NBPR.Buildroot.Build (NBPR v0.2.1)

Drives a per-package Buildroot build.

Given a patched BR source tree (from NBPR.Buildroot.Source.ensure!/2), a stable output dir, a rendered defconfig (from NBPR.Buildroot.Defconfig.render!/3), and a Buildroot package name, produces per-package output at <output_dir>/per-package/<pkg>/{target,staging}.

The actual build is delegated to a NBPR.Buildroot.Backend — native make inside the canonical env, or a container runtime (docker/podman) elsewhere. NBPR.Buildroot.Backend.select/0 picks the appropriate one. This module owns the shared build env and the spec hand-off.

Output dir reuse

The caller supplies the output_dir. For interactive speed, use a stable per-(system, BR-version) path — the toolchain extraction, host-skeleton, host-fakedate, and other shared steps then survive between invocations and only the package being rebuilt actually compiles. make olddefconfig reconciles defconfig drift across builds (e.g. enabling a different BR2_PACKAGE_*=y).

Summary

Functions

build!(br_source, output_dir, defconfig_text, br_package, extra_env \\ [], opts \\ [])

Builds br_package against defconfig_text using the BR tree at br_source, with output going to output_dir. Returns the harvest dir (containing per-package/<br_package>/), ready for NBPR.Buildroot.Harvest.harvest!/2.

Functions

build!(br_source, output_dir, defconfig_text, br_package, extra_env \\ [], opts \\ [])

@spec build!(
  Path.t(),
  Path.t(),
  String.t(),
  String.t(),
  [{String.t(), String.t()}],
  keyword()
) ::
  Path.t()

extra_env is merged into the make invocation's env. Use it to pass Nerves-specific variables that the system's defconfig references — most importantly NERVES_DEFCONFIG_DIR (so BR2_GLOBAL_PATCH_DIR resolves) and BR2_EXTERNAL (so the system's BR external tree is visible).

output_dir is created if missing. Existing contents are preserved — this is the design — so subsequent builds reuse the toolchain, skeleton, and other unchanging packages. To force from-scratch, File.rm_rf!(output_dir) before calling.

opts accepts :extra_mounts — additional host paths a container backend bind-mounts at the same path inside the container.