默认的日志格式：

'$remote_addr - $remote_user [$time_local] "$request" '

'$status $body_bytes_sent "$http_referer" ''"$http_user_agent" "$http_x_forwarded_for"';

由于默认的日志格式不能满足日常查看需要求，对其进行调整

修改后的日志格式：

'$remote_addr - $remote_user [$time_local] $request_time $request_method "$request_uri" $http_host '

'$status $body_bytes_sent $upstream_response_time $upstream_addr $upstream_status "$http_referer" $request_body''"$http_user_agent" "$http_x_forwarded_for" ';

json日志格式:

log_format json '{"remote_addr":"$remote_addr",'                 '"remote_user":"$remote_user",'                 '"access_time":"$time_local",'                 '"request_method":"$request_method",'                 '"request_uri":"$request_uri",'                 '"http_host":"$http_host",'                 '"status":"$status",'                 '"body_bytes_sent":"$body_bytes_sent",'                 '"request_time":"$request_time",'                 '"status":"$status",'                 '"up_response_time":"$upstream_response_time",'                 '"up_addr":"$upstream_addr",'                 '"up_status":"$upstream_status",'                 '"http_referrer":"$http_referer",'                 '"agent":"$http_user_agent",'                 '"http_x_forwarded_for":"$http_x_forwarded_for"}';