Yii 框架日誌功能全面解讀：配置、核心邏輯、多路由與擴充實戰

Yi 採分層日誌架構：CLogger 收集暫存記憶體，CLogRouter 於請求結束分發至多個處理器 (CFileLogRoute、CEmailLogRoute 等)。本文涵蓋頁面級日誌、Yii2 元件擴充、核心邏輯流程、多路由配置與自訂郵件日誌實戰。

頁面級日誌開啟 (Yii 1.x)

'log' => array(
    'class' => 'CLogRouter',
    'routes' => array(
        array(
            'class' => 'CFileLogRoute',
            'levels' => 'error, warning',
        ),
        array(
            'class' => 'CWebLogRoute',
            'levels' => 'trace',
            'categories' => 'system.db.*',
        ),
    ),
),

Yii2 日誌元件擴充：按等級分檔、日期前綴

namespace common\components;
use Yii;
use yii\helpers\FileHelper;
class FileTarget extends \yii\log\FileTarget {
    public $enableDatePrefix = false;
    public $enableCategoryDir = false;
    private $_logFilePath = '';
    public function init() {
        if ($this->logFile === null) {
            $this->logFile = Yii::$app->getRuntimePath() . '/logs/app.log';
        } else {
            $this->logFile = Yii::getAlias($this->logFile);
        }
        $this->_logFilePath = dirname($this->logFile);
        if ($this->enableDatePrefix) {
            $filename = basename($this->logFile);
            $this->logFile = $this->_logFilePath . '/' . date('Ymd') . '_' . $filename;
        }
        if (!is_dir($this->_logFilePath)) {
            FileHelper::createDirectory($this->_logFilePath, $this->dirMode, true);
        }
        if ($this->maxLogFiles < 1) $this->maxLogFiles = 1;
        if ($this->maxFileSize < 1) $this->maxFileSize = 1;
    }
}

配置範例：四等級分檔、每日輪轉、含請求變數

'log' => [
    'traceLevel' => YII_DEBUG ? 3 : 0,
    'targets' => [
        ['class' => 'common\components\FileTarget', 'levels' => ['error'], 'logVars' => ['_GET','_POST','_FILES','_COOKIE','_SESSION','_SERVER'], 'logFile' => '@app/runtime/logs/error/app.log', 'enableDatePrefix' => true, 'maxFileSize' => 1024, 'maxLogFiles' => 100],
        ['class' => 'common\components\FileTarget', 'levels' => ['warning'], 'logVars' => ['_GET','_POST','_FILES','_COOKIE','_SESSION','_SERVER'], 'logFile' => '@app/runtime/logs/warning/app.log', 'enableDatePrefix' => true, 'maxFileSize' => 1024, 'maxLogFiles' => 100],
        ['class' => 'common\components\FileTarget', 'levels' => ['info'], 'logVars' => ['_GET','_POST','_FILES','_COOKIE','_SESSION','_SERVER'], 'logFile' => '@app/runtime/logs/info/app.log', 'enableDatePrefix' => true, 'maxFileSize' => 1024, 'maxLogFiles' => 100],
        ['class' => 'common\components\FileTarget', 'levels' => ['trace'], 'logVars' => ['_GET','_POST','_FILES','_COOKIE','_SESSION','_SERVER'], 'logFile' => '@app/runtime/logs/trace/app.log', 'enableDatePrefix' => true, 'maxFileSize' => 1024, 'maxLogFiles' => 100],
    ],
],

Yii 1.x 日誌核心邏輯

收集階段

Yii::log($message, CLogger::LEVEL_ERROR, $category);

1. 產生 CLogger 實例
2. YII_DEBUG 且非 profile 等級 → 產生回溯資訊附加
3. CLogger::log() 暫存記憶體

寫入時機

CLogRouter::init() 綁定兩事件：

• Yii::getLogger()->onFlush → collectLogs() (記憶體超量時刷新)
• Yii::app()->onEndRequest → processLogs() (請求結束處理)

CApplication::run() 結束呼叫 onEndRequest 觸發寫入。

處理流程

1. CLogRouter::processLogs() 遍歷路由
2. 各路由 collectLogs($levels, $categories) 從 Logger 取得並過濾
3. processLogs($logs) 實際寫入 (檔案、資料庫、郵件等)

CFileLogRoute 內建日誌輪轉 (LogRotate) 功能。

多路由實戰：資料庫錯誤郵件通知 + 檔案記錄

自訂郵件路由類別

class myEmailLogRoute extends CEmailLogRoute {
    // 重寫 sendEmail() 使用 SMTP 驗證發送
}

配置雙路由

'log' => array(
    'class' => 'CLogRouter',
    'routes' => array(
        array('class' => 'CFileLogRoute', 'levels' => 'error, warning, trace'),
        array(
            'class' => 'myEmailLogRoute',
            'levels' => 'error',
            'categories' => 'exception.CDbException',
            'host' => 'mail.163.com',
            'port' => 25,
            'user' => 'jeff_yu',
            'password' => 'your_password',
            'timeout' => 30,
            'emails' => 'jeff_yu@gmail.com',
            'sentFrom' => 'jeff_yu@gmail.com',
        ),
    ),
),

同一份日誌可同時寫檔、發郵件、存資料庫，極具彈性。