[esp32] Automatic CONFIG_LWIP_MAX_SOCKETS configuration based on component needs

esphome/components/api/__init__.py

@@ -155,6 +155,17 @@ def _validate_api_config(config: ConfigType) -> ConfigType:
     return config
 
 
+def _consume_api_sockets(config: ConfigType) -> ConfigType:
+    """Register socket needs for API component."""
+    from esphome.components import socket
+
+    # API needs 1 listening socket + typically 3 concurrent client connections
+    # (not max_connections, which is the upper limit rarely reached)
+    sockets_needed = 1 + 3
+    socket.consume_sockets(sockets_needed, "api")(config)
+    return config
+
+
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -222,6 +233,7 @@ CONFIG_SCHEMA = cv.All(
     ).extend(cv.COMPONENT_SCHEMA),
     cv.rename_key(CONF_SERVICES, CONF_ACTIONS),
     _validate_api_config,
+    _consume_api_sockets,
 )
 
 

esphome/components/esp32/__init__.py

@@ -1,3 +1,4 @@
+import contextlib
 from dataclasses import dataclass
 import itertools
 import logging
@@ -102,6 +103,10 @@ COMPILER_OPTIMIZATIONS = {
     "SIZE": "CONFIG_COMPILER_OPTIMIZATION_SIZE",
 }
 
+# Socket limit configuration for ESP-IDF
+# ESP-IDF CONFIG_LWIP_MAX_SOCKETS has range 1-253, default 10
+DEFAULT_MAX_SOCKETS = 10  # ESP-IDF default
+
 ARDUINO_ALLOWED_VARIANTS = [
     VARIANT_ESP32,
     VARIANT_ESP32C3,
@@ -855,6 +860,67 @@ async def to_code(config):
         add_idf_sdkconfig_option("CONFIG_LWIP_DNS_SUPPORT_MDNS_QUERIES", False)
     if not advanced.get(CONF_ENABLE_LWIP_BRIDGE_INTERFACE, False):
         add_idf_sdkconfig_option("CONFIG_LWIP_BRIDGEIF_MAX_PORTS", 0)
+
+    # Calculate and set CONFIG_LWIP_MAX_SOCKETS based on component needs
+    # Socket component tracks consumer needs via consume_sockets() called during config validation
+    # This code runs in to_code() after all components have registered their socket needs
+    # User-provided sdkconfig_options take precedence
+    from esphome.components.socket import KEY_SOCKET_CONSUMERS
+
+    # Check if user manually specified CONFIG_LWIP_MAX_SOCKETS
+    user_max_sockets = conf.get(CONF_SDKCONFIG_OPTIONS, {}).get(
+        "CONFIG_LWIP_MAX_SOCKETS"
+    )
+
+    socket_consumers: dict[str, int] = CORE.data.get(KEY_SOCKET_CONSUMERS, {})
+    total_sockets = sum(socket_consumers.values())
+    components_list = (
+        ", ".join(f"{name}={count}" for name, count in sorted(socket_consumers.items()))
+        if total_sockets > 0
+        else ""
+    )
+
+    if user_max_sockets is None:
+        # Auto-calculate based on component needs
+        # Use at least the ESP-IDF default (10), or the total needed by components
+        max_sockets = max(DEFAULT_MAX_SOCKETS, total_sockets)
+
+        if total_sockets > 0:
+            log_level = (
+                logging.INFO if max_sockets > DEFAULT_MAX_SOCKETS else logging.DEBUG
+            )
+            _LOGGER.log(
+                log_level,
+                "Setting CONFIG_LWIP_MAX_SOCKETS to %d (registered: %s)",
+                max_sockets,
+                components_list,
+            )
+
+        add_idf_sdkconfig_option("CONFIG_LWIP_MAX_SOCKETS", max_sockets)
+    else:
+        # User specified their own value - respect it
+        _LOGGER.info(
+            "Using user-provided CONFIG_LWIP_MAX_SOCKETS: %s",
+            user_max_sockets,
+        )
+
+        # Warn if user's value is less than what components need
+        if total_sockets > 0:
+            user_sockets_int = 0
+            with contextlib.suppress(ValueError, TypeError):
+                user_sockets_int = int(user_max_sockets)
+
+            if user_sockets_int < total_sockets:
+                _LOGGER.warning(
+                    "CONFIG_LWIP_MAX_SOCKETS is set to %d but your configuration needs %d sockets (registered: %s). "
+                    "You may experience socket exhaustion errors. Consider increasing to at least %d.",
+                    user_sockets_int,
+                    total_sockets,
+                    components_list,
+                    total_sockets,
+                )
+        # User's value already added via sdkconfig_options processing
+
     if advanced.get(CONF_EXECUTE_FROM_PSRAM, False):
         add_idf_sdkconfig_option("CONFIG_SPIRAM_FETCH_INSTRUCTIONS", True)
         add_idf_sdkconfig_option("CONFIG_SPIRAM_RODATA", True)

esphome/components/esp32_camera_web_server/__init__.py

@@ -1,6 +1,7 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.const import CONF_ID, CONF_MODE, CONF_PORT
+from esphome.types import ConfigType
 
 CODEOWNERS = ["@ayufan"]
 AUTO_LOAD = ["camera"]
@@ -13,13 +14,27 @@ Mode = esp32_camera_web_server_ns.enum("Mode")
 
 MODES = {"STREAM": Mode.STREAM, "SNAPSHOT": Mode.SNAPSHOT}
 
-CONFIG_SCHEMA = cv.Schema(
-    {
-        cv.GenerateID(): cv.declare_id(CameraWebServer),
-        cv.Required(CONF_PORT): cv.port,
-        cv.Required(CONF_MODE): cv.enum(MODES, upper=True),
-    },
-).extend(cv.COMPONENT_SCHEMA)
+
+def _consume_camera_web_server_sockets(config: ConfigType) -> ConfigType:
+    """Register socket needs for camera web server."""
+    from esphome.components import socket
+
+    # Each camera web server instance needs 1 listening socket + 1-2 client connections
+    sockets_needed = 2
+    socket.consume_sockets(sockets_needed, "esp32_camera_web_server")(config)
+    return config
+
+
+CONFIG_SCHEMA = cv.All(
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(CameraWebServer),
+            cv.Required(CONF_PORT): cv.port,
+            cv.Required(CONF_MODE): cv.enum(MODES, upper=True),
+        },
+    ).extend(cv.COMPONENT_SCHEMA),
+    _consume_camera_web_server_sockets,
+)
 
 
 async def to_code(config):

esphome/components/esphome/ota/__init__.py

@@ -103,7 +103,16 @@ def ota_esphome_final_validate(config):
         )
 
 
-CONFIG_SCHEMA = (
+def _consume_ota_sockets(config: ConfigType) -> ConfigType:
+    """Register socket needs for OTA component."""
+    from esphome.components import socket
+
+    # OTA needs 1 listening socket (client connections are temporary during updates)
+    socket.consume_sockets(1, "ota")(config)
+    return config
+
+
+CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
             cv.GenerateID(): cv.declare_id(ESPHomeOTAComponent),
@@ -130,7 +139,8 @@ CONFIG_SCHEMA = (
         }
     )
     .extend(BASE_OTA_SCHEMA)
-    .extend(cv.COMPONENT_SCHEMA)
+    .extend(cv.COMPONENT_SCHEMA),
+    _consume_ota_sockets,
 )
 
 FINAL_VALIDATE_SCHEMA = ota_esphome_final_validate

esphome/components/mdns/__init__.py

@@ -46,6 +46,19 @@ SERVICE_SCHEMA = cv.Schema(
     }
 )
 
+
+def _consume_mdns_sockets(config):
+    """Register socket needs for mDNS component."""
+    if config.get(CONF_DISABLED):
+        return config
+
+    from esphome.components import socket
+
+    # mDNS needs 2 sockets (IPv4 + IPv6 multicast)
+    socket.consume_sockets(2, "mdns")(config)
+    return config
+
+
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -55,6 +68,7 @@ CONFIG_SCHEMA = cv.All(
         }
     ),
     _remove_id_if_disabled,
+    _consume_mdns_sockets,
 )
 
 

esphome/components/mqtt/__init__.py

@@ -210,6 +210,15 @@ def validate_fingerprint(value):
     return value
 
 
+def _consume_mqtt_sockets(config):
+    """Register socket needs for MQTT component."""
+    from esphome.components import socket
+
+    # MQTT needs 1 socket for the broker connection
+    socket.consume_sockets(1, "mqtt")(config)
+    return config
+
+
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -306,6 +315,7 @@ CONFIG_SCHEMA = cv.All(
     ),
     validate_config,
     cv.only_on([PLATFORM_ESP32, PLATFORM_ESP8266, PLATFORM_BK72XX]),
+    _consume_mqtt_sockets,
 )
 
 

esphome/components/socket/__init__.py

@@ -1,3 +1,5 @@
+from collections.abc import Callable, MutableMapping
+
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.core import CORE
@@ -9,6 +11,32 @@ IMPLEMENTATION_LWIP_TCP = "lwip_tcp"
 IMPLEMENTATION_LWIP_SOCKETS = "lwip_sockets"
 IMPLEMENTATION_BSD_SOCKETS = "bsd_sockets"
 
+# Socket tracking infrastructure
+# Components register their socket needs and platforms read this to configure appropriately
+KEY_SOCKET_CONSUMERS = "socket_consumers"
+
+
+def consume_sockets(
+    value: int, consumer: str
+) -> Callable[[MutableMapping], MutableMapping]:
+    """Register socket usage for a component.
+
+    Args:
+        value: Number of sockets needed by the component
+        consumer: Name of the component consuming the sockets
+
+    Returns:
+        A validator function that records the socket usage
+    """
+
+    def _consume_sockets(config: MutableMapping) -> MutableMapping:
+        consumers: dict[str, int] = CORE.data.setdefault(KEY_SOCKET_CONSUMERS, {})
+        consumers[consumer] = consumers.get(consumer, 0) + value
+        return config
+
+    return _consume_sockets
+
+
 CONFIG_SCHEMA = cv.Schema(
     {
         cv.SplitDefault(

esphome/components/web_server/__init__.py

@@ -136,6 +136,18 @@ def _final_validate_sorting(config: ConfigType) -> ConfigType:
 
 FINAL_VALIDATE_SCHEMA = _final_validate_sorting
 
+
+def _consume_web_server_sockets(config: ConfigType) -> ConfigType:
+    """Register socket needs for web_server component."""
+    from esphome.components import socket
+
+    # Web server needs 1 listening socket + typically 2 concurrent client connections
+    # (browser makes 2 connections for page + event stream)
+    sockets_needed = 3
+    socket.consume_sockets(sockets_needed, "web_server")(config)
+    return config
+
+
 sorting_group = {
     cv.Required(CONF_ID): cv.declare_id(cg.int_),
     cv.Required(CONF_NAME): cv.string,
@@ -205,6 +217,7 @@ CONFIG_SCHEMA = cv.All(
     validate_local,
     validate_sorting_groups,
     validate_ota,
+    _consume_web_server_sockets,
 )