These are probably questions for people who have written modules for Nginx.

So I have written a module with a handler that processes incoming requests and then would either initiate a subrequest (through its body filter) or returns 200 back. If a subrequest is called, the module will use the subrequest's response to generate the response for the original request. Clearly, the subrequest is to a proxy that is already defined in the configuration file.
The first question is how do I know if my proxy is timed out? Would my module's body or header filter be called if there is a timeout? if so, what do I look for in those methods to know there is a timeout?
The second question is whether or not there is anyway we can log whatever information we want within the module. In other words, the config file only specifies the location of the access_log file and doesn't specify any attributes to be logged, but then somewhere in the module (possibly in the header filter??), we call a method to log whatever we want.

Thanks,
-M