由于未在调试模式下运行，因此Flask会抑制您的（调试）日志消息。如果将以下标志设置为True，则代码将起作用。
app.run(debug=True)
这些消息现在将按预期显示。
BennyE$ python3 stackoverflow.py 2015-03-08 12:04:04,650 ERROR: firs test message... [in stackoverflow.py:31] * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit) * Restarting with stat2015-03-08 12:04:04,807 ERROR: firs test message... [in stackoverflow.py:31]--------------------------------------------------------------------------------DEBUG in stackoverflow [stackoverflow.py:11]:second test message...--------------------------------------------------------------------------------2015-03-08 12:04:13,789 DEBUG: second test message... [in stackoverflow.py:11]192.168.178.23 - - [08/Mar/2015 12:04:13] "GET / HTTP/1.1" 200 ---------------------------------------------------------------------------------DEBUG in stackoverflow [stackoverflow.py:11]:second test message...--------------------------------------------------------------------------------2015-03-08 12:04:14,899 DEBUG: second test message... [in stackoverflow.py:11]192.168.178.23 - - [08/Mar/2015 12:04:14] "GET / HTTP/1.1" 200 -
这是关联的输出文件中的输出：
BennyE$ cat output.log 2015-03-08 11:58:22,226 ERROR: firs test message... [in stackoverflow.py:31]2015-03-08 12:04:04,650 ERROR: firs test message... [in stackoverflow.py:31]2015-03-08 12:04:04,807 ERROR: firs test message... [in stackoverflow.py:31]2015-03-08 12:04:13,789 DEBUG: second test message... [in stackoverflow.py:11]2015-03-08 12:04:14,899 DEBUG: second test message... [in stackoverflow.py:11]
