def __init__(self, cached=False):
# get the global config, if cached = False a new config instance will
# be returned with the up-to-date configuration.
global_config = glbl_cfg(cached=cached)
# list the condemned hosts, hosts may be suffixed with `!`
condemned_hosts = [
get_fqdn_by_host(host.split('!')[0])
for host in global_config.get(['suite servers', 'condemned hosts'])
]
# list configured run hosts eliminating any which cannot be contacted
# or which are condemned
self.hosts = []
for host in (global_config.get(['suite servers', 'run hosts'])
or ['localhost']):
try:
if get_fqdn_by_host(host) not in condemned_hosts:
self.hosts.append(host)
except socket.gaierror:
pass
# determine the server ranking and acceptance thresholds if configured
self.rank_method = global_config.get(
['suite servers', 'run host select', 'rank'])
self.parsed_thresholds = self.parse_thresholds(
global_config.get(
['suite servers', 'run host select', 'thresholds']))
def __init__(self, cached=False):
# get the global config, if cached = False a new config instance will
# be returned with the up-to-date configuration.
global_config = glbl_cfg(cached=cached)
# list the condemned hosts, hosts may be suffixed with `!`
condemned_hosts = [
get_fqdn_by_host(host.split('!')[0]) for host in
global_config.get(['suite servers', 'condemned hosts'])]
# list configured run hosts eliminating any which cannot be contacted
# or which are condemned
self.hosts = []
for host in (
global_config.get(['suite servers', 'run hosts']) or
['localhost']):
try:
if get_fqdn_by_host(host) not in condemned_hosts:
self.hosts.append(host)
except socket.gaierror:
pass
# determine the server ranking and acceptance thresholds if configured
self.rank_method = global_config.get(
['suite servers', 'run host select', 'rank'])
self.parsed_thresholds = self.parse_thresholds(global_config.get(
['suite servers', 'run host select', 'thresholds']))
def test_get_fqdn_by_host_on_bad_host(self):
"""get_fqdn_by_host bad host."""
bad_host = 'nosuchhost.nosuchdomain.org'
try: # Future: Replace with assertRaises context manager syntax
get_fqdn_by_host(bad_host)
except IOError as exc:
self.assertEqual(exc.filename, bad_host)
self.assertEqual(
"[Errno -2] Name or service not known: '%s'" % bad_host,
str(exc))
def test_get_fqdn_by_host_on_bad_host(self):
"""get_fqdn_by_host bad host."""
bad_host = 'nosuchhost.nosuchdomain.org'
try: # Future: Replace with assertRaises context manager syntax
get_fqdn_by_host(bad_host)
except IOError as exc:
self.assertEqual(exc.filename, bad_host)
self.assertEqual(
"[Errno -2] Name or service not known: '%s'" % bad_host,
str(exc))
def test_get_fqdn_by_host_on_bad_host(self):
"""get_fqdn_by_host bad host."""
bad_host = 'nosuchhost.nosuchdomain.org'
with self.assertRaisesRegex(
IOError, r"(\[Errno -2\] Name or service|"
r"\[Errno 8\] nodename nor servname provided, or)"
r" not known: '{}'".format(bad_host)) as ctx:
get_fqdn_by_host(bad_host)
self.assertEqual(ctx.exception.filename, bad_host)
def get_location(suite: str, owner: str, host: str):
"""Extract host and port from a suite's contact file.
NB: if it fails to load the suite contact file, it will exit.
Args:
suite (str): suite name
owner (str): owner of the suite
host (str): host name
Returns:
Tuple[str, int, int]: tuple with the host name and port numbers.
Raises:
ClientError: if the suite is not running.
"""
try:
contact = load_contact_file(suite, owner, host)
except SuiteServiceFileError:
raise ClientError(f'Contact info not found for suite '
f'"{suite}", suite not running?')
if not host:
host = contact[ContactFileFields.HOST]
host = get_fqdn_by_host(host)
port = int(contact[ContactFileFields.PORT])
pub_port = int(contact[ContactFileFields.PUBLISH_PORT])
return host, port, pub_port
def get_location(cls, suite: str, owner: str, host: str):
"""Extract host and port from a suite's contact file.
NB: if it fails to load the suite contact file, it will exit.
Args:
suite (str): suite name
owner (str): owner of the suite
host (str): host name
Returns:
Tuple[str, int]: tuple with the host name and port number.
Raises:
ClientError: if the suite is not running.
"""
try:
contact = SuiteSrvFilesManager().load_contact_file(
suite, owner, host)
except SuiteServiceFileError:
raise ClientError(f'Contact info not found for suite '
f'"{suite}", suite not running?')
if not host:
host = contact[SuiteSrvFilesManager.KEY_HOST]
host = get_fqdn_by_host(host)
port = int(contact[SuiteSrvFilesManager.KEY_PORT])
return host, port
def get_location(workflow: str):
"""Extract host and port from a workflow's contact file.
NB: if it fails to load the workflow contact file, it will exit.
Args:
workflow (str): workflow name
Returns:
Tuple[str, int, int]: tuple with the host name and port numbers.
Raises:
ClientError: if the workflow is not running.
CylcVersionError: if target is a Cylc 7 (or earlier) workflow.
"""
try:
contact = load_contact_file(workflow)
except ServiceFileError:
raise WorkflowStopped(workflow)
host = contact[ContactFileFields.HOST]
host = get_fqdn_by_host(host)
port = int(contact[ContactFileFields.PORT])
if ContactFileFields.PUBLISH_PORT in contact:
pub_port = int(contact[ContactFileFields.PUBLISH_PORT])
else:
version = (contact['CYLC_VERSION']
if 'CYLC_VERSION' in contact else None)
raise CylcVersionError(version=version)
return host, port, pub_port
def test_get_fqdn_by_host_on_bad_host():
"""get_fqdn_by_host bad host.
Warning:
This test can fail due to ISP/network configuration
(for example ISP may reroute failed DNS to custom search page)
e.g: https://www.virginmedia.com/help/advanced-network-error-search
"""
bad_host = 'nosuchhost.nosuchdomain.org'
with pytest.raises(IOError) as exc:
get_fqdn_by_host(bad_host)
assert re.match(
r"(\[Errno -2\] Name or service|"
r"\[Errno 8\] nodename nor servname provided, or)"
r" not known: '{}'".format(bad_host), str(exc.value))
assert exc.value.filename == bad_host
def test_should_auto_restart(
host,
stop_mode,
condemned_hosts,
auto_restart_time,
should_auto_restart
):
"""Ensure the suite only auto-restarts when appropriate."""
# mock a scheduler object
scheduler = Mock(
host=get_fqdn_by_host(host),
stop_mode=stop_mode,
auto_restart_time=auto_restart_time
)
# mock a workflow configuration object
cfg = Mock()
cfg.get = lambda x: condemned_hosts
# test
assert _should_auto_restart(scheduler, cfg) == should_auto_restart
def _should_auto_restart(scheduler, current_glbl_cfg):
# check if workflow host is condemned - if so auto restart
if scheduler.stop_mode is None:
for host in current_glbl_cfg.get(
['scheduler', 'run hosts', 'condemned']):
if host.endswith('!'):
# host ends in an `!` -> force shutdown mode
mode = AutoRestartMode.FORCE_STOP
host = host[:-1]
else:
# normal mode (stop and restart the workflow)
mode = AutoRestartMode.RESTART_NORMAL
if scheduler.auto_restart_time is not None:
# workflow is already scheduled to stop-restart only
# AutoRestartMode.FORCE_STOP can override this.
continue
if get_fqdn_by_host(host) == scheduler.host:
# this host is condemned, take the appropriate action
return mode
return False
def get_location(workflow: str):
"""Extract host and port from a workflow's contact file.
NB: if it fails to load the workflow contact file, it will exit.
Args:
workflow (str): workflow name
Returns:
Tuple[str, int, int]: tuple with the host name and port numbers.
Raises:
ClientError: if the workflow is not running.
"""
try:
contact = load_contact_file(workflow)
except ServiceFileError:
raise WorkflowStopped(workflow)
host = contact[ContactFileFields.HOST]
host = get_fqdn_by_host(host)
port = int(contact[ContactFileFields.PORT])
pub_port = int(contact[ContactFileFields.PUBLISH_PORT])
return host, port, pub_port
def select_host(hosts,
ranking_string=None,
blacklist=None,
blacklist_name=None):
"""Select a host from the provided list.
If no ranking is provided (in `ranking_string`) then random selection
is used.
Args:
hosts (list):
List of host names to choose from.
NOTE: Host names must be identifiable from the host where the
call is executed.
ranking_string (str):
A multiline string containing Python expressions to filter
hosts by e.g::
# only consider hosts with less than 70% cpu usage
# and a server load of less than 5
cpu_percent() < 70
getloadavg()[0] < 5
And or Python statements to rank hosts by e.g::
# rank by used cpu, then by load average as a tie-break
# (lower scores are better)
cpu_percent()
getloadavg()
Comments are allowed using `#` but not inline comments.
blacklist (list):
List of host names to filter out.
Can be short host names (do not have to be fqdn values)
blacklist_name (str):
The reason for blacklisting these hosts
(used for exceptions).
Raises:
HostSelectException:
In the event that no hosts are available / meet the specified
criterion.
socket.gaierror:
This may be raised in the event of unknown host names
for some installations or not for others.
Returns:
tuple - (hostname, fqdn) the chosen host
hostname (str):
The hostname as provided to this function.
fqdn (str):
The fully qualified domain name of this host.
"""
# standardise host names - remove duplicate items
hostname_map = { # note dictionary keys filter out duplicates
get_fqdn_by_host(host): host
for host in hosts
}
hosts = list(hostname_map)
if blacklist:
blacklist = list(set(map(get_fqdn_by_host, blacklist)))
# dict of conditions and whether they have been met (for error reporting)
data = {host: {} for host in hosts}
# filter out `filter_hosts` if provided
if blacklist:
hosts, data = _filter_by_hostname(hosts,
blacklist,
blacklist_name,
data=data)
if not hosts:
# no hosts provided / left after filtering
raise HostSelectException(data)
rankings = []
if ranking_string:
# parse rankings
rankings = list(_get_rankings(ranking_string))
if not rankings:
# no metrics or ranking required, pick host at random
hosts = [random.choice(list(hosts))] # nosec
if not rankings and len(hosts) == 1:
return hostname_map[hosts[0]], hosts[0]
# filter and sort by rankings
metrics = list({x for x, _ in rankings}) # required metrics
results, data = _get_metrics( # get data from each host
hosts, metrics, data)
hosts = list(results) # some hosts might not be contactable
# stop here if we don't need to proceed
if not hosts:
# no hosts provided / left after filtering
raise HostSelectException(data)
if not rankings and len(hosts) == 1:
return hostname_map[hosts[0]], hosts[0]
hosts, data = _filter_by_ranking(
# filter by rankings, sort by ranking
hosts,
rankings,
results,
data=data)
if not hosts:
# no hosts provided / left after filtering
raise HostSelectException(data)
return hostname_map[hosts[0]], hosts[0]
NOTE: these are functional tests, for unit tests see the docstrings in
the host_select module.
"""
import socket
import pytest
from cylc.flow.exceptions import HostSelectException
from cylc.flow.host_select import (select_host, select_suite_host)
from cylc.flow.hostuserutil import get_fqdn_by_host
from cylc.flow.parsec.exceptions import ListValueError
localhost, localhost_aliases, _ = socket.gethostbyname_ex('localhost')
localhost_fqdn = get_fqdn_by_host(localhost)
# NOTE: ensure that all localhost aliases are actually aliases of localhost,
# it would appear that this is not always the case
# on Travis-CI on of the aliases has a different fqdn from the fqdn
# of the host it is an alias of
localhost_aliases = [
alias for alias in localhost_aliases
if get_fqdn_by_host(alias) == localhost_fqdn
]
def test_localhost():
"""Basic test with one host to choose from."""
assert select_host([localhost]) == (localhost, localhost_fqdn)
the host_select module.
"""
from shlex import quote
import socket
from subprocess import call, DEVNULL
import pytest
from cylc.flow.cfgspec.glbl_cfg import glbl_cfg
from cylc.flow.exceptions import HostSelectException
from cylc.flow.host_select import (select_host, select_suite_host)
from cylc.flow.hostuserutil import get_fqdn_by_host
local_host, local_host_alises, _ = socket.gethostbyname_ex('localhost')
local_host_fqdn = get_fqdn_by_host(local_host)
try:
# get a suitable remote host for running tests on
# NOTE: do NOT copy this testing approach in other python tests
remote_platform = glbl_cfg().get(
['platforms', '_remote_background_shared_tcp', 'hosts'], [])[0]
# don't run tests unless host is contactable
if call(['ssh', quote(remote_platform), 'hostname'],
stdin=DEVNULL,
stdout=DEVNULL,
stderr=DEVNULL):
raise KeyError('remote platform')
# get the fqdn for this host
remote_platform_fqdn = get_fqdn_by_host(remote_platform)
except (KeyError, IndexError):
