Added timeout for TCP calls such as connect, send, recv (#3432)

* Now lets test on windows

* I guess testing on windows passes.

* Update tcp_client-windows.h

Added default value to argument

* Final edit

* Update tcp_client-windows.h

Changed improper misplaced includes.

include/spdlog/details/tcp_client-windows.h

@@ -58,8 +58,81 @@ public:
 
     SOCKET fd() const { return socket_; }
     
+    int connect_socket_with_timeout(SOCKET sockfd,
+                                    const struct sockaddr *addr,
+                                    int addrlen,
+                                    const timeval &tv) {
+        // If no timeout requested, do a normal blocking connect.
+        if (tv.tv_sec == 0 && tv.tv_usec == 0) {
+            int rv = ::connect(sockfd, addr, addrlen);
+            if (rv == SOCKET_ERROR && WSAGetLastError() == WSAEISCONN) {
+                return 0;
+            }
+            return rv;
+        }
+
+        // Switch to non‐blocking mode
+        u_long mode = 1UL;
+        if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        int rv = ::connect(sockfd, addr, addrlen);
+        int last_error = WSAGetLastError();
+        if (rv == 0 || last_error == WSAEISCONN) {
+            mode = 0UL;
+            if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+                return SOCKET_ERROR;
+            }
+            return 0;
+        }
+        if (last_error != WSAEWOULDBLOCK) {
+            // Real error
+            mode = 0UL;
+            if (::ioctlsocket(sockfd, FIONBIO, &mode)) {
+                return SOCKET_ERROR;
+            }
+            return SOCKET_ERROR;
+        }
+
+        // Wait until socket is writable or timeout expires
+        fd_set wfds;
+        FD_ZERO(&wfds);
+        FD_SET(sockfd, &wfds);
+
+        rv = ::select(0, nullptr, &wfds, nullptr, const_cast<timeval *>(&tv));
+
+        // Restore blocking mode regardless of select result
+        mode = 0UL;
+        if (::ioctlsocket(sockfd, FIONBIO, &mode) == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        if (rv == 0) {
+            WSASetLastError(WSAETIMEDOUT);
+            return SOCKET_ERROR;
+        }
+        if (rv == SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+
+        int so_error = 0;
+        int len = sizeof(so_error);
+        if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, reinterpret_cast<char *>(&so_error), &len) ==
+            SOCKET_ERROR) {
+            return SOCKET_ERROR;
+        }
+        if (so_error != 0 && so_error != WSAEISCONN) {
+            // connection failed
+            WSASetLastError(so_error);
+            return SOCKET_ERROR;
+        }
+
+        return 0;  // success
+    }
+
     // try to connect or throw on failure
-    void connect(const std::string &host, int port) {
+    void connect(const std::string &host, int port, int timeout_ms = 0) {
         if (is_connected()) {
             close();
         }
@@ -71,6 +144,10 @@ public:
         hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
         hints.ai_protocol = 0;
 
+        timeval tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+
         auto port_str = std::to_string(port);
         struct addrinfo *addrinfo_result;
         auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
@@ -82,7 +159,6 @@ public:
         }
 
         // Try each address until we successfully connect(2).
-
         for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next) {
             socket_ = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
             if (socket_ == INVALID_SOCKET) {
@@ -90,18 +166,24 @@ public:
                 WSACleanup();
                 continue;
             }
-            if (::connect(socket_, rp->ai_addr, (int)rp->ai_addrlen) == 0) {
+            if (connect_socket_with_timeout(socket_, rp->ai_addr, (int)rp->ai_addrlen, tv) == 0) {
+                last_error = 0;
                 break;
-            } else {
-                last_error = ::WSAGetLastError();
-                close();
             }
+            last_error = WSAGetLastError();
+            ::closesocket(socket_);
+            socket_ = INVALID_SOCKET;
         }
         ::freeaddrinfo(addrinfo_result);
         if (socket_ == INVALID_SOCKET) {
             WSACleanup();
             throw_winsock_error_("connect failed", last_error);
         }
+        if (timeout_ms > 0) {
+            DWORD tv = static_cast<DWORD>(timeout_ms);
+            ::setsockopt(socket_, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof(tv));
+            ::setsockopt(socket_, SOL_SOCKET, SO_SNDTIMEO, (const char *)&tv, sizeof(tv));
+        }
 
         // set TCP_NODELAY
         int enable_flag = 1;

include/spdlog/details/tcp_client.h

@@ -39,8 +39,72 @@ public:
 
     ~tcp_client() { close(); }
 
+    int connect_socket_with_timeout(int sockfd,
+                                    const struct sockaddr *addr,
+                                    socklen_t addrlen,
+                                    const timeval &tv) {
+        // Blocking connect if timeout is zero
+        if (tv.tv_sec == 0 && tv.tv_usec == 0) {
+            int rv = ::connect(sockfd, addr, addrlen);
+            if (rv < 0 && errno == EISCONN) {
+                // already connected, treat as success
+                return 0;
+            }
+            return rv;
+        }
+
+        // Non-blocking path
+        int orig_flags = ::fcntl(sockfd, F_GETFL, 0);
+        if (orig_flags < 0) {
+            return -1;
+        }
+        if (::fcntl(sockfd, F_SETFL, orig_flags | O_NONBLOCK) < 0) {
+            return -1;
+        }
+
+        int rv = ::connect(sockfd, addr, addrlen);
+        if (rv == 0 || (rv < 0 && errno == EISCONN)) {
+            // immediate connect or already connected
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return 0;
+        }
+        if (errno != EINPROGRESS) {
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return -1;
+        }
+
+        // wait for writability
+        fd_set wfds;
+        FD_ZERO(&wfds);
+        FD_SET(sockfd, &wfds);
+
+        struct timeval tv_copy = tv;
+        rv = ::select(sockfd + 1, nullptr, &wfds, nullptr, &tv_copy);
+        if (rv <= 0) {
+            // timeout or error
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            if (rv == 0) errno = ETIMEDOUT;
+            return -1;
+        }
+
+        // check socket error
+        int so_error = 0;
+        socklen_t len = sizeof(so_error);
+        if (::getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &so_error, &len) < 0) {
+            ::fcntl(sockfd, F_SETFL, orig_flags);
+            return -1;
+        }
+        ::fcntl(sockfd, F_SETFL, orig_flags);
+        if (so_error != 0 && so_error != EISCONN) {
+            errno = so_error;
+            return -1;
+        }
+
+        return 0;
+    }
+
     // try to connect or throw on failure
-    void connect(const std::string &host, int port) {
+    void connect(const std::string &host, int port, int timeout_ms = 0) {
         close();
         struct addrinfo hints {};
         memset(&hints, 0, sizeof(struct addrinfo));
@@ -49,6 +113,10 @@ public:
         hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
         hints.ai_protocol = 0;
 
+        struct timeval tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+
         auto port_str = std::to_string(port);
         struct addrinfo *addrinfo_result;
         auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
@@ -69,8 +137,9 @@ public:
                 last_errno = errno;
                 continue;
             }
-            rv = ::connect(socket_, rp->ai_addr, rp->ai_addrlen);
-            if (rv == 0) {
+            ::fcntl(socket_, F_SETFD, FD_CLOEXEC);
+            if (connect_socket_with_timeout(socket_, rp->ai_addr, rp->ai_addrlen, tv) == 0) {
+                last_errno = 0;
                 break;
             }
             last_errno = errno;
@@ -82,6 +151,12 @@ public:
             throw_spdlog_ex("::connect failed", last_errno);
         }
 
+        if (timeout_ms > 0) {
+            // Set timeouts for send and recv
+            ::setsockopt(socket_, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof(tv));
+            ::setsockopt(socket_, SOL_SOCKET, SO_SNDTIMEO, (const char *)&tv, sizeof(tv));
+        }
+
         // set TCP_NODELAY
         int enable_flag = 1;
         ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag),

include/spdlog/sinks/tcp_sink.h

@@ -31,6 +31,7 @@ namespace sinks {
 struct tcp_sink_config {
     std::string server_host;
     int server_port;
+    int timeout_ms = 0; // The timeout for all 3 major socket operations that is connect, send, and recv
     bool lazy_connect = false;  // if true connect on first log call instead of on construction
 
     tcp_sink_config(std::string host, int port)
@@ -44,10 +45,22 @@ public:
     // connect to tcp host/port or throw if failed
     // host can be hostname or ip address
 
+    explicit tcp_sink(const std::string &host,
+                      int port,
+                      int timeout_ms = 0,
+                      bool lazy_connect = false)
+        : config_{host, port} {
+        config_.timeout_ms = timeout_ms;
+        config_.lazy_connect = lazy_connect;
+        if (!config_.lazy_connect) {
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
+        }
+    }
+
     explicit tcp_sink(tcp_sink_config sink_config)
         : config_{std::move(sink_config)} {
         if (!config_.lazy_connect) {
-            this->client_.connect(config_.server_host, config_.server_port);
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
         }
     }
 
@@ -58,7 +71,7 @@ protected:
         spdlog::memory_buf_t formatted;
         spdlog::sinks::base_sink<Mutex>::formatter_->format(msg, formatted);
         if (!client_.is_connected()) {
-            client_.connect(config_.server_host, config_.server_port);
+            client_.connect(config_.server_host, config_.server_port, config_.timeout_ms);
         }
         client_.send(formatted.data(), formatted.size());
     }