nats-io/nats.py v0.8.0

Release v0.8.0

on GitHub

Added

• Support for drain mode (#82)

  This feature allows clients to gracefully disconect, letting the subscribers
  handle any inflight messages that may have been sent by the server already.

  async def handler(msg):
    print("[Received] ", msg)
    await nc.publish(msg.reply, b'I can help')
  
    # Can check whether client is in draining state
    if nc.is_draining:
      print("Connection is draining")
  
  await nc.subscribe("help", "workers", cb=handler)
  
  requests = []
  for i in range(0, 1000):
      request = nc.request("help", b'help!', 0.2)
      requests.append(request)
  
  # Wait for all the responses
  responses = await asyncio.gather(*requests)
  print("Received {} responses", len(responses))
  
  # Gracefully close the connection.
  await nc.drain()

  Example usage can be found at:
  https://github.com/nats-io/asyncio-nats/blob/e1996e7c4ae30daa63c49af20700d42fad1bd2f2/examples/drain-sub.py

• Support for no_echo mode (#74)

  When connected to a NATS Server v1.2.0 or above, a client can now opt to avoid
  receiving messages that it itself has published.

  await ncA.connect(no_echo=True)
  await ncB.connect()
  
  async def handler(msg):
    # Messages sent by `ncA' will not be received.
    print("[Received] ", msg)
  
  await ncA.subscribe("greetings", cb=handler)
  await ncA.publish("greetings", b'Hello World!')
  await ncB.publish("greetings", b'Hello World!')

• Added connect_timeout option to disconnect from unhealthy servers in the pool (https://github.com/nats-io/asyncio-nats/pull/83/files)

  # Give up if can't connect to a server in 5 seconds
  await nc.connect("demo.nats.io:4222", connect_timeout=5)

• Added loop parameter to connect to set the event loop like in asyncio APIs

  await nc.connect("demo.nats.io", loop=asyncio.new_event_loop())

Improved

• connect API is now modeled to work more closely to how the Go client works:

  # Assume 'nats://' scheme
  await nc.connect("demo.nats.io:4222")
  
  # Complete with scheme a la Go client classic usage.
  await nc.connect("nats://demo.nats.io:4222")
  
  # Use default 4222 port.
  await nc.connect("demo.nats.io")
  
  # Explicit cluster list
  await nc.connect(servers="demo.nats.io")

Fixed

• Examples and tests now support Python 3.7 (#71)

• Added user, password, token parameters to set the auth credentials for servers that were discovered implicitly. (f8c28b3)

  # Set user and info credentials
  await nc.connect("127.0.0.1:4222", user="foo", password="bar")
  
  # Token
  await nc.connect("127.0.0.1:4222", token="secretoken")

Changed

• Examples were changed to use async/ await instead of asyncio.coroutine and yield from (e1996e7)

Deprecated

• Removed Python 3.4 from build (b2ee929)

• Tests are now using async/await syntax throughout (#78)
  In the next v1.0 release client will be solely using async/await syntax (#68)