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API for logging - clojure-contrib v1.1 (stable)

by Alex Taggart, Timothy Pratley
Full namespace name: clojure.contrib.logging

Overview

Logging macros which delegate to a specific logging implementation. At
macro-expansion-time a specific implementation is selected from, in order,
Apache commons-logging, log4j, and finally java.util.logging.

Logging levels are specified by clojure keywords corresponding to the
values used in log4j and commons-logging:
  :trace, :debug, :info, :warn, :error, :fatal

Logging occurs with the log macro, or the level-specific convenience macros,
which write either directly or via an agent.  For performance reasons, direct
logging is enabled by default, but setting the *allow-direct-logging* boolean
atom to false will disable it. If logging is invoked within a transaction it
will always use an agent.

The log macros will not evaluate their 'message' unless the specific logging
level is in effect. Alternately, you can use the spy macro when you have code
that needs to be evaluated, and also want to output the code and its result to
the debug log.

Unless otherwise specified, the current namespace (as identified by *ns*) will
be used as the log-ns (similar to how the java class name is usually used).
Note: your log configuration should display the name that was passed to the
logging implementation, and not perform stack-inspection, otherwise you'll see
something like "fn__72$impl_write_BANG__39__auto____81" in your logs.

Use the enabled? macro to write conditional code against the logging level
(beyond simply whether or not to call log, which is handled automatically).

You can redirect all java writes of System.out and System.err to the log
system by calling log-capture!.  To rebind *out* and *err* to the log system
invoke with-logs.  In both cases a log-ns (e.g., "com.example.captured")
needs to be specified to namespace the output.

Public Variables and Functions


*allow-direct-logging*

var

  
A boolean indicating whether direct logging (as opposed to via an agent) is
allowed when not operating from within a transaction. Defaults to true.

  
  
  Source


  

  

  
*impl-name*

  var

  

  
The name of the logging implementation used.

  
  
  Source


  

  

  
*logging-agent*

  var

  

  
The default agent used for performing logging durng a transaction or when
direct logging is disabled.

  
  
  Source


  

  

  
agent-write!

  function

  
Usage: (agent-write! _ log level message throwable)


  
Writes the message immediately, and ignores the first argument. Used by the
logging agent. End-users should never need to call this function.

  
  
  Source


  

  

  
debug

  macro

  
Usage: (debug message)
       (debug message throwable)


  
Logs a message at the debug level.

  
  
  Source


  

  

  
enabled?

  macro

  
Usage: (enabled? level)
       (enabled? level log-ns)


  
Returns true if the specific logging level is enabled.  Use of this function
should only be necessary if one needs to execute alternate code paths beyond
whether the log should be written to.

  
  
  Source


  

  

  
error

  macro

  
Usage: (error message)
       (error message throwable)


  
Logs a message at the error level.

  
  
  Source


  

  

  
fatal

  macro

  
Usage: (fatal message)
       (fatal message throwable)


  
Logs a message at the fatal level.

  
  
  Source


  

  

  
impl-enabled?

  var

  

  
Implementation-specific check if a particular level is enabled. End-users
should not need to call this function.

  
  
  Source


  

  

  
impl-get-log

  var

  

  
Returns an implementation-specific log by string namespace. End-users should
not need to call this function.

  
  
  Source


  

  

  
impl-write!

  var

  

  
Implementation-specific write of a log message. End-users should not need to
call this function.

  
  
  Source


  

  

  
info

  macro

  
Usage: (info message)
       (info message throwable)


  
Logs a message at the info level.

  
  
  Source


  

  

  
log

  macro

  
Usage: (log level message)
       (log level message throwable)
       (log level message throwable log-ns)


  
Logs a message, either directly or via an agent. Also see the level-specific
convenience macros.

  
  
  Source


  

  

  
log-capture!

  function

  
Usage: (log-capture! log-ns)


  
Captures System.out and System.err, redirecting all writes of those streams
to :info and :error logging, respectively. The specified log-ns value will
be used to namespace all redirected logging. NOTE: this will not redirect
output of *out* or *err*; for that, use with-logs.

  
  
  Source


  

  

  
log-stream

  function

  
Usage: (log-stream level log-ns)


  
Creates a PrintStream that will output to the log. End-users should not need
to invoke this function.

  
  
  Source


  

  

  
log-uncapture!

  function

  
Usage: (log-uncapture!)


  
Restores System.out and System.err to their original values.

  
  
  Source


  

  

  
spy

  macro

  
Usage: (spy expr)


  
Evaluates expr and outputs the form and its result to the debug log; returns 
the result of expr.

  
  
  Source


  

  

  
trace

  macro

  
Usage: (trace message)
       (trace message throwable)


  
Logs a message at the trace level.

  
  
  Source


  

  

  
warn

  macro

  
Usage: (warn message)
       (warn message throwable)


  
Logs a message at the warn level.

  
  
  Source


  

  

  
with-logs

  macro

  
Usage: (with-logs log-ns & body)


  
Evaluates exprs in a context in which *out* and *err* are bound to :info and
:error logging, respectively. The specified log-ns value will be used to
namespace all redirected logging.

  
  
  Source






              

            

          

	

	
      

      
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