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lix/tests/functional2/testlib/fixtures/nix.py
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piegamesandeldritch horrors 567348a90c testlib: default nix fixture to also test all daemon protocols (2/3)
This commit enables the parametrization for "legacy-combined" protocol.
All failing tests with that have been either fixed or disabled. Notably:

- A couple of tests (e.g. involving builders) could be made to work with
a non-local store, but this would require some refactoring to testlib in
order to make certain configuration settings generic over local and
remote operations. We've disabled those for now, in order to make
progress
- The store tests all run locally only because of their nature
- The flakes tests also all run locally only because my energy for
fixing them is limited (and it's a *lot* of test failures, with probably
little overall benefit in terms of test coverage)

Change-Id: I56fa249a64f7c17c952f688ec89e9687f2a13f12
2026-06-28 18:17:57 +02:00

469 lines
18 KiB
Python

import contextlib
import copy
import dataclasses
import sys
from functools import partialmethod, partial
from pathlib import Path
from typing import Any, Literal, get_args
from collections.abc import Callable, Generator
import shutil
import subprocess
import logging
import pytest
from testlib.fixtures.command import CommandResult, Command
from testlib.fixtures.env import ManagedEnv
from testlib.utils import is_value_of_type
from textwrap import dedent
type _NixSettingValue = str | int | list[str] | bool | None
type _NixValue = str | int | float | list[_NixValue] | dict[str, _NixValue] | bool | None
def _serialise_config(value: _NixSettingValue) -> str:
if is_value_of_type(value, list[str]):
return " ".join(_serialise_config(e) for e in value)
if is_value_of_type(value, bool):
return "true" if value else "false"
if is_value_of_type(value, str | int):
return str(value)
msg = f"Value is unsupported in nix config: {value!r}, must be {_NixSettingValue.__value__}"
raise ValueError(msg)
def serialise_nix(value: _NixValue) -> str:
"""
Serialises the given python object into a nix represenatation.
NOTE: this interface does not allow accessing variables unless using interpolation, as all strings will be surrounded by quotes.
"""
def escape(v: str) -> str:
if "\\r" in v:
raise ValueError("\\r is not supported for conversion")
escaped = v.replace("\\", "\\\\").replace("$", "\\$").replace('"', '\\"')
return f'"{escaped}"'
if is_value_of_type(value, list[_NixValue.__value__]):
return f"[{' '.join([serialise_nix(v) for v in value])}]"
if is_value_of_type(value, dict[str, _NixValue.__value__]):
return dedent(f"""
{{
{"\n ".join([f"{escape(k)} = {serialise_nix(v)};" for k, v in value.items()])}
}}
""")
if is_value_of_type(value, bool):
return "true" if value else "false"
if is_value_of_type(value, int | float):
return str(value)
if is_value_of_type(value, str):
return escape(value)
if is_value_of_type(value, None):
return "null"
msg = f"Value is unsupported in nix code: {value!r}"
raise ValueError(msg)
class NixSettings:
"""Settings for invoking Nix"""
def __init__(self):
self._settings: dict[str, _NixSettingValue] = {
# Running the test suite creates a lot of stores in the test root (somewhere under TMPDIR).
# Obviously, they are not critical for system operation, so there is no need to reserve space.
# The cleanup will only happen a couple of runs later, wasting space in the meantime.
# Effectively disable this space reserve to reduce the waste considerably (by about 98%).
"gc-reserved-space": 0,
"show-trace": True,
"sandbox": True,
# explicitly disable substitution by default, otherwise we may attempt to contact
# substituters and slow down many tests with pointless connection retry timeouts.
"substituters": [],
"extra-sandbox-paths": [],
"extra-experimental-features": [],
"extra-deprecated-features": [],
}
def __getattr__(self, attr: str) -> _NixSettingValue:
if attr.startswith("__"):
return super().__getattr__(attr)
return self._settings[attr.replace("_", "-")]
def __setattr__(self, attr: str, value: _NixSettingValue):
if attr == "_settings":
super().__setattr__(attr, value)
else:
self._settings[attr.replace("_", "-")] = value
def __getitem__(self, attr: str) -> _NixSettingValue:
return self._settings[attr]
def __setitem__(self, attr: str, value: str):
self._settings[attr] = value
def pop(self, attr: str, default: str | None = None):
self._settings.pop(attr, default)
def add_xp_feature(self, *names: str):
self["extra-experimental-features"] += names
def add_dp_feature(self, *names: str):
self["extra-deprecated-features"] += names
def update(self, args: dict[str, _NixSettingValue] | None = None, **kwargs):
"""
Overrides the settings with the given dict or kwargs.
"""
self._settings.update(kwargs | (args or {}))
def clone(self) -> "NixSettings":
"""
shortcut to clone the settings to a new object
"""
return self.with_settings()
def with_settings(
self, args: dict[str, _NixSettingValue] | None = None, **kwargs
) -> "NixSettings":
"""
Copies the current settings into a new object, overriding the provided ones.
:returns: A new Settings object with overridden settings
"""
new_settings = NixSettings()
new_settings._settings = copy.deepcopy(self._settings)
new_settings.update(args, **kwargs)
return new_settings
def to_config(self, env: ManagedEnv) -> str:
config = ""
self["extra-sandbox-paths"] += env.path.to_sandbox_paths()
def field_may(name: str, value: Any, serializer: Callable[[Any], str] = _serialise_config):
nonlocal config
if value is not None:
config += f"{name} = {serializer(value)}\n"
for name, value in self._settings.items():
field_may(name, value)
return config
def to_env_overlay(self, env: ManagedEnv) -> None:
cfg = self.to_config(env)
(env.dirs.nix_conf_dir / "nix.conf").write_text(cfg)
env.set_env("NIX_CONFIG", cfg)
@dataclasses.dataclass
class Nix:
env: ManagedEnv
logger: logging.Logger
_settings: NixSettings | None = dataclasses.field(init=False, default=None)
uses_daemon: bool = False
@property
def _nix_executable(self) -> Path:
if nix_bin_dir := self.env.dirs.nix_bin_dir:
return Path(nix_bin_dir) / "nix"
if from_path := shutil.which("nix"):
return Path(from_path)
raise ValueError(
"Couldn't find a Nix command to execute! Set NIX_BIN_DIR or fix your environment"
)
@property
def settings(self) -> NixSettings:
"""
:return: the settings for the nix instance
"""
if self._settings is None:
self._settings = NixSettings()
self._settings.store = f"local?root={self.env.dirs.test_root}"
if sys.platform == "linux":
# sandbox build dir cannot be withing store dir. choose a short non-overlapping path.
self._settings.sandbox_build_dir = (
"/build-f2" if self.env.dirs.test_root.parts[1] != "build-f2" else "/build.f2"
)
return self._settings
def nix_cmd(self, argv: list[str], flake: bool = False, cwd: Path | None = None) -> Command:
"""
Constructs a NixCommand with the appropriate settings.
"""
# Create a copy of settings to not have a writing side effect
settings = self.settings.clone()
if flake:
settings.add_xp_feature("nix-command", "flakes")
settings.to_env_overlay(self.env)
return Command(argv=argv, exe=self._nix_executable, _env=self.env, cwd=cwd)
def nix(
self, cmd: list[str], nix_exe: str = "nix", flake: bool = False, cwd: Path | None = None
) -> Command:
return self.nix_cmd([nix_exe, *cmd], flake=flake, cwd=cwd)
# Mark each of these as correct as they are not ClassVars, but we also don't want to turn off RUF045
nix_build = partialmethod(nix, nix_exe="nix-build") # noqa: RUF045
nix_shell = partialmethod(nix, nix_exe="nix-shell") # noqa: RUF045
nix_store = partialmethod(nix, nix_exe="nix-store") # noqa: RUF045
nix_env = partialmethod(nix, nix_exe="nix-env") # noqa: RUF045
nix_instantiate = partialmethod(nix, nix_exe="nix-instantiate") # noqa: RUF045
nix_channel = partialmethod(nix, nix_exe="nix-channel") # noqa: RUF045
nix_prefetch_url = partialmethod(nix, nix_exe="nix-prefetch-url") # noqa: RUF045
def eval(
self, expr: str, settings: NixSettings | None = None, flags: list[str] | None = None
) -> CommandResult:
"""
calls `nix eval --json --expr {expr}` using the given expression
:param expr: what to evaluate
:param settings: if none, the global settings will be used, otherwise the given one
:param flags: if none, empty list, otherwise pass flags to the CLI invocation
:return: result of the evaluation
"""
if flags is None:
flags = []
orig = self.settings.clone()
self._settings = settings or self.settings
self.settings.add_xp_feature("nix-command")
cmd = self.nix(["eval", "--json", *flags, "--expr", expr])
# restore previous settings
self._settings = orig
return cmd.run()
def eval_builtin(self, name: str, *args: _NixValue) -> CommandResult:
"""
This is a high-level wrapper, to easily evaluate and obtain the result of a builtin.
In the background, it calls `nix eval --json --expr builtins.{name} {args}`
It is recommended to call `.json()` on the return value.
:param name: name of the builtin
:param args: list of arguments to provide to the builtin
:return: result of the evaluation
"""
args = [serialise_nix(arg) for arg in args]
return self.eval(f"builtins.{name} {' '.join(args)}")
@property
def store_dir(self) -> Path:
"""
The actual NIX_STORE_DIR this Nix command uses.
"""
assert self.env.dirs.real_store_dir is not None, "bug in ManagedEnv"
return self.env.dirs.real_store_dir
def physical_store_path_for(self, path: str | Path) -> Path:
"""
Takes a /nix/store/… path and rewrites it to be relative to this Nix's NIX_STORE_DIR.
Nix accepts and returns store paths as `/nix/store` even when that's not where `NIX_STORE_DIR`
physically is on the filesystem. Since we move the conceptual root for Nix to `test_root`,
these "virtual" paths differ from the physical ones. So this function will convert `/nix/store`
"virtual" paths to their real, physical location on the system.
Basically, if you're passing it to `nix build` or `nix-store` or whatever, you want the
`/nix/store` version. If you're passing it to a Python API (like pathlib.Path.exists()) or a
command that operates on arbitrary files instead of store paths, you want the output of this
function.
:param path: a string or Path to convert
:return: a Path object holding the rewritten, physical system path to the store entry
"""
return (
Path(str(path).replace("/nix/store", self.store_dir.as_posix()))
if str(path).startswith("/nix/store")
else Path(path)
)
def hash_path(self, store_path: str | Path, *args: str) -> str:
"""
Shortcut to use `nix hash path {store_path}`, converting "virtual" store paths returned
from Nix to their physical system paths including the test root.
:param store_path: store path of the derivation or entry to hash
"""
actual_path = self.physical_store_path_for(store_path).as_posix()
res = self.nix(["hash", "path", actual_path, *args], flake=True).run().ok()
return res.stdout_plain
def clear_store(self):
"""
Clears the test-owned store (and state) and resets them to an empty state
"""
nix_store_dir = self.env.dirs.real_store_dir
state_dir = self.env.dirs.nix_state_dir
# Make store writable
Command(["chmod", "-R", "+w", nix_store_dir], self.env).run().ok()
shutil.rmtree(nix_store_dir)
shutil.rmtree(state_dir)
# Re-create the directories
nix_store_dir.mkdir()
state_dir.mkdir()
_fully_sandboxed = (
sys.platform == "linux"
and Path("/proc/self/ns/user").is_symlink()
and subprocess.run(["unshare", "--user", "--mount", "--pid", "true"]).returncode == 0
)
def pytest_runtest_setup(item: pytest.Item):
for mark in item.iter_markers(name="full_sandbox"):
if not _fully_sandboxed:
pytest.skip(f"{sys.platform} does not support full sandboxing")
type NixDaemon = Callable[..., contextlib.AbstractAsyncContextManager[Nix]]
# NOTE: the order of items here is important. the daemon fixture requires
# the first item in this list to be the last socket opened by the daemon.
type NixDaemonProtocol = Literal["legacy-combined", "legacy", "lix-xp-1"]
daemon_protocols: list[NixDaemonProtocol] = get_args(NixDaemonProtocol.__value__)
_daemon_protocol_xp_features: dict[NixDaemon, list[str]] = {"lix-xp-1": ["rpc-sockets"]}
@contextlib.contextmanager
def _daemon_wrapper(
default_protocol: NixDaemonProtocol,
nix: Nix,
args: list[str] | None = None,
settings: dict[str, _NixSettingValue] | None = None,
protocol: NixDaemonProtocol | None = None,
**kwargs,
) -> contextlib.AbstractAsyncContextManager[Nix]:
protocol = protocol or default_protocol
daemon = copy.deepcopy(nix)
daemon.logger = nix.logger.getChild("daemon")
daemon.settings["allowed-users"] = ["*"]
daemon.settings["trusted-users"] = []
daemon.settings.store = f"local?root={nix.env.dirs.test_root}"
daemon.settings.update(settings)
if requires_features := _daemon_protocol_xp_features.get(protocol):
daemon.settings.add_xp_feature(*requires_features)
sockets_dir = Path(daemon.env.dirs.nix_state_dir) / "daemon-socket"
sockets = [sockets_dir / "socket", sockets_dir / "lix-xp-1/socket"]
for p in sockets:
p.unlink(missing_ok=True)
proc = daemon.nix(args or [], nix_exe="nix-daemon", **kwargs).start()
def log_daemon_result(result: CommandResult | None, level: int):
if result:
daemon.logger.log(level, "daemon exited with code %i", result.rc)
daemon.logger.log(level, "stdout: %s", result.stdout_s)
daemon.logger.log(level, "stderr: %s", result.stderr_s)
else:
daemon.logger.error("daemon exited unexpectedly")
# wait for daemon to come up. this may take a while under load.
# we wait only for the first socket in the list, expecting that
# it'll be the last one opened by the daemon. this is to ensure
# that we always return correctly regardless of rpc xp settings
while not sockets[0].exists():
if status := proc.wait(0.01):
log_daemon_result(status, logging.ERROR)
raise RuntimeError("daemon exited during startup")
inner = copy.deepcopy(nix)
inner.uses_daemon = True
socket_path = sockets_dir / "socket" if protocol == "legacy-combined" else sockets_dir
inner.settings.store = f"unix://{socket_path}?protocol={protocol}"
try:
timeout, level = 1, logging.ERROR
yield inner
# 5 seconds should be enough to wait for a *graceful* exit.
timeout, level = 5, logging.DEBUG
finally:
result = proc.terminate(timeout)
if not result:
result = proc.kill()
log_daemon_result(result, level)
def _nix_plain_impl(
tmp_path: Path, env: ManagedEnv, logger: logging.Logger
) -> Generator[Nix, Any, None]:
yield Nix(env, logger)
# when things are done using the nix store, the permissions for the store are read only
# after the test was executed, we set the permissions to rwx (write being the important part)
# for pytest to be able to delete the files during cleanup
cmd = Command(argv=["chmod", "-R", "+w", str(tmp_path.absolute())], _env=env)
cmd.run().ok()
@pytest.fixture
def nix(
tmp_path: Path, env: ManagedEnv, logger: logging.Logger, request: pytest.FixtureRequest
) -> Generator[Nix, Any, None]:
"""
Provides a rich way of calling `nix`.
For pre-applied commands use `nix.nix_instantiate`, `nix.nix_build` etc.
After configuring the command, use `.run()` to run it
"""
for nix in _nix_plain_impl(tmp_path, env, logger):
if getattr(request, "param", None) is None:
yield nix
else:
with _daemon_wrapper(request.param, nix) as inner:
yield inner
@pytest.fixture(params=daemon_protocols)
def daemon(request: pytest.FixtureRequest) -> NixDaemon:
"""
paramterize every daemon tests to run using all supported nix protocols
"""
return partial(_daemon_wrapper, request.param)
def pytest_generate_tests(metafunc: pytest.Metafunc):
"""
Generate parametrized tests from all tests that use the Nix fixture to test
nix with all available daemon protocols, *unless* those tests are marked with `no_daemon`
"""
if "nix" not in metafunc.fixturenames or "daemon" in metafunc.fixturenames:
return
if not list(metafunc.definition.iter_markers("no_daemon")):
protocols = [None, "legacy-combined"]
# do not enable them the protocols for now
# protocols += daemon_protocols # noqa ERA001
ids = protocols
metafunc.parametrize("nix", protocols, indirect=True, ids=ids)
@pytest.fixture
def enable_diverted_store(nix: Nix):
"""
clear NIX_STORE_DIR, resetting it to the default (ie /nix/store).
this makes builds impossible on platforms that cannot bind-mount,
(e.g. macos) but it is important for eval result reproducibility.
while builds may not work, substitution should still be possible.
"""
nix.env.dirs.nix_store_dir = None
nix.settings.sandbox_build_dir = None
def with_diverted_store(func: Callable[[Any], None]) -> Callable[[Any], None]:
return pytest.mark.usefixtures("enable_diverted_store")(func)