| Introduction |
The Access Log Valve creates log files in the same format as those created by standard web servers. These logs can later be analyzed by standard log analysis tools to track page hit counts, user session activity, and so on. The files produces by this Valve are rolled over nightly at midnight. This Valve may be associated with any Catalina container (Context, Host, or Engine), and will record ALL requests processed by that container. |
| Attributes |
The Access Log Valve supports the following configuration attributes:
| Attribute | Description |
className | Java class name of the implementation to use. This MUST be set to org.apache.catalina.valves.AccessLogValve to use the default access log valve. To use a more optimized access log valve designed for production use, you MUST set this attribute to org.apache.catalina.valves.FastCommonAccessLogValve. In this case, only the common and combined patterns are supported. |
directory | Absolute or relative pathname of a directory in which log files created by this valve will be placed. If a relative path is specified, it is interpreted as relative to $CATALINA_HOME. If no directory attribute is specified, the default value is "logs" (relative to $CATALINA_HOME). |
pattern | A formatting layout identifying the various information fields from the request and response to be logged, or the word common or combined to select a standard format. See below for more information on configuring this attribute. Note that the optimized access does only support common and combined as the value for this attribute. |
prefix | The prefix added to the start of each log file's name. If not specified, the default value is "access_log.". To specify no prefix, use a zero-length string. |
resolveHosts | Set to true to convert the IP address of the remote host into the corresponding host name via a DNS lookup. Set to false to skip this lookup, and report the remote IP address instead. |
suffix | The suffix added to the end of each log file's name. If not specified, the default value is "". To specify no suffix, use a zero-length string. |
rotatable | Default true. Flag to determine if log rotation should occur. If set to false, then this file is never rotated and fileDateFormat is ignored. Use with caution! |
condition | Turns on conditional logging. If set, requests will be logged only if ServletRequest.getAttribute() is null. For example, if this value is set to junk, then a particular request will only be logged if ServletRequest.getAttribute("junk") == null. The use of Filters is an easy way to set/unset the attribute in the ServletRequest on many different requests. |
fileDateFormat | Allows a customized date format in the access log file name. The date format also decides how often the file is rotated. If you wish to rotate every hour, then set this value to: yyyy-MM-dd.HH |
Values for the pattern attribute are made up of literal text strings, combined with pattern identifiers prefixed by the "%" character to cause replacement by the corresponding variable value from the current request and response. The following pattern codes are supported:
-
%a - Remote IP address
-
%A - Local IP address
-
%b - Bytes sent, excluding HTTP headers, or '-' if zero
-
%B - Bytes sent, excluding HTTP headers
-
%h - Remote host name (or IP address if
resolveHosts is false) -
%H - Request protocol
-
%l - Remote logical username from identd (always returns '-')
-
%m - Request method (GET, POST, etc.)
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%p - Local port on which this request was received
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%q - Query string (prepended with a '?' if it exists)
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%r - First line of the request (method and request URI)
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%s - HTTP status code of the response
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%S - User session ID
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%t - Date and time, in Common Log Format
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%u - Remote user that was authenticated (if any), else '-'
-
%U - Requested URL path
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%v - Local server name
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%D - Time taken to process the request, in millis
-
%T - Time taken to process the request, in seconds
-
%I - current request thread name (can compare later with stacktraces)
There is also support to write information from the cookie, incoming header, outgoing response headers, the Session or something else in the ServletRequest. It is modeled after the apache syntax:
-
%{xxx}i for incoming request headers -
%{xxx}o for outgoing response headers -
%{xxx}c for a specific request cookie -
%{xxx}r xxx is an attribute in the ServletRequest -
%{xxx}s xxx is an attribute in the HttpSession
The shorthand pattern name common (which is also the default) corresponds to '%h %l %u %t "%r" %s %b'. The shorthand pattern name combined appends the values of the Referer and User-Agent headers, each in double quotes, to the common pattern described in the previous paragraph. |
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