Handle sigterm, in the same way we handle sigint (ros2#1771)

Signed-off-by: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>

rclcpp/include/rclcpp/context.hpp

@@ -75,7 +75,7 @@ class Context : public std::enable_shared_from_this<Context>
    * 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.
+   * See the shutdown_on_signal option in the InitOptions class.
    */
   RCLCPP_PUBLIC
   Context();
@@ -93,7 +93,7 @@ class Context : public std::enable_shared_from_this<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_handlers() or use rclcpp::init().
-   * In addition to installing the signal handlers, the shutdown_on_sigint
+   * In addition to installing the signal handlers, the shutdown_on_signal
    * of the InitOptions needs to be `true` for this context to be shutdown by
    * the signal handler, otherwise it will be passed over.
    *
@@ -268,7 +268,7 @@ class Context : public std::enable_shared_from_this<Context>
    *
    *   - this context is shutdown()
    *   - this context is destructed (resulting in shutdown)
-   *   - this context has shutdown_on_sigint=true and SIGINT occurs (resulting in shutdown)
+   *   - this context has shutdown_on_signal=true and SIGINT/SIGTERM occurs (resulting in shutdown)
    *   - interrupt_all_sleep_for() is called
    *
    * \param[in] nanoseconds A std::chrono::duration representing how long to sleep for.

rclcpp/include/rclcpp/init_options.hpp

@@ -29,7 +29,7 @@ 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;
+  bool shutdown_on_signal = true;
 
   /// Constructor
   /**

rclcpp/include/rclcpp/utilities.hpp

@@ -42,6 +42,20 @@ std::string to_string(T value)
 
 namespace rclcpp
 {
+
+/// Option to indicate which signal handlers rclcpp should install.
+enum class SignalHandlerOptions
+{
+  /// Install both sigint and sigterm, this is the default behavior.
+  All,
+  /// Install only a sigint handler.
+  SigInt,
+  /// Install only a sigterm handler.
+  SigTerm,
+  /// Do not install any signal handler.
+  None,
+};
+
 /// Initialize communications via the rmw implementation and set up a global signal handler.
 /**
  * Initializes the global context which is accessible via the function
@@ -50,10 +64,16 @@ namespace rclcpp
  * rclcpp::install_signal_handlers().
  *
  * \sa rclcpp::Context::init() for more details on arguments and possible exceptions
+ *
+ * \param signal_handler_options option to indicate which signal handlers should be installed.
  */
 RCLCPP_PUBLIC
 void
-init(int argc, char const * const argv[], const InitOptions & init_options = InitOptions());
+init(
+  int argc,
+  char const * const argv[],
+  const InitOptions & init_options = InitOptions(),
+  SignalHandlerOptions signal_handler_options = SignalHandlerOptions::All);
 
 /// Install the global signal handler for rclcpp.
 /**
@@ -67,17 +87,26 @@ init(int argc, char const * const argv[], const InitOptions & init_options = Ini
  *
  * This function is thread-safe.
  *
+ * \param signal_handler_options option to indicate which signal handlers should be installed.
  * \return true if signal handler was installed by this function, false if already installed.
  */
 RCLCPP_PUBLIC
 bool
-install_signal_handlers();
+install_signal_handlers(SignalHandlerOptions signal_handler_options = SignalHandlerOptions::All);
 
 /// Return true if the signal handlers are installed, otherwise false.
 RCLCPP_PUBLIC
 bool
 signal_handlers_installed();
 
+/// Get the current signal handler options.
+/**
+ * If no signal handler is installed, SignalHandlerOptions::None is returned.
+ */
+RCLCPP_PUBLIC
+SignalHandlerOptions
+get_current_signal_handler_options();
+
 /// Uninstall the global signal handler for rclcpp.
 /**
  * This function does not necessarily need to be called, but can be used to

rclcpp/src/rclcpp/init_options.cpp

@@ -43,7 +43,7 @@ InitOptions::InitOptions(const rcl_init_options_t & init_options)
 InitOptions::InitOptions(const InitOptions & other)
 : InitOptions(*other.get_rcl_init_options())
 {
-  shutdown_on_sigint = other.shutdown_on_sigint;
+  shutdown_on_signal = other.shutdown_on_signal;
   initialize_logging_ = other.initialize_logging_;
 }
 
@@ -70,7 +70,7 @@ InitOptions::operator=(const InitOptions & other)
     if (RCL_RET_OK != ret) {
       rclcpp::exceptions::throw_from_rcl_error(ret, "failed to copy rcl init options");
     }
-    this->shutdown_on_sigint = other.shutdown_on_sigint;
+    this->shutdown_on_signal = other.shutdown_on_signal;
     this->initialize_logging_ = other.initialize_logging_;
   }
   return *this;