offline_archive.bzlThe nix package build's stand-in for reindeer's http_archive: the sandbox has no network, and buck2's downloader takes no file:// URL (measured 2026-09-26: "Error building request: invalid format"). nix fetches every crate by the sha256 third-party/BUCK records and places it at third-party/crates/<name>; package.nix loads this over the builtin, so the BUCK file itself is unchanged. The output directory is named after the target, as http_archive's is, because the generated crate_roots are written relative to it.
10def _extract_impl(ctx): 11 out = ctx.actions.declare_output(ctx.label.name, dir = True) 12 ctx.actions.run( 13 cmd_args( 14 "sh", 15 "-c", 16 'mkdir -p "$1" && tar -xzf "$2" -C "$1" --strip-components="$3"', 17 "--", 18 out.as_output(), 19 ctx.attrs.src, 20 str(ctx.attrs.strip_components), 21 ), 22 category = "extract_crate", 23 ) 24 return [DefaultInfo(default_output = out)]
26_extract = rule( 27 impl = _extract_impl, 28 attrs = { 29 "src": attrs.source(), 30 "strip_components": attrs.int(), 31 }, 32) 33 34def http_archive(name, sha256, strip_prefix, urls, visibility = None, **_kwargs): 35 _extract( 36 name = name, 37 src = "crates/" + name, 38 strip_components = len(strip_prefix.split("/")), 39 visibility = visibility, 40 )