Can you remove sakai core tools you don't want/need?

Question

Something I've been wondering recently, is it possible to actually "remove" core tools from the sakai vanilla build without a huge effort (editing loads of config files)?

I know about stealthing tools (https://confluence.sakaiproject.org/display/DOC/Provisional+Tools) and I "think" there's some way to "disable" tools (or is that just stealthing?), but simply to remove the possibility of potential problems and lower the service memory footprint + startup time it would be nice if there was a supported means to "not have X Y or Z tool in the service at all".

I've never tried just removing jars to see what happens, but I suspect that mightn't be a good idea and probably needs to be compiled up with tools deployed to the webapp directory, which I would think means changing a whole load of maven files to do a "mvn clean install sakai:deploy" that would be lighter.

Answer 1

The Sakai architecture is actually more akin to a lot of loosely (or tightly in some cases) coupled tools than a unified system. This is an advantage from the perspective that you can do exactly the thing you want to do here. It is a disadvantage from a unified user experience perspective (though that is not an architectural limitation but rather a side effect of how the tool teams were run early on in the project).

If you want to remove a tool (like Samigo for this example) then you can simply delete the war file (and directory) related to it from your TOMCAT_HOME/webapps directory. Run this from your tomcat home directory:

rm -rf webapps/samigo-app*

When you startup tomcat, the tool will not be loaded and things will work fine (assuming there is not another tool or part of Sakai that expects that one to be there). Some tools like resources (sakai-content-tool) should not be removed for that reason (though stealthing them would be fine).

Please note that only removing the tool will not save you as much as you might hope since there is also a service related to most tools which lines in TOMCAT_HOME/components. The service component is actually an exploded war file (basically the same as the tool webapp) but it has not interface and has to follow some Sakai conventions in order to load properly. In the case of Samigo again, you could remove it like so (running from your tomcat home):

rm -rf components/samigo-pack

You should NOT do this while the system is running. You should also NOT remove the API jars from shared.

When you restart Sakai after removing the component you will see a more significant drop in the resources since the tool service is no longer loaded in memory and initialized. I saw about 5 second reduction in startup time (90s to 85s) and about a 25MB reduction in JVM memory used (from 795 to 770) by removing Samigo and it's service.

Your best bet would be to "trial and error" out the optimal solution for your situation and try removing a tool and it's service (if it has one) and seeing if things startup without errors and if the tools you do use work as expected.

Also, please note that removing a tool will NOT remove the tool pages in existing courses. You will end up with a page which simply displays nothing (because Sakai sees it as an empty page in the course now). If you add the tool back into the system then it will appear on the page again.

UPDATE: If you want to remove the blank tool page there is one easy option. The easy option is to just go into the site and remove the page the tool is on. This can be done from the Sites admin tool.

Alternatively, you could go into the database and remove all the pages which contain the specific tool id. This is pretty risky though so I don't recommend it. Generally, the removal of a tool like this would happen before the tool is used in production so hopefully this is a rare case.