def push_set_entry(self, k, v):
for sv in self.active_servers:
if lib.raft_is_leader(sv.raft):
ety = self.add_entry(lib.RAFT_LOGTYPE_NORMAL,
SetRaftEntry(k, v))
e = sv.recv_entry(ety)
assert e == 0
break
def _check_election_safety(self):
"""
FIXME: this is O(n^2)
Election Safety
At most one leader can be elected in a given term.
"""
for i, sv1 in enumerate(net.active_servers):
if not lib.raft_is_leader(sv1.raft):
continue
for sv2 in net.active_servers[i + 1:]:
term1 = lib.raft_get_current_term(sv1.raft)
term2 = lib.raft_get_current_term(sv2.raft)
if lib.raft_is_leader(sv2.raft) and term1 == term2:
logging.error("election safety invalidated")
print(sv1, sv2, term1)
print('partitions:', self.partitions)
sys.exit(1)
def push_set_entry(self, k, v):
for sv in self.active_servers:
if lib.raft_is_leader(sv.raft):
ety = ffi.new('msg_entry_t*')
ety.term = 0
ety.id = self.new_entry_id()
ety.type = lib.RAFT_LOGTYPE_NORMAL
change = ffi.new_handle(SetRaftEntry(k, v))
ety.data.buf = change
ety.data.len = ffi.sizeof(ety.data.buf)
self.entries.append((ety, change))
e = sv.recv_entry(ety)
assert e == 0
break
def remove_member(self):
if not self.leader:
logging.error('no leader')
return
leader = self.leader
server = self.random.choice(self.active_servers)
if not lib.raft_is_leader(leader.raft):
return
if lib.raft_voting_change_is_in_progress(leader.raft):
# logging.error('{} voting change in progress'.format(server))
return
if leader == server:
# logging.error('can not remove leader')
return
if server.connection_status in [NODE_CONNECTING, NODE_DISCONNECTING]:
# logging.error('can not remove server that is changing connection status')
return
if NODE_DISCONNECTED == server.connection_status:
self.remove_server(server)
return
# Create a new configuration entry to be processed by the leader
ety = ffi.new('msg_entry_t*')
ety.term = 0
ety.id = self.new_entry_id()
assert server.connection_status == NODE_CONNECTED
ety.type = lib.RAFT_LOGTYPE_DEMOTE_NODE
change = ffi.new_handle(ChangeRaftEntry(server.id))
ety.data.buf = change
ety.data.len = ffi.sizeof(ety.data.buf)
assert (lib.raft_entry_is_cfg_change(ety))
self.entries.append((ety, change))
e = leader.recv_entry(ety)
if 0 != e:
logging.error(err2str(e))
return
else:
self.num_membership_changes += 1
# Wake up new node
assert NODE_CONNECTED == server.connection_status
server.set_connection_status(NODE_DISCONNECTING)
def entry_apply(self, ety, idx):
# collect stats
if self.network.latest_applied_log_idx < idx:
self.network.latest_applied_log_idx = idx
self.network.latest_applied_log_iteration = self.network.iteration
e = self._check_log_matching(ety, idx)
if e is not None:
return e
change = ffi.from_handle(ety.data.buf)
if ety.type == lib.RAFT_LOGTYPE_NORMAL:
self.fsm_dict[change.key] = change.val
elif ety.type == lib.RAFT_LOGTYPE_DEMOTE_NODE:
if change.node_id == lib.raft_get_nodeid(self.raft):
# logging.warning("{} shutting down because of demotion".format(self))
return lib.RAFT_ERR_SHUTDOWN
# Follow up by removing the node by receiving new entry
elif lib.raft_is_leader(self.raft):
new_ety = ffi.new('msg_entry_t*')
new_ety.term = 0
new_ety.id = self.network.new_entry_id()
new_ety.type = lib.RAFT_LOGTYPE_REMOVE_NODE
new_ety.data.buf = ety.data.buf
new_ety.data.len = ffi.sizeof(ety.data.buf)
assert(lib.raft_entry_is_cfg_change(new_ety))
e = self.recv_entry(new_ety)
assert e == 0
elif ety.type == lib.RAFT_LOGTYPE_REMOVE_NODE:
if change.node_id == lib.raft_get_nodeid(self.raft):
# logging.warning("{} shutting down because of removal".format(self))
return lib.RAFT_ERR_SHUTDOWN
elif ety.type == lib.RAFT_LOGTYPE_ADD_NODE:
if change.node_id == self.id:
self.set_connection_status(NODE_CONNECTED)
elif ety.type == lib.RAFT_LOGTYPE_ADD_NONVOTING_NODE:
pass
return 0
def add_member(self):
if net.num_of_servers <= len(self.active_servers):
return
if not self.leader:
logging.error('no leader')
return
leader = self.leader
if not lib.raft_is_leader(leader.raft):
return
if lib.raft_voting_change_is_in_progress(leader.raft):
# logging.error('{} voting change in progress'.format(server))
return
server = RaftServer(self)
# Create a new configuration entry to be processed by the leader
ety = ffi.new('msg_entry_t*')
ety.term = 0
ety.id = self.new_entry_id()
ety.type = lib.RAFT_LOGTYPE_ADD_NONVOTING_NODE
change = ffi.new_handle(ChangeRaftEntry(server.id))
ety.data.buf = change
ety.data.len = ffi.sizeof(ety.data.buf)
assert (lib.raft_entry_is_cfg_change(ety))
self.entries.append((ety, change))
e = leader.recv_entry(ety)
if 0 != e:
logging.error(err2str(e))
return
else:
self.num_membership_changes += 1
# Wake up new node
server.set_connection_status(NODE_CONNECTING)
assert server.udata
added_node = lib.raft_add_non_voting_node(server.raft, server.udata,
server.id, 1)
assert added_node
def remove_member(self):
if not self.leader:
logger.error('no leader')
return
leader = self.leader
server = self.random.choice(self.active_servers)
if not lib.raft_is_leader(leader.raft):
return
if lib.raft_voting_change_is_in_progress(leader.raft):
# logger.error('{} voting change in progress'.format(server))
return
if leader == server:
# logger.error('can not remove leader')
return
if server.connection_status in [NODE_CONNECTING, NODE_DISCONNECTING]:
# logger.error('can not remove server that is changing connection status')
return
if NODE_DISCONNECTED == server.connection_status:
self.remove_server(server)
return
# Create a new configuration entry to be processed by the leader
ety = self.add_entry(lib.RAFT_LOGTYPE_DEMOTE_NODE,
ChangeRaftEntry(server.id))
assert server.connection_status == NODE_CONNECTED
assert (lib.raft_entry_is_cfg_change(ety))
e = leader.recv_entry(ety)
if 0 != e:
logger.error(err2str(e))
return
else:
self.num_membership_changes += 1
# Wake up new node
assert NODE_CONNECTED == server.connection_status
server.set_connection_status(NODE_DISCONNECTING)
def add_member(self):
if net.num_of_servers <= len(self.active_servers):
return
if not self.leader:
logger.error('no leader')
return
leader = self.leader
if not lib.raft_is_leader(leader.raft):
return
if lib.raft_voting_change_is_in_progress(leader.raft):
# logger.error('{} voting change in progress'.format(server))
return
server = RaftServer(self)
# Create a new configuration entry to be processed by the leader
ety = self.add_entry(lib.RAFT_LOGTYPE_ADD_NONVOTING_NODE,
ChangeRaftEntry(server.id))
assert (lib.raft_entry_is_cfg_change(ety))
e = leader.recv_entry(ety)
if 0 != e:
logger.error(err2str(e))
return
else:
self.num_membership_changes += 1
# Wake up new node
server.set_connection_status(NODE_CONNECTING)
assert server.udata
added_node = lib.raft_add_non_voting_node(server.raft, server.udata,
server.id, 1)
assert added_node
def toggle_membership(self):
if not self.leader:
logging.error('no leader')
return
leader = self.leader
server = self.random.choice(self.active_servers)
if not lib.raft_is_leader(leader.raft):
return
if lib.raft_voting_change_is_in_progress(leader.raft):
# logging.error('{} voting change in progress'.format(server))
return
if leader == server:
# logging.error('can not remove leader')
return
if server.connection_status in [NODE_CONNECTING, NODE_DISCONNECTING]:
# logging.error('can not remove server that is changing connection status')
return
if NODE_DISCONNECTED == server.connection_status:
self.remove_server(server)
server = RaftServer(self)
# Create a new configuration entry to be processed by the leader
ety = ffi.new('msg_entry_t*')
ety.term = 0
ety.id = self.new_entry_id()
if server.connection_status == NODE_CONNECTED:
ety.type = lib.RAFT_LOGTYPE_DEMOTE_NODE
else:
ety.type = lib.RAFT_LOGTYPE_ADD_NONVOTING_NODE
change = ffi.new_handle(ChangeRaftEntry(server.id))
ety.data.buf = change
ety.data.len = ffi.sizeof(ety.data.buf)
assert(lib.raft_entry_is_cfg_change(ety))
self.entries.append((ety, change))
# logging.warning("{}> {} Membership change {}: ety.id:{} id:{} {}".format(
# self.iteration,
# server,
# "ADD" if ety.type == lib.RAFT_LOGTYPE_ADD_NONVOTING_NODE else "DEMOTE",
# ety.id,
# lib.raft_get_nodeid(leader.raft),
# server.id,
# ))
e = leader.recv_entry(ety)
if 0 != e:
logging.error(err2str(e))
return
else:
self.num_membership_changes += 1
# Wake up new node
if NODE_DISCONNECTED == server.connection_status:
server.set_connection_status(NODE_CONNECTING)
assert server.udata
added_node = lib.raft_add_non_voting_node(server.raft, server.udata, server.id, 1)
assert added_node
elif NODE_CONNECTED == server.connection_status:
server.set_connection_status(NODE_DISCONNECTING)
else:
logging.warning('Unknown status set {}'.format(server.connection_status))