NBPR.Artifact (NBPR v0.2.0)

Cache-key, naming, and on-disk layout for NBPR package artefacts.

An nbpr artefact is a tarball produced by source-building a Buildroot package against a specific (system, system-version, build-options) tuple. This module is the single source of truth for:

the canonical cache key derived from those inputs
the canonical tarball filename
the local cache directory where the extracted tree lives

Tarball layout (matches Nerves.Artifact.Archive's --strip-components=1 contract so we can reuse its extractor later):

<package>-<version>-<system>-<system_version>/
  manifest.json
  target/         # rootfs overlay
  staging/        # sysroot overlay (optional)
  legal-info/

All functions here are pure. I/O lives in Mix.Tasks.Nbpr.Fetch and the resolver implementations.

Summary

Returns the absolute path to the extracted artefact directory under the Nerves data dir. Mirrors Nerves.Env.data_dir/0's behaviour: respects NERVES_ARTIFACTS_DIR, falls back to $XDG_DATA_HOME/nerves, then ~/.local/share/nerves.

cache_key(inputs)

Returns a 16-character hex digest derived from a SHA-256 over the canonical encoding of all inputs. The encoding sorts build_opts so that opt order doesn't perturb the key.

dir_name(inputs)

Returns the directory name (no leading path) where the extracted artefact will live. This is also the single top-level directory expected inside the tarball.

download_path(inputs)

Returns the absolute path where the downloaded tarball is staged before extraction. Sibling to the artefacts dir, mirroring Nerves' dl/ convention.

manifest(inputs)

Returns a JSON-serialisable map describing the artefact for inclusion as manifest.json inside the tarball. Lets consumers verify that an extracted artefact matches the cache key they expected.

tarball_name(inputs)

Returns the canonical tarball filename for a given set of build inputs.

Types

build_inputs()

@type build_inputs() :: %{
  package_name: String.t(),
  package_version: String.t(),
  system_app: atom(),
  system_version: String.t(),
  build_opts: keyword()
}

Functions

cache_dir(inputs)

@spec cache_dir(build_inputs()) :: String.t()