services/gradio-logger.ts

/**
 * Gradio関連のログ出力を統一的に管理するロガー
 * JSON形式で構造化ログを出力
 */

/**
 * ログ用の時刻フォーマットを生成
 * @returns {string} YYYY/MM/DD HH:MM:SS形式の時刻文字列
 */
function getLogTimestamp(): string {
  // JST (Asia/Tokyo) タイムゾーンで日時を取得
  const now = new Date();
  const jstDate = new Date(now.toLocaleString('ja-JP', { timeZone: 'Asia/Tokyo' }));

  const year = jstDate.getFullYear();
  const month = String(jstDate.getMonth() + 1).padStart(2, '0');
  const day = String(jstDate.getDate()).padStart(2, '0');
  const hours = String(jstDate.getHours()).padStart(2, '0');
  const minutes = String(jstDate.getMinutes()).padStart(2, '0');
  const seconds = String(jstDate.getSeconds()).padStart(2, '0');
  return `${year}/${month}/${day} ${hours}:${minutes}:${seconds}`;
}

interface BaseLogData {
  timestamp: string;
  component: 'Pool' | 'API';
  event: string;
  userIdentifier?: string;
  backend?: string;
}

interface PoolLogData extends BaseLogData {
  component: 'Pool';
}

interface APILogData extends BaseLogData {
  component: 'API';
  endpoint?: string;
  apiName?: string;
  userEmail?: string;
}

interface ErrorLogData extends BaseLogData {
  errorType?: 'CONNECTION' | 'TRANSIENT' | 'PERMANENT';
  error?: string;
}

type LogData = PoolLogData | APILogData | ErrorLogData;

/**
 * [Pool]ログを出力
 */
function logPool(event: string, userIdentifier?: string, backend?: string): void {
  const logData: PoolLogData = {
    timestamp: getLogTimestamp(),
    component: 'Pool',
    event,
    ...(userIdentifier && { userIdentifier }),
    ...(backend && { backend }),
  };
  console.log(JSON.stringify(logData));
}

/**
 * エラーオブジェクトを文字列に変換
 * @param error - エラーオブジェクト
 * @returns エラー情報を含む文字列
 */
function serializeError(error: unknown): string {
  if (error instanceof Error) {
    const details: Record<string, unknown> = {
      message: error.message,
      name: error.name,
    };

    // エラーコード（ECONNREFUSED等）を取得
    if ('code' in error && error.code) {
      details.code = error.code;
    }

    // ステータスコード（HTTP 403等）を取得
    if ('status' in error && typeof error.status === 'number') {
      details.status = error.status;
    }

    // その他の有用なプロパティを取得
    if ('cause' in error && error.cause) {
      details.cause = String(error.cause);
    }

    return JSON.stringify(details);
  }

  if (typeof error === 'object' && error !== null) {
    try {
      return JSON.stringify(error);
    } catch {
      return String(error);
    }
  }

  return String(error);
}

/**
 * [Pool]エラーログを出力
 */
function logPoolError(
  event: string,
  error: unknown,
  errorType?: 'CONNECTION' | 'TRANSIENT' | 'PERMANENT',
  userIdentifier?: string,
  backend?: string,
): void {
  const logData: ErrorLogData = {
    timestamp: getLogTimestamp(),
    component: 'Pool',
    event,
    error: serializeError(error),
    ...(errorType && { errorType }),
    ...(userIdentifier && { userIdentifier }),
    ...(backend && { backend }),
  };
  console.error(JSON.stringify(logData));
}

/**
 * [API REQUEST]ログを出力
 */
function logAPIRequest(apiName: string, endpoint: string, userIdentifier: string, backend: string, userEmail?: string): void {
  const logData: APILogData = {
    timestamp: getLogTimestamp(),
    component: 'API',
    event: 'REQUEST',
    apiName,
    endpoint,
    userIdentifier,
    backend,
    ...(userEmail && { userEmail }),
  };
  console.log(JSON.stringify(logData));
}

/**
 * [API RESPONSE]ログを出力（成功時）
 */
function logAPIResponse(
  apiName: string,
  endpoint: string,
  userIdentifier: string,
  backend: string,
  durationMs: number,
  responseSizeMB: number,
  userEmail?: string,
): void {
  const logData = {
    timestamp: getLogTimestamp(),
    component: 'API',
    event: 'RESPONSE',
    apiName,
    endpoint,
    userIdentifier,
    backend,
    durationSec: Math.round(durationMs / 1000),
    responseSizeMB,
    ...(userEmail && { userEmail }),
    ...(responseSizeMB > 1 && { warning: 'Large response' }),
  };
  console.log(JSON.stringify(logData));
}

export const gradioLogger = {
  logPool,
  logPoolError,
  logAPIRequest,
  logAPIResponse,
};

// レガシーログ用にgetLogTimestampもエクスポート
export { getLogTimestamp };