Build OpenEmber

OpenEmber uses Kconfig to produce build/.config, then scripts generate build/config.cmake for CMake. Linux with GCC/G++ is recommended; check the repo’s CMakeLists.txt for the minimum CMake version.

Prerequisites

• Linux
• CMake (see main repo)
• A toolchain and basic build tools
• protoc and Protobuf C++ development libraries (default: openember-msgs enabled)
• Optional: sudo apt install libssl-dev for some dependencies

kconfig-frontends can be downloaded automatically (e.g. kconfig-frontends-nox under .kconfig-frontends/) without root.

Recommended: ember one-shot build

From the openember repository root:

chmod +x ./scripts/ember   # once
./scripts/ember build

If ember is on your PATH via openember-cli:

ember build

What it does:

• If build/.config is missing, generates a default config non-interactively and writes build/config.cmake.
• Then runs cmake -S . -B build and cmake --build.
• The first menuconfig may download kconfig-frontends-nox into .kconfig-frontends/.

Common subcommands:

Command	Description
./scripts/ember menuconfig [build_dir]	Interactive Kconfig → .config + refresh config.cmake
./scripts/ember genconfig [build_dir]	Rewrite config.cmake from .config
./scripts/ember update [build_dir]	cmake -S . -B <dir> (alias: configure)
./scripts/ember build [build_dir]	Bootstrap config if needed, then full build
./scripts/ember all [build_dir]	menuconfig + update + build
./scripts/ember clean [build_dir]	Remove the build directory

Parallelism is controlled by OPENEMBER_JOBS (default: nproc). On machines with many cores and large link steps, lower it:

OPENEMBER_JOBS=4 ./scripts/ember build

See ember CLI for install, env management (ember add / use), and the full command set.

The top-level CMakeLists.txt includes config.cmake from the build directory when present.

Scripts + CMake (manual)

bash scripts/kconfig/menuconfig.sh build
# CI / no TTY:
# OPENEMBER_KCONFIG_NONINTERACTIVE=1 bash scripts/kconfig/menuconfig.sh build

bash scripts/kconfig/genconfig.sh build

cmake -S . -B build
cmake --build build -j"$(nproc)"

Makefile helpers

make menuconfig
make genconfig
make update
make build
# or: make all

Message protocol dependency

OpenEmber enables OPENEMBER_ENABLE_MSGS=ON by default and builds/links C++ Protobuf bindings from openember-msgs. In Kconfig this lives under Communication / Messages.

Generated sources land under generated/openember/msgs/ (*.pb.h / *.pb.cc), compiled into openember_msgs_cpp (openember::msgs_cpp).

Suggested layout:

Projects/OpenEmber/
├── openember/
└── openember-msgs/

If openember-msgs is not a sibling checkout:

cmake -S . -B build \
  -DOPENEMBER_MSGS_SOURCE=LOCAL \
  -DOPENEMBER_MSGS_LOCAL_SOURCE=/path/to/openember-msgs

Default OPENEMBER_MSGS_SOURCE=FETCH pulls a main archive at configure time. Disable with -DOPENEMBER_ENABLE_MSGS=OFF when not needed.

Debian/Ubuntu:

sudo apt install protobuf-compiler libprotobuf-dev

More detail: openember-msgs.

Outputs

Binaries usually land under build/bin/ depending on enabled modules and examples.

Troubleshooting

• Missing build/.config: run ./scripts/ember menuconfig, menuconfig.sh, or non-interactive generation first.
• OOM / terminal dies during build: default -j$(nproc) may be too high; set a smaller OPENEMBER_JOBS.
• Script permission issues: invoke with bash scripts/...; do not build as root/sudo.
• Permission denied on build/bin/...: check for empty files, missing execute bits (ls -l), and whether build/ is owned by root.

More detail: upstream build.md.