今天在用uwsgi+nginx在部署flask应用时，遇到502的错误，vim /var/log/nginx/error.log查看nginx的错误日志，提示如下错误信息：
2018/07/22 00:46:36 [crit] 15890#15890: *74 connect() to unix:/root/jianshuvue/jianshu.sock failed (13: Permission denied) while connecting to upstream, client: 120.42.13.98, server: jianshu.weiweiblog.cn, request: "GET /favicon.ico HTTP/1.1", upstream: "uwsgi://unix:/root/jianshuvue/jianshu.sock:", host: "jianshu.weiweiblog.cn", referrer: "http://jianshu.weiweiblog.cn/jianshu/67eb7ed414d3"
Permission denied，一看就知道是权限出了问题，通过ps -ef | grep nginx,查看nginx的进程信息：
root 15889 1 0 00:01 ? 00:00:00 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
www-data 15890 15889 0 00:01 ? 00:00:00 nginx: worker process
root 16795 15654 0 00:48 pts/3 00:00:00 grep --color=auto nginx
发现nginx进程的用户是nginx，而我们创建/root/jianshuvue/jianshu.sock文件的用户是root，因此，只要把nginx的进程user改为root即可，vim /etc/nginx/nginx.conf:
1 # user www-data;
2 user root;
3 worker_processes auto;
4 pid /run/nginx.pid;
之后，/etc/init.d/nginx restart重启nginx，就可以正常访问网站了。
