org.apache.catalina.valves
Class AccessLogValve

java.lang.Object
  org.apache.catalina.valves.ValveBase
      org.apache.catalina.valves.AccessLogValve

All Implemented Interfaces:

javax.management.MBeanRegistration, AccessLog, Contained, Lifecycle, Valve

Direct Known Subclasses:

ExtendedAccessLogValve, FastCommonAccessLogValve

public class AccessLogValve
extends ValveBase
implements AccessLog, Lifecycle

Implementation of the Valve interface that generates a web server access log with the detailed line contents matching a configurable pattern. The syntax of the available patterns is similar to that supported by the Apache HTTP Server mod_log_config module. As an additional feature, automatic rollover of log files when the date changes is also supported.

Patterns for the logged message may include constant text or any of the following replacement strings, for which the corresponding information from the specified Response is substituted:

• %a - Remote IP address
• %A - Local IP address
• %b - Bytes sent, excluding HTTP headers, or '-' if no bytes were sent
• %B - Bytes sent, excluding HTTP headers
• %h - Remote host name
• %H - Request protocol
• %l - Remote logical username from identd (always returns '-')
• %m - Request method
• %p - Local port
• %q - Query string (prepended with a '?' if it exists, otherwise an empty string
• %r - First line of the request
• %s - HTTP status code of the response
• %S - User session ID
• %t - Date and time, in Common Log Format format
• %u - Remote user that was authenticated
• %U - Requested URL path
• %v - Local server name
• %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)

In addition, the caller can specify one of the following aliases for commonly utilized patterns:

• common - %h %l %u %t "%r" %s %b
• combined - %h %l %u %t "%r" %s %b "%{Referer}i" "%{User-Agent}i"

There is also support to write information from the cookie, incoming header, the Session or something else in the ServletRequest.
It is modeled after the Apache HTTP Server log configuration syntax:

• %{xxx}i for incoming headers
• %{xxx}o for outgoing response headers
• %{xxx}c for a specific cookie
• %{xxx}r xxx is an attribute in the ServletRequest
• %{xxx}s xxx is an attribute in the HttpSession

Log rotation can be on or off. This is dictated by the rotatable property.

For UNIX users, another field called checkExists is also available. If set to true, the log file's existence will be checked before each logging. This way an external log rotator can move the file somewhere and Tomcat will start with a new file.

For JMX junkies, a public method called rotate has been made available to allow you to tell this instance to move the existing log file to somewhere else and start writing a new log file.

Conditional logging is also supported. This can be done with the condition property. If the value returned from ServletRequest.getAttribute(condition) yields a non-null value, the logging will be skipped.

For extended attributes coming from a getAttribute() call, it is you responsibility to ensure there are no newline or control characters.

Author:

Craig R. McClanahan, Jason Brittain, Remy Maucherat, Takayuki Kaneko, Peter Rossbach

info

protected static final java.lang.String info

The descriptive information about this implementation.

See Also:

Constant Field Values

lifecycle

protected LifecycleSupport lifecycle

The lifecycle event support for this component.

months

protected static final java.lang.String[] months

The set of month abbreviations for log messages.

enabled

protected boolean enabled

enabled this component

pattern

protected java.lang.String pattern

The pattern used to format our access log lines.

prefix

protected java.lang.String prefix

The prefix that is added to log file filenames.

rotatable

protected boolean rotatable

Should we rotate our log file? Default is true (like old behavior)

sm

protected StringManager sm

The string manager for this package.

started

protected boolean started

Has this component been started yet?

suffix

protected java.lang.String suffix

The suffix that is added to log file filenames.

writer

protected java.io.PrintWriter writer

The PrintWriter to which we are currently logging, if any.

fileDateFormatter

protected java.text.SimpleDateFormat fileDateFormatter

A date formatter to format a Date into a date in the format "yyyy-MM-dd".

currentLogFile

protected java.io.File currentLogFile

The current log file we are writing to. Helpful when checkExists is true.

condition

protected java.lang.String condition

Are we doing conditional logging. default false.

fileDateFormat

protected java.lang.String fileDateFormat

Date format to place in log file name. Use at your own risk!

encoding

protected java.lang.String encoding

Character set used by the log file. If it is null, the system default character set will be used. An empty string will be treated as null when this property is assigned.

logElements

protected AccessLogValve.AccessLogElement[] logElements

Array of AccessLogElement, they will be used to make log message.

AccessLogValve

public AccessLogValve()

getEnabled

public boolean getEnabled()

Returns:

Returns the enabled.

setEnabled

public void setEnabled(boolean enabled)

Parameters:

enabled - The enabled to set.

getDirectory

public java.lang.String getDirectory()

Return the directory in which we create log files.

setDirectory

public void setDirectory(java.lang.String directory)

Set the directory in which we create log files.

Parameters:

directory - The new log file directory

getInfo

public java.lang.String getInfo()

Return descriptive information about this implementation.

Specified by:

getInfo in interface Valve

Overrides:

getInfo in class ValveBase

getPattern

public java.lang.String getPattern()

Return the format pattern.

setPattern

public void setPattern(java.lang.String pattern)

Set the format pattern, first translating any recognized alias.

Parameters:

pattern - The new pattern

isCheckExists

public boolean isCheckExists()

Check for file existence before logging.

setCheckExists

public void setCheckExists(boolean checkExists)

Set whether to check for log file existence before logging.

Parameters:

checkExists - true meaning to check for file existence.

getPrefix

public java.lang.String getPrefix()

Return the log file prefix.

setPrefix

public void setPrefix(java.lang.String prefix)

Set the log file prefix.

Parameters:

prefix - The new log file prefix

isRotatable

public boolean isRotatable()

Should we rotate the access log.

Returns:

true if the access log should be rotated

setRotatable

public void setRotatable(boolean rotatable)

Configure whether the access log should be rotated.

Parameters:

rotatable - true if the log should be rotated

isBuffered

public boolean isBuffered()

Is the logging buffered

setBuffered

public void setBuffered(boolean buffered)

Set the value if the logging should be buffered

Parameters:

buffered - true if buffered.

getSuffix

public java.lang.String getSuffix()

Return the log file suffix.

setSuffix

public void setSuffix(java.lang.String suffix)

Set the log file suffix.

Parameters:

suffix - The new log file suffix

setResolveHosts

public void setResolveHosts(boolean resolveHosts)

Set the resolve hosts flag.

Parameters:

resolveHosts - The new resolve hosts value

isResolveHosts

public boolean isResolveHosts()

Get the value of the resolve hosts flag.

getCondition

public java.lang.String getCondition()

Return whether the attribute name to look for when performing conditional loggging. If null, every request is logged.

setCondition

public void setCondition(java.lang.String condition)

Set the ServletRequest.attribute to look for to perform conditional logging. Set to null to log everything.

Parameters:

condition - Set to null to log everything

getFileDateFormat

public java.lang.String getFileDateFormat()

Return the date format date based log rotation.

setFileDateFormat

public void setFileDateFormat(java.lang.String fileDateFormat)

Set the date format date based log rotation.

getEncoding

public java.lang.String getEncoding()

Return the character set name that is used to write the log file.

Returns:

Character set name, or null if the system default character set is used.

setEncoding

public void setEncoding(java.lang.String encoding)

Set the character set that is used to write the log file.

Parameters:

encoding - The name of the character set.

backgroundProcess

public void backgroundProcess()

Execute a periodic task, such as reloading, etc. This method will be invoked inside the classloading context of this container. Unexpected throwables will be caught and logged.

Specified by:

backgroundProcess in interface Valve

Overrides:

backgroundProcess in class ValveBase

invoke

public void invoke(Request request,
                   Response response)
            throws java.io.IOException,
                   javax.servlet.ServletException

Log a message summarizing the specified request and response, according to the format specified by the pattern property.

Specified by:

invoke in interface Valve

Specified by:

invoke in class ValveBase

Parameters:

request - Request being processed

response - Response being processed

Throws:

java.io.IOException - if an input/output error has occurred

javax.servlet.ServletException - if a servlet error has occurred

log

public void log(Request request,
                Response response,
                long time)

Description copied from interface: AccessLog

Add the request/response to the access log using the specified processing time.

Specified by:

log in interface AccessLog

Parameters:

request - Request (associated with the response) to log

response - Response (associated with the request) to log

time - Time taken to process the request/response in milliseconds (use 0 if not known)

rotate

public boolean rotate(java.lang.String newFileName)

Rename the existing log file to something else. Then open the old log file name up once again. Intended to be called by a JMX agent.

Parameters:

newFileName - The file name to move the log file entry to

Returns:

true if a file was rotated with no error

log

public void log(java.lang.String message)

Log the specified message to the log file, switching files if the date has changed since the previous log call.

Parameters:

message - Message to be logged

open

protected void open()

Open the new log file for the date specified by dateStamp.

addLifecycleListener

public void addLifecycleListener(LifecycleListener listener)

Add a lifecycle event listener to this component.

Specified by:

addLifecycleListener in interface Lifecycle

Parameters:

listener - The listener to add

findLifecycleListeners

public LifecycleListener[] findLifecycleListeners()

Get the lifecycle listeners associated with this lifecycle. If this Lifecycle has no listeners registered, a zero-length array is returned.

Specified by:

findLifecycleListeners in interface Lifecycle

removeLifecycleListener

public void removeLifecycleListener(LifecycleListener listener)

Remove a lifecycle event listener from this component.

Specified by:

removeLifecycleListener in interface Lifecycle

Parameters:

listener - The listener to add

start

public void start()
           throws LifecycleException

Prepare for the beginning of active use of the public methods of this component. This method should be called after configure(), and before any of the public methods of the component are utilized.

Specified by:

start in interface Lifecycle

Throws:

LifecycleException - if this component detects a fatal error that prevents this component from being used

stop

public void stop()
          throws LifecycleException

Gracefully terminate the active use of the public methods of this component. This method should be the last one called on a given instance of this component.

Specified by:

stop in interface Lifecycle

Throws:

LifecycleException - if this component detects a fatal error that needs to be reported

createLogElements

protected AccessLogValve.AccessLogElement[] createLogElements()

parse pattern string and create the array of AccessLogElement

createAccessLogElement

protected AccessLogValve.AccessLogElement createAccessLogElement(java.lang.String header,
                                                                 char pattern)

create an AccessLogElement implementation which needs header string

createAccessLogElement

protected AccessLogValve.AccessLogElement createAccessLogElement(char pattern)

create an AccessLogElement implementation