Hi I started to look into how to add tenant support to Sling.
This is my test scenario: I have an /apps/foo/bar/html.esp and a /apps/tenant1/foo/bar/html.esp and a /content/mynode entry. The title of the second html.esp is different so that I know which one is loaded. Changes to the code: 1) Added get/setSearchPathExtension() to the Resource Resolver and its implementation. 2) In the SlingRequestProcessorImpl I extract the tenant from the first sub domain (no OSGi Service yet) and prepend it with /apps/ to the Search Path Extension 3) In the Servlet Resolver added the code to set the Search Path Extension from the Resource’s Resource Resolver onto the Script Resource Resolver. Ran it and it showed the Tenant Specific ESP when the host name has a tenant it as sub domain and the original ESP when used with localhost. This shows that is it basically possible to thread through the tenant Search Path on a per-call basis to the Servlet Resolver. There is still much to do like the Cache handling in the Servlet Resolver and a OSGi service that provides the tenant from a request. I can create an Issue and add a patch of my changes to it if anyone is interested. Cheers - Andy On Feb 17, 2014, at 6:58 PM, Andreas Schaefer Sr. <schaef...@me.com> wrote: > Hi > > I am working for a client which needs support for tenants and because the > current implementation of the Tenants in Sling is just that but no > integration I started to code a workaround. For now I have a patch that does > the trick but it is not clean because I use a Servlet Filter to place the > tenant id on a thread local instance. Afterwards I started to look into how > to implemented this cleanly into the current version of Sling. > > There are a few areas that need to be changed in order to implement tenant > support. For now I am only looking into how to implement a “per-call overlays > of servlets / JSPs” in order to give tenants the chance to change aspects of > their presentation. > > 1) Tenant Identification: Sling must be able to identify a tenant. This can > be a sub domain, path, cookies or even parameters. This means the client > needs to provide a service which is then used by Sling in order to retrieve > the tenant and provide it to whomever wants to use it. > > 2) Servlet Resolver needs to be changed twofolds > a) Being able to extend the search path for Servlets / JSPs based on > the tenant’s data > b) Caching the Servlets / JPSs separated for different tenants > > 3) Change the Felix OSGi Web Plugin to allow the clients to add properties > (single and multi values) > > > For 1) I would suggest just to define an interface the client can implement > as an OSGi service which is used to identify a tenant. Then somewhere in the > SlingMainServlet or the Request Data the Tenant is retrieved set on the Sling > Http Servlet Request and if applicable the Search Path of the Resource > Resolver is “enhanced/extended”. > > For 2) I would suggest to add a new property to the Resource Resolver which > contains the Search Path Extension. Because the Servlet Resolver uses the > Administrative Resource Resolver we need a way to “Enhance the Search Path” > for that particular call. This could be done with a one-off wrapper. Based on > the Extended Search Path we can determine which Servlet is an overlay and > cache the overlays separately. > > 3) should be straight forward. > > Carsten was suggesting something like a TenantProvider like the > ServletProvider but in the current code the ServletProvider is called with > either the Sling Servlet Request, the Resource or a Resource Resolver and > path. This means the tenant id must be available to any of these calls which > would require to put the tenant id inside the Resource Resolver. > > Let me know what you think. > > - Andy Schaefer >
