Merge pull request #6472 from murgatroid99/ruby_signal_handling2

Make Ruby library terminate on Ctrl+C on client and server

src/ruby/ext/grpc/rb_grpc.c

@@ -50,6 +50,7 @@
 #include "rb_loader.h"
 #include "rb_server.h"
 #include "rb_server_credentials.h"
+#include "rb_signal.h"
 
 static VALUE grpc_rb_cTimeVal = Qnil;
 
@@ -332,6 +333,7 @@ void Init_grpc_c() {
   Init_grpc_channel_credentials();
   Init_grpc_server();
   Init_grpc_server_credentials();
+  Init_grpc_signals();
   Init_grpc_status_codes();
   Init_grpc_time_consts();
 }

src/ruby/ext/grpc/rb_signal.c

@@ -0,0 +1,70 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <ruby/ruby.h>
+#include <signal.h>
+#include <stdbool.h>
+
+#include <grpc/support/log.h>
+
+#include "rb_grpc.h"
+
+static void (*old_sigint_handler)(int);
+static void (*old_sigterm_handler)(int);
+
+static volatile bool signal_received = false;
+
+/* This has to be handled at the C level instead of Ruby, because Ruby signal
+ * handlers are constrained to run in the main interpreter thread. If that main
+ * thread is blocked on grpc_completion_queue_pluck, the signal handlers will
+ * never run */
+static void handle_signal(int signum) {
+  signal_received = true;
+  if (signum == SIGINT) {
+    old_sigint_handler(signum);
+  } else if (signum == SIGTERM) {
+    old_sigterm_handler(signum);
+  }
+}
+
+static VALUE grpc_rb_signal_received(VALUE self) {
+  (void)self;
+  return signal_received ? Qtrue : Qfalse;
+}
+
+void Init_grpc_signals() {
+  old_sigint_handler = signal(SIGINT, handle_signal);
+  old_sigterm_handler = signal(SIGTERM, handle_signal);
+  rb_define_singleton_method(grpc_rb_mGrpcCore, "signal_received?",
+                             grpc_rb_signal_received, 0);
+}

src/ruby/ext/grpc/rb_signal.h

@@ -0,0 +1,39 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_RB_SIGNAL_H_
+#define GRPC_RB_SIGNAL_H_
+
+void Init_grpc_signals();
+
+#endif  /* GRPC_RB_SIGNAL_H_ */

src/ruby/lib/grpc.rb

@@ -33,6 +33,7 @@ require_relative 'grpc/errors'
 require_relative 'grpc/grpc'
 require_relative 'grpc/logconfig'
 require_relative 'grpc/notifier'
+require_relative 'grpc/signals'
 require_relative 'grpc/version'
 require_relative 'grpc/core/time_consts'
 require_relative 'grpc/generic/active_call'
@@ -47,3 +48,5 @@ begin
 ensure
   file.close
 end
+
+GRPC::Signals.wait_for_signals

src/ruby/lib/grpc/generic/active_call.rb

@@ -28,7 +28,9 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 require 'forwardable'
+require 'weakref'
 require_relative 'bidi_call'
+require_relative '../signals'
 
 class Struct
   # BatchResult is the struct returned by calls to call#start_batch.
@@ -121,6 +123,10 @@ module GRPC
       @unmarshal = unmarshal
       @metadata_tag = metadata_tag
       @op_notifier = nil
+      weak_self = WeakRef.new(self)
+      remove_handler = GRPC::Signals.register_handler(&weak_self
+                                                        .method(:cancel))
+      ObjectSpace.define_finalizer(self, remove_handler)
     end
 
     # output_metadata are provides access to hash that can be used to

src/ruby/lib/grpc/generic/rpc_server.rb

@@ -28,46 +28,13 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 require_relative '../grpc'
+require_relative '../signals'
 require_relative 'active_call'
 require_relative 'service'
 require 'thread'
 
-# A global that contains signals the gRPC servers should respond to.
-$grpc_signals = []
-
 # GRPC contains the General RPC module.
 module GRPC
-  # Handles the signals in $grpc_signals.
-  #
-  # @return false if the server should exit, true if not.
-  def handle_signals
-    loop do
-      sig = $grpc_signals.shift
-      case sig
-      when 'INT'
-        return false
-      when 'TERM'
-        return false
-      when nil
-        return true
-      end
-    end
-    true
-  end
-  module_function :handle_signals
-
-  # Sets up a signal handler that adds signals to the signal handling global.
-  #
-  # Signal handlers should do as little as humanly possible.
-  # Here, they just add themselves to $grpc_signals
-  #
-  # RpcServer (and later other parts of gRPC) monitors the signals
-  # $grpc_signals in its own non-signal context.
-  def trap_signals
-    %w(INT TERM).each { |sig| trap(sig) { $grpc_signals << sig } }
-  end
-  module_function :trap_signals
-
   # Pool is a simple thread pool.
   class Pool
     # Default keep alive period is 1s
@@ -328,23 +295,6 @@ module GRPC
       end
     end
 
-    # Runs the server in its own thread, then waits for signal INT or TERM on
-    # the current thread to terminate it.
-    def run_till_terminated
-      GRPC.trap_signals
-      t = Thread.new do
-        run
-      end
-      t.abort_on_exception = true
-      wait_till_running
-      until running_state == :stopped
-        sleep SIGNAL_CHECK_PERIOD
-        break unless GRPC.handle_signals
-      end
-      stop
-      t.join
-    end
-
     # handle registration of classes
     #
     # service is either a class that includes GRPC::GenericService and whose
@@ -403,9 +353,14 @@ module GRPC
         transition_running_state(:running)
         @run_cond.broadcast
       end
+      remove_signal_handler = GRPC::Signals.register_handler { stop }
       loop_handle_server_calls
+      # Remove signal handler when server stops
+      remove_signal_handler.call
     end
 
+    alias_method :run_till_terminated, :run
+
     # Sends RESOURCE_EXHAUSTED if there are too many unprocessed jobs
     def available?(an_rpc)
       jobs_count, max = @pool.jobs_waiting, @max_waiting_requests

src/ruby/lib/grpc/signals.rb

@@ -0,0 +1,69 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'thread'
+require_relative 'grpc'
+
+# GRPC contains the General RPC module.
+module GRPC
+  # Signals contains gRPC functions related to signal handling
+  module Signals
+    @interpreter_exiting = false
+    @signal_handlers = []
+    @handlers_mutex = Mutex.new
+
+    def register_handler(&handler)
+      @handlers_mutex.synchronize do
+        @signal_handlers.push(handler)
+        handler.call if @exit_signal_received
+      end
+      # Returns a function to remove the handler
+      lambda do
+        @handlers_mutex.synchronize { @signal_handlers.delete(handler) }
+      end
+    end
+    module_function :register_handler
+
+    def wait_for_signals
+      t = Thread.new do
+        sleep 0.1 until GRPC::Core.signal_received? || @interpreter_exiting
+        unless @interpreter_exiting
+          @handlers_mutex.synchronize do
+            @signal_handlers.each(&:call)
+          end
+        end
+      end
+      at_exit do
+        @interpreter_exiting = true
+        t.join
+      end
+    end
+    module_function :wait_for_signals
+  end
+end