Merge branch 'fix_watchdog_reset_idf_web_server' into integration

esphome/components/web_server/web_server.cpp

@@ -127,6 +127,10 @@ void DeferredUpdateEventSource::process_deferred_queue_() {
       deferred_queue_.erase(deferred_queue_.begin());
       this->consecutive_send_failures_ = 0;  // Reset failure count on successful send
     } else {
+      // NOTE: Similar logic exists in web_server_idf/web_server_idf.cpp in AsyncEventSourceResponse::process_buffer_()
+      // The implementations differ due to platform-specific APIs (DISCARDED vs HTTPD_SOCK_ERR_TIMEOUT, close() vs
+      // fd_.store(0)), but the failure counting and timeout logic should be kept in sync. If you change this logic,
+      // also update the ESP-IDF implementation.
       this->consecutive_send_failures_++;
       if (this->consecutive_send_failures_ >= MAX_CONSECUTIVE_SEND_FAILURES) {
         // Too many failures, connection is likely dead

esphome/components/web_server_idf/web_server_idf.cpp

@@ -4,6 +4,8 @@
 #include <memory>
 #include <cstring>
 #include <cctype>
+#include <sys/socket.h>
+#include <errno.h>
 
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
@@ -46,6 +48,28 @@ DefaultHeaders default_headers_instance;
 
 DefaultHeaders &DefaultHeaders::Instance() { return default_headers_instance; }
 
+namespace {
+// Non-blocking send function to prevent watchdog timeouts when TCP buffers are full
+int nonblocking_send(httpd_handle_t hd, int sockfd, const char *buf, size_t buf_len, int flags) {
+  if (buf == nullptr) {
+    return HTTPD_SOCK_ERR_INVALID;
+  }
+
+  // Use MSG_DONTWAIT to prevent blocking when TCP send buffer is full
+  int ret = send(sockfd, buf, buf_len, flags | MSG_DONTWAIT);
+  if (ret < 0) {
+    if (errno == EAGAIN || errno == EWOULDBLOCK) {
+      // Buffer full - retry later
+      return HTTPD_SOCK_ERR_TIMEOUT;
+    }
+    // Real error
+    ESP_LOGD(TAG, "send error: errno %d", errno);
+    return HTTPD_SOCK_ERR_FAIL;
+  }
+  return ret;
+}
+}  // namespace
+
 void AsyncWebServer::end() {
   if (this->server_) {
     httpd_stop(this->server_);
@@ -384,6 +408,9 @@ AsyncEventSourceResponse::AsyncEventSourceResponse(const AsyncWebServerRequest *
   this->hd_ = req->handle;
   this->fd_.store(httpd_req_to_sockfd(req));
 
+  // Use non-blocking send to prevent watchdog timeouts when TCP buffers are full
+  httpd_sess_set_send_override(this->hd_, this->fd_.load(), nonblocking_send);
+
   // Configure reconnect timeout and send config
   // this should always go through since the tcp send buffer is empty on connect
   std::string message = ws->get_config_json();
@@ -459,15 +486,45 @@ void AsyncEventSourceResponse::process_buffer_() {
     return;
   }
 
-  int bytes_sent = httpd_socket_send(this->hd_, this->fd_.load(), event_buffer_.c_str() + event_bytes_sent_,
-                                     event_buffer_.size() - event_bytes_sent_, 0);
-  if (bytes_sent == HTTPD_SOCK_ERR_TIMEOUT || bytes_sent == HTTPD_SOCK_ERR_FAIL) {
-    // Socket error - just return, the connection will be closed by httpd
-    // and our destroy callback will be called
+  size_t remaining = event_buffer_.size() - event_bytes_sent_;
+  int bytes_sent =
+      httpd_socket_send(this->hd_, this->fd_.load(), event_buffer_.c_str() + event_bytes_sent_, remaining, 0);
+  if (bytes_sent == HTTPD_SOCK_ERR_TIMEOUT) {
+    // EAGAIN/EWOULDBLOCK - socket buffer full, try again later
+    // NOTE: Similar logic exists in web_server/web_server.cpp in DeferredUpdateEventSource::process_deferred_queue_()
+    // The implementations differ due to platform-specific APIs (HTTPD_SOCK_ERR_TIMEOUT vs DISCARDED, fd_.store(0) vs
+    // close()), but the failure counting and timeout logic should be kept in sync. If you change this logic, also
+    // update the Arduino implementation.
+    this->consecutive_send_failures_++;
+    if (this->consecutive_send_failures_ >= MAX_CONSECUTIVE_SEND_FAILURES) {
+      // Too many failures, connection is likely dead
+      ESP_LOGW(TAG, "Closing stuck EventSource connection after %" PRIu16 " failed sends",
+               this->consecutive_send_failures_);
+      this->fd_.store(0);  // Mark for cleanup
+      this->deferred_queue_.clear();
+    }
     return;
   }
+  if (bytes_sent == HTTPD_SOCK_ERR_FAIL) {
+    // Real socket error - connection will be closed by httpd and destroy callback will be called
+    return;
+  }
+  if (bytes_sent <= 0) {
+    // Unexpected error or zero bytes sent
+    ESP_LOGW(TAG, "Unexpected send result: %d", bytes_sent);
+    return;
+  }
+
+  // Successful send - reset failure counter
+  this->consecutive_send_failures_ = 0;
   event_bytes_sent_ += bytes_sent;
 
+  // Log partial sends for debugging
+  if (event_bytes_sent_ < event_buffer_.size()) {
+    ESP_LOGV(TAG, "Partial send: %d/%zu bytes (total: %zu/%zu)", bytes_sent, remaining, event_bytes_sent_,
+             event_buffer_.size());
+  }
+
   if (event_bytes_sent_ == event_buffer_.size()) {
     event_buffer_.resize(0);
     event_bytes_sent_ = 0;

esphome/components/web_server_idf/web_server_idf.h

@@ -283,6 +283,8 @@ class AsyncEventSourceResponse {
   std::unique_ptr<esphome::web_server::ListEntitiesIterator> entities_iterator_;
   std::string event_buffer_{""};
   size_t event_bytes_sent_;
+  uint16_t consecutive_send_failures_{0};
+  static constexpr uint16_t MAX_CONSECUTIVE_SEND_FAILURES = 2500;  // ~20 seconds at 125Hz loop rate
 };
 
 using AsyncEventSourceClient = AsyncEventSourceResponse;