记录程序详细异常信息到日志：

import sys
import traceback

try:
    asdf
except:
    exc_type, exc_value, exc_traceback = sys.exc_info()
    lines = traceback.format_exception(exc_type, exc_value, exc_traceback)
    exception_info = ''.join(lines)
    # 记录到日志（这里仅打印出）
    print exception_info