Handling socket errors in recursive functions

[rodolfomiranda]

I was dealing with a problem when creating an AID where one of AID is down when collecting receipts. That situation may cause a socket error in a call to socket.getaddrinfo form hio, raising an error.
The error code is dependent on the operating system, it can be caused for several reasons for example a problem in domain name resolution.

That error is propagated back to keripy and keria where the exception is not being handled.

In my case, keria crashed in line 442 of the following function that treats receipts with witnesses.

keria/src/keria/app/agenting.py

Lines 430 to 444 in c38a54b

	def recur(self, tyme=None):
	while True:
	if self.witners:
	msg = self.witners.popleft()
	serder = msg["serder"]
	# If we are a rotation event, may need to catch new witnesses up to current key state
	if serder.ked['t'] in (Ilks.rot, Ilks.drt):
	adds = serder.ked["ba"]
	for wit in adds:
	yield from self.receiptor.catchup(serder.pre, wit)
	yield from self.receiptor.receipt(serder.pre, serder.sn)
	yield self.tock

Note that it's a recursive function that can make the keria process to crash as a whole.
I can create a PR to handle the exception there and safeguard the process by doing nothing but logging the error. I want to receive feedback for that approach. Other option may be to handle on the receiptor function in keripy

https://github.com/WebOfTrust/keripy/blob/543057e2d30712477b114f64c158dbf1564149fa/src/keri/app/agenting.py#L40

[rodolfomiranda]

Fixed in keripy PR #273