def get(self, payload, address):
message = ''
if payload[0] == 'request':
value = self.data.get(payload[4], '')
if not value:
value = self.relay(
payload[1],
payload[4]) or '' # returns empty string if result is None
result = [
'response', 'get',
self.queue.status(), 'key', payload[4], 'value', value
]
message = encode_bencode(result)
self.deliver(message, address, identifier=payload[2])
dispatch_status('get', 'response', 'to', address[1])
elif payload[0] == 'relay':
value = self.data.get(payload[4], '')
result = [
'relay', 'get', self.record, 'key', payload[4], 'value', value
]
message = encode_bencode(result)
self.transmit(message, address)
dispatch_status('get', 'relay', 'to', address[1])
return message
def get(self, payload, address):
message = ''
if payload[0] == 'request':
value = self.data.get(payload[4], '')
if not value:
value = self.relay(payload[1], payload[4])
result = [
'response', 'get', payload[2], 'key', payload[4], 'value',
value, 'status',
self.egress.status()
]
message = encode_bencode(result)
self.deliver(message, address, identifier=payload[2])
dispatch_status('get', 'response', 'to', address[1])
elif payload[0] == 'relay-request':
value = self.data.get(payload[4], '')
result = [
'relay-response', 'get', self.identifier, 'key', payload[4],
'value', value
]
message = encode_bencode(result)
self.transmit(message, address)
dispatch_status('get', 'relay-response', 'to', address[1])
def replay(self, payload, address):
'''
Re-sends message in buffer to balancer.
'''
message = self.queue.get(payload[2])[0]
self.sock.sendto(message, address)
dispatch_status(payload[1], 're-response', 'to', address[1])
def set(self, payload, address):
message = ''
if payload[0] == 'request':
value = self.relay(payload[1], payload[4], payload[6]) or ''
if not value:
self.data[payload[4]] = payload[6]
result = [
'response', 'set',
self.queue.status(), 'key', payload[4], 'value', payload[6]
]
message = encode_bencode(result)
self.deliver(message, address, identifier=payload[2])
dispatch_status('set', 'response', 'to', address[1])
elif payload[0] == 'relay':
value = ''
if payload[4] in self.data:
self.data[payload[4]] = payload[6]
value = payload[6]
result = [
'relay', 'set', self.record, 'key', payload[4], 'value', value
]
message = encode_bencode(result)
self.transmit(message, address)
dispatch_status('set', 'relay', 'to', address[1])
return message
def execute(self, command):
if command[0] == 'status':
if os.getenv('BALANCER_DEBUG'):
sys.stderr.write(str(dt.now()) + ' INFO status broadcast\n')
self.broadcast()
elif command[0] == 'reset':
if os.getenv('BALANCER_DEBUG'):
sys.stderr.write(str(dt.now()) + ' WARN database reset\n')
self.reset()
elif command[0] in ['get', 'set']:
key = command[1]
value = '' if command[0] == 'get' else command[2]
payload = ['request', command[0], self.counter, 'key', key, 'value', value]
message = encode_bencode(payload)
target = self.choose()
if os.getenv('BALANCER_DEBUG'):
dispatch_status(payload[1], payload[0], 'to', target)
attempt = 0
while attempt < 3:
if os.getenv('BALANCER_DEBUG'):
sys.stderr.write(str(dt.now()) + ' INFO attempt ' + str(attempt + 1) + ' of 3\n')
increment = True if attempt == 0 else False # only increment if 1st attempt
address = (NODE_IP, target)
self.send(message, address, increment=increment)
try:
self.sock.settimeout(1)
response, address = self.sock.recvfrom(1024)
if os.getenv('BALANCER_DEBUG'):
dispatch_status(command[0], 'response', 'from', target)
result = decode_bencode(response)
output = result[6] + '\n' if command[0] == 'get' else 'success!\n'
self.status[target] = result[2]
if os.getenv('EXAMPLE'):
activity = [self.status[target] for target in self.targets]
sys.stderr.write(str(activity)[1:-1] + '\n')
break
sys.stderr.write(output)
break
except socket.timeout:
if os.getenv('BALANCER_DEBUG'):
sys.stderr.write(str(dt.now()) + ' WARN timeout\n')
attempt += 1
if attempt == 3 and not os.getenv('EXAMPLE'):
sys.stderr.write('failed!\n')
def status(self, address):
if not self.data:
sys.stderr.write(str(dt.now()) + ' WARN database empty\n')
return None
sys.stderr.write(str(dt.now()) + ' INFO contents start\n')
for key, value in self.data.iteritems():
sys.stderr.write(key + ': ' + value + '\n')
sys.stderr.write(str(dt.now()) + ' INFO contents end\n')
self.heartbeat(address)
dispatch_status('status', 'response', 'to', address[1])
def process(self, payload, address):
if payload[0] == 'request':
self.target = address
elif payload[0] == 'relay-response':
dispatch_status(payload[1], 'relay-response', 'from', address[1])
if payload[6]:
self.outcome.put(payload[4], payload[6])
return None
self.ingress.put((payload, address))
def status(self, address):
if not self.data:
sys.stderr.write(str(dt.now()) + ' WARN database empty\n')
return None
sys.stderr.write(str(dt.now()) + ' INFO database contents start\n')
for key, value in self.data.iteritems():
sys.stderr.write(key + ': ' + value + '\n')
sys.stderr.write(str(dt.now()) + ' INFO database contents end\n')
result = ['response', 'status', self.queue.status()]
message = encode_bencode(result)
self.sock.sendto(message, address)
dispatch_status('status', 'response', 'to', address[1])
def get(self, command, send=True):
target = self.choose()
if os.getenv('BALANCER_DEBUG'):
dispatch_status('get', 'request', 'to', target)
payload = ['request', 'get', self.identifier, 'key', command[1]]
message = encode_bencode(payload)
address = (NODE_IP, target)
if send:
result = self.send(message, address, identifier=payload[2])
if not os.getenv('EXAMPLE'):
sys.stderr.write(result + '\n')
return message
def relay(self, task, key, value=''):
payload = [
'relay-request', task,
str(self.identifier), 'key', key, 'value', value
]
message = encode_bencode(payload)
for peer in self.peers:
address = (NODE_IP, peer)
self.transmit(message, address)
dispatch_status(task, 'relay-request', 'to', peer)
time.sleep(0.01)
if key in self.outcome.data:
return self.outcome.get(key)
return ''
def relay(self, task, key, value=''):
'''
Sends message to all nodes to find specific key
'''
payload = ['relay', task, str(self.record), 'key', key, 'value', value]
message = encode_bencode(payload)
for peer in self.peers:
self.transmit(message, (NODE_IP, peer))
dispatch_status(payload[1], payload[0], 'to', peer)
try:
self.sock.settimeout(self.timeout)
response, address = self.sock.recvfrom(1024)
dispatch_status(payload[1], payload[0], 'from', peer)
result = decode_bencode(response)
if result[6]:
return result[6]
except socket.timeout:
sys.stderr.write(str(dt.now()) + ' WARN timeout\n')
def execute(self, request, address):
payload = decode_bencode(request)
if self.queue.get(payload[2]): # check if message in buffer
dispatch_status(payload[1], 're-request', 'from', address[1])
self.replay(payload, address)
return None
if payload[1] == 'status':
dispatch_status('status', 'request', 'from', address[1])
self.status(address)
elif payload[1] == 'reset':
dispatch_status('reset', 'request', 'from', address[1])
self.reset()
elif payload[1] == 'get':
dispatch_status('get', payload[0], 'from', address[1])
self.get(payload, address)
elif payload[1] == 'set':
dispatch_status('set', payload[0], 'from', address[1])
self.set(payload, address)
def replay(self, payload, address):
message = self.egress.get(payload[2])[0]
self.deliver(message, address)
dispatch_status(payload[1], 're-response', 'to', address[1])
def execute(self):
while True:
if not self.ingress.empty():
payload, address = self.ingress.get()
if payload[0][:5] != 'relay' and self.egress.get(payload[2]):
dispatch_status(payload[1], 're-request', 'from',
address[1])
self.replay(payload, address)
continue
if payload[1] == 'status':
dispatch_status('status', 'request', 'from', address[1])
self.status(address)
elif payload[1] == 'reset':
dispatch_status('reset', 'request', 'from', address[1])
self.reset()
elif payload[1] == 'exit':
dispatch_status('exit', 'request', 'from', address[1])
self.exit()
elif payload[1] == 'get':
dispatch_status('get', payload[0], 'from', address[1])
self.get(payload, address)
elif payload[1] == 'set':
dispatch_status('set', payload[0], 'from', address[1])
self.set(payload, address)
