Event code in Magento v1.7 not working - events

Question

G'Day all,
I'm trying to write my first magento event handler to capture "checkout_cart_save_after" but I can't get my Observer.php code to fire, after 2 days of looking at web sites on magento events I understand the whole process but the code is not running.. I'm perplexed as to why.
Here is the modules xml file in /var/magento/app/etc/modules/
<?xml version="1.0"?>
<config>
<modules>
<Namespace_Yourmodule>
<codePool>local</codePool>
<active>true</active>
<version>1.0.0</version>
</Namespace_Yourmodule>
</modules>
</config>
As you can see I'm just using Namespace and Yourmodule as I'm writing a tutorial for others....
In my module's etc directory (/var/magento/app/code/local/Namespace/Yourmodule/Module) I have config.xml
<?xml version="1.0"?>
<global>
<events>
<checkout_cart_save_after>
<observers>
<yourmodule_after_observer>
<type>singleton</type>
<class>Namespace_Yourmodule_Model_Observer</class>
<method>checkout_cart_save_after</method>
</yourmodule_after_observer>
</observers>
</checkout_cart_save_after>
</events>
</global>
and in the Modules directory I have my Observer.php file:
class Namespace_Yourmodule_Model_Observer
{
/*----------------------------------------
*
* LogInfo()
*
* Basic logging of activity to disk for debugging
*/
public function LogInfo($msg)
{
$logfile="/logs/Namespace-module.log";
$fd=fopen($logfile,"a");
if($fd)
{
fwrite($fd,$msg."\n");
fclose($fd);
}
}
public function checkout_cart_save_before($observer)
{
LogInfo("save_before called");
}
public function checkout_cart_save_after($observer)
{
LogInfo("save_after called");
}
}
The result of trying to add and remove items from the cart is that no log file is crearted and when manually created, no data is written, system.log shows no errors, if I skew the XML it reports the errror, so the XML file is being read.
Any thoughts on what I have missed???
Sid
Update 12/2:
I have spent the weekend on this and solved the issue, thanks for the hints, it was a combination of minor things that I should have picked up and the format of the XML file now matches what has been suggested above... there is now a tutorial! I have fully documented the process with working code and config files.
See http://z900collector.wordpress.com/magento/magento-events/

Answer 1

Try updating your config.xml to
<?xml version="1.0"?>
<config>
<modules>
<Namespace_Yourmodule>
<version>1.0</version>
</Namespace_Yourmodule>
</modules>
<global>
<!--helpers>
<yourmodule>
<class>Namespace_Yourmodule_Helper</class>
</yourmodule>
</helpers-->
<models>
<yourmodule>
<class>Namespace_Yourmodule_Model</class>
</yourmodule>
</models>
<events>
<checkout_cart_save_after>
<observers>
<yourmodule_after_observer>
<type>singleton</type>
<class>Namespace_Yourmodule_Model_Observer</class>
<method>checkout_cart_save_after</method>
</yourmodule_after_observer>
</observers>
</checkout_cart_save_after>
</events>
</global>
</config>
See Customize Magento using Event/Observer