Workflows for Elixir Nerves

Jason Johnson

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Now is the best time to get started with Nerves.

"What about the chip shortage? Why now?"

Reasons

 (congrats Masatoshi!     )

Workflows include: connecting to, interfacing with, and loading firmware to Nerves targets.

What/How?

Burning firmware to a microSD card is the most primitive workflow for Nerves and        necessary.

 

Use one of: mix burn, fwup, dd, or Etcher.

Use cases

• Early development
• Custom Nerves system
• Unsupported development board/hardware
• Device provisioning sequences

Drawbacks

• Cumbersome
• Wears out SD cards
• Interrupts "flow"

Benefits

• Ensures fresh firmware
• Sometimes it's faster than WiFi

 

What/How?

Allows you to open a direct console connection to the Nerves target through a terminal emulator like screen.

Use cases

• Early development
• Firmware debugging
• Hardware debugging

Drawbacks

• Wires
• Confusing tx/rx
• Impaired console
• Not always available

Benefits

• See console output immediately
• No networking!

 

What/How?

Some Nerves targets include HDMI or HDMI mini ports that you can connect directly to an external display.

Use cases

• Early development
• Hardware debugging
• Kiosks

Drawbacks

• Wires
• Not always available

Benefits

• See console output early
• No networking!

What/How?

This is the suggested path of least resistance for connecting to your Nerves target in the official Getting Started guide.

Use cases

• Easy configuration
• Early development
• Other options unavailable

Drawbacks

• Wires
• Requires DATA cable, not just power
• Local networking with mDNS sometimes tricky

Benefits

• Fast, easy, convenient(?)
• Supplies both power and data

What/How?

There are a LOT of ways your Nerves target can be configured to use WiFi. Vintage Net provides support for all the common and some uncommon WiFi configurations.

Use cases

• Hobby projects
• Prototyping
• Commercial use

Drawbacks

• Even with Vintage Net, wireless networking may present confusing situations.

Benefits

• No wires!
• Commonly available
• Vintage Net Wizard

What/How?

The  REPL experience is an essential aspect of working with Elixir. Nerves enables iEx sessions with the target over ssh.

Use cases

• During active development on the host
• While running tests
• For remote shell connections to target(s)
• Pretty much anytime!

Drawbacks

• Possible to break things
• May produce confusing code situations

Benefits

• Access logs, debug, inspect, and run code
• Interact with runtime environment
• RingLogger
• RamoopsLogger
• Toolshed
• Copy and paste method

What/How?

This magical package enables fast and easy OTA updates to Nerves targets.

Use cases

• Project development
• Library development
• Hardware hacking

Drawbacks

• May present confusing situations
• All modules replaced each time
• Doesn't support changes to config
• Doesn't support changes to dependencies

Benefits

• No wires!
• Tight feedback loop
• Relatively easy to setup
• Combine with OTP to quickly iterate on supervision trees

kentaro/mix_tasks_upload_hotswap

Passes compiled modules to IEx.Helpers.nl/2, which leverages Erlang's rpc:call to load new BEAM code.

What/How?

A special blend of powerful abstractions rolled into a small set of battle-tested Erlang libraries. Including the classics like supervisors, processes, links, and GenServer.

Use cases

• Concurrent process management
• Tweaking startup sequences
• Designing supervision trees
• Debugging failure conditions

Drawbacks?

Benefits

• Direct control over process restarts
• Great DX with Hotswap or iEx
• Process inspection and communication
• Fine grained control

What/How?

A library for managing live, interactive, and collaborative code notebooks. Get started by downloading a pre-built firmware release that includes Livebook and some demo notebooks.

Use cases

• Experimenting with new hardware
• Documentation and guides
• Onboarding developers
• Demos!

Drawbacks

• Security considerations
• Overwriting notebooks by burning

Benefits

• It's a live coding journal that runs on Nerves!
• Collaborative
• Reproducible
• Tight feedback loop

https://livebook.dev/

What/How?

"An open-source firmware updates server"...

Also includes:

Use cases

• Commercial
• Consultancy
• Community(?)

Drawbacks

• Community hosted version no longer available
• Hard to configure self-hosted Nerves Hub

Benefits

• OTA updates
• Products
• Deployments
• Tags

Install on AWS with nerves-hub/terraform repo.

Run as separate services on another platform.