def test_acceptor_should_not_accept_before_grant():
acceptor = Acceptor(SuggestionId(0, '0'), None)
assert acceptor.last_value is None
assert acceptor.grant_id is None
sug = SuggestionId(0, '0')
with pytest.raises(Exception):
assert acceptor.should_accept(sug)
async def propose(self, key, value):
loop = asyncio.get_running_loop()
serial = self.table.wid
sug_id = SuggestionId(serial, self.name)
proposer = Proposer(
self.peers,
sug_id,
[key, value],
)
tasks = []
for peer in self.peers:
task = loop.create_task(self.peer_protocols[peer].permission(str(sug_id)))
tasks.append(task)
for name, result in await asyncio.gather(*tasks):
if result:
proposer.grant(name)
tasks = []
if not proposer.can_propose:
raise Exception("Unable to propose value")
for peer in self.peers:
task = loop.create_task(self.peer_protocols[peer].propose(str(sug_id), [key, value]))
tasks.append(task)
for name, result in await asyncio.gather(*tasks):
if result:
proposer.accept(name)
if not proposer.value_accepted:
raise Exception("Value not accepted")
tasks = []
for peer in self.peers:
task = loop.create_task(self.peer_protocols[peer].learn([key, value]))
tasks.append(task)
for name, result in await asyncio.gather(*tasks):
log.debug("Learner response %s %r", name, result)
return str(sug_id), value
def test_proposer_grant():
config = {
'a': ('127.0.0.1', 55501),
'b': ('127.0.0.1', 55502),
'c': ('127.0.0.1', 55503),
}
sug_id = SuggestionId(1, 'a')
proposer = Proposer(config, sug_id, 'test value')
assert proposer.can_propose == False
proposer.grant('a')
proposer.grant('b')
assert proposer.can_propose == True
def test_proposer_accept():
config = {
'a': ('127.0.0.1', 55501),
'b': ('127.0.0.1', 55502),
'c': ('127.0.0.1', 55503),
}
sug_id = SuggestionId(1, 'a')
proposer = Proposer(config, sug_id, 'test value')
assert proposer.value_accepted is False
proposer.accept('a')
proposer.accept('b')
assert proposer.value_accepted is True
def test_paxos():
config = {
'a': ('127.0.0.1', 55501),
'b': ('127.0.0.1', 55502),
'c': ('127.0.0.1', 55503),
}
sug_id = SuggestionId(0, '0')
acceptors = {k: Acceptor(sug_id, None) for k in config}
sug_id = SuggestionId(1, 'a')
value = 'meh'
proposer = Proposer(
config,
sug_id,
value,
)
learner = Learner()
for a in proposer.peers:
assert acceptors[a].should_grant(sug_id)
acceptors[a].grant(sug_id)
for a in proposer.peers:
assert acceptors[a].should_accept(sug_id)
acceptors[a].accept(sug_id, value)
learner.learn(value)
assert learner.value == value
def test_acceptor_grant():
acceptor = Acceptor(SuggestionId(0, '0'), None)
sug = SuggestionId(0, 'a')
acceptor.grant(sug)
acceptor.grant_id == sug
def test_acceptor_should_not_accept_after_grant():
acceptor = Acceptor(SuggestionId(0, '0'), None, SuggestionId(0, 'b'))
# Grant id is grater than id to be accepted
sug = SuggestionId(0, 'a')
assert acceptor.should_accept(sug) is False
def test_acceptor_should_accept():
acceptor = Acceptor(SuggestionId(0, '0'), None, SuggestionId(0, 'a'))
sug = SuggestionId(0, 'a')
assert acceptor.should_accept(sug) is True
def test_acceptor_should_not_grant():
acceptor = Acceptor(SuggestionId(0, '0'), None)
sug = SuggestionId(0, '0')
assert acceptor.should_grant(sug) is False
def test_suggestion_id_parse():
sug = SuggestionId.parse('1,a')
assert sug.uid == 1
assert sug.node == 'a'
def test_suggestion_id_to_str():
assert str(SuggestionId('1', 'a')) == '1,a'