Add a method for the TERM signal handling (#475)

lib/inc/drogon/HttpAppFramework.h

@@ -1023,6 +1023,19 @@ class HttpAppFramework : public trantor::NonCopyable
      */
     virtual HttpAppFramework &setHomePage(const std::string &homePageFile) = 0;
 
+    /**
+     * @brief Set the TERM Signal Handler. This method provides a way to users
+     * for exiting program gracefully. When the TERM signal is received after
+     * app().run() is called, the handler is invoked. Drogon uses a default
+     * signal handler for the TERM signal, which calls the 'app().quit()' method
+     * when the TERM signal is received.
+     *
+     * @param handler
+     * @return HttpAppFramework&
+     */
+    virtual HttpAppFramework &setTermSignalHandler(
+        const std::function<void()> &handler) = 0;
+
     /// Get homepage, default is "index.html"
     /**
      * @note

lib/src/HttpAppFrameworkImpl.cc

@@ -105,15 +105,17 @@ std::string getVersion()
 {
     return DROGON_VERSION;
 }
+
 std::string getGitCommit()
 {
     return DROGON_VERSION_SHA1;
 }
+
 HttpResponsePtr defaultErrorHandler(HttpStatusCode code)
 {
     return std::make_shared<HttpResponseImpl>(code, CT_TEXT_HTML);
 }
-}  // namespace drogon
+
 static void godaemon(void)
 {
     printf("Initializing daemon mode\n");
@@ -151,6 +153,18 @@ static void godaemon(void)
 
     return;
 }
+
+static void TERMFunction(int sig)
+{
+    if (sig == SIGTERM)
+    {
+        LOG_WARN << "SIGTERM signal received.";
+        HttpAppFrameworkImpl::instance().getTermSignalHandler()();
+    }
+}
+
+}  // namespace drogon
+
 HttpAppFrameworkImpl::~HttpAppFrameworkImpl() noexcept
 {
 // Destroy the following objects before the loop destruction
@@ -413,7 +427,7 @@ void HttpAppFrameworkImpl::run()
         getLoop()->resetAfterFork();
 #endif
     }
-
+    signal(SIGTERM, TERMFunction);
     // set logger
     if (!logPath_.empty())
     {

lib/src/HttpAppFrameworkImpl.h

@@ -333,6 +333,16 @@ class HttpAppFrameworkImpl : public HttpAppFramework
     {
         return homePageFile_;
     }
+    virtual HttpAppFramework &setTermSignalHandler(
+        const std::function<void()> &handler) override
+    {
+        termSignalHandler_ = handler;
+        return *this;
+    }
+    const std::function<void()> &getTermSignalHandler() const
+    {
+        return termSignalHandler_;
+    }
     size_t getClientMaxBodySize() const
     {
         return clientMaxBodySize_;
@@ -536,6 +546,7 @@ class HttpAppFrameworkImpl : public HttpAppFramework
     size_t clientMaxMemoryBodySize_{64 * 1024};
     size_t clientMaxWebSocketMessageSize_{128 * 1024};
     std::string homePageFile_{"index.html"};
+    std::function<void()> termSignalHandler_{[]() { app().quit(); }};
     std::unique_ptr<SessionManager> sessionManagerPtr_;
     Json::Value jsonConfig_;
     HttpResponsePtr custom404_;

trantor

@@ -1 +1 @@
-Subproject commit 55232baacebb77036babfeb8c652420032241b01
+Subproject commit 3692af0ca6282854c26cf3deb9fe31d78e2434b0