def main():
nc = NATS()
try:
# Setting explicit list of servers in a cluster and
# max reconnect retries.
servers = [
"nats://127.0.0.1:4222", "nats://127.0.0.1:4223",
"nats://127.0.0.1:4224"
]
yield nc.connect(max_reconnect_attempts=2, servers=servers)
except ErrNoServers:
print("No servers available!")
return
@tornado.gen.coroutine
def message_handler(msg):
subject = msg.subject
reply = msg.reply
data = msg.data.decode()
for i in range(0, 20):
yield nc.publish(reply, "i={i}".format(i=i).encode())
yield nc.subscribe("help.>", cb=message_handler)
@tornado.gen.coroutine
def request_handler(msg):
subject = msg.subject
reply = msg.reply
data = msg.data.decode()
print("Received a message on '{subject} {reply}': {data}".format(
subject=subject, reply=reply, data=data))
# Signal the server to stop sending messages after we got 10 already.
yield nc.request("help.please", b'help', expected=10, cb=request_handler)
# Flush connection to server, returns when all messages have been processed.
# It raises a timeout if roundtrip takes longer than 1 second.
yield nc.flush()
# Drain gracefully closes the connection, allowing all subscribers to
# handle any pending messages inflight that the server may have sent.
yield nc.drain()
# Drain works async in the background.
yield tornado.gen.sleep(1)
def main():
nc = NATS()
conn_closed = tornado.concurrent.Future()
def closed_cb():
conn_closed.set_result(True)
# Set pool servers in the cluster and give a name to the client.
yield nc.connect("127.0.0.1:4222", closed_cb=closed_cb)
@tornado.gen.coroutine
def handler(msg):
# Can check whether client is in draining state
if nc.is_draining:
print("[Status ] Draining, will disconnect soon...")
print("[Received] {}".format(msg.data))
yield nc.publish(msg.reply, b'I can help')
yield nc.subscribe("help", "workers", cb=handler)
responses = []
@tornado.gen.coroutine
def send_requests():
# Send 100 async requests and wait for all the responses.
for i in range(0, 1000):
try:
response = yield nc.request("help",
'[{}] help!'.format(i),
timeout=0.1)
responses.append(response)
except:
break
loop.current().spawn_callback(send_requests)
yield tornado.gen.sleep(1)
# Gracefully close the connection and wait for closed callback to be signaled.
yield nc.drain()
yield conn_closed
print("Received {} responses".format(len(responses)))
