foolscap: "an inbound callRemote ... failed" log entries include all arguments

[daira]

For example:

allmydata.storage.backends.cloud.cloud_common.CloudError: ("try 1 failed: PUT object ('shares/oh/ohcac6xn5ot7hxwfcstdeqcf4e/0.16624',) {}", '')
]
03:53:03.778 L23 []#87614 an inbound callRemote that we [n4zt] executed (on behalf of someone else, TubID uzie) failed
03:53:03.778 L10 []#87615  reqID=66831, rref=<allmydata.storage.bucket.BucketWriter object at 0x3bf6b50>, methname=RIBucketWriter.write
03:53:03.792 L10 []#87616  args=[8716681284L, '<VERY long string>']
03:53:03.792 L10 []#87617  kwargs={}
03:53:03.792 L10 []#87618  the LOCAL failure was: [...]

Note that in this case the cloud backend has avoided logging the data that we attempted to write, but foolscap has logged it, causing a temporarily memory leak and resulting in performance problems when argument strings are large.

In other cases, logging the arguments of remote operations may leak secrets into the log (see also #562 and related tickets).