Tomcat AccessLog 格式化

有的时候我们要使用日志分析工具对日志进行分析，需要对日志进行格式化，比如，要把accessLog格式化成这样的格式

c-ip s-ip x-InstancePort date time-taken x-Protocol cs-method cs-uri sc-status x-ResponseSize bytes x-Referrer x-UserAgent

在tomcat的conf/server.xml加入配置：

<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%{X-Real-IP}i %A %p %{yyyy-MM-dd HH:mm:ss}t %D %H %m %U %s %B %B %{Referer}i %{User-Agent}i" />

关于accessLog的官方说明，请看 http://tomcat.apache.org/tomcat-8.0-doc/config/valve.html#Access_Logging

常用配置如下：

%a - Remote IP address --远程IP地址
%A - Local IP address --本地IP地址
%b - Bytes sent, excluding HTTP headers, or '-' if zero --发送的字节数(Bytes sent), 不包括HTTP headers的字节，如果为0则展示'-'
%B - Bytes sent, excluding HTTP headers --发送的字节数(Bytes sent), 不包括HTTP headers的字节
%h - Remote host name (or IP address if enableLookups for the connector is false) --远程主机名称(如果resolveHosts为false则展示IP)
%H - Request protocol --请求协议
%l - Remote logical username from identd (always returns '-') --远程用户名，始终为'-'(Remote logical username from identd)
%m - Request method (GET, POST, etc.) --请求的方法(GET, POST等)
%p - Local port on which this request was received. See also %{xxx}p below. --接受请求的本地端口
%q - Query string (prepended with a '?' if it exists) --查询字符串，如果存在，有一个前置的'?'
%r - First line of the request (method and request URI) --请求的第一行(包括请求方法和请求的URI)
%s - HTTP status code of the response --response的HTTP状态码(200,404等)
%S - User session ID --用户的session ID
%t - Date and time, in Common Log Format --日期和时间，Common Log Format格式
%u - Remote user that was authenticated (if any), else '-' --被认证的远程用户, 不存在则展示'-'
%U - Requested URL path --请求URL路径
%v - Local server name --本地服务名
%D - Time taken to process the request, in millis --处理请求的时间，单位为毫秒
%T - Time taken to process the request, in seconds --处理请求的时间，单位为秒
%F - Time taken to commit the response, in millis --提交响应的时间，以毫秒为单位
%I - Current request thread name (can compare later with stacktraces) --当前请求的线程名

Access Log中也支持cookie，请求header，响应headers，Session或者其他在ServletRequest中的对象的信息

%{xxx}i write value of incoming header with name xxx
%{xxx}o write value of outgoing header with name xxx
%{xxx}c write value of cookie with name xxx
%{xxx}r write value of ServletRequest attribute with name xxx
%{xxx}s write value of HttpSession attribute with name xxx
%{xxx}p write local (server) port (xxx==local) or remote (client) port (xxx=remote)
%{xxx}t write timestamp at the end of the request formatted using the enhanced SimpleDateFormat pattern xxx

如果tomcat前面有nginx做负载均衡，则要修改nginx的配置

Nginx的server主机配置段中添加：

proxy_set_header X-Real-IP $remote_addr; #真实的远端IP地址

然后再tomcat accessLog用%{X-Real-IP}i 获取即可