logger = logging.getLogger(__file__)
-def cmd_showing_output(command: str) -> None:
+def cmd_showing_output(command: str, ) -> int:
+ """Kick off a child process. Capture and print all output that it
+ produces on stdout and stderr. Wait for the subprocess to exit
+ and return the exit value as the return code of this function.
+
+ """
line_enders = set([b'\n', b'\r'])
p = subprocess.Popen(
command,
sel = selectors.DefaultSelector()
sel.register(p.stdout, selectors.EVENT_READ)
sel.register(p.stderr, selectors.EVENT_READ)
- while True:
+ should_exit = False
+ while not should_exit:
for key, _ in sel.select():
char = key.fileobj.read(1)
if not char:
- p.wait()
- return
+ should_exit = True
if key.fileobj is p.stdout:
sys.stdout.buffer.write(char)
if char in line_enders:
sys.stderr.buffer.write(char)
if char in line_enders:
sys.stderr.flush()
+ p.wait()
+ return p.returncode
def cmd_with_timeout(command: str, timeout_seconds: Optional[float]) -> int:
- """
- Run a command but do not let it run for more than timeout seconds.
+ """Run a command but do not let it run for more than timeout seconds.
+ Doesn't capture or rebroadcast command output. Function returns
+ the exit value of the command or raises a TimeoutExpired exception
+ if the deadline is exceeded.
>>> cmd_with_timeout('/bin/echo foo', 10.0)
0
def cmd(command: str, timeout_seconds: Optional[float] = None) -> str:
- """Run a command with everything encased in a string and return
- the output text as a string. Raises subprocess.CalledProcessError.
+ """Run a command and capture its output to stdout (only) in a string.
+ Return that string as this function's output. Raises
+ subprocess.CalledProcessError or TimeoutExpired on error.
>>> cmd('/bin/echo foo')[:-1]
'foo'
"""
ret = subprocess.run(
- command, shell=True, capture_output=True, check=True, timeout=timeout_seconds,
+ command,
+ shell=True,
+ capture_output=True,
+ check=True,
+ timeout=timeout_seconds,
).stdout
return ret.decode("utf-8")
-def run_silently(command: str) -> None:
+def run_silently(command: str, timeout_seconds: Optional[float] = None) -> None:
"""Run a command silently but raise subprocess.CalledProcessError if
it fails.
"""
subprocess.run(
- command, shell=True, stderr=subprocess.DEVNULL,
- stdout=subprocess.DEVNULL, capture_output=False, check=True
+ command,
+ shell=True,
+ stderr=subprocess.DEVNULL,
+ stdout=subprocess.DEVNULL,
+ capture_output=False,
+ check=True,
+ timeout=timeout_seconds,
)