@@ -23,6 +23,7 @@ import functools as ft

 import asyncio

 from asyncio.subprocess import PIPE, DEVNULL

 from asyncio import create_subprocess_exec as subprocess

+from subprocess import SubprocessError

 from collections import OrderedDict

 from pathlib import Path

@@ -304,3 +305,37 @@ async def lock_subprocess(*args, lockfile, **kwargs):

         when_dead.add_done_callback(unlock)

     return proc

+

+

+async def ping(host, timeout):

+    """Return the round-trip time to a host using ICMP ECHO.

+

+    Parameters

+    ----------

+    host : str

+        The host to ping. May be a hostname, ip address, or anything else

+        recognized by 'ping'.

+    timeout : int

+        Time in seconds after which to stop waiting for a response.

+

+    Returns

+    -------

+    rtt : float

+        The average round trip time in milliseconds.

+

+    Raises

+    ------

+    SubprocessError if 'ping' returns a non-zero exit code.

+    """

+    cmd = f"/bin/ping -w{int(timeout)} {host}"

+    proc = await asyncio.create_subprocess_exec(*cmd.split(),

+                                                stdout=PIPE, stderr=DEVNULL)

+    stdout, _ = await proc.communicate()

+    if proc.returncode != 0:

+        raise SubprocessError(proc.returncode)

+

+    *_, rtt_line, _ = stdout.decode().split('\n')

+    assert _ == ''  # sanity check

+    *_, data, _ = rtt_line.split()

+    _, avg, *_ = data.split('/')

+    return float(avg)