When uwsgi is deployed to nginx, invalid request block size: 4161 (max 4096) appears)

 

After using Flask to create a web platform, log on to openid and deploy it on nginx using the uwsgi service. There is no problem in running, but the error 502 occurs occasionally during login, generally, after successful login, no subsequent operations will go wrong.

After viewing the uwsgi log, it is found that the following error occurs:

Invalid request block size: 4161 (max 4096)... skip

Cause: by default, uwsgi allocates a small buffer (4 k) to receive the header information of each request. If "invalid request block size" is displayed in the log ", it means you need a larger buffer.

The problem is that the url address contains more than 4096 characters, and 4096 is the default value of buffer-size in uwsgi configuration. Therefore, you only need to increase the buffer-size.

I use uwsgi-x to specify the uwsgi configuration file to start the server. Therefore, you only need to modify it to the following method:

Uwsgi-x platform. uwsgi. xml -- buffer-size 32768

To modify the parameters, run the following command for uwsgi:

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Uwsgi-B 8192

You can also modify the uwsgi startup configuration file, such as uwsgi. ini, to add the following configuration:

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Buffer-size = 8192

The problem is basically solved. Why does this problem happen occasionally? This is because the openid will carry a parameter named next_url during login, which is used to specify the address to return after successful login. If this next_url is too long, it will cause the url address to exceed 4096, sometimes next_url =/, that is, the root address of the website, the url length will not exceed 4096. It is also related to the length of login information returned by openid. As a result, some people will never see this error, and some may occasionally encounter this problem.