A simple python agent demonstrating the remote access capabilities of Cumulocity. Main Purpose is to demonstrate and use the Cloud Remote Access in other Agents. The module 'DeviceProxy' can be re-used and easily embedded into your Python project. It supports multiple parallel connections. It was tested in Python3.

• Install Python 2 or Python3 if not already installed. This module has been tested with Python3.

IMPORTANT

If you're running Cumulocity 10.7+ please continue with the next bullet point.

The following step should only performed for Cumulocity Versions < 10.7. Otherwise this will lead to issues.

• Import the Smart REST Template to Cumulocity which contains a Response Template for Remote Access Connect Operation.

• Change the c8yagnet.py header to your C8Y Credentials (device_id, baseurl, tenant, user and password must be set)
• Your Tenant must have subscribed to the feature cloud-remote-access. If you don't see that in your subscribed applications ask you Administrator to get it subscribed.
• Your user must have the permission to use the Cloud Remote Access Feature. There is a permission Remote Access which needs to be assigned to your user by your Administrator.
• If you don't see any Tab in Device Management Remote Access it is most likely because of one of the above mentioned bullet points.
• To test it you need a local SSH Server e.g. from Docker Hub running and accessible by your C8Y Agent. Please note that if you run your Agent in another docker container that the IP configured in the UI is the host IP address. You can find it out resolving the dns host.docker.internal most likely it is 192.168.65.2
• This is not only limited to SSH Server but also supports VNC and Telnet. At least VNC has been successfully tested.

• Install all dependencies by:

pip install -r requirements.txt

• Afterwards run:

python c8yagent.py

• In your Device Management you will se a Device Remote Access Demo Device <your device_id> with a Tab Remote Access Create a new Connection by Add endpoint and configure the required fields. Also make sure you set the correct credentials like User + PW or Private/Public Keys. The Host Key can be kept empty.
• Click on Connect and check if everything is working as expected.

Add c8y-device-proxy to your requirements.txt and import it to your Module which handles Cumulocity Operations.

pip install c8y-device-proxy

Alternatively copy the c8ydp package to your project.

from c8ydp.device_proxy import DeviceProxy, WebSocketFailureException

For Cumulocity Version >= 10.7: Make sure you subscribe to the Static Template Topic and you handle the message with Id 530

subscribe(mqttClient, 's/ds',0)

For Cumulcity Version < 10.7: Make sure you subscribe to the Smart REST Template id Example:

subscribe(mqttClient, f's/dc/{template_id}',0)

On received and valid Operation initialize the DeviceProxy module with the required and documented arguments. Please note that the Device Proxy supports Basic Auth with Tenant, User, Password and Device Certificates using a token. Either the basic credentials or the token must be set by initializing the DeviceProxy module.

Run the function DeviceProxy.connect().

For getting informed that the Web Socket Connection has been terminated add a close handler function in the constructor with 2 arguments for 'close_status' and 'close_reason'

def on_close_handler(close_status, close_reason):
    logger.info(f'Device Proxy has been closed with status {close_status}, reason {close_reason}')

...

device_proxy = DeviceProxy(tcp_host, tcp_port, tcp_buffer_size, connection_key, baseurl, tenantuser, password, token, on_close_handler)

• Check the status of the Operation in Control Tab and the failed Operations with the failure reason.
• Increase the Log Level of the Agent and Debug to the DeviceProxy Module to check what's going on.

These tools are provided as-is and without warranty or support. They do not constitute part of the Software AG product suite. Users are free to use, fork and modify them, subject to the license agreement. While Software AG welcomes contributions, we cannot guarantee to include every contribution in the master project.

For more information you can Ask a Question in the TECHcommunity Forums. You can find additional information in the Software AG TECHcommunity.