def build_nar(cls, store_path, compression_type="xz", quiet=False):
"""Build a nix archive (nar) and return the resulting path."""
if compression_type not in cls.NAR_PATH_CACHE:
raise ValueError("Unsupported compression type: {}"
.format(compression_type))
if store_path in cls.NAR_PATH_CACHE[compression_type]:
return cls.NAR_PATH_CACHE[compression_type][store_path]
logging.info("Kicking off NAR build of {}, {} compression"
.format(basename(store_path), compression_type))
# Construct a nix expression which will produce a nar.
nar_expr = "".join([
"(import <nix/nar.nix> {",
'storePath = "{}";'.format(store_path),
'hashAlgo = "sha256";',
'compressionType = "{}";'.format(compression_type),
"})"])
# Nix-build this expression, resulting in a store object.
nar_dir = strip_output(
nix_cmd("nix-build", ["--expr", nar_expr, "--no-out-link"]),
hide_stderr=quiet)
return cls.register_nar_path(nar_dir, store_path, compression_type)
def import_to_store(self):
"""Import this NarExport into the local nix store."""
proc = Popen(nix_cmd("nix-store", ["--import", "-vvvvv"]),
stdin=PIPE, stdout=PIPE, stderr=PIPE)
out, err = proc.communicate(input=self.to_bytes())
if proc.returncode == 0:
return decode_str(out)
else:
raise NixImportFailed(err, store_path=self.store_path)
def get_nar_dir(cls, store_path, compression_type):
"""Get the directory of a nix archive without building it."""
if compression_type not in ("xz", "bzip2"):
raise ValueError(
"Unsupported compression type: {}".format(compression_type))
# Construct a nix expression which will produce a nar.
nar_expr = "".join([
"(import <nix/nar.nix> {", 'storePath = "{}";'.format(store_path),
'hashAlgo = "sha256";',
'compressionType = "{}";'.format(compression_type), "})"
])
# Nix-build this expression, resulting in a store object.
derivation_path = strip_output(
nix_cmd("nix-instantiate",
["--expr", nar_expr, "--no-gc-warning"]))
derivation = Derivation.parse_derivation_file(derivation_path)
return derivation.outputs["out"]
def get_nar_dir(cls, store_path, compression_type):
"""Get the directory of a nix archive without building it."""
if compression_type not in ("xz", "bzip2"):
raise ValueError("Unsupported compression type: {}"
.format(compression_type))
# Construct a nix expression which will produce a nar.
nar_expr = "".join([
"(import <nix/nar.nix> {",
'storePath = "{}";'.format(store_path),
'hashAlgo = "sha256";',
'compressionType = "{}";'.format(compression_type),
"})"])
# Nix-build this expression, resulting in a store object.
derivation_path = strip_output(
nix_cmd("nix-instantiate", ["--expr", nar_expr, "--no-gc-warning"]))
derivation = Derivation.parse_derivation_file(derivation_path)
return derivation.outputs["out"]
def from_store_path(cls, store_path, compression_type="xz"):
"""Load a narinfo from a store path.
:param store_path: Path in the nix store to load info on.
:type store_path: ``str``
:param compression_type: What type of compression to use on the NAR.
:return: A NarInfo for the path.
:rtype: :py:class:`NarInfo`
"""
if store_path in cls.NARINFO_CACHE[compression_type]:
return cls.NARINFO_CACHE[compression_type][store_path]
# Build the compressed version. Compute its hash and size.
nar_path = cls.build_nar(store_path, compression_type=compression_type)
du = strip_output("du -sb {}".format(nar_path))
file_size = int(du.split()[0])
file_hash = strip_output(
nix_cmd("nix-hash",
["--type", "sha256", "--base32", "--flat", nar_path]))
nar_size = query_store(store_path, "--size")
nar_hash = query_store(store_path, "--hash")
references = query_store(store_path, "--references").split()
deriver = query_store(store_path, "--deriver")
extension = ".nar." + ("bz2" if compression_type == "bzip2" else "xz")
narinfo = cls(
url="nar/{}{}".format(basename(store_path)[:32], extension),
compression=compression_type,
store_path=store_path,
nar_hash=nar_hash,
nar_size=nar_size,
file_size=str(file_size),
file_hash="sha256:{}".format(file_hash),
references=references,
deriver=None if deriver == "unknown-deriver" else deriver,
signature=None)
cls.NARINFO_CACHE[compression_type][store_path] = narinfo
return narinfo
def from_store_path(cls, store_path, compression_type="xz"):
"""Load a narinfo from a store path.
:param store_path: Path in the nix store to load info on.
:type store_path: ``str``
:param compression_type: What type of compression to use on the NAR.
:return: A NarInfo for the path.
:rtype: :py:class:`NarInfo`
"""
if store_path in cls.NARINFO_CACHE[compression_type]:
return cls.NARINFO_CACHE[compression_type][store_path]
# Build the compressed version. Compute its hash and size.
nar_path = cls.build_nar(store_path, compression_type=compression_type)
du = strip_output("du -sb {}".format(nar_path))
file_size = int(du.split()[0])
file_hash = strip_output(nix_cmd("nix-hash", ["--type", "sha256",
"--base32", "--flat", nar_path]))
nar_size = query_store(store_path, "--size")
nar_hash = query_store(store_path, "--hash")
references = query_store(store_path, "--references").split()
deriver = query_store(store_path, "--deriver")
extension = ".nar." + ("bz2" if compression_type == "bzip2" else "xz")
narinfo = cls(
url="nar/{}{}".format(basename(store_path)[:32], extension),
compression=compression_type,
store_path=store_path,
nar_hash=nar_hash,
nar_size=nar_size,
file_size=str(file_size),
file_hash="sha256:{}".format(file_hash),
references=references,
deriver=None if deriver == "unknown-deriver" else deriver,
signature=None
)
cls.NARINFO_CACHE[compression_type][store_path] = narinfo
return narinfo
