Implement receiving of CAN messages via MQTT

This is mainly intended for debugging.

Author: ranma

include/BatteryCanReceiver.h

@@ -4,6 +4,7 @@
 #include "Battery.h"
 #include <driver/twai.h>
 #include <Arduino.h>
+#include <espMqttClient.h>
 
 class BatteryCanReceiver : public BatteryProvider {
 public:
@@ -26,4 +27,14 @@ class BatteryCanReceiver : public BatteryProvider {
 
 private:
     char const* _providerName = "Battery CAN";
+
+    enum CanInterface {
+      kTwai,
+      kMqtt,
+    } _canInterface;
+    String _canTopic;
+
+    void postMessage(twai_message_t&& rx_message);
+    void onMqttMessageCAN(espMqttClientTypes::MessageProperties const& properties,
+            char const* topic, uint8_t const* payload, size_t len, size_t index, size_t total);
 };

include/Configuration.h

@@ -134,12 +134,14 @@ struct BATTERY_CONFIG_T {
     bool Enabled;
     bool VerboseLogging;
     uint8_t Provider;
+    uint8_t CanInterface;
     uint8_t JkBmsInterface;
     uint8_t JkBmsPollingInterval;
     char MqttSocTopic[MQTT_MAX_TOPIC_STRLEN + 1];
     char MqttSocJsonPath[BATTERY_JSON_MAX_PATH_STRLEN + 1];
     char MqttVoltageTopic[MQTT_MAX_TOPIC_STRLEN + 1];
     char MqttVoltageJsonPath[BATTERY_JSON_MAX_PATH_STRLEN + 1];
+    char MqttCANTopic[MQTT_MAX_TOPIC_STRLEN + 1];
     BatteryVoltageUnit MqttVoltageUnit;
     bool EnableDischargeCurrentLimit;
     float DischargeCurrentLimit;

include/defaults.h

@@ -154,6 +154,8 @@
 #define BATTERY_ENABLE_DISCHARGE_CURRENT_LIMIT false
 #define BATTERY_DISCHARGE_CURRENT_LIMIT 0
 #define BATTERY_USE_BATTERY_REPORTED_DISCHARGE_CURRENT_LIMIT false
+#define BATTERY_CAN_INTERFACE 0
+#define BATTERY_CAN_TOPIC "debug/battery/can/message"
 
 #define HUAWEI_ENABLED false
 #define HUAWEI_CAN_CONTROLLER_FREQUENCY 8000000UL

src/BatteryCanReceiver.cpp

@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
+#include "Configuration.h"
 #include "BatteryCanReceiver.h"
+#include "MqttSettings.h"
 #include "MessageOutput.h"
 #include "PinMapping.h"
 #include <driver/twai.h>
@@ -12,6 +14,24 @@ bool BatteryCanReceiver::init(bool verboseLogging, char const* providerName)
     MessageOutput.printf("[%s] Initialize interface...\r\n",
             _providerName);
 
+    auto const& config = Configuration.get();
+    _canTopic = config.Battery.MqttCANTopic;
+    _canInterface = static_cast<enum CanInterface>(config.Battery.CanInterface);
+    if (_canInterface == kMqtt) {
+        MqttSettings.subscribe(_canTopic, 0/*QoS*/,
+                std::bind(&BatteryCanReceiver::onMqttMessageCAN,
+                    this, std::placeholders::_1, std::placeholders::_2,
+                    std::placeholders::_3, std::placeholders::_4,
+                    std::placeholders::_5, std::placeholders::_6)
+                );
+
+        if (_verboseLogging) {
+            MessageOutput.printf("BatteryCanReceiver: Subscribed to '%s' for CAN messages\r\n",
+                _canTopic.c_str());
+        }
+        return true;
+    }
+
     const PinMapping_t& pin = PinMapping.get();
     MessageOutput.printf("[%s] Interface rx = %d, tx = %d\r\n",
             _providerName, pin.battery_rx, pin.battery_tx);
@@ -82,6 +102,11 @@ bool BatteryCanReceiver::init(bool verboseLogging, char const* providerName)
 
 void BatteryCanReceiver::deinit()
 {
+    if (_canInterface == kMqtt) {
+        MqttSettings.unsubscribe(_canTopic);
+        return;
+    }
+
     // Stop TWAI driver
     esp_err_t twaiLastResult = twai_stop();
     switch (twaiLastResult) {
@@ -111,6 +136,10 @@ void BatteryCanReceiver::deinit()
 
 void BatteryCanReceiver::loop()
 {
+    if (_canInterface == kMqtt) {
+        return;  // Mqtt CAN messages are event-driven
+    }
+
     // Check for messages. twai_receive is blocking when there is no data so we return if there are no frames in the buffer
     twai_status_info_t status_info;
     esp_err_t twaiLastResult = twai_get_status_info(&status_info);
@@ -139,6 +168,80 @@ void BatteryCanReceiver::loop()
         return;
     }
 
+    postMessage(std::move(rx_message));
+}
+
+
+void BatteryCanReceiver::onMqttMessageCAN(espMqttClientTypes::MessageProperties const& properties,
+        char const* topic, uint8_t const* payload, size_t len, size_t index, size_t total)
+{
+    std::string value(reinterpret_cast<const char*>(payload), len);
+    JsonDocument json;
+
+    auto log = [this, topic](char const* format, auto&&... args) -> void {
+        MessageOutput.printf("[%s] Topic '%s': ", _providerName, topic);
+        MessageOutput.printf(format, args...);
+        MessageOutput.println();
+    };
+
+    const DeserializationError error = deserializeJson(json, value);
+    if (error) {
+        log("cannot parse payload '%s' as JSON", value.c_str());
+        return;
+    }
+
+    if (json.overflowed()) {
+        log("payload too large to process as JSON");
+        return;
+    }
+
+    int canID = json["id"] | -1;
+    if (canID == -1) {
+        log("JSON is missing message id");
+        return;
+    }
+
+    twai_message_t rx_message = {};
+    rx_message.identifier = canID;
+    int maxLen = sizeof(rx_message.data);
+
+    JsonVariant canData = json["data"];
+    if (canData.isNull()) {
+        log("JSON is missing message data");
+        return;
+    }
+
+    if (canData.is<char const*>()) {
+      String strData = canData.as<String>();
+      int len = strData.length();
+      if (len > maxLen) {
+          log("JSON data has more than %d elements", maxLen);
+          return;
+      }
+
+      rx_message.data_length_code = len;
+      for (int i = 0; i < len; i++) {
+        rx_message.data[i] = strData[i];
+      }
+    } else {
+      JsonArray arrayData = canData.as<JsonArray>();
+      int len = arrayData.size();
+      if (len > maxLen) {
+          log("JSON data has more than %d elements", maxLen);
+          return;
+      }
+
+      rx_message.data_length_code = len;
+      for (int i = 0; i < len; i++) {
+        rx_message.data[i] = arrayData[i];
+      }
+    }
+
+    postMessage(std::move(rx_message));
+}
+
+void BatteryCanReceiver::postMessage(twai_message_t&& rx_message)
+{
     if (_verboseLogging) {
         MessageOutput.printf("[%s] Received CAN message: 0x%04X -",
                 _providerName, rx_message.identifier);

src/Configuration.cpp

@@ -92,6 +92,8 @@ void ConfigurationClass::serializeBatteryConfig(BatteryConfig const& source, Jso
     target["mqtt_discharge_current_topic"] = config.Battery.MqttDischargeCurrentTopic;
     target["mqtt_discharge_current_json_path"] = config.Battery.MqttDischargeCurrentJsonPath;
     target["mqtt_amperage_unit"] = config.Battery.MqttAmperageUnit;
+    target["can_interface"] = config.Battery.CanInterface;
+    target["mqtt_can_topic"] = config.Battery.MqttCANTopic;
 }
 
 bool ConfigurationClass::write()
@@ -375,6 +377,8 @@ void ConfigurationClass::deserializeBatteryConfig(JsonObject const& source, Batt
     strlcpy(target.MqttSocJsonPath, source["mqtt_soc_json_path"] | source["mqtt_json_path"] | "", sizeof(config.Battery.MqttSocJsonPath)); // mqtt_soc_json_path was previously saved as mqtt_json_path. Be nice and also try old key.
     strlcpy(target.MqttVoltageTopic, source["mqtt_voltage_topic"] | "", sizeof(config.Battery.MqttVoltageTopic));
     strlcpy(target.MqttVoltageJsonPath, source["mqtt_voltage_json_path"] | "", sizeof(config.Battery.MqttVoltageJsonPath));
+    target.CanInterface = source["can_interface"] | BATTERY_CAN_INTERFACE;
+    strlcpy(target.MqttCANTopic, source["mqtt_can_topic"] | BATTERY_CAN_TOPIC, sizeof(config.Battery.MqttCANTopic));
     target.MqttVoltageUnit = source["mqtt_voltage_unit"] | BatteryVoltageUnit::Volts;
     target.EnableDischargeCurrentLimit = source["enable_discharge_current_limit"] | BATTERY_ENABLE_DISCHARGE_CURRENT_LIMIT;
     target.DischargeCurrentLimit = source["discharge_current_limit"] | BATTERY_DISCHARGE_CURRENT_LIMIT;

webapp/src/locales/de.json

@@ -664,6 +664,12 @@
     "batteryadmin": {
         "BatterySettings": "Batterie Einstellungen",
         "BatteryConfiguration": "Generelle Schnittstelleneinstellungen",
+        "CanConfiguration": "CAN Einstellungen",
+        "CanInterface": "Schnittstellentyp",
+        "CanInterfaceTwai": "CAN-Transceiver an der MCU",
+        "CanInterfaceMqtt": "MQTT Broker",
+        "CanMqttTopic": "Topic für CAN-Nachrichten",
+        "CanMqttTopicHint": "Nachrichten sollte im JSON-Format mit 'id' und 'data' feldern sein.",
         "EnableBattery": "Aktiviere Schnittstelle",
         "VerboseLogging": "@:base.VerboseLogging",
         "Provider": "Datenanbieter",

webapp/src/locales/en.json

@@ -666,6 +666,12 @@
     "batteryadmin": {
         "BatterySettings": "Battery Settings",
         "BatteryConfiguration": "General Interface Settings",
+        "CanConfiguration": "CAN Interface Settings",
+        "CanInterface": "Interface Type",
+        "CanInterfaceTwai": "CAN Transceiver on MCU",
+        "CanInterfaceMqtt": "MQTT Topic",
+        "CanMqttTopic": "CAN Message Topic",
+        "CanMqttTopicHint": "Messages should be JSON with 'id' and 'data' fields.",
         "EnableBattery": "Enable Interface",
         "VerboseLogging": "@:base.VerboseLogging",
         "Provider": "Data Provider",

webapp/src/types/BatteryConfig.ts

@@ -4,6 +4,8 @@ export interface BatteryConfig {
     provider: number;
     jkbms_interface: number;
     jkbms_polling_interval: number;
+    can_interface: number;
+    mqtt_can_topic: string;
     mqtt_soc_topic: string;
     mqtt_soc_json_path: string;
     mqtt_voltage_topic: string;

webapp/src/views/BatteryAdminView.vue

@@ -33,6 +33,40 @@
                 </div>
             </CardElement>
 
+            <CardElement
+                v-show="batteryConfigList.enabled && providerUsesCanList.includes(batteryConfigList.provider)"
+                :text="$t('batteryadmin.CanConfiguration')"
+                textVariant="text-bg-primary"
+                addSpace
+            >
+                <div class="row mb-3">
+                    <label class="col-sm-2 col-form-label">
+                        {{ $t('batteryadmin.CanInterface') }}
+                    </label>
+                    <div class="col-sm-10">
+                        <select class="form-select" v-model="batteryConfigList.can_interface">
+                            <option
+                                v-for="canInterface in canInterfaceTypeList"
+                                :key="canInterface.key"
+                                :value="canInterface.key"
+                            >
+                                {{ $t(`batteryadmin.CanInterface` + canInterface.value) }}
+                            </option>
+                        </select>
+                    </div>
+                </div>
+
+                <InputElement
+                    v-show="batteryConfigList.can_interface == 1"
+                    :label="$t('batteryadmin.CanMqttTopic')"
+                    v-model="batteryConfigList.mqtt_can_topic"
+                    type="text"
+                    maxlength="256"
+                >
+                    <div class="alert alert-secondary" role="alert" v-html="$t('batteryadmin.CanMqttTopicHint')"></div>
+                </InputElement>
+            </CardElement>
+
             <CardElement
                 v-show="batteryConfigList.enabled && batteryConfigList.provider == 1"
                 :text="$t('batteryadmin.JkBmsConfiguration')"
@@ -235,6 +269,11 @@ export default defineComponent({
                 { key: 4, value: 'PytesCan' },
                 { key: 5, value: 'SBSCan' },
             ],
+            providerUsesCanList: [0, 4, 5],
+            canInterfaceTypeList: [
+                { key: 0, value: 'Twai' },
+                { key: 1, value: 'Mqtt' },
+            ],
             jkBmsInterfaceTypeList: [
                 { key: 0, value: 'Uart' },
                 { key: 1, value: 'Transceiver' },