Golioth Gives Embedded IoT Devices an SSH-Like Remote Zephyr Shell

Internet of Things (IoT) specialist Golioth has come up with a new trick for users of its platform: interacting with their embedded devices through a Secure Shell (SSH)-like connection — "with limitations," the company admits.

"This is a hack day project we did at Golioth to utilize Remote Procedure Calls (RPCs) in the Golioth Firmware SDK [Software Development Kit] to send and receive data from an embedded cellular device," Golioth's Chris Gammell explains. "These RPCs directly interact with the Zephyr Shell. We then created a web frontend that can utilize the Golioth REST API to send commands down and see what is coming back on the shell. In the process, we can command the boards to do interesting things!"

As you might expect from a hack-day project, the feature comes with some hefty caveats. The first is that while Gammell describes it as being like Secure Shell (SSH), the popular remote connection standard, it's actually something different. The text-based shell is accessed in-browser, and provides access to the device's Zephyr real-time operating system (RTOS). "The Zephyr shell was never intended to do the same amount of interaction [as a Linux shell]," Gammel admits, "it's really meant for debug and direct user input."

It's also somewhat inefficient, in terms of data usage and a device's battery life — and, Gammell says, "is not needed for IoT operations. But," he continues, "I have always wanted a remote shell because it's the way that I'm used to interacting with higher powered devices like a Raspberry Pi (over SSH). We also used to have this buried in our Firmware SDK, but it was available on so few devices that it wasn't worth promoting. I always loved the idea of it though because of the flexibility."

More information, including a link to the demo app, is available on the Golioth blog.