log failures better: add caller stack

[Brian Warner]

When a method fails, we can log some information about it (if that option is turned on in the Tub). The information logged looks like this:

2007/09/08 19:10 -0700 [Negotiation,client] an outbound callRemote (that we sent to someone else) failed on the far end
2007/09/08 19:10 -0700 [Negotiation,client]  reqID=858, rref=<RemoteReference at 0x48b37174 [pb://onxnl2fpfqruabaku26fa4t5543vj3at@207.7.153.181:36611,127.0.0.1:36611/vdrive]>, methname=get

and includes the remote stack trace.

This information is missing the following useful pieces:

• the RemoteInterface? in use: that methname=get is hard to use without knowing exactly which "get" method we're talking about
• the stack trace (or at least the top-most frame) of the callRemote(), so we can find out why we were sending this message

[Brian Warner]

it looks like the interface name should be included in that log message in [cc600fb8f9b525101bd82231f846d8dda7244739], which was released in foolscap-0.1.7 .

So the only remaining piece is the stack trace (or a few frames of it) that led up the the callRemote().

[Brian Warner]

first task is to measure how long it takes to capture a short stack frame. If it's less than a millisecond I'm ok with adding it to callRemote.

[davidsarah]

I would find this useful.