What is the best way to remotely reset the server cache in a web farm?

Question

Each of our production web servers maintains its own cache for separate web sites (ASP.NET Web Applications). Currently to clear a cache we log into the server and "touch" the web.config file.

Does anyone have an example of a safe/secure way to remotely reset the cache for a specific web application? Ideally we'd be able to say "clear the cache for app X running on all servers" but also "clear the cache for app X running on server Y".

Edits/Clarifications:

• I should probably clarify that doing this via the application itself isn't really an option (i.e. some sort of log in to the application, surf to a specific page or handler that would clear the cache). In order to do something like this we'd need to disable/bypass logging and stats tracking code, or mess up our stats.

• Yes, the cache expires regularly. What I'd like to do though is setup something so I can expire a specific cache on demand, usually after we change something in the database (we're using SQL 2000). We can do this now but only by logging in to the servers themselves.

Answer 1

This may not be "elegant", but you could setup a scheduled task that executes a batch script. The script would essentially "touch" the web.config (or some other file that causes a re-compile) for you.

Otherwise, is your application cache not set to expire after N minutes?

Answer 2

For each application, you could write a little cache-dump.aspx script to kill the cache/application data. Copy it to all your applications and write a hub script to manage the calling.

For security, you could add all sorts of authentication-lookups or IP-checking.

Here the way I do the actual app-dumping:

Context.Application.Lock()
Context.Session.Abandon()
Context.Application.RemoveAll()
Context.Application.UnLock()

Answer 3

Found a DevX article regarding a touch utility that look useful.

I'm going to try combining that with either a table in the database (add a record and the touch utility finds it and updates the appropriate web.config file) or a web service (make a call and the touch utility gets called to update the appropriate web.config file)