IoT Edge CAN Support

Chase Hollingsead 6

I'm currently working on an IoT Edge Module that needs to read / write data via the host computer's CAN bus ports (can0, can1, etc). Is it possible to bind the CAN bus ports to the IoT Edge module via the deployment.json file? I'm assuming you can since you are able to bind tcp ports, but I haven't seen anything in the Microsoft documentation on how you would bind CAN ports to a container.

AshokPeddakotla-MSFT 32,946 Reputation points

2022-01-12T10:51:42.25+00:00

@Chase Hollingsead Welcome to Microsoft Q&A forum!

Thanks for your query. Community SME's on this topic or our team will review your scenario and circle back at the possible earliest time.
AshokPeddakotla-MSFT 32,946 Reputation points

2022-01-12T13:49:56.357+00:00

@Chase Hollingsead Did you already check this documentation? Map host port to module port

1 answer

Sander van de Velde | MVP 32,011 Reputation points MVP

2022-01-12T14:48:54.687+00:00
Hello @Chase Hollingsead ,

it seems you want to access a can bus on Linux?

In general, via the Azure IoT Edge Container Create Options, extra settings regarding the sandbox behavior of an IoT Edge module can be passed.

This way, eg. access to file system folders, port mappings or serial port access is controlled.

Here is an example of getting access to /dev/ttyS0, a serial port.

If a can bus port is available as /dev/can0 or /dev/can1, this could work for you too?

Next to that, the Azure IoT Edge 'user' needs to have access to the actual device.

You can give everyone access like this, just to test:

sudo chmod 777 /dev/????

Note: In production, perhaps 777 is just a bit too much freedom...

Keep in mind, this line will need to be added to the crontab on the device to survive a reboot.

Can you try this out?
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Chase Hollingsead 6 Reputation points

2022-01-12T15:35:56.687+00:00

This seems to be what I need. Let me try this and if it works, I'll accept this as the answer.

Thanks!

Sander van de Velde | MVP 32,011 Reputation points MVP

2022-02-04T17:21:58.66+00:00

Hello @Chase Hollingsead ,

did you have some time to test this?

Can you share your findings?

Chase Hollingsead 6 Reputation points

2022-02-04T17:23:16.833+00:00

Unfortunately we're still working through the CAN hardware to be able to even get to the point to where we can test the binding of the CAN ports to the container. We're actively working on this, and I 100% will respond as soon as we make significant progress.

Chase Hollingsead 6 Reputation points

2022-02-09T22:37:05.683+00:00

Actually, I had a quick question about the example that you sent. In the portConfigs section, it seems that all of those settings are specifically related to serial/rs232 communications. Do you have any documentation / examples of what those configurations would be for a SocketCAN port, or if these configuration options are even necessary? If I don't specify anything in the portConfigs section, will it just use whatever the ports have configured on the host?

Sander van de Velde | MVP 32,011 Reputation points MVP

2022-02-10T18:00:36.28+00:00

Hello @Chase Hollingsead ,

yes, as said above, this is a sample for serial ports.

I do not have experience or access to devices having a can bus but I hope these pop up in the /dev folder.

If this is the case and your application could run on the command-line using these 'devices' this could work for docker containers too, running inside an equal application.

Can you confirm the can bus devices are available in /dev ?

Chase Hollingsead 6 Reputation points

2022-02-10T22:13:06.267+00:00

They are currently not in the list of devices. The can cards show up under the /dev/ folder as ttyACM0, but when running the commands to bring up can0 and can1, they show up in the network interfaces if I run the ifconfig command, but not under the list of devices.

Chase Hollingsead 6 Reputation points

2022-02-11T16:11:25.85+00:00

Just to close the loop on this, since the SocketCAN ports didn't show up under the /dev/ folder, I wasn't able to bind them to the container with the way @Sander van de Velde | MVP proposed. However, because they showed up as network interfaces, I was able to modify the HostConfig settings in the deployment file, so that way the docker container would have access to all the same interfaces that the host had. Once I did that, I was able to bind to the SocketCAN ports.

For completeness, this is what my deployment.debug.template.json file looked like for the module:

"ModuleName": { "version": "1.0.0", "type": "docker", "status": "running", "restartPolicy": "always", "settings": { "image": "${MODULEDIR<../ModuleName>.debug}", "createOptions": { "NetworkingConfig": { "EndpointsConfig": { "host": {} } }, "HostConfig": { "NetworkMode": "host", "LogConfig": { "Type": "json-file", "Config": { "max-size": "10m", "max-file": "7" } } } } } }

Sander van de Velde | MVP 32,011 Reputation points MVP

2022-02-12T12:02:03.32+00:00

Hello @Chase Hollingsead ,

Thanks for the update. Nice to see Container Create options come to the rescue once again :-)

If the reply was helpful please don't forget to upvote and/or accept as the answer, so others with the same question can find it more easily.
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IoT Edge CAN Support

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