Links Top Level Elements Connectors Containers Nested Components | The Logger Component| Introduction |
A Logger element represents a destination for
logging, debugging, and error messages (including stack tracebacks)
for a Catalina container (Engine,
Host, or Context).
In addition, Loggers associated with an Engine or a Host are automatically
inherited by lower-level containers, unless explicitly overridden.
If you are interested in producing access logs like a web server does
(for example, to run hit count analysis software), you will want to configure
an Access Log Valve component on
your Engine,
Host, or
Context.
For a more in-depth description of the class loader hierarchy
that is implemented by Catalina, see FIXME - Reference.
The description below uses the variable name $CATALINA_HOME
to refer to the directory into which you have installed Tomcat 4,
and is the base directory against which most relative paths are
resolved. However, if you have configured Tomcat 4 for multiple
instances by setting a CATALINA_BASE directory, you should use
$CATALINA_BASE instead of $CATALINA_HOME for each of these
references.
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| Attributes |
| Common Attributes |
All implementations of Logger
support the following attributes:
| Attribute | Description |
|---|
className |
Java class name of the implementation to use. This class must
implement the org.apache.catalina.Logger interface.
| verbosity |
The verbosity level for this logger. Messages with a higher
verbosity level than the specified value will be silently ignored.
Available levels are 0 (fatal messages only), 1 (errors), 2
(warnings), 3 (information), and 4 (debug). If not specified, the
default value will be 1 (error).
NOTE - Only messages logged with an explicit
verbosity level are compared to this value. Messages logged with
no explicit verbosity level are logged unconditionally.
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| Standard Implementation |
Unlike most Catalina components, there are several standard
Logger implementations available. As a result,
the className attribute MUST be used to select the
implementation you wish to use.
File Logger (org.apache.catalina.logger.FileLogger)
The File Logger records all logged messages to
disk file(s) in a specified directory. The actual filenames of the
log files are created from a configured prefix, the current date in
YYYY-MM-DD format, and a configured suffix. On the first logged
message after midnight each day, the current log file will be closed
and a new file opened for the new date, without having to shut down
Catalina in order to perform this switch.
The File Logger supports the following attributes:
| Attribute | Description |
|---|
directory |
Absolute or relative pathname of a directory in which log files
created by this logger 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).
| prefix |
The prefix added to the start of each log file's name. If not
specified, the default value is "catalina.". To specify no prefix,
use a zero-length string.
| suffix |
The suffix added to the end of each log file's name. If not
specified, the default value is ".log". To specify no suffix,
use a zero-length string.
| timestamp |
Set to true to cause all logged messages to be
date and time stamped. Set to false (the default)
to skip date/time stamping.
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Standard Error Logger (org.apache.catalina.logger.SystemErrLogger)
The Standard Error Logger records all logged messages
to whatever stream the standard error output of Catalina is pointed at.
The default Catalina startup script points this at file
logs/catalina.out relative to $CATALINA_HOME. This
logger supports no additional attributes.
Standard Output Logger (org.apache.catalina.logger.SystemOutLogger)
The Standard Output Logger records all logged messages
to whatever stream the standard output of Catalina is pointed at.
The default Catalina startup script points this at file
logs/catalina.out relative to $CATALINA_HOME. This
logger supports no additional attributes.
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