Advanced servers support clean shutdown via SIGINT or SIGTERM

fix #1026

CHANGELOG.md

@@ -3,6 +3,7 @@ Version 158:
 * Tidy up end_of_stream javadoc
 * Tidy up websocket docs
 * Examples set reuse_address(true)
+* Advanced servers support clean shutdown via SIGINT or SIGTERM
 
 --------------------------------------------------------------------------------
 

doc/qbk/00_main.qbk

@@ -28,7 +28,7 @@
 
 [template source_file[path] '''<ulink url="../../'''[path]'''">'''[path]'''</ulink>''']
 [template include_file[path][^<'''<ulink url="../../../../'''[path]'''">'''[path]'''</ulink>'''>]]
-[template issue[n] '''(<ulink url="https://github.com/boostorg/beast/issues/'''[n]'''">#'''[n]'''</ulink>)''']
+[template issue[n] '''<ulink url="https://github.com/boostorg/beast/issues/'''[n]'''">#'''[n]'''</ulink>''']
 
 [def __N3747__                  [@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3747.pdf [*N3747]]]
 [def __NetTS__                  [@http://cplusplus.github.io/networking-ts/draft.pdf [*Networking.TS]]]

doc/qbk/02_examples.qbk

@@ -180,7 +180,9 @@ and illustrate the implementation of advanced features.
             [HTTP pipelining]
             [Asynchronous timeouts]
             [Dual protocols: HTTP and WebSocket]
-            [WebSocket use idle ping for timeout]]]
+            [WebSocket use idle ping for timeout]
+            [Clean exit via SIGINT (CTRL+C) or SIGTERM (kill)]
+        ]]
         [[example_src example/advanced/server/advanced_server.cpp advanced_server.cpp]]
 ][
         [Advanced, flex (plain + SSL)]
@@ -189,7 +191,9 @@ and illustrate the implementation of advanced features.
             [Asynchronous timeouts]
             [Dual protocols: HTTP and WebSocket]
             [WebSocket use idle ping for timeout]
-            [Flexible ports: plain and SSL on the same port]]]
+            [Flexible ports: plain and SSL on the same port]
+            [Clean exit via SIGINT (CTRL+C) or SIGTERM (kill)]
+        ]]
         [[example_src example/advanced/server-flex/advanced_server_flex.cpp advanced_server_flex.cpp]]
 ]]
 

doc/qbk/09_releases.qbk

@@ -20,9 +20,9 @@ to update to the latest Boost release.
 
 * Move-only completion handlers are supported throughout the library
 
-* [issue 899] Advanced server examples support idle websocket pings and timeouts
+* ([issue 899]) Advanced server examples support idle websocket pings and timeouts
 
-* [issue 849] WebSocket permessage-deflate support is now a compile-time
+* ([issue 849]) WebSocket permessage-deflate support is now a compile-time
   feature.  This adds an additional `bool` template parameter to
   [link beast.ref.boost__beast__websocket__stream `websocket::stream`]
   When `deflateSupported` is `true`, the stream will be capable of
@@ -34,7 +34,7 @@ to update to the latest Boost release.
   will be excluded from function instantiations. Programs which set
   `deflateSupported` to `false` when instantiating streams will be smaller.
 
-* [issue 949] WebSocket error codes are revised. New
+* ([issue 949]) WebSocket error codes are revised. New
   [link beast.ref.boost__beast__websocket__error error codes]
   are added for more fine-grained failure outcomes. Messages for error
   codes are more verbose to help pinpoint the problem. Error codes are
@@ -56,11 +56,11 @@ to update to the latest Boost release.
 
 [*Improvements]
 
-* [issue 857]
+* ([issue 857])
   [link beast.ref.boost__beast__http__basic_fields `http::basic_fields`]
   uses less storage
 
-* [issue 894]
+* ([issue 894])
   [link beast.ref.boost__beast__http__basic_fields `http::basic_fields`]
   exception specifiers are provided
 
@@ -68,45 +68,47 @@ to update to the latest Boost release.
 
 * Add [include_file boost/beast/websocket/stream_fwd.hpp]
 
-* [issue 955] The asynchronous SSL detector example uses a stackless coroutine
+* ([issue 955]) The asynchronous SSL detector example uses a stackless coroutine
 
 * [link beast.ref.boost__beast__bind_handler `bind_handler`]
   works with boost placeholders
 
 * Examples set `reuse_address(true)`
 
+* ([issue 1026]) Advanced servers support clean shutdown via SIGINT or SIGTERM
+
 [*Fixes]
 
 * Fix "warning: ‘const’ type qualifier on return type has no effect"
 
-* [issue 916] Tidy up `ssl_stream` special members in
+* ([issue 916]) Tidy up `ssl_stream` special members in
   [source_file example/common/ssl_stream.hpp]
 
-* [issue 918] Calls to `<algorithm>` are protected from macros
+* ([issue 918]) Calls to `<algorithm>` are protected from macros
 
-* [issue 954] The control callback is invoked on the proper executor
+* ([issue 954]) The control callback is invoked on the proper executor
 
-* [issue 994] Fix iterator version of
+* ([issue 994]) Fix iterator version of
   [link beast.ref.boost__beast__http__basic_fields.erase.overload1 `http::basic_fields::erase`]
 
-* [issue 992] Fix use-after-move in example request handlers
+* ([issue 992]) Fix use-after-move in example request handlers
 
-* [issue 988] Type check completion handlers
+* ([issue 988]) Type check completion handlers
 
-* [issue 985] Tidy up
+* ([issue 985]) Tidy up
   [link beast.ref.boost__beast__bind_handler `bind_handler`]
   doc
 
 * Fix memory leak in advanced server examples
 
-* [issue 1000] Fix soft-mutex assert in websocket stream.
+* ([issue 1000]) Fix soft-mutex assert in websocket stream.
   This resolves the assert `"ws_.wr_block_ == tok_"`.
 
-* [issue 1019] Fix fallthrough warnings
+* ([issue 1019]) Fix fallthrough warnings
 
-* [issue 1024] Fix teardown for TIME_WAIT
+* ([issue 1024]) Fix teardown for TIME_WAIT
 
-* [issue 1030] Fix big-endian websocket masking
+* ([issue 1030]) Fix big-endian websocket masking
 
 [*API Changes]
 
@@ -126,19 +128,19 @@ to update to the latest Boost release.
   constructor signature for state objects used with `handler_ptr`
   to receive a `const` reference to the handler.
 
-* [issue 896]
+* ([issue 896])
   [link beast.ref.boost__beast__http__basic_fields `http::basic_fields`]
   does not support fancy pointers
 
 * [link beast.ref.boost__beast__http__parser `http::parser`]
   is no longer [*MoveConstructible]
 
-* [issue 930] `http::serializer::reader_impl` is deprecated and will
+* ([issue 930]) `http::serializer::reader_impl` is deprecated and will
   be removed in the next release. Actions required: Call
   [link beast.ref.boost__beast__http__serializer.writer_impl `http::serializer::writer_impl`]
   instead of `serializer::reader_impl`.
 
-* [issue 884] The __BodyReader__ and __BodyWriter__ concept constructor
+* ([issue 884]) The __BodyReader__ and __BodyWriter__ concept constructor
   requirements have changed. They now require the header and body
   elements to be passed as distinct
   [link beast.ref.boost__beast__http__header `http::header`]

example/advanced/server-flex/advanced_server_flex.cpp

@@ -23,6 +23,7 @@
 #include <boost/beast/version.hpp>
 #include <boost/asio/bind_executor.hpp>
 #include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/signal_set.hpp>
 #include <boost/asio/ssl/stream.hpp>
 #include <boost/asio/strand.hpp>
 #include <boost/asio/steady_timer.hpp>
@@ -1272,6 +1273,17 @@ int main(int argc, char* argv[])
         tcp::endpoint{address, port},
         doc_root)->run();
 
+    // Capture SIGINT and SIGTERM to perform a clean shutdown
+    boost::asio::signal_set signals(ioc, SIGINT, SIGTERM);
+    signals.async_wait(
+        [&](boost::system::error_code const&, int)
+        {
+            // Stop the `io_context`. This will cause `run()`
+            // to return immediately, eventually destroying the
+            // `io_context` and all of the sockets in it.
+            ioc.stop();
+        });
+
     // Run the I/O service on the requested number of threads
     std::vector<std::thread> v;
     v.reserve(threads - 1);
@@ -1283,5 +1295,11 @@ int main(int argc, char* argv[])
         });
     ioc.run();
 
+    // (If we get here, it means we got a SIGINT or SIGTERM)
+
+    // Block until all the threads exit
+    for(auto& t : v)
+        t.join();
+
     return EXIT_SUCCESS;
 }

example/advanced/server/advanced_server.cpp

@@ -19,6 +19,7 @@
 #include <boost/beast/version.hpp>
 #include <boost/asio/bind_executor.hpp>
 #include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/signal_set.hpp>
 #include <boost/asio/strand.hpp>
 #include <boost/asio/steady_timer.hpp>
 #include <boost/make_unique.hpp>
@@ -815,6 +816,17 @@ int main(int argc, char* argv[])
         tcp::endpoint{address, port},
         doc_root)->run();
 
+    // Capture SIGINT and SIGTERM to perform a clean shutdown
+    boost::asio::signal_set signals(ioc, SIGINT, SIGTERM);
+    signals.async_wait(
+        [&](boost::system::error_code const&, int)
+        {
+            // Stop the `io_context`. This will cause `run()`
+            // to return immediately, eventually destroying the
+            // `io_context` and all of the sockets in it.
+            ioc.stop();
+        });
+
     // Run the I/O service on the requested number of threads
     std::vector<std::thread> v;
     v.reserve(threads - 1);
@@ -826,5 +838,11 @@ int main(int argc, char* argv[])
         });
     ioc.run();
 
+    // (If we get here, it means we got a SIGINT or SIGTERM)
+
+    // Block until all the threads exit
+    for(auto& t : v)
+        t.join();
+
     return EXIT_SUCCESS;
 }