NBPR.Artifact.Cache (NBPR v0.2.1)

On-disk cache for NBPR package artefacts.

Pure path/key logic lives in NBPR.Artifact; this module owns the I/O — checking whether an artefact is already extracted, and atomically extracting a downloaded tarball into the cache directory.

Extraction goes via a sibling temp directory and then a rename, so a failed extract never leaves a half-populated cache directory behind.

Summary

Functions

extract!(tarball_path, inputs)

Extracts a downloaded tarball into the canonical cache directory for the given inputs.

list()

Lists extracted artefacts in the cache root.

remove!(path)

Removes a single cache entry by absolute path. Returns :ok.

valid?(inputs)

Returns true when the artefact is already extracted into the cache directory. Currently a presence check; manifest-based verification is added alongside the resolver in a later commit.

Types

entry()

@type entry() :: %{
  dir: String.t(),
  path: String.t(),
  manifest: map() | nil,
  mtime: integer()
}

Functions

extract!(tarball_path, inputs)

@spec extract!(Path.t(), NBPR.Artifact.build_inputs()) :: :ok

Extracts a downloaded tarball into the canonical cache directory for the given inputs.

The tarball is expected to contain exactly one top-level directory (matching Nerves' --strip-components=1 convention); the contents of that directory become the cache directory's contents. Extraction is atomic via a temp directory + rename.

list()

@spec list() :: [entry()]

Lists extracted artefacts in the cache root.

An entry is a cache-root subdirectory containing a manifest.json — this skips siblings like dl/ (staged downloads) and system-source/. Each entry carries its directory name, absolute path, parsed manifest (or nil if the JSON is unreadable), and POSIX mtime. Sorted newest-first.

remove!(path)

@spec remove!(Path.t()) :: :ok

Removes a single cache entry by absolute path. Returns :ok.

valid?(inputs)

@spec valid?(NBPR.Artifact.build_inputs()) :: boolean()

Returns true when the artefact is already extracted into the cache directory. Currently a presence check; manifest-based verification is added alongside the resolver in a later commit.