subscription for the clock callback
   using MessageT = rosgraph_msgs::msg::Clock;

rclcpp/include/rclcpp/timer.hpp

@@ -24,6 +24,7 @@
 #include <utility>
 
 #include "rclcpp/clock.hpp"
+#include "rclcpp/context.hpp"
 #include "rclcpp/function_traits.hpp"
 #include "rclcpp/macros.hpp"
 #include "rclcpp/rate.hpp"
@@ -45,7 +46,10 @@ public:
   RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(TimerBase)
 
   RCLCPP_PUBLIC
-  explicit TimerBase(Clock::SharedPtr clock, std::chrono::nanoseconds period);
+  explicit TimerBase(
+    Clock::SharedPtr clock,
+    std::chrono::nanoseconds period,
+    rclcpp::Context::SharedPtr context);
 
   RCLCPP_PUBLIC
   ~TimerBase();
@@ -114,9 +118,10 @@ public:
    * \param[in] callback User-specified callback function.
    */
   explicit GenericTimer(
-    Clock::SharedPtr clock, std::chrono::nanoseconds period, FunctorT && callback
+    Clock::SharedPtr clock, std::chrono::nanoseconds period, FunctorT && callback,
+    rclcpp::Context::SharedPtr context
   )
-  : TimerBase(clock, period), callback_(std::forward<FunctorT>(callback))
+  : TimerBase(clock, period, context), callback_(std::forward<FunctorT>(callback))
   {
   }
 
@@ -128,7 +133,7 @@ public:
   }
 
   void
-  execute_callback()
+  execute_callback() override
   {
     rcl_ret_t ret = rcl_timer_call(timer_handle_.get());
     if (ret == RCL_RET_TIMER_CANCELED) {
@@ -165,8 +170,8 @@ public:
     callback_(*this);
   }
 
-  virtual bool
-  is_steady()
+  bool
+  is_steady() override
   {
     return clock_->get_clock_type() == RCL_STEADY_TIME;
   }
@@ -189,9 +194,12 @@ class WallTimer : public GenericTimer<FunctorT>
 public:
   RCLCPP_SMART_PTR_DEFINITIONS(WallTimer)
 
-  explicit WallTimer(std::chrono::nanoseconds period, FunctorT && callback)
+  WallTimer(
+    std::chrono::nanoseconds period,
+    FunctorT && callback,
+    rclcpp::Context::SharedPtr context)
   : GenericTimer<FunctorT>(
-      std::make_shared<Clock>(RCL_STEADY_TIME), period, std::move(callback))
+      std::make_shared<Clock>(RCL_STEADY_TIME), period, std::move(callback), context)
   {}
 
 protected:

rclcpp/include/rclcpp/utilities.hpp

@@ -20,6 +20,8 @@
 #include <limits>
 #include <vector>
 
+#include "rclcpp/context.hpp"
+#include "rclcpp/init_options.hpp"
 #include "rclcpp/visibility_control.hpp"
 
 #include "rcl/guard_condition.h"
@@ -48,28 +50,75 @@ namespace rclcpp
 {
 /// Initialize communications via the rmw implementation and set up a global signal handler.
 /**
- * \param[in] argc Number of arguments.
- * \param[in] argv Argument vector. Will eventually be used for passing options to rclcpp.
+ * Initializes the global context which is accessible via the function
+ * rclcpp::contexts::default_context::get_global_default_context().
+ * Also, installs the global signal handlers with the function
+ * rclcpp::install_signal_handlers().
+ *
+ * \sa rclcpp::Context::init() for more details on arguments and possible exceptions
  */
 RCLCPP_PUBLIC
 void
-init(int argc, char const * const argv[]);
+init(int argc, char const * const argv[], const InitOptions & init_options = InitOptions());
+
+/// Install the global signal handler for rclcpp.
+/**
+ * This function should only need to be run one time per process.
+ * It is implicitly run by rclcpp::init(), and therefore this function does not
+ * need to be run manually if rclcpp::init() has already been run.
+ *
+ * The signal handler will shutdown all initialized context.
+ * It will also interrupt any blocking functions in ROS allowing them react to
+ * any changes in the state of the system (like shutdown).
+ *
+ * This function is thread-safe.
+ *
+ * \return true if signal handler was installed by this function, false if already installed.
+ */
+RCLCPP_PUBLIC
+bool
+install_signal_handlers();
+
+/// Return true if the signal handlers are installed, otherwise false.
+RCLCPP_PUBLIC
+bool
+signal_handlers_installed();
+
+/// Uninstall the global signal handler for rclcpp.
+/**
+ * This function does not necessarily need to be called, but can be used to
+ * undo what rclcpp::install_signal_handlers() or rclcpp::init() do with
+ * respect to signal handling.
+ * If you choose to use it, this function only needs to be run one time.
+ * It is implicitly run by rclcpp::shutdown(), and therefore this function does
+ * not need to be run manually if rclcpp::shutdown() has already been run.
+ *
+ * This function is thread-safe.
+ *
+ * \return true if signal handler was uninstalled by this function, false if was not installed.
+ */
+RCLCPP_PUBLIC
+bool
+uninstall_signal_handlers();
 
 /// Initialize communications via the rmw implementation and set up a global signal handler.
 /**
  * Additionally removes ROS-specific arguments from the argument vector.
- * \param[in] argc Number of arguments.
- * \param[in] argv Argument vector.
+ *
+ * \sa rclcpp::Context::init() for more details on arguments and possible exceptions
  * \returns Members of the argument vector that are not ROS arguments.
  */
 RCLCPP_PUBLIC
 std::vector<std::string>
-init_and_remove_ros_arguments(int argc, char const * const argv[]);
+init_and_remove_ros_arguments(
+  int argc,
+  char const * const argv[],
+  const InitOptions & init_options = InitOptions());
 
 /// Remove ROS-specific arguments from argument vector.
 /**
  * Some arguments may not have been intended as ROS arguments.
- * This function populates a the aruments in a vector.
+ * This function populates the arguments in a vector.
  * Since the first argument is always assumed to be a process name, the vector
  * will always contain the process name.
  *
@@ -82,27 +131,70 @@ std::vector<std::string>
 remove_ros_arguments(int argc, char const * const argv[]);
 
 /// Check rclcpp's status.
-/** \return True if SIGINT hasn't fired yet, false otherwise. */
+/**
+ * This may return false for a context which has been shutdown, or for a
+ * context that was shutdown due to SIGINT being received by the rclcpp signal
+ * handler.
+ *
+ * If nullptr is given for the context, then the global context is used, i.e.
+ * the context initialized by rclcpp::init().
+ *
+ * \param[in] context Check for shutdown of this Context.
+ * \return true if shutdown has been called, false otherwise
+ */
 RCLCPP_PUBLIC
 bool
-ok();
+ok(rclcpp::Context::SharedPtr context = nullptr);
 
-/// Returns true if init() has already been called.
-/** \return True if init() has been called, false otherwise. */
+/// Return true if init() has already been called for the given context.
+/**
+ * If nullptr is given for the context, then the global context is used, i.e.
+ * the context initialized by rclcpp::init().
+ *
+ * Deprecated, as it is no longer different from rcl_ok().
+ *
+ * \param[in] context Check for initialization of this Context.
+ * \return true if the context is initialized, and false otherwise
+ */
 RCLCPP_PUBLIC
 bool
-is_initialized();
+is_initialized(rclcpp::Context::SharedPtr context = nullptr);
 
-/// Notify the signal handler and rmw that rclcpp is shutting down.
+/// Shutdown rclcpp context, invalidating it for derived entities.
+/**
+ * If nullptr is given for the context, then the global context is used, i.e.
+ * the context initialized by rclcpp::init().
+ *
+ * If the global context is used, then the signal handlers are also uninstalled.
+ *
+ * This will also cause the "on_shutdown" callbacks to be called.
+ *
+ * \sa rclcpp::Context::shutdown()
+ * \param[in] context to be shutdown
+ * \return true if shutdown was successful, false if context was already shutdown
+ */
+RCLCPP_PUBLIC
+bool
+shutdown(
+  rclcpp::Context::SharedPtr context = nullptr,
+  const std::string & reason = "user called rclcpp::shutdown()");
+
+/// Register a function to be called when shutdown is called on the context.
+/**
+ * If nullptr is given for the context, then the global context is used, i.e.
+ * the context initialized by rclcpp::init().
+ *
+ * Note that these callbacks should be non-blocking and not throw exceptions,
+ * as they may be called from signal handlers and from the destructor of the
+ * context.
+ *
+ * \sa rclcpp::Context::on_shutdown()
+ * \param[in] callback to be called when the given context is shutdown
+ * \param[in] context with which to associate the context
+ */
 RCLCPP_PUBLIC
 void
-shutdown();
-
-/// Register a function to be called when shutdown is called.
-/** Calling the callbacks is the last thing shutdown() does. */
-RCLCPP_PUBLIC
-void
-on_shutdown(std::function<void(void)> callback);
+on_shutdown(std::function<void()> callback, rclcpp::Context::SharedPtr context = nullptr);
 
 /// Get a handle to the rmw guard condition that manages the signal handler.
 /**
@@ -112,21 +204,28 @@ on_shutdown(std::function<void(void)> callback);
  * that the same guard condition is not reused across wait sets (e.g., when
  * using multiple executors in the same process). Will throw an exception if
  * initialization of the guard condition fails.
- * \param wait_set Pointer to the rcl_wait_set_t that will be using the
+ *
+ * \param[in] wait_set Pointer to the rcl_wait_set_t that will be using the
  *   resulting guard condition.
+ * \param[in] context The context associated with the guard condition.
  * \return Pointer to the guard condition.
  */
 RCLCPP_PUBLIC
 rcl_guard_condition_t *
-get_sigint_guard_condition(rcl_wait_set_t * wait_set);
+get_sigint_guard_condition(rcl_wait_set_t * wait_set, rclcpp::Context::SharedPtr context);
 
 /// Release the previously allocated guard condition that manages the signal handler.
 /**
  * If you previously called get_sigint_guard_condition() for a given wait set
- * to get a sigint guard condition, then you should call release_sigint_guard_condition()
- * when you're done, to free that condition.  Will throw an exception if
- * get_sigint_guard_condition() wasn't previously called for the given wait set.
- * \param wait_set Pointer to the rcl_wait_set_t that was using the
+ * to get a sigint guard condition, then you should call
+ * release_sigint_guard_condition() when you're done, to free that condition.
+ * Will throw an exception if get_sigint_guard_condition() wasn't previously
+ * called for the given wait set.
+ *
+ * If nullptr is given for the context, then the global context is used, i.e.
+ * the context initialized by rclcpp::init().
+ *
+ * \param[in] wait_set Pointer to the rcl_wait_set_t that was using the
  *   resulting guard condition.
  */
 RCLCPP_PUBLIC
@@ -135,12 +234,26 @@ release_sigint_guard_condition(rcl_wait_set_t * wait_set);
 
 /// Use the global condition variable to block for the specified amount of time.
 /**
+ * This function can be interrupted early if the associated context becomes
+ * invalid due to rclcpp::shutdown() or the signal handler.
+ *
+ * If nullptr is given for the context, then the global context is used, i.e.
+ * the context initialized by rclcpp::init().
+ *
  * \param[in] nanoseconds A std::chrono::duration representing how long to sleep for.
+ * \param[in] context which may interrupt this sleep
  * \return True if the condition variable did not timeout.
  */
 RCLCPP_PUBLIC
 bool
-sleep_for(const std::chrono::nanoseconds & nanoseconds);
+sleep_for(
+  const std::chrono::nanoseconds & nanoseconds,
+  rclcpp::Context::SharedPtr context = nullptr);
+
+/// Notify all blocking calls so they can check for changes in rclcpp::ok().
+RCLCPP_PUBLIC
+void
+notify_all();
 
 /// Safely check if addition will overflow.
 /**

rclcpp/src/rclcpp/client.cpp

@@ -37,17 +37,20 @@ ClientBase::ClientBase(
   rclcpp::node_interfaces::NodeBaseInterface * node_base,
   rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph)
 : node_graph_(node_graph),
-  node_handle_(node_base->get_shared_rcl_node_handle())
+  node_handle_(node_base->get_shared_rcl_node_handle()),
+  context_(node_base->get_context())
 {
   std::weak_ptr<rcl_node_t> weak_node_handle(node_handle_);
-  client_handle_ = std::shared_ptr<rcl_client_t>(
-    new rcl_client_t, [weak_node_handle](rcl_client_t * client)
+  rcl_client_t * new_rcl_client = new rcl_client_t;
+  *new_rcl_client = rcl_get_zero_initialized_client();
+  client_handle_.reset(
+    new_rcl_client, [weak_node_handle](rcl_client_t * client)
     {
       auto handle = weak_node_handle.lock();
       if (handle) {
         if (rcl_client_fini(client, handle.get()) != RCL_RET_OK) {
           RCLCPP_ERROR(
-            rclcpp::get_logger(rcl_node_get_logger_name(handle.get())).get_child("rclcpp"),
+            rclcpp::get_node_logger(handle.get()).get_child("rclcpp"),
             "Error in destruction of rcl client handle: %s", rcl_get_error_string().str);
           rcl_reset_error();
         }
@@ -59,7 +62,6 @@ ClientBase::ClientBase(
       }
       delete client;
     });
-  *client_handle_.get() = rcl_get_zero_initialized_client();
 }
 
 ClientBase::~ClientBase()
@@ -94,6 +96,13 @@ ClientBase::service_is_ready() const
     this->get_rcl_node_handle(),
     this->get_client_handle().get(),
     &is_ready);
+  if (RCL_RET_NODE_INVALID == ret) {
+    const rcl_node_t * node_handle = this->get_rcl_node_handle();
+    if (node_handle && !rcl_context_is_valid(node_handle->context)) {
+      // context is shutdown, do a soft failure
+      return false;
+    }
+  }
   if (ret != RCL_RET_OK) {
     throw_from_rcl_error(ret, "rcl_service_server_is_available failed");
   }
@@ -128,7 +137,7 @@ ClientBase::wait_for_service_nanoseconds(std::chrono::nanoseconds timeout)
   }
   // continue forever if timeout is negative, otherwise continue until out of time_to_wait
   do {
-    if (!rclcpp::ok()) {
+    if (!rclcpp::ok(this->context_)) {
       return false;
     }
     // Limit each wait to 100ms to workaround an issue specific to the Connext RMW implementation.

rclcpp/src/rclcpp/context.cpp

@@ -14,6 +14,203 @@
 
 #include "rclcpp/context.hpp"
 
+#include <memory>
+#include <mutex>
+#include <string>
+#include <vector>
+
+#include "rcl/init.h"
+#include "rclcpp/exceptions.hpp"
+#include "rclcpp/logging.hpp"
+
+/// Mutex to protect initialized contexts.
+static std::mutex g_contexts_mutex;
+/// Weak list of context to be shutdown by the signal handler.
+static std::vector<std::weak_ptr<rclcpp::Context>> g_contexts;
+
 using rclcpp::Context;
 
-Context::Context() {}
+Context::Context()
+: rcl_context_(nullptr), shutdown_reason_("") {}
+
+Context::~Context()
+{
+  // acquire the init lock to prevent race conditions with init and shutdown
+  // this will not prevent errors, but will maybe make them easier to reproduce
+  std::lock_guard<std::recursive_mutex> lock(init_mutex_);
+  try {
+    this->shutdown("context destructor was called while still not shutdown");
+    // at this point it is shutdown and cannot reinit
+    // clean_up will finalize the rcl context
+    this->clean_up();
+  } catch (const std::exception & exc) {
+    RCLCPP_ERROR(rclcpp::get_logger("rclcpp"), "unhandled exception in ~Context(): %s", exc.what());
+  } catch (...) {
+    RCLCPP_ERROR(rclcpp::get_logger("rclcpp"), "unhandled exception in ~Context()");
+  }
+}
+
+RCLCPP_LOCAL
+void
+__delete_context(rcl_context_t * context)
+{
+  if (context) {
+    if (rcl_context_is_valid(context)) {
+      RCLCPP_ERROR(
+        rclcpp::get_logger("rclcpp"), "rcl context unexpectedly not shutdown during cleanup");
+    } else {
+      // if context pointer is not null and is shutdown, then it's ready for fini
+      rcl_ret_t ret = rcl_context_fini(context);
+      if (RCL_RET_OK != ret) {
+        RCLCPP_ERROR(
+          rclcpp::get_logger("rclcpp"),
+          "failed to finalize context: %s", rcl_get_error_string().str);
+        rcl_reset_error();
+      }
+    }
+    delete context;
+  }
+}
+
+void
+Context::init(
+  int argc,
+  char const * const argv[],
+  const rclcpp::InitOptions & init_options)
+{
+  std::lock_guard<std::recursive_mutex> init_lock(init_mutex_);
+  if (this->is_valid()) {
+    throw rclcpp::ContextAlreadyInitialized();
+  }
+  this->clean_up();
+  rcl_context_.reset(new rcl_context_t, __delete_context);
+  *rcl_context_.get() = rcl_get_zero_initialized_context();
+  rcl_ret_t ret = rcl_init(argc, argv, init_options.get_rcl_init_options(), rcl_context_.get());
+  if (RCL_RET_OK != ret) {
+    rcl_context_.reset();
+    rclcpp::exceptions::throw_from_rcl_error(ret, "failed to initialize rcl");
+  }
+  init_options_ = init_options;
+
+  std::lock_guard<std::mutex> lock(g_contexts_mutex);
+  g_contexts.push_back(this->shared_from_this());
+}
+
+bool
+Context::is_valid() const
+{
+  // Take a local copy of the shared pointer to avoid it getting nulled under our feet.
+  auto local_rcl_context = rcl_context_;
+  if (!local_rcl_context) {
+    return false;
+  }
+  return rcl_context_is_valid(local_rcl_context.get());
+}
+
+const rclcpp::InitOptions &
+Context::get_init_options() const
+{
+  return init_options_;
+}
+
+rclcpp::InitOptions
+Context::get_init_options()
+{
+  return init_options_;
+}
+
+std::string
+Context::shutdown_reason()
+{
+  std::lock_guard<std::recursive_mutex> lock(init_mutex_);
+  return shutdown_reason_;
+}
+
+bool
+Context::shutdown(const std::string & reason, bool notify_all)
+{
+  // prevent races
+  std::lock_guard<std::recursive_mutex> init_lock(init_mutex_);
+  // ensure validity
+  if (!this->is_valid()) {
+    // if it is not valid, then it cannot be shutdown
+    return false;
+  }
+  // rcl shutdown
+  rcl_ret_t ret = rcl_shutdown(rcl_context_.get());
+  if (RCL_RET_OK != ret) {
+    rclcpp::exceptions::throw_from_rcl_error(ret);
+  }
+  // set shutdown reason
+  shutdown_reason_ = reason;
+  // call each shutdown callback
+  for (const auto & callback : on_shutdown_callbacks_) {
+    callback();
+  }
+  // notify all blocking calls, if asked
+  if (notify_all) {
+    rclcpp::notify_all();
+  }
+  // remove self from the global contexts
+  std::lock_guard<std::mutex> context_lock(g_contexts_mutex);
+  for (auto it = g_contexts.begin(); it != g_contexts.end(); ) {
+    auto shared_context = it->lock();
+    if (shared_context.get() == this) {
+      it = g_contexts.erase(it);
+      break;
+    } else {
+      ++it;
+    }
+  }
+  return true;
+}
+
+rclcpp::Context::OnShutdownCallback
+Context::on_shutdown(OnShutdownCallback callback)
+{
+  on_shutdown_callbacks_.push_back(callback);
+  return callback;
+}
+
+const std::vector<rclcpp::Context::OnShutdownCallback> &
+Context::get_on_shutdown_callbacks() const
+{
+  return on_shutdown_callbacks_;
+}
+
+std::vector<rclcpp::Context::OnShutdownCallback> &
+Context::get_on_shutdown_callbacks()
+{
+  return on_shutdown_callbacks_;
+}
+
+std::shared_ptr<rcl_context_t>
+Context::get_rcl_context()
+{
+  return rcl_context_;
+}
+
+void
+Context::clean_up()
+{
+  shutdown_reason_ = "";
+  rcl_context_.reset();
+}
+
+std::vector<Context::SharedPtr>
+rclcpp::get_contexts()
+{
+  std::lock_guard<std::mutex> lock(g_contexts_mutex);
+  std::vector<Context::SharedPtr> shared_contexts;
+  for (auto it = g_contexts.begin(); it != g_contexts.end(); /* noop */) {
+    auto context_ptr = it->lock();
+    if (!context_ptr) {
+      // remove invalid weak context pointers
+      it = g_contexts.erase(it);
+    } else {
+      ++it;
+      shared_contexts.push_back(context_ptr);
+    }
+  }
+  return shared_contexts;
+}

rclcpp/src/rclcpp/executor.cpp

@@ -30,6 +30,7 @@
 
 #include "rcutils/logging_macros.h"
 
+using rclcpp::exceptions::throw_from_rcl_error;
 using rclcpp::executor::AnyExecutable;
 using rclcpp::executor::Executor;
 using rclcpp::executor::ExecutorArgs;
@@ -40,24 +41,26 @@ Executor::Executor(const ExecutorArgs & args)
   memory_strategy_(args.memory_strategy)
 {
   rcl_guard_condition_options_t guard_condition_options = rcl_guard_condition_get_default_options();
-  if (rcl_guard_condition_init(
-      &interrupt_guard_condition_, guard_condition_options) != RCL_RET_OK)
-  {
-    throw std::runtime_error(
-            std::string("Failed to create interrupt guard condition in Executor constructor: ") +
-            rcl_get_error_string().str);
+  rcl_ret_t ret = rcl_guard_condition_init(
+    &interrupt_guard_condition_, args.context->get_rcl_context().get(), guard_condition_options);
+  if (RCL_RET_OK != ret) {
+    throw_from_rcl_error(ret, "Failed to create interrupt guard condition in Executor constructor");
   }
 
   // The number of guard conditions is always at least 2: 1 for the ctrl-c guard cond,
   // and one for the executor's guard cond (interrupt_guard_condition_)
 
   // Put the global ctrl-c guard condition in
-  memory_strategy_->add_guard_condition(rclcpp::get_sigint_guard_condition(&wait_set_));
+  memory_strategy_->add_guard_condition(
+    rclcpp::get_sigint_guard_condition(&wait_set_, args.context));
 
   // Put the executor's guard condition in
   memory_strategy_->add_guard_condition(&interrupt_guard_condition_);
   rcl_allocator_t allocator = memory_strategy_->get_allocator();
 
+  // Store the context for later use.
+  context_ = args.context;
+
   if (rcl_wait_set_init(
       &wait_set_, 0, 2, 0, 0, 0, allocator) != RCL_RET_OK)
   {
@@ -103,7 +106,7 @@ Executor::~Executor()
   }
   // Remove and release the sigint guard condition
   memory_strategy_->remove_guard_condition(
-    rclcpp::get_sigint_guard_condition(&wait_set_));
+    rclcpp::get_sigint_guard_condition(&wait_set_, context_));
   rclcpp::release_sigint_guard_condition(&wait_set_);
 }
 

rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp

@@ -70,11 +70,11 @@ MultiThreadedExecutor::get_number_of_threads()
 void
 MultiThreadedExecutor::run(size_t)
 {
-  while (rclcpp::ok() && spinning.load()) {
+  while (rclcpp::ok(this->context_) && spinning.load()) {
     executor::AnyExecutable any_exec;
     {
       std::lock_guard<std::mutex> wait_lock(wait_mutex_);
-      if (!rclcpp::ok() || !spinning.load()) {
+      if (!rclcpp::ok(this->context_) || !spinning.load()) {
         return;
       }
       if (!get_next_executable(any_exec)) {

rclcpp/src/rclcpp/executors/single_threaded_executor.cpp

@@ -30,7 +30,7 @@ SingleThreadedExecutor::spin()
     throw std::runtime_error("spin() called while already spinning");
   }
   RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
-  while (rclcpp::ok() && spinning.load()) {
+  while (rclcpp::ok(this->context_) && spinning.load()) {
     rclcpp::executor::AnyExecutable any_executable;
     if (get_next_executable(any_executable)) {
       execute_any_executable(any_executable);

rclcpp/src/rclcpp/graph_listener.cpp

@@ -35,17 +35,26 @@ namespace rclcpp
 namespace graph_listener
 {
 
-GraphListener::GraphListener()
-: is_started_(false), is_shutdown_(false), shutdown_guard_condition_(nullptr)
+GraphListener::GraphListener(std::shared_ptr<rclcpp::Context> parent_context)
+: is_started_(false),
+  is_shutdown_(false),
+  interrupt_guard_condition_context_(nullptr),
+  shutdown_guard_condition_(nullptr)
 {
+  // TODO(wjwwood): make a guard condition class in rclcpp so this can be tracked
+  //   automatically with the rcl guard condition
+  // hold on to this context to prevent it from going out of scope while this
+  // guard condition is using it.
+  interrupt_guard_condition_context_ = parent_context->get_rcl_context();
   rcl_ret_t ret = rcl_guard_condition_init(
     &interrupt_guard_condition_,
+    interrupt_guard_condition_context_.get(),
     rcl_guard_condition_get_default_options());
   if (RCL_RET_OK != ret) {
     throw_from_rcl_error(ret, "failed to create interrupt guard condition");
   }
 
-  shutdown_guard_condition_ = rclcpp::get_sigint_guard_condition(&wait_set_);
+  shutdown_guard_condition_ = rclcpp::get_sigint_guard_condition(&wait_set_, parent_context);
 }
 
 GraphListener::~GraphListener()
@@ -337,6 +346,7 @@ GraphListener::shutdown()
       listener_thread_.join();
     }
     rcl_ret_t ret = rcl_guard_condition_fini(&interrupt_guard_condition_);
+    interrupt_guard_condition_context_.reset();  // release context guard condition was using
     if (RCL_RET_OK != ret) {
       throw_from_rcl_error(ret, "failed to finalize interrupt guard condition");
     }

rclcpp/src/rclcpp/init_options.cpp

@@ -0,0 +1,86 @@
+// Copyright 2018 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "rclcpp/init_options.hpp"
+
+#include "rclcpp/exceptions.hpp"
+#include "rclcpp/logging.hpp"
+
+namespace rclcpp
+{
+
+InitOptions::InitOptions(rcl_allocator_t allocator)
+: init_options_(new rcl_init_options_t)
+{
+  *init_options_ = rcl_get_zero_initialized_init_options();
+  rcl_ret_t ret = rcl_init_options_init(init_options_.get(), allocator);
+  if (RCL_RET_OK != ret) {
+    rclcpp::exceptions::throw_from_rcl_error(ret, "failed to initialized rcl init options");
+  }
+}
+
+InitOptions::InitOptions(const rcl_init_options_t & init_options)
+: init_options_(new rcl_init_options_t)
+{
+  *init_options_ = rcl_get_zero_initialized_init_options();
+  rcl_ret_t ret = rcl_init_options_copy(&init_options, init_options_.get());
+  if (RCL_RET_OK != ret) {
+    rclcpp::exceptions::throw_from_rcl_error(ret, "failed to copy rcl init options");
+  }
+}
+
+InitOptions::InitOptions(const InitOptions & other)
+: InitOptions(*other.get_rcl_init_options())
+{}
+
+InitOptions &
+InitOptions::operator=(const InitOptions & other)
+{
+  if (this != &other) {
+    this->finalize_init_options();
+    rcl_ret_t ret = rcl_init_options_copy(other.get_rcl_init_options(), init_options_.get());
+    if (RCL_RET_OK != ret) {
+      rclcpp::exceptions::throw_from_rcl_error(ret, "failed to copy rcl init options");
+    }
+  }
+  return *this;
+}
+
+InitOptions::~InitOptions()
+{
+  this->finalize_init_options();
+}
+
+void
+InitOptions::finalize_init_options()
+{
+  if (init_options_) {
+    rcl_ret_t ret = rcl_init_options_fini(init_options_.get());
+    if (RCL_RET_OK != ret) {
+      RCLCPP_ERROR(
+        rclcpp::get_logger("rclcpp"),
+        "failed to finalize rcl init options: %s", rcl_get_error_string().str);
+      rcl_reset_error();
+    }
+    *init_options_ = rcl_get_zero_initialized_init_options();
+  }
+}
+
+const rcl_init_options_t *
+InitOptions::get_rcl_init_options() const
+{
+  return init_options_.get();
+}
+
+}  // namespace rclcpp

rclcpp/src/rclcpp/logger.cpp

@@ -16,10 +16,12 @@
 
 #include "rclcpp/logger.hpp"
 
+#include "rclcpp/logging.hpp"
+
 namespace rclcpp
 {
 
-rclcpp::Logger
+Logger
 get_logger(const std::string & name)
 {
 #if RCLCPP_LOGGING_ENABLED
@@ -30,4 +32,16 @@ get_logger(const std::string & name)
 #endif
 }
 
+Logger
+get_node_logger(const rcl_node_t * node)
+{
+  const char * logger_name = rcl_node_get_logger_name(node);
+  if (nullptr == logger_name) {
+    auto logger = rclcpp::get_logger("rclcpp");
+    RCLCPP_ERROR(logger, "failed to get logger name from node at address %p", node);
+    return logger;
+  }
+  return rclcpp::get_logger(logger_name);
+}
+
 }  // namespace rclcpp

rclcpp/src/rclcpp/node.cpp

@@ -79,7 +79,8 @@ Node::Node(
       node_base_,
       node_topics_,
       node_graph_,
-      node_services_
+      node_services_,
+      node_logging_
     )),
   node_waitables_(new rclcpp::node_interfaces::NodeWaitables(node_base_.get())),
   use_intra_process_comms_(use_intra_process_comms)
@@ -255,6 +256,12 @@ Node::get_node_graph_interface()
   return node_graph_;
 }
 
+rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr
+Node::get_node_logging_interface()
+{
+  return node_logging_;
+}
+
 rclcpp::node_interfaces::NodeTimersInterface::SharedPtr
 Node::get_node_timers_interface()
 {

rclcpp/src/rclcpp/node_interfaces/node_base.cpp

@@ -22,8 +22,8 @@
 #include "rcl/arguments.h"
 #include "rclcpp/exceptions.hpp"
 #include "rcutils/logging_macros.h"
-#include "rmw/validate_node_name.h"
 #include "rmw/validate_namespace.h"
+#include "rmw/validate_node_name.h"
 
 using rclcpp::exceptions::throw_from_rcl_error;
 
@@ -43,7 +43,8 @@ NodeBase::NodeBase(
 {
   // Setup the guard condition that is notified when changes occur in the graph.
   rcl_guard_condition_options_t guard_condition_options = rcl_guard_condition_get_default_options();
-  rcl_ret_t ret = rcl_guard_condition_init(&notify_guard_condition_, guard_condition_options);
+  rcl_ret_t ret = rcl_guard_condition_init(
+    &notify_guard_condition_, context->get_rcl_context().get(), guard_condition_options);
   if (ret != RCL_RET_OK) {
     throw_from_rcl_error(ret, "failed to create interrupt guard condition");
   }
@@ -113,7 +114,10 @@ NodeBase::NodeBase(
   // TODO(wjwwood): pass the Allocator to the options
   options.domain_id = domain_id;
 
-  ret = rcl_node_init(rcl_node.get(), node_name.c_str(), namespace_.c_str(), &options);
+  ret = rcl_node_init(
+    rcl_node.get(),
+    node_name.c_str(), namespace_.c_str(),
+    context->get_rcl_context().get(), &options);
   if (ret != RCL_RET_OK) {
     // Finalize the interrupt guard condition.
     finalize_notify_guard_condition();

rclcpp/src/rclcpp/node_interfaces/node_clock.cpp

@@ -23,18 +23,21 @@ NodeClock::NodeClock(
   rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base,
   rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics,
   rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph,
-  rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services)
+  rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services,
+  rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging)
 : node_base_(node_base),
   node_topics_(node_topics),
   node_graph_(node_graph),
   node_services_(node_services),
+  node_logging_(node_logging),
   ros_clock_(std::make_shared<rclcpp::Clock>(RCL_ROS_TIME))
 {
   time_source_.attachNode(
     node_base_,
     node_topics_,
     node_graph_,
-    node_services_);
+    node_services_,
+    node_logging_);
   time_source_.attachClock(ros_clock_);
 }
 

rclcpp/src/rclcpp/node_interfaces/node_graph.cpp

@@ -30,7 +30,9 @@ using rclcpp::graph_listener::GraphListener;
 
 NodeGraph::NodeGraph(rclcpp::node_interfaces::NodeBaseInterface * node_base)
 : node_base_(node_base),
-  graph_listener_(node_base->get_context()->get_sub_context<GraphListener>()),
+  graph_listener_(
+    node_base->get_context()->get_sub_context<GraphListener>(node_base->get_context())
+  ),
   should_add_to_graph_listener_(true),
   graph_users_count_(0)
 {}
@@ -334,8 +336,8 @@ NodeGraph::wait_for_graph_change(
       throw EventNotRegisteredError();
     }
   }
-  auto pred = [&event]() {
-      return event->check() || !rclcpp::ok();
+  auto pred = [&event, context = node_base_->get_context()]() {
+      return event->check() || !rclcpp::ok(context);
     };
   std::unique_lock<std::mutex> graph_lock(graph_mutex_);
   if (!pred()) {

rclcpp/src/rclcpp/node_interfaces/node_parameters.cpp

@@ -64,7 +64,7 @@ NodeParameters::NodeParameters(
   }
   const rcl_node_options_t * options = rcl_node_get_options(node);
   if (nullptr == options) {
-    throw std::runtime_error("Need valid node options NodeParameters");
+    throw std::runtime_error("Need valid node options in NodeParameters");
   }
 
   // Get paths to yaml files containing initial parameter values
@@ -93,7 +93,8 @@ NodeParameters::NodeParameters(
 
   // global before local so that local overwrites global
   if (options->use_global_arguments) {
-    get_yaml_paths(rcl_get_global_arguments());
+    auto context_ptr = node_base->get_context()->get_rcl_context();
+    get_yaml_paths(&(context_ptr->global_arguments));
   }
   get_yaml_paths(&(options->arguments));
 

rclcpp/src/rclcpp/subscription.cpp

@@ -41,7 +41,7 @@ SubscriptionBase::SubscriptionBase(
     {
       if (rcl_subscription_fini(rcl_subs, node_handle.get()) != RCL_RET_OK) {
         RCLCPP_ERROR(
-          rclcpp::get_logger(rcl_node_get_logger_name(node_handle.get())).get_child("rclcpp"),
+          rclcpp::get_node_logger(node_handle.get()).get_child("rclcpp"),
           "Error in destruction of rcl subscription handle: %s",
           rcl_get_error_string().str);
         rcl_reset_error();

rclcpp/src/rclcpp/time_source.cpp

@@ -21,10 +21,9 @@
 
 #include "rcl/time.h"
 
-#include "rcutils/logging_macros.h"
-
 #include "rclcpp/clock.hpp"
 #include "rclcpp/exceptions.hpp"
+#include "rclcpp/logging.hpp"
 #include "rclcpp/node.hpp"
 #include "rclcpp/time.hpp"
 #include "rclcpp/time_source.hpp"
@@ -34,14 +33,16 @@ namespace rclcpp
 {
 
 TimeSource::TimeSource(std::shared_ptr<rclcpp::Node> node)
-: clock_subscription_(nullptr),
+: logger_(rclcpp::get_logger("rclcpp")),
+  clock_subscription_(nullptr),
   ros_time_active_(false)
 {
   this->attachNode(node);
 }
 
 TimeSource::TimeSource()
-: ros_time_active_(false)
+: logger_(rclcpp::get_logger("rclcpp")),
+  ros_time_active_(false)
 {
 }
 
@@ -51,21 +52,26 @@ void TimeSource::attachNode(rclcpp::Node::SharedPtr node)
     node->get_node_base_interface(),
     node->get_node_topics_interface(),
     node->get_node_graph_interface(),
-    node->get_node_services_interface());
+    node->get_node_services_interface(),
+    node->get_node_logging_interface());
 }
 
 void TimeSource::attachNode(
-  const rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface,
-  const rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics_interface,
-  const rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_interface,
-  const rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services_interface)
+  rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface,
+  rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr node_topics_interface,
+  rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph_interface,
+  rclcpp::node_interfaces::NodeServicesInterface::SharedPtr node_services_interface,
+  rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging_interface)
 {
   node_base_ = node_base_interface;
   node_topics_ = node_topics_interface;
   node_graph_ = node_graph_interface;
   node_services_ = node_services_interface;
+  node_logging_ = node_logging_interface;
   // TODO(tfoote): Update QOS
 
+  logger_ = node_logging_->get_logger();
+
   parameter_client_ = std::make_shared<rclcpp::AsyncParametersClient>(
     node_base_,
     node_topics_,
@@ -111,7 +117,7 @@ void TimeSource::detachClock(std::shared_ptr<rclcpp::Clock> clock)
   if (result != associated_clocks_.end()) {
     associated_clocks_.erase(result);
   } else {
-    RCUTILS_LOG_ERROR("Failed to remove clock");
+    RCLCPP_ERROR(logger_, "failed to remove clock");
   }
 }
 
@@ -200,7 +206,7 @@ void TimeSource::on_parameter_event(const rcl_interfaces::msg::ParameterEvent::S
       rclcpp::ParameterEventsFilter::EventType::CHANGED});
   for (auto & it : filter.get_events()) {
     if (it.second->value.type != ParameterType::PARAMETER_BOOL) {
-      RCUTILS_LOG_ERROR("use_sim_time parameter set to something besides a bool");
+      RCLCPP_ERROR(logger_, "use_sim_time parameter set to something besides a bool");
       continue;
     }
     if (it.second->value.bool_value) {

rclcpp/src/rclcpp/timer.cpp

@@ -18,13 +18,22 @@
 #include <string>
 #include <memory>
 
+#include "rclcpp/contexts/default_context.hpp"
 #include "rcutils/logging_macros.h"
 
 using rclcpp::TimerBase;
 
-TimerBase::TimerBase(rclcpp::Clock::SharedPtr clock, std::chrono::nanoseconds period)
+TimerBase::TimerBase(
+  rclcpp::Clock::SharedPtr clock,
+  std::chrono::nanoseconds period,
+  rclcpp::Context::SharedPtr context)
+: clock_(clock), timer_handle_(nullptr)
 {
-  clock_ = clock;
+  if (nullptr == context) {
+    context = rclcpp::contexts::default_context::get_global_default_context();
+  }
+
+  auto rcl_context = context->get_rcl_context();
 
   timer_handle_ = std::shared_ptr<rcl_timer_t>(
     new rcl_timer_t, [ = ](rcl_timer_t * timer) mutable
@@ -36,15 +45,16 @@ TimerBase::TimerBase(rclcpp::Clock::SharedPtr clock, std::chrono::nanoseconds pe
         rcl_reset_error();
       }
       delete timer;
-      // Captured shared pointer by copy, reset to make sure timer is finalized before clock
+      // Captured shared pointers by copy, reset to make sure timer is finalized before clock
       clock.reset();
+      rcl_context.reset();
     });
 
   *timer_handle_.get() = rcl_get_zero_initialized_timer();
 
   rcl_clock_t * clock_handle = clock_->get_clock_handle();
   if (rcl_timer_init(
-      timer_handle_.get(), clock_handle, period.count(), nullptr,
+      timer_handle_.get(), clock_handle, rcl_context.get(), period.count(), nullptr,
       rcl_get_default_allocator()) != RCL_RET_OK)
   {
     RCUTILS_LOG_ERROR_NAMED(

rclcpp/src/rclcpp/utilities.cpp

@@ -24,7 +24,10 @@
 #include <string>
 #include <vector>
 
+#include "rclcpp/contexts/default_context.hpp"
+#include "rclcpp/logging.hpp"
 #include "rclcpp/exceptions.hpp"
+#include "rclcpp/scope_exit.hpp"
 
 #include "rcl/error_handling.h"
 #include "rcl/rcl.h"
@@ -39,15 +42,18 @@
 #define HAS_SIGACTION
 #endif
 
-/// Represent the status of the global interrupt signal.
-static volatile sig_atomic_t g_signal_status = 0;
-/// Guard conditions for interrupting the rmw implementation when the global interrupt signal fired.
-static std::map<rcl_wait_set_t *, rcl_guard_condition_t> g_sigint_guard_cond_handles;
+/// Mutex to protect installation and uninstallation of signal handlers.
+static std::mutex g_signal_handlers_mutex;
+/// Atomic bool to control setup of signal handlers.
+static std::atomic<bool> g_signal_handlers_installed(false);
+
 /// Mutex to protect g_sigint_guard_cond_handles
 static std::mutex g_sigint_guard_cond_handles_mutex;
+/// Guard conditions for interrupting the rmw implementation when the global interrupt signal fired.
+static std::map<rcl_wait_set_t *, rcl_guard_condition_t> g_sigint_guard_cond_handles;
+
 /// Condition variable for timed sleep (see sleep_for).
 static std::condition_variable g_interrupt_condition_variable;
-static std::atomic<bool> g_is_interrupted(false);
 /// Mutex for protecting the global condition variable.
 static std::mutex g_interrupt_mutex;
 
@@ -109,25 +115,6 @@ set_signal_handler(int signal_value, signal_handler_t signal_handler)
 #endif
 }
 
-void
-trigger_interrupt_guard_condition(int signal_value)
-{
-  g_signal_status = signal_value;
-  {
-    std::lock_guard<std::mutex> lock(g_sigint_guard_cond_handles_mutex);
-    for (auto & kv : g_sigint_guard_cond_handles) {
-      rcl_ret_t status = rcl_trigger_guard_condition(&(kv.second));
-      if (status != RCL_RET_OK) {
-        RCUTILS_LOG_ERROR_NAMED(
-          "rclcpp",
-          "failed to trigger guard condition: %s", rcl_get_error_string().str);
-      }
-    }
-  }
-  g_is_interrupted.store(true);
-  g_interrupt_condition_variable.notify_all();
-}
-
 void
 #ifdef HAS_SIGACTION
 signal_handler(int signal_value, siginfo_t * siginfo, void * context)
@@ -135,8 +122,7 @@ signal_handler(int signal_value, siginfo_t * siginfo, void * context)
 signal_handler(int signal_value)
 #endif
 {
-  // TODO(wjwwood): remove? move to console logging at some point?
-  printf("signal_handler(%d)\n", signal_value);
+  RCLCPP_INFO(rclcpp::get_logger("rclcpp"), "signal_handler(signal_value=%d)", signal_value);
 
 #ifdef HAS_SIGACTION
   if (old_action.sa_flags & SA_SIGINFO) {
@@ -158,18 +144,31 @@ signal_handler(int signal_value)
   }
 #endif
 
-  trigger_interrupt_guard_condition(signal_value);
+  for (auto context_ptr : rclcpp::get_contexts()) {
+    if (context_ptr->get_init_options().shutdown_on_sigint) {
+      // do not notify all, instead do that once after all are shutdown
+      context_ptr->shutdown("signal handler", false /* notify_all */);
+    }
+  }
+  rclcpp::notify_all();
 }
 
 void
-rclcpp::init(int argc, char const * const argv[])
+rclcpp::init(int argc, char const * const argv[], const rclcpp::InitOptions & init_options)
 {
-  g_is_interrupted.store(false);
-  if (rcl_init(argc, argv, rcl_get_default_allocator()) != RCL_RET_OK) {
-    std::string msg = "failed to initialize rmw implementation: ";
-    msg += rcl_get_error_string().str;
-    rcl_reset_error();
-    throw std::runtime_error(msg);
+  using rclcpp::contexts::default_context::get_global_default_context;
+  get_global_default_context()->init(argc, argv, init_options);
+  // Install the signal handlers.
+  rclcpp::install_signal_handlers();
+}
+
+bool
+rclcpp::install_signal_handlers()
+{
+  std::lock_guard<std::mutex> lock(g_signal_handlers_mutex);
+  bool already_installed = g_signal_handlers_installed.exchange(true);
+  if (already_installed) {
+    return false;
   }
 #ifdef HAS_SIGACTION
   struct sigaction action;
@@ -178,25 +177,43 @@ rclcpp::init(int argc, char const * const argv[])
   action.sa_sigaction = ::signal_handler;
   action.sa_flags = SA_SIGINFO;
   ::old_action = set_sigaction(SIGINT, action);
-  // Register an on_shutdown hook to restore the old action.
-  rclcpp::on_shutdown(
-    []() {
-      set_sigaction(SIGINT, ::old_action);
-    });
 #else
   ::old_signal_handler = set_signal_handler(SIGINT, ::signal_handler);
-  // Register an on_shutdown hook to restore the old signal handler.
-  rclcpp::on_shutdown(
-    []() {
-      set_signal_handler(SIGINT, ::old_signal_handler);
-    });
 #endif
+  RCLCPP_DEBUG(rclcpp::get_logger("rclcpp"), "signal handler installed");
+  return true;
+}
+
+bool
+rclcpp::signal_handlers_installed()
+{
+  return g_signal_handlers_installed.load();
+}
+
+bool
+rclcpp::uninstall_signal_handlers()
+{
+  std::lock_guard<std::mutex> lock(g_signal_handlers_mutex);
+  bool installed = g_signal_handlers_installed.exchange(false);
+  if (!installed) {
+    return false;
+  }
+#ifdef HAS_SIGACTION
+  set_sigaction(SIGINT, ::old_action);
+#else
+  set_signal_handler(SIGINT, ::old_signal_handler);
+#endif
+  RCLCPP_DEBUG(rclcpp::get_logger("rclcpp"), "signal handler uninstalled");
+  return true;
 }
 
 std::vector<std::string>
-rclcpp::init_and_remove_ros_arguments(int argc, char const * const argv[])
+rclcpp::init_and_remove_ros_arguments(
+  int argc,
+  char const * const argv[],
+  const rclcpp::InitOptions & init_options)
 {
-  rclcpp::init(argc, argv);
+  rclcpp::init(argc, argv, init_options);
   return rclcpp::remove_ros_arguments(argc, argv);
 }
 
@@ -210,7 +227,7 @@ rclcpp::remove_ros_arguments(int argc, char const * const argv[])
 
   ret = rcl_parse_arguments(argc, argv, alloc, &parsed_args);
   if (RCL_RET_OK != ret) {
-    exceptions::throw_from_rcl_error(ret, "failed to parse arguments");
+    rclcpp::exceptions::throw_from_rcl_error(ret, "failed to parse arguments");
   }
 
   int nonros_argc = 0;
@@ -225,7 +242,7 @@ rclcpp::remove_ros_arguments(int argc, char const * const argv[])
 
   if (RCL_RET_OK != ret) {
     // Not using throw_from_rcl_error, because we may need to append deallocation failures.
-    exceptions::RCLErrorBase base_exc(ret, rcl_get_error_state());
+    rclcpp::exceptions::RCLErrorBase base_exc(ret, rcl_get_error_state());
     rcl_reset_error();
     if (NULL != nonros_argv) {
       alloc.deallocate(nonros_argv, alloc.state);
@@ -236,7 +253,7 @@ rclcpp::remove_ros_arguments(int argc, char const * const argv[])
         rcl_get_error_string().str;
       rcl_reset_error();
     }
-    throw exceptions::RCLError(base_exc, "");
+    throw rclcpp::exceptions::RCLError(base_exc, "");
   }
 
   std::vector<std::string> return_arguments;
@@ -252,63 +269,75 @@ rclcpp::remove_ros_arguments(int argc, char const * const argv[])
 
   ret = rcl_arguments_fini(&parsed_args);
   if (RCL_RET_OK != ret) {
-    exceptions::throw_from_rcl_error(ret, "failed to cleanup parsed arguments, leaking memory");
+    rclcpp::exceptions::throw_from_rcl_error(
+      ret, "failed to cleanup parsed arguments, leaking memory");
   }
 
   return return_arguments;
 }
 
 bool
-rclcpp::ok()
+rclcpp::ok(rclcpp::Context::SharedPtr context)
 {
-  return ::g_signal_status == 0;
+  using rclcpp::contexts::default_context::get_global_default_context;
+  if (nullptr == context) {
+    context = get_global_default_context();
+  }
+  return context->is_valid();
 }
 
 bool
-rclcpp::is_initialized()
+rclcpp::is_initialized(rclcpp::Context::SharedPtr context)
 {
-  return rcl_ok();
+  return rclcpp::ok(context);
 }
 
-static std::mutex on_shutdown_mutex_;
-static std::vector<std::function<void(void)>> on_shutdown_callbacks_;
-
-void
-rclcpp::shutdown()
+bool
+rclcpp::shutdown(rclcpp::Context::SharedPtr context, const std::string & reason)
 {
-  trigger_interrupt_guard_condition(SIGINT);
+  using rclcpp::contexts::default_context::get_global_default_context;
+  auto default_context = get_global_default_context();
+  if (nullptr == context) {
+    context = default_context;
+  }
 
-  {
-    std::lock_guard<std::mutex> lock(on_shutdown_mutex_);
-    for (auto & on_shutdown_callback : on_shutdown_callbacks_) {
-      on_shutdown_callback();
-    }
+  bool ret = context->shutdown(reason);
+
+  // Uninstall the signal handlers if this is the default context's shutdown.
+  if (context == default_context) {
+    uninstall_signal_handlers();
   }
+
+  return ret;
 }
 
 void
-rclcpp::on_shutdown(std::function<void(void)> callback)
+rclcpp::on_shutdown(std::function<void()> callback, rclcpp::Context::SharedPtr context)
 {
-  std::lock_guard<std::mutex> lock(on_shutdown_mutex_);
-  on_shutdown_callbacks_.push_back(callback);
+  using rclcpp::contexts::default_context::get_global_default_context;
+  if (nullptr == context) {
+    context = get_global_default_context();
+  }
+  context->on_shutdown(callback);
 }
 
 rcl_guard_condition_t *
-rclcpp::get_sigint_guard_condition(rcl_wait_set_t * wait_set)
+rclcpp::get_sigint_guard_condition(rcl_wait_set_t * wait_set, rclcpp::Context::SharedPtr context)
 {
   std::lock_guard<std::mutex> lock(g_sigint_guard_cond_handles_mutex);
   auto kv = g_sigint_guard_cond_handles.find(wait_set);
   if (kv != g_sigint_guard_cond_handles.end()) {
     return &kv->second;
   } else {
-    rcl_guard_condition_t handle =
-      rcl_get_zero_initialized_guard_condition();
+    using rclcpp::contexts::default_context::get_global_default_context;
+    if (nullptr == context) {
+      context = get_global_default_context();
+    }
+    rcl_guard_condition_t handle = rcl_get_zero_initialized_guard_condition();
     rcl_guard_condition_options_t options = rcl_guard_condition_get_default_options();
-    if (rcl_guard_condition_init(&handle, options) != RCL_RET_OK) {
-      // *INDENT-OFF* (prevent uncrustify from making unnecessary indents here)
-      throw std::runtime_error(std::string(
-        "Couldn't initialize guard condition: ") + rcl_get_error_string().str);
-      // *INDENT-ON*
+    auto ret = rcl_guard_condition_init(&handle, context->get_rcl_context().get(), options);
+    if (RCL_RET_OK != ret) {
+      rclcpp::exceptions::throw_from_rcl_error(ret, "Couldn't initialize guard condition: ");
     }
     g_sigint_guard_cond_handles[wait_set] = handle;
     return &g_sigint_guard_cond_handles[wait_set];
@@ -338,20 +367,38 @@ rclcpp::release_sigint_guard_condition(rcl_wait_set_t * wait_set)
 }
 
 bool
-rclcpp::sleep_for(const std::chrono::nanoseconds & nanoseconds)
+rclcpp::sleep_for(const std::chrono::nanoseconds & nanoseconds, rclcpp::Context::SharedPtr context)
 {
   std::chrono::nanoseconds time_left = nanoseconds;
   {
     std::unique_lock<std::mutex> lock(::g_interrupt_mutex);
     auto start = std::chrono::steady_clock::now();
+    // this will release the lock while waiting
     ::g_interrupt_condition_variable.wait_for(lock, nanoseconds);
     time_left -= std::chrono::steady_clock::now() - start;
   }
-  if (time_left > std::chrono::nanoseconds::zero() && !g_is_interrupted) {
+  if (time_left > std::chrono::nanoseconds::zero() && ok(context)) {
     return sleep_for(time_left);
   }
   // Return true if the timeout elapsed successfully, otherwise false.
-  return !g_is_interrupted;
+  return ok(context);
+}
+
+void
+rclcpp::notify_all()
+{
+  {
+    std::lock_guard<std::mutex> lock(g_sigint_guard_cond_handles_mutex);
+    for (auto & kv : g_sigint_guard_cond_handles) {
+      rcl_ret_t status = rcl_trigger_guard_condition(&(kv.second));
+      if (status != RCL_RET_OK) {
+        RCUTILS_LOG_ERROR_NAMED(
+          "rclcpp",
+          "failed to trigger guard condition: %s", rcl_get_error_string().str);
+      }
+    }
+  }
+  g_interrupt_condition_variable.notify_all();
 }
 
 const char *

rclcpp/test/test_init.cpp

@@ -25,5 +25,5 @@ TEST(TestInit, is_initialized) {
 
   rclcpp::shutdown();
 
-  EXPECT_TRUE(rclcpp::is_initialized());
+  EXPECT_FALSE(rclcpp::is_initialized());
 }

rclcpp/test/test_utilities.cpp

@@ -17,6 +17,7 @@
 #include <string>
 #include <memory>
 
+#include "rclcpp/contexts/default_context.hpp"
 #include "rclcpp/exceptions.hpp"
 #include "rclcpp/utilities.hpp"
 
@@ -49,5 +50,34 @@ TEST(TestUtilities, init_with_args) {
   ASSERT_EQ(1u, other_args.size());
   ASSERT_EQ(std::string{"process_name"}, other_args[0]);
 
-  EXPECT_TRUE(rclcpp::is_initialized());
+  EXPECT_TRUE(rclcpp::ok());
+  rclcpp::shutdown();
+}
+
+TEST(TestUtilities, multi_init) {
+  auto context1 = std::make_shared<rclcpp::contexts::default_context::DefaultContext>();
+  auto context2 = std::make_shared<rclcpp::contexts::default_context::DefaultContext>();
+
+  EXPECT_FALSE(rclcpp::ok(context1));
+  EXPECT_FALSE(rclcpp::ok(context2));
+
+  context1->init(0, nullptr);
+
+  EXPECT_TRUE(rclcpp::ok(context1));
+  EXPECT_FALSE(rclcpp::ok(context2));
+
+  context2->init(0, nullptr);
+
+  EXPECT_TRUE(rclcpp::ok(context1));
+  EXPECT_TRUE(rclcpp::ok(context2));
+
+  rclcpp::shutdown(context1);
+
+  EXPECT_FALSE(rclcpp::ok(context1));
+  EXPECT_TRUE(rclcpp::ok(context2));
+
+  rclcpp::shutdown(context2);
+
+  EXPECT_FALSE(rclcpp::ok(context1));
+  EXPECT_FALSE(rclcpp::ok(context2));
 }

rclcpp_lifecycle/include/rclcpp_lifecycle/lifecycle_node_impl.hpp

@@ -141,7 +141,7 @@ LifecycleNode::create_wall_timer(
 {
   auto timer = rclcpp::WallTimer<CallbackT>::make_shared(
     std::chrono::duration_cast<std::chrono::nanoseconds>(period),
-    std::move(callback));
+    std::move(callback), this->node_base_->get_context());
   node_timers_->add_timer(timer, group);
   return timer;
 }

rclcpp_lifecycle/src/lifecycle_node.cpp

@@ -86,7 +86,8 @@ LifecycleNode::LifecycleNode(
       node_base_,
       node_topics_,
       node_graph_,
-      node_services_
+      node_services_,
+      node_logging_
     )),
   node_waitables_(new rclcpp::node_interfaces::NodeWaitables(node_base_.get())),
   use_intra_process_comms_(use_intra_process_comms),