farmbot_os/BUILDING.md

Advanced Things that you shouldn't need to worry about.

Documentation

Documentation isn't stored in source control, because it is large and changes frequently. Raise an issue if you would like them published on HEX.

To view documentation:

cd ~/farmbot/os
MIX_ENV=dev mix deps.get
MIX_ENV=dev mix docs

Tests

Tests coverage is a work in progress and all help is appreciated!

export MIX_ENV=test
mix deps.get
mix test

Code Styling and Consistency

Credo doesn't work very well on umbrella projects, so I only enforce credo on the main application.

Note: this will show all #TODOS in the application.

cd ~/farmbot/os/apps/farmbot
export MIX_ENV=dev
mix deps.get
mix credo --strict

Building the Linux RootFS

cd ~/farmbot/os
# this should set up the environment needed to build the system
MIX_ENV=prod mix farmbot.system

# If that gives an error try this:
git clone https://github.com/nerves-project/nerves_system_br deps/nerves_system_br
# then try again.

# Now that the environment is set up you should change into the new dir it told you too.
cd apps/NERVES_SYSTEM_*
# from this dir we have a few different things we can configure in buildroot.

# To add/remove linux packages.
make menuconfig

# To add/remove busybox packages.
make busybox-menuconfig

# To add/enable/disable features in the kernel.
make linux-menuconfig

# Save those configs

# For buildroot packages
make savedefconfig

# For busybox config
cp build/busybox*/.config ../nerves_system_*/busybox_defconfig

# for linux config
cp build/linux*/.config ../nerves_system_*/linux-*.defconfig

# To make your configuration
make

# that will take a while depending on your machine. You will see the build output in your terminal.
# on a core i7, 32 gigs or ram, nvme ssd machine, it takes about 15-20 minutes depending on if ccache is enabled.

# when the rootfs build finishes to use said rootfs in building firmware:
cd ~/farmbot/os
MIX_ENV=prod NERVES_SYSTEM=~/farmbot/os/apps/NERVES_SYSTEM_* mix firmware

# this can then be uploaded to the device. (note you need an ip address)
MIX_ENV=prod NERVES_SYSTEM=~/farmbot/os/apps/NERVES_SYSTEM_* mix firmware --upload

# or burned
MIX_ENV=prod NERVES_SYSTEM=~/farmbot/os/apps/NERVES_SYSTEM_* mix firmware
MIX_ENV=prod bash scripts/burn.sh

Porting to a New System

There are several options for porting FarmBot to non-Raspberry Pi systems. One option is to use the RPI3 system as a template:

cd ~/os/farmbot/os/apps
mix new nerves_system_newboard

At bare minimum you will need the following files files, using the RPI3 system as a template:

nerves_system_newboard
├── rootfs-additions
├── busybox_defconfig
├── fwup.conf
├── linux-VERSION.defconfig
├── mix.exs
├── nerves.exs
└── nerves_defconfig

Lets go thru those files and folders and explain what each one is.

• rootfs-additions thechnically this is optional but that will never happen. there is usually some prop files needed like wireless firmware, erlinit config etc.
• busybox_defconfig This file has extra configs for Farmbot System. We require a few extra packages in busybox to be enabled.
  • mkfs.ext
• fwup.conf FwUp is how farmbot updates and builds its firmware. This can be configured how ever your platfrom requires, but we require a few basic things
  • one squashfs system partition which will ALWAYS read only.
  • one data partition. This can be any filesystem as long as it supports symbolic links. It will be mounted read only MOST of the time
• linux.defconfig The configuration for the Linux Kernel on this board.
• mix.exs a description of this project. requires a bit of configuration. see rpi3 system for example.
• nerves.exs configures a nerves target. See RPI3 System for examples.
• nerves_defconfig The buildroot configuration. Needs a bit of specifics.

  buildroot
  ├── packages
  |    ├── networking
  |    |   ├── hostapd
  |    |   ├── dnsmasq
  |    |   ├── dropbear
  |    |   └── iw
  |    |
  |    └── hardware handling
  |        └── avrdude
  |
  └── filesystem
      └── squashfs