nixpkgs/nixos/lib/test-driver/test_driver/driver.py
Alyssa Ross 845576aac4
nixos/test-driver: undeprecate create_machine
This warning was added a year and a half ago, but still no test in
NixOS directly instantiates the machine class, presumably because it's
not actually possible for a test to do so without losing
functionality.  For example, there's no way for a NixOS test to access
the output directory that create_machine passes to the Machine
constructor.

This warning is therefore just contributing to alert fatigue for
users, who are unable to follow its advice.  Once it's actually
possible to do what it suggests, the warning can be reintroduced.
2023-05-27 12:56:04 +00:00

236 lines
7.7 KiB
Python

from contextlib import contextmanager
from pathlib import Path
from typing import Any, Dict, Iterator, List, Union, Optional, Callable, ContextManager
import os
import re
import tempfile
from test_driver.logger import rootlog
from test_driver.machine import Machine, NixStartScript, retry
from test_driver.vlan import VLan
from test_driver.polling_condition import PollingCondition
def get_tmp_dir() -> Path:
"""Returns a temporary directory that is defined by TMPDIR, TEMP, TMP or CWD
Raises an exception in case the retrieved temporary directory is not writeable
See https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir
"""
tmp_dir = Path(tempfile.gettempdir())
tmp_dir.mkdir(mode=0o700, exist_ok=True)
if not tmp_dir.is_dir():
raise NotADirectoryError(
f"The directory defined by TMPDIR, TEMP, TMP or CWD: {tmp_dir} is not a directory"
)
if not os.access(tmp_dir, os.W_OK):
raise PermissionError(
f"The directory defined by TMPDIR, TEMP, TMP, or CWD: {tmp_dir} is not writeable"
)
return tmp_dir
def pythonize_name(name: str) -> str:
return re.sub(r"^[^A-z_]|[^A-z0-9_]", "_", name)
class Driver:
"""A handle to the driver that sets up the environment
and runs the tests"""
tests: str
vlans: List[VLan]
machines: List[Machine]
polling_conditions: List[PollingCondition]
def __init__(
self,
start_scripts: List[str],
vlans: List[int],
tests: str,
out_dir: Path,
keep_vm_state: bool = False,
):
self.tests = tests
self.out_dir = out_dir
tmp_dir = get_tmp_dir()
with rootlog.nested("start all VLans"):
vlans = list(set(vlans))
self.vlans = [VLan(nr, tmp_dir) for nr in vlans]
def cmd(scripts: List[str]) -> Iterator[NixStartScript]:
for s in scripts:
yield NixStartScript(s)
self.polling_conditions = []
self.machines = [
Machine(
start_command=cmd,
keep_vm_state=keep_vm_state,
name=cmd.machine_name,
tmp_dir=tmp_dir,
callbacks=[self.check_polling_conditions],
out_dir=self.out_dir,
)
for cmd in cmd(start_scripts)
]
def __enter__(self) -> "Driver":
return self
def __exit__(self, *_: Any) -> None:
with rootlog.nested("cleanup"):
for machine in self.machines:
machine.release()
def subtest(self, name: str) -> Iterator[None]:
"""Group logs under a given test name"""
with rootlog.nested("subtest: " + name):
try:
yield
return True
except Exception as e:
rootlog.error(f'Test "{name}" failed with error: "{e}"')
raise e
def test_symbols(self) -> Dict[str, Any]:
@contextmanager
def subtest(name: str) -> Iterator[None]:
return self.subtest(name)
general_symbols = dict(
start_all=self.start_all,
test_script=self.test_script,
machines=self.machines,
vlans=self.vlans,
driver=self,
log=rootlog,
os=os,
create_machine=self.create_machine,
subtest=subtest,
run_tests=self.run_tests,
join_all=self.join_all,
retry=retry,
serial_stdout_off=self.serial_stdout_off,
serial_stdout_on=self.serial_stdout_on,
polling_condition=self.polling_condition,
Machine=Machine, # for typing
)
machine_symbols = {pythonize_name(m.name): m for m in self.machines}
# If there's exactly one machine, make it available under the name
# "machine", even if it's not called that.
if len(self.machines) == 1:
(machine_symbols["machine"],) = self.machines
vlan_symbols = {
f"vlan{v.nr}": self.vlans[idx] for idx, v in enumerate(self.vlans)
}
print(
"additionally exposed symbols:\n "
+ ", ".join(map(lambda m: m.name, self.machines))
+ ",\n "
+ ", ".join(map(lambda v: f"vlan{v.nr}", self.vlans))
+ ",\n "
+ ", ".join(list(general_symbols.keys()))
)
return {**general_symbols, **machine_symbols, **vlan_symbols}
def test_script(self) -> None:
"""Run the test script"""
with rootlog.nested("run the VM test script"):
symbols = self.test_symbols() # call eagerly
exec(self.tests, symbols, None)
def run_tests(self) -> None:
"""Run the test script (for non-interactive test runs)"""
self.test_script()
# TODO: Collect coverage data
for machine in self.machines:
if machine.is_up():
machine.execute("sync")
def start_all(self) -> None:
"""Start all machines"""
with rootlog.nested("start all VMs"):
for machine in self.machines:
machine.start()
def join_all(self) -> None:
"""Wait for all machines to shut down"""
with rootlog.nested("wait for all VMs to finish"):
for machine in self.machines:
machine.wait_for_shutdown()
def create_machine(self, args: Dict[str, Any]) -> Machine:
tmp_dir = get_tmp_dir()
if args.get("startCommand"):
start_command: str = args.get("startCommand", "")
cmd = NixStartScript(start_command)
name = args.get("name", cmd.machine_name)
else:
cmd = Machine.create_startcommand(args) # type: ignore
name = args.get("name", "machine")
return Machine(
tmp_dir=tmp_dir,
out_dir=self.out_dir,
start_command=cmd,
name=name,
keep_vm_state=args.get("keep_vm_state", False),
)
def serial_stdout_on(self) -> None:
rootlog._print_serial_logs = True
def serial_stdout_off(self) -> None:
rootlog._print_serial_logs = False
def check_polling_conditions(self) -> None:
for condition in self.polling_conditions:
condition.maybe_raise()
def polling_condition(
self,
fun_: Optional[Callable] = None,
*,
seconds_interval: float = 2.0,
description: Optional[str] = None,
) -> Union[Callable[[Callable], ContextManager], ContextManager]:
driver = self
class Poll:
def __init__(self, fun: Callable):
self.condition = PollingCondition(
fun,
seconds_interval,
description,
)
def __enter__(self) -> None:
driver.polling_conditions.append(self.condition)
def __exit__(self, a, b, c) -> None: # type: ignore
res = driver.polling_conditions.pop()
assert res is self.condition
def wait(self, timeout: int = 900) -> None:
def condition(last: bool) -> bool:
if last:
rootlog.info(f"Last chance for {self.condition.description}")
ret = self.condition.check(force=True)
if not ret and not last:
rootlog.info(
f"({self.condition.description} failure not fatal yet)"
)
return ret
with rootlog.nested(f"waiting for {self.condition.description}"):
retry(condition, timeout=timeout)
if fun_ is None:
return Poll
else:
return Poll(fun_)