[WIP] LibreMesh OpenWrt Buildroot docker

A set of dockerfiles to build LibreMesh using a precompiled OpenWrt BuildRoot.

Some images are available also in the official docker registry They are huge (9-10GB), however the download could be faster than build all from scratch.

docker pull agave0/openwrt-buildroot:ath79-generic-v23.05.5

Summary of benefits:

• efficiently and fastly test which device fails:
  • too small (running make with -i or --ignore-errors)
  • version_dist hardcoded 8chars (firmware-utils)
  • firmware-utils use custom messages to say the initramfs/sysupgrade/factory was too big (maybe a sort of numeric error codes could be asked/proposed)
• this turns out something similar to make clean but that if you turn it off and on again it has already compiled everything and all the kernel_modules (if you don't need to modify the kernel)
• shared kmods:
  • across different flavors
  • could eventually be used by a ci to rebuild libremesh firmwares at commit (maybe only for a subset of targets)
  • this by producing a kind of snapshot that however keep the same kernel modules in common, when not varying the underlying openwrt distribution

todos:

• resetup the share of same toolchain for same archs
• include scripts to generate configs/23.05.5/*.autogen
• publish the tools+toolchains docker images
• remove kernel modules that no one will ever want to install on libremesh, and that are more appropriate on a plain openwrt (video, sound)
• of openwrt 23.05.5 only 56/75 targets are built, check if all excluded_targets are really exotic
• eventually test external_toolchain on openwrt-24
• eventually try with strace to understand which path are never touched and that could be safely removed

Build a single image

make \
  TARGET=x86 \
  SUBTARGET=64 \
  OPENWRT_VERSION=23.05.5 \
  EXTRA_IMAGE_NAME=

Use the docker image

Start the container

docker run -it libremesh/openwrt-buildroot:x86-64-v23.05.5

From inside the container select a device from menuconfig

make menuconfig

Build libremesh for that device

date ; make -j$(nproc) > build_log.txt 2>&1 ; date

Images sizes and time

This example is based on a pc 4core, 16GB ram, not SSD.
Every step depends also on network resources.

Dockerfile steps

Shared between all docker images

size	time	step
80.6MB		0. debian:bullseye-slim
795MB		1. install build system essentials
841MB		2. download openwrt
1.09GB		3. download feeds
1.68GB		4. download kernel and packages related archives

To update

• build tools
• build toolchain
• make a first build without selecting any profile

Removed because external toolchain is broken in 23.05.5 [1] Specific to each target/subtarget | 2.28GB | | 5. download sdk and extract tools and toolchain (ath79/generic) | | 10.5GB | ~57min | 6. make a first build (ath79/generic) |

Tests

Tests were made on:

• x86/64 running in qemu
• ath79/generic Ubiquiti LiteBeam M5 (XW)
• ath79/nand Meraki MR18

Resources

• External Toolchain https://openwrt.org/docs/guide-developer/external_toolchain
• Build all host tools https://github.com/openwrt/openwrt/commit/ebabdff4017fe2ed14491908ebe00589de0da189
• Reusing toolchain https://forum.openwrt.org/t/reusing-openwrt-based-toolchain-as-external-toolchain/66989

[1] These packages comes without the correct versions:

• libatomic1
• libc
• libgcc1
• libpthread
• librt
• libstdcpp6 This error seems to disappear on 24.10.0-rc5 A list of related fixes should includes at least:
• scripts/ext-toolchain: implement external GCC version detection: openwrt/openwrt#13735