Change var in other namespace

[vitalyper]

clojure.tools.logging defines *logger-factory* and initializes it with
first logger implementation on the class path

(def ^{:doc
"An instance satisfying the impl/LoggerFactory protocol. Used
internally to
obtain an impl/Logger. Defaults to the value returned from impl/
find-factory."
:dynamic true}
*logger-factory*
(impl/find-factory))

In my own namespace I want to redefine *logger-factory* to log4j one.
Tried different variations (def, set!, etc) in 1.3.0 with no avail.
(ns my.foo
(:gen-class)
(:use
[clojure.tools.logging :only (*logger-factory* info debug)])
(:require
[clojure.string :as s1]
[clojure.tools.logging.impl :as log-impl])
)

(defn init-logging
"Force log4j factory for core tools logging"
[]
(def *logger-factory* (log-impl/log4j-factory)))
; CompilerException java.lang.IllegalStateException: *logger-factory*
already refers to: #'clojure.tools.logging/*logger-factory* in
namespace: infrared.common

[Mark Rathwell]

You rebind dynamic vars with binding, so your use would look something
like this:

(binding [*logger-factory* (log-impl/log4j-factory)]
(do-stuff-with-the-logger-factory-rebound))

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[Sean Corfield]

Note: if you just want something that will execute at startup and
force _all_ logging to use log4j, instead of wrapping code in (binding
..) then you probably want something like this:

(ns your.namespace
(:require [clojure.tools.logging :as log])
(:require [clojure.tools.logging.impl :as impl]))

(alter-var-root (var log/*logger-factory*) (constantly (impl/log4j-factory)))

This is what we ended with in our code to ensure log4j was selected at
startup...

Sean

[vitalyper]

Thanks, Sean. Exactly what I was looking for.
IMO, clojure.tools.logging could of made this easier: log
implementation from classpath by default with override by client when
needed.

On Nov 17, 11:32 pm, Sean Corfield <seancorfi...@gmail.com> wrote:
> Note: if you just want something that will execute at startup and
> force _all_ logging to use log4j, instead of wrapping code in (binding
> ..) then you probably want something like this:
>
> (ns your.namespace
>   (:require [clojure.tools.logging :as log])
>   (:require [clojure.tools.logging.impl :as impl]))
>
> (alter-var-root (var log/*logger-factory*) (constantly (impl/log4j-factory)))
>
> This is what we ended with in our code to ensure log4j was selected at
> startup...
>
> Sean
>
>
>
>
>
>
>
> On Thu, Nov 17, 2011 at 7:04 PM, Mark Rathwell <mark.rathw...@gmail.com> wrote:
> > You rebind dynamic vars with binding, so your use would look something
> > like this:
>
> > (binding [*logger-factory* (log-impl/log4j-factory)]
> >  (do-stuff-with-the-logger-factory-rebound))
>

[Sean Corfield]

On Fri, Nov 18, 2011 at 6:35 AM, vitalyper <vita...@yahoo.com> wrote:
> IMO, clojure.tools.logging could of made this easier: log
> implementation from classpath by default with override by client when
> needed.

I agree but when I brought the issue up, there didn't seem to be much
support for making it easier... Perhaps a ticket in JIRA might garner
some votes?
--
Sean A Corfield -- (904) 302-SEAN
An Architect's View -- http://corfield.org/
World Singles, LLC. -- http://worldsingles.com/

"Perfection is the enemy of the good."
-- Gustave Flaubert, French realist novelist (1821-1880)

[himangshu]

this reply was god sent to me. I use tomcat and war to deploy my clojure code. the default thing was just not compiling. Although I do not have slf4j in my classpath. find logger was still giving slf4j and when it encountered first logging statement, the code used to crap out saying class not found exception