feat: added signal handlers, gracefully shutdown, stacktrace on excep…

…tions, saving configs

.github/workflows/linux-build-test.yml

@@ -18,21 +18,21 @@ jobs:
         std: [ 17 ]
         include:
           - cxx: g++-9
-            other_pkgs: g++-9 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev
+            other_pkgs: g++-9 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev libboost-stacktrace-dev
           - cxx: g++-10
-            other_pkgs: g++-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev
+            other_pkgs: g++-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev libboost-stacktrace-dev
           - cxx: clang++-9
-            other_pkgs: clang-9 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev
+            other_pkgs: clang-9 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev libboost-stacktrace-dev
           - cxx: clang++-10
-            other_pkgs: clang-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev
+            other_pkgs: clang-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev libboost-stacktrace-dev
           - cxx: clang++-10
             build_type: Debug
             std: 17
-            other_pkgs: clang-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev
+            other_pkgs: clang-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev libboost-stacktrace-dev
           - cxx: clang++-10
             build_type: Release
             std: 17
-            other_pkgs: clang-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev
+            other_pkgs: clang-10 libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev libboost-stacktrace-dev
 
     steps:
       - uses: actions/checkout@v2

README.md

@@ -54,7 +54,7 @@ Unit tests will live under `tests/`, they'll be focused on testing the library p
 ## Dependencies
 
 ```
-cmake g++-10 gcc-10 libpipewire-0.3-dev libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev
+cmake g++-10 gcc-10 libpipewire-0.3-dev libboost-thread-dev libboost-filesystem-dev libboost-log-dev libssl-dev libboost-stacktrace-dev
 ```
 
 ## Acknowledgements

src/wolf/CMakeLists.txt

@@ -12,9 +12,31 @@ FetchContent_Declare(
 
 FetchContent_MakeAvailable(fmtlib)
 
-find_package(Boost REQUIRED COMPONENTS log_setup log)
+find_package(Boost
+        REQUIRED COMPONENTS
+        log_setup
+        log
+        stacktrace_basic)
 include_directories(${Boost_INCLUDE_DIRS})
 
+
+### Boost stacktrace exception handling
+# adapted from https://github.com/jschueller/boost-stacktrace-example/blob/master/CMakeLists.txt
+# also see: https://www.boost.org/doc/libs/develop/doc/html/stacktrace/configuration_and_build.html
+find_library(BOOST_STACKTRACE_BACKTRACE_LIBRARY NAMES boost_stacktrace_backtrace)
+if (UNIX)
+    message(STATUS "Using Boost::stacktrace/addr2line")
+    add_definitions(-D_GNU_SOURCE=1)
+    target_compile_definitions(wolf PRIVATE BOOST_STACKTRACE_USE_ADDR2LINE)
+    target_link_libraries(wolf PRIVATE dl)
+elseif (MINGW AND BOOST_STACKTRACE_BACKTRACE_LIBRARY)
+    message(STATUS "Using Boost::stacktrace/backtrace")
+    target_compile_definitions(wolf PRIVATE BOOST_STACKTRACE_USE_BACKTRACE)
+    target_link_libraries(wolf PRIVATE boost_stacktrace_backtrace backtrace)
+else ()
+    message(STATUS "Using Boost::stacktrace/basic")
+endif ()
+
 # Some libraries don't work with FetchContent_Declare out of the box
 # We have to manually git clone them and adding them into `libraries`
 target_include_directories(wolf PRIVATE libraries .)

src/wolf/rest/servers.cpp

@@ -14,28 +14,6 @@ using HttpServer = SimpleWeb::Server<SimpleWeb::HTTP>;
 
 namespace HTTPServers {
 
-/**
- * @brief Create an HTTPS server
- *
- * @param pkey_filename
- * @param cert_filename
- * @return std::unique_ptr<HttpsServer>
- */
-std::unique_ptr<HttpsServer> createHTTPS(const std::string &pkey_filename,
-                                         const std::string &cert_filename,
-                                         const std::shared_ptr<moonlight::Config> &config) {
-  return std::make_unique<HttpsServer>(cert_filename, pkey_filename, config);
-}
-
-/**
- * @brief Create an HTTP server
- *
- * @return std::unique_ptr<HttpServer>
- */
-std::unique_ptr<HttpServer> createHTTP() {
-  return std::make_unique<HttpServer>();
-}
-
 /**
  * @brief Start the generic server on the specified port
  * @return std::thread: the thread where this server will run

src/wolf/wolf.cpp

@@ -1,9 +1,11 @@
-#include <vector>
-
+#include <boost/filesystem.hpp>
+#include <boost/stacktrace.hpp>
+#include <csignal>
 #include <helpers/logger.hpp>
 #include <moonlight/config.hpp>
 #include <moonlight/data-structures.hpp>
 #include <rest/servers.cpp>
+#include <vector>
 
 /**
  * @brief Will try to load the config file and fallback to defaults
@@ -58,17 +60,45 @@ initialize(const std::string &config_file, const std::string &pkey_filename, con
   return std::make_shared<LocalState>(state);
 }
 
+/**
+ * Taken from: https://stackoverflow.com/questions/11468414/using-auto-and-lambda-to-handle-signal
+ * in order to have pass a lambda with variable capturing
+ */
+namespace {
+std::function<void(int)> shutdown_handler;
+void signal_handler(int signal) {
+  shutdown_handler(signal);
+}
+} // namespace
+
+/**
+ * @brief: if an exception was raised we should have created a dump file, here we can pretty print it
+ */
+void check_exceptions() {
+  if (boost::filesystem::exists("./backtrace.dump")) {
+    std::ifstream ifs("./backtrace.dump");
+
+    auto st = boost::stacktrace::stacktrace::from_dump(ifs);
+    logs::log(logs::error, "Previous run crashed: \n{}", to_string(st));
+
+    // cleaning up
+    ifs.close();
+    boost::filesystem::remove("./backtrace.dump");
+  }
+}
+
 /**
  * @brief here's where the magic starts
  */
 int main(int argc, char *argv[]) {
   logs::init(logs::trace);
+  check_exceptions();
 
   auto config_file = "config.json";
   auto local_state = initialize(config_file, "key.pem", "cert.pem");
 
-  auto https_server = HTTPServers::createHTTPS("key.pem", "cert.pem", local_state->config);
-  auto http_server = HTTPServers::createHTTP();
+  auto https_server = std::make_unique<HttpsServer>("cert.pem", "key.pem", local_state->config);
+  auto http_server = std::make_unique<HttpServer>();
 
   auto https_thread = HTTPServers::startServer(https_server.get(),
                                                *local_state,
@@ -77,12 +107,26 @@ int main(int argc, char *argv[]) {
                                               *local_state,
                                               local_state->config->map_port(moonlight::Config::HTTP_PORT));
 
-  https_thread.join();
-  http_thread.join();
+  // Exception and termination handling
+  shutdown_handler = [&](int signum) {
+    logs::log(logs::info, "Received interrupt signal {}, clean exit", signum);
+    if (signum == SIGABRT || signum == SIGSEGV) {
+      auto trace_file = "./backtrace.dump";
+      logs::log(logs::info, "Dumping stacktrace to {}", trace_file);
+      boost::stacktrace::safe_dump_to(trace_file);
+    }
+
+    logs::log(logs::info, "Saving back current configuration to file: {}", config_file);
+    local_state->config->saveCurrentConfig(config_file);
 
-  // TODO: clean exit
+    exit(signum);
+  };
+  std::signal(SIGINT, signal_handler);
+  std::signal(SIGTERM, signal_handler);
+  std::signal(SIGQUIT, signal_handler);
+  std::signal(SIGSEGV, signal_handler);
+  std::signal(SIGABRT, signal_handler);
 
-  logs::log(logs::info, "Saving back current configuration to file: {}", config_file);
-  local_state->config->saveCurrentConfig(config_file);
-  return 0;
+  https_thread.join();
+  http_thread.join();
 }