Run the example

  1. Install and run the device gateway
  2. Download the Python client library
  3. Copy the root certificate of the gateway to your working directory. As default, the certificate(ca.crt) resides in cert of the installation directory.

  4. Change the server information in example/connect/test/test.py as needed.

     # the path of the root certificate
 GATEWAY_CA_FILE = '../../../../cert/gateway/ca.crt'

 # the address of the gateway
 GATEWAY_IP = '192.168.0.2'
 GATEWAY_PORT = 4000
  5. Run. 
     cd example/connect/test
 python test.py

1. CLI

With the Command-Line Interface(CLI), you can test 5 functions related to connection management.

===== Main Menu =====

(1) Search devices
(2) Connect to a device synchronously
(3) Manage asynchronous connections
(4) Accept devices
(5) Device menu
(q) Quit

>>>>> Select a menu:

(1) Search devices

To connect devices, you have to know their addresses and related options such as connection mode. By using Connect.SearchDevice, you can get these information in a subnet.

>>>>> Select a menu: 1
Searching devices in the subnet...
***** Found devices: 9
[deviceID: 544114231
type: BIOENTRY_W2
useDHCP: true
IPAddr: "192.168.0.104"
port: 51211
, deviceID: 540092578
type: BIOSTATION_L2
useDHCP: true
IPAddr: "192.168.0.120"
port: 51211
useSSL: true
, deviceID: 846
type: BIOLITE_N2
useDHCP: true
IPAddr: "192.168.0.117"
port: 51211

(2) Connect to a device synchronously

The simplest way of connecting to a device is to use Connect.Connect.

>>>>> Select a menu: 2
>> Enter the IP address of the device: 192.168.0.104
>> Enter the port of the device (default: 51211):
>> Use SSL y/n (default: n):
Connecting to 192.168.0.104:51211...
[TCP_CONNECTED] Device 544114231
Connected to 544114231

(3) Manage asynchronous connections

When you have to manage permanent connections to multiple devices, asynchronous APIs would be a better choice. With these APIs, the gateway will handle connections to devices in the background. For example, if some devices are disconnected, the gateway will try to reconnect them automatically.

>>>>> Select a menu: 3

***** Async connections: 0
[]

===== Async Menu =====

(1) Add async connections
(2) Delete async connections
(3) Refresh the connection list
(q) Return to Main Menu

>>>>> Select a menu: 1
>> Enter the device ID (Press just ENTER if no more device): 540092578
>> Enter the IP address of the device: 192.168.0.120
>> Enter the port of the device (default: 51211):
>> Use SSL y/n (default: n): y
>> Enter the device ID (Press just ENTER if no more device): 939504224
>> Enter the IP address of the device: 192.168.0.110
>> Enter the port of the device (default: 51211):
>> Use SSL y/n (default: n):
>> Enter the device ID (Press just ENTER if no more device):

***** Async connections: 2
[deviceID: 939504224
IPAddr: "192.168.0.110"
port: 51211
autoReconnect: true
, deviceID: 540092578
IPAddr: "192.168.0.120"
port: 51211
autoReconnect: true
useSSL: true
]

[TCP_CONNECTED] Device 939504224
[TLS_CONNECTED] Device 540092578

(4) Accept devices

In some environments, the devices should connect to the gateway, not vice versa. For devices to connect to the gateway, you have to do the followings;

  1. Change the connection mode to DEVICE_TO_SERVER using Connect.SetConnectionMode.
  2. By default, the gateway will not accept any incoming connections. You have to add the devices to the accept filter using Connect.SetAcceptFilter.
>>>>> Select a menu: 4
***** Pending devices: 1
[deviceID: 939342898
IPAddr: "192.168.0.121"
lastTry: 1584650963
]
***** Accept filter:

===== Accept Menu =====

(1) Add devices to the filter
(2) Delete devices from the filter
(3) Allow all devices
(4) Disallow all devices
(5) Refresh the pending device list
(q) Return to Main Menu

>>>>> Select a menu: 3
***** Accept filter:  allowAll: true

[TLS_CONNECTED] Device 939342898

Apart from the IP address, there are two important options for device connections. You can change the connection mode using Connect.SetConnectionMode and enable/disable SSL using the SSL APIs.

>>>>> Select a menu: 5
***** Managed devices: 1
[deviceID: 939342898
connectionMode: DEVICE_TO_SERVER
IPAddr: "192.168.0.121"
status: TLS_CONNECTED
useSSL: true
]

===== Device Menu =====

(1) Set connection mode
(2) Enable SSL
(3) Disable SSL
(4) Disconnect
(5) Disconnect All
(6) Refresh the device list
(q) Return to Main Menu

>>>>> Select a menu: 3
Enter the device ID (Press just ENTER if no more device): 939342898
Enter the device ID (Press just ENTER if no more device):

To change these options, you have to connect to the devices first using menu (2) ~ (4).

2. Synchronous connections

You can use the Synchronous APIs to manage the connections by yourself.

class ConnectSvc:
  # ...

  def connect(self, connInfo):
    response = self.stub.Connect(connect_pb2.ConnectRequest(connectInfo=connInfo))
    return response.deviceID

  def disconnect(self, deviceIDs):
    self.stub.Disconnect(connect_pb2.DisconnectRequest(deviceIDs=deviceIDs))

connInfo = getConnectInfo(); # getting the connection info from user

try:
  devID = connectSvc.connect(connInfo)

  # do something with the device

  deviceIDs = [devID]
  connectSvc.disconnect(deviceIDs)

except grpc.RpcError as e:
  print(f'Cannot connect to the device: {e}')

3. Asynchronous connections

With the Asynchronous APIs, you only have to register or deregister devices. The gateway will handle all the connection related tasks in the background.

class ConnectSvc:
  # ...
  def addAsyncConnection(self, connInfos):
    self.stub.AddAsyncConnection(connect_pb2.AddAsyncConnectionRequest(connectInfos=connInfos))

  def deleteAsyncConnection(self, deviceIDs):
    self.stub.DeleteAsyncConnection(connect_pb2.DeleteAsyncConnectionRequest(deviceIDs=deviceIDs))
}

You have to use Connect.GetDeviceList to get the status of the registered devices.

connInfos = []

try:
  devList = connectSvc.getDeviceList()

  for dev in devList:
    if dev.autoReconnect:
      connInfos.append(dev)

  print(f'\n***** Async connections: {len(connInfos)}', flush=True)

except grpc.RpcError as e:
  print(f'Cannot show the async connections: {e}')

4. Accept devices

class ConnectSvc:
  # ...
  def getAcceptFilter(self):
    response = self.stub.GetAcceptFilter(connect_pb2.GetAcceptFilterRequest())
    return response.filter

  def setAcceptFilter(self, filter):
    self.stub.SetAcceptFilter(connect_pb2.SetAcceptFilterRequest(filter=filter))      
}

By default, the gateway will not accept any incoming connections. Connect.GetPendingList can be used to get the devices, which are trying to connect to the gateway but not in the accept filter.

class ConnectSvc:
  # ...
  def getPendingList(self):
    response = self.stub.GetPendingList(connect_pb2.GetPendingListRequest())
    return response.deviceInfos
}

You can allow all the incoming connections by setting AcceptFilter.allowAll to true. Or, you can specify the devices to be allowed in AcceptFilter.deviceIDs.

# allow all devices
filter = connect_pb2.AcceptFilter(allowAll=True)
connectSvc.setAcceptFilter(filter)

# add specific devices to the filter
deviceIDs = getDeviceIDs()

filter = connectSvc.getAcceptFilter()
filter.allowAll = False

for devID in deviceIDs:
  existing = False
  for existingDevID in filter.deviceIDs:
    if devID == existingDevID:
      existing = True
      break

  if not existing:
    filter.deviceIDs.append(devID)

connectSvc.setAcceptFilter(filter)

5. Connection status

Apart from Connect.GetDeviceList, you can also get the realtime update using Connect.SubscribeStatus.

def getDeviceStatus(statusCh):
  try:
    for status in statusCh:
      if status.status == connect_pb2.DISCONNECTED:
        print(f'[DISCONNECTED] Device {status.deviceID}', flush=True)
      elif status.status == connect_pb2.TLS_CONNECTED:
        print(f'[TLS_CONNECTED] Device {status.deviceID}', flush=True)
      elif status.status == connect_pb2.TCP_CONNECTED:
        print(f'[TCP_CONNECTED] Device {status.deviceID}', flush=True)

  except grpc.RpcError as e:
    if e.code() == grpc.StatusCode.CANCELLED:
      print('Subscription is cancelled', flush=True)    
    else:
      print(f'Cannot get the device status: {e}')   

# start monitoring the status changes
statusCh = connectSvc.subscribe(QUEUE_SIZE)
statusThread = threading.Thread(target=getDeviceStatus, args=(statusCh,))
statusThread.start()

# stop monitoring
statusCh.cancel()
statusThread.join()

6. Connection mode

class ConnectSvc:
  # ...
  def setConnectionMode(self, deviceIDs, mode):
    self.stub.SetConnectionModeMulti(connect_pb2.SetConnectionModeMultiRequest(deviceIDs=deviceIDs, connectionMode=mode))

After setting the connection mode, you have to use different APIs accordingly. With SERVER_TO_DEVICE, you should use the Synchronous APIs or the Asynchronous APIs. to connect to the devices. With DEVICE_TO_SERVER, the AcceptFilter should be configured correctly.

7. SSL

TLS 1.2 can be used for more secure communication between the gateway and devices. Refer to Secure Communication for details.

class ConnectSvc:
  # ...
  def enableSSL(self, deviceIDs):
    self.stub.EnableSSLMulti(connect_pb2.EnableSSLMultiRequest(deviceIDs=deviceIDs))

  def disableSSL(self, deviceIDs):
    self.stub.DisableSSLMulti(connect_pb2.DisableSSLMultiRequest(deviceIDs=deviceIDs))

Updated: