Merge pull request #6611 from murgatroid99/ruby_signal_handling_improvement

Handle signals properly when dropping GVL

src/ruby/ext/grpc/rb_completion_queue.c

@@ -52,21 +52,41 @@ typedef struct next_call_stack {
   grpc_event event;
   gpr_timespec timeout;
   void *tag;
+  volatile int interrupted;
 } next_call_stack;
 
 /* Calls grpc_completion_queue_next without holding the ruby GIL */
 static void *grpc_rb_completion_queue_next_no_gil(void *param) {
   next_call_stack *const next_call = (next_call_stack*)param;
-  next_call->event =
-      grpc_completion_queue_next(next_call->cq, next_call->timeout, NULL);
+  gpr_timespec increment = gpr_time_from_millis(20, GPR_TIMESPAN);
+  gpr_timespec deadline;
+  do {
+    deadline = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), increment);
+    next_call->event = grpc_completion_queue_next(next_call->cq,
+                                                  deadline, NULL);
+    if (next_call->event.type != GRPC_QUEUE_TIMEOUT ||
+        gpr_time_cmp(deadline, next_call->timeout) > 0) {
+      break;
+    }
+  } while (!next_call->interrupted);
   return NULL;
 }
 
 /* Calls grpc_completion_queue_pluck without holding the ruby GIL */
 static void *grpc_rb_completion_queue_pluck_no_gil(void *param) {
   next_call_stack *const next_call = (next_call_stack*)param;
-  next_call->event = grpc_completion_queue_pluck(next_call->cq, next_call->tag,
-                                                 next_call->timeout, NULL);
+  gpr_timespec increment = gpr_time_from_millis(20, GPR_TIMESPAN);
+  gpr_timespec deadline;
+  do {
+    deadline = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), increment);
+    next_call->event = grpc_completion_queue_pluck(next_call->cq,
+                                                   next_call->tag,
+                                                   deadline, NULL);
+    if (next_call->event.type != GRPC_QUEUE_TIMEOUT ||
+        gpr_time_cmp(deadline, next_call->timeout) > 0) {
+      break;
+    }
+  } while (!next_call->interrupted);
   return NULL;
 }
 
@@ -139,6 +159,11 @@ static VALUE grpc_rb_completion_queue_alloc(VALUE cls) {
   return TypedData_Wrap_Struct(cls, &grpc_rb_completion_queue_data_type, cq);
 }
 
+static void unblock_func(void *param) {
+  next_call_stack *const next_call = (next_call_stack*)param;
+  next_call->interrupted = 1;
+}
+
 /* Blocks until the next event for given tag is available, and returns the
  * event. */
 grpc_event grpc_rb_completion_queue_pluck_event(VALUE self, VALUE tag,
@@ -158,8 +183,23 @@ grpc_event grpc_rb_completion_queue_pluck_event(VALUE self, VALUE tag,
     next_call.tag = ROBJECT(tag);
   }
   next_call.event.type = GRPC_QUEUE_TIMEOUT;
-  rb_thread_call_without_gvl(grpc_rb_completion_queue_pluck_no_gil,
-                             (void *)&next_call, NULL, NULL);
+  /* Loop until we finish a pluck without an interruption. The internal
+     pluck function runs either until it is interrupted or it gets an
+     event, or time runs out.
+
+     The basic reason we need this relatively complicated construction is that
+     we need to re-acquire the GVL when an interrupt comes in, so that the ruby
+     interpreter can do what it needs to do with the interrupt. But we also need
+     to get back to plucking when the interrupt has been handled. */
+  do {
+    next_call.interrupted = 0;
+    rb_thread_call_without_gvl(grpc_rb_completion_queue_pluck_no_gil,
+                               (void *)&next_call, unblock_func,
+                               (void *)&next_call);
+    /* If an interrupt prevented pluck from returning useful information, then
+       any plucks that did complete must have timed out */
+  } while (next_call.interrupted &&
+           next_call.event.type == GRPC_QUEUE_TIMEOUT);
   return next_call.event;
 }
 

src/ruby/ext/grpc/rb_completion_queue.h

@@ -46,7 +46,7 @@ grpc_completion_queue *grpc_rb_get_wrapped_completion_queue(VALUE v);
  *
  * This avoids having code that holds the GIL repeated at multiple sites.
  */
-grpc_event grpc_rb_completion_queue_pluck_event(VALUE cqueue, VALUE tag,
+grpc_event grpc_rb_completion_queue_pluck_event(VALUE self, VALUE tag,
                                                 VALUE timeout);
 
 /* Initializes the CompletionQueue class. */

src/ruby/ext/grpc/rb_grpc.c

@@ -50,7 +50,6 @@
 #include "rb_loader.h"
 #include "rb_server.h"
 #include "rb_server_credentials.h"
-#include "rb_signal.h"
 
 static VALUE grpc_rb_cTimeVal = Qnil;
 
@@ -333,7 +332,6 @@ 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_server.c

@@ -60,6 +60,7 @@ typedef struct grpc_rb_server {
   VALUE mark;
   /* The actual server */
   grpc_server *wrapped;
+  grpc_completion_queue *queue;
 } grpc_rb_server;
 
 /* Destroys server instances. */
@@ -145,6 +146,7 @@ static VALUE grpc_rb_server_init(VALUE self, VALUE cqueue, VALUE channel_args) {
   }
   grpc_server_register_completion_queue(srv, cq, NULL);
   wrapper->wrapped = srv;
+  wrapper->queue = cq;
 
   /* Add the cq as the server's mark object. This ensures the ruby cq can't be
      GCed before the server */

src/ruby/ext/grpc/rb_signal.c

-/*
- *
- * 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

-/*
- *
- * 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

@@ -33,7 +33,6 @@ 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'
@@ -48,5 +47,3 @@ begin
 ensure
   file.close
 end
-
-GRPC::Signals.wait_for_signals

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

@@ -30,7 +30,6 @@
 require 'forwardable'
 require 'weakref'
 require_relative 'bidi_call'
-require_relative '../signals'
 
 class Struct
   # BatchResult is the struct returned by calls to call#start_batch.
@@ -123,10 +122,6 @@ 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

@@ -28,7 +28,6 @@
 # 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'
@@ -353,10 +352,7 @@ 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

src/ruby/lib/grpc/signals.rb

-# 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