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Diffstat (limited to 'charms/trusty/ceilometer/charmhelpers/core/hookenv.py')
| -rw-r--r-- | charms/trusty/ceilometer/charmhelpers/core/hookenv.py | 1009 |
1 files changed, 0 insertions, 1009 deletions
diff --git a/charms/trusty/ceilometer/charmhelpers/core/hookenv.py b/charms/trusty/ceilometer/charmhelpers/core/hookenv.py deleted file mode 100644 index 0132129..0000000 --- a/charms/trusty/ceilometer/charmhelpers/core/hookenv.py +++ /dev/null @@ -1,1009 +0,0 @@ -# Copyright 2014-2015 Canonical Limited. -# -# This file is part of charm-helpers. -# -# charm-helpers is free software: you can redistribute it and/or modify -# it under the terms of the GNU Lesser General Public License version 3 as -# published by the Free Software Foundation. -# -# charm-helpers is distributed in the hope that it will be useful, -# but WITHOUT ANY WARRANTY; without even the implied warranty of -# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -# GNU Lesser General Public License for more details. -# -# You should have received a copy of the GNU Lesser General Public License -# along with charm-helpers. If not, see <http://www.gnu.org/licenses/>. - -"Interactions with the Juju environment" -# Copyright 2013 Canonical Ltd. -# -# Authors: -# Charm Helpers Developers <juju@lists.ubuntu.com> - -from __future__ import print_function -import copy -from distutils.version import LooseVersion -from functools import wraps -import glob -import os -import json -import yaml -import subprocess -import sys -import errno -import tempfile -from subprocess import CalledProcessError - -import six -if not six.PY3: - from UserDict import UserDict -else: - from collections import UserDict - -CRITICAL = "CRITICAL" -ERROR = "ERROR" -WARNING = "WARNING" -INFO = "INFO" -DEBUG = "DEBUG" -MARKER = object() - -cache = {} - - -def cached(func): - """Cache return values for multiple executions of func + args - - For example:: - - @cached - def unit_get(attribute): - pass - - unit_get('test') - - will cache the result of unit_get + 'test' for future calls. - """ - @wraps(func) - def wrapper(*args, **kwargs): - global cache - key = str((func, args, kwargs)) - try: - return cache[key] - except KeyError: - pass # Drop out of the exception handler scope. - res = func(*args, **kwargs) - cache[key] = res - return res - wrapper._wrapped = func - return wrapper - - -def flush(key): - """Flushes any entries from function cache where the - key is found in the function+args """ - flush_list = [] - for item in cache: - if key in item: - flush_list.append(item) - for item in flush_list: - del cache[item] - - -def log(message, level=None): - """Write a message to the juju log""" - command = ['juju-log'] - if level: - command += ['-l', level] - if not isinstance(message, six.string_types): - message = repr(message) - command += [message] - # Missing juju-log should not cause failures in unit tests - # Send log output to stderr - try: - subprocess.call(command) - except OSError as e: - if e.errno == errno.ENOENT: - if level: - message = "{}: {}".format(level, message) - message = "juju-log: {}".format(message) - print(message, file=sys.stderr) - else: - raise - - -class Serializable(UserDict): - """Wrapper, an object that can be serialized to yaml or json""" - - def __init__(self, obj): - # wrap the object - UserDict.__init__(self) - self.data = obj - - def __getattr__(self, attr): - # See if this object has attribute. - if attr in ("json", "yaml", "data"): - return self.__dict__[attr] - # Check for attribute in wrapped object. - got = getattr(self.data, attr, MARKER) - if got is not MARKER: - return got - # Proxy to the wrapped object via dict interface. - try: - return self.data[attr] - except KeyError: - raise AttributeError(attr) - - def __getstate__(self): - # Pickle as a standard dictionary. - return self.data - - def __setstate__(self, state): - # Unpickle into our wrapper. - self.data = state - - def json(self): - """Serialize the object to json""" - return json.dumps(self.data) - - def yaml(self): - """Serialize the object to yaml""" - return yaml.dump(self.data) - - -def execution_environment(): - """A convenient bundling of the current execution context""" - context = {} - context['conf'] = config() - if relation_id(): - context['reltype'] = relation_type() - context['relid'] = relation_id() - context['rel'] = relation_get() - context['unit'] = local_unit() - context['rels'] = relations() - context['env'] = os.environ - return context - - -def in_relation_hook(): - """Determine whether we're running in a relation hook""" - return 'JUJU_RELATION' in os.environ - - -def relation_type(): - """The scope for the current relation hook""" - return os.environ.get('JUJU_RELATION', None) - - -@cached -def relation_id(relation_name=None, service_or_unit=None): - """The relation ID for the current or a specified relation""" - if not relation_name and not service_or_unit: - return os.environ.get('JUJU_RELATION_ID', None) - elif relation_name and service_or_unit: - service_name = service_or_unit.split('/')[0] - for relid in relation_ids(relation_name): - remote_service = remote_service_name(relid) - if remote_service == service_name: - return relid - else: - raise ValueError('Must specify neither or both of relation_name and service_or_unit') - - -def local_unit(): - """Local unit ID""" - return os.environ['JUJU_UNIT_NAME'] - - -def remote_unit(): - """The remote unit for the current relation hook""" - return os.environ.get('JUJU_REMOTE_UNIT', None) - - -def service_name(): - """The name service group this unit belongs to""" - return local_unit().split('/')[0] - - -@cached -def remote_service_name(relid=None): - """The remote service name for a given relation-id (or the current relation)""" - if relid is None: - unit = remote_unit() - else: - units = related_units(relid) - unit = units[0] if units else None - return unit.split('/')[0] if unit else None - - -def hook_name(): - """The name of the currently executing hook""" - return os.environ.get('JUJU_HOOK_NAME', os.path.basename(sys.argv[0])) - - -class Config(dict): - """A dictionary representation of the charm's config.yaml, with some - extra features: - - - See which values in the dictionary have changed since the previous hook. - - For values that have changed, see what the previous value was. - - Store arbitrary data for use in a later hook. - - NOTE: Do not instantiate this object directly - instead call - ``hookenv.config()``, which will return an instance of :class:`Config`. - - Example usage:: - - >>> # inside a hook - >>> from charmhelpers.core import hookenv - >>> config = hookenv.config() - >>> config['foo'] - 'bar' - >>> # store a new key/value for later use - >>> config['mykey'] = 'myval' - - - >>> # user runs `juju set mycharm foo=baz` - >>> # now we're inside subsequent config-changed hook - >>> config = hookenv.config() - >>> config['foo'] - 'baz' - >>> # test to see if this val has changed since last hook - >>> config.changed('foo') - True - >>> # what was the previous value? - >>> config.previous('foo') - 'bar' - >>> # keys/values that we add are preserved across hooks - >>> config['mykey'] - 'myval' - - """ - CONFIG_FILE_NAME = '.juju-persistent-config' - - def __init__(self, *args, **kw): - super(Config, self).__init__(*args, **kw) - self.implicit_save = True - self._prev_dict = None - self.path = os.path.join(charm_dir(), Config.CONFIG_FILE_NAME) - if os.path.exists(self.path): - self.load_previous() - atexit(self._implicit_save) - - def load_previous(self, path=None): - """Load previous copy of config from disk. - - In normal usage you don't need to call this method directly - it - is called automatically at object initialization. - - :param path: - - File path from which to load the previous config. If `None`, - config is loaded from the default location. If `path` is - specified, subsequent `save()` calls will write to the same - path. - - """ - self.path = path or self.path - with open(self.path) as f: - self._prev_dict = json.load(f) - for k, v in copy.deepcopy(self._prev_dict).items(): - if k not in self: - self[k] = v - - def changed(self, key): - """Return True if the current value for this key is different from - the previous value. - - """ - if self._prev_dict is None: - return True - return self.previous(key) != self.get(key) - - def previous(self, key): - """Return previous value for this key, or None if there - is no previous value. - - """ - if self._prev_dict: - return self._prev_dict.get(key) - return None - - def save(self): - """Save this config to disk. - - If the charm is using the :mod:`Services Framework <services.base>` - or :meth:'@hook <Hooks.hook>' decorator, this - is called automatically at the end of successful hook execution. - Otherwise, it should be called directly by user code. - - To disable automatic saves, set ``implicit_save=False`` on this - instance. - - """ - with open(self.path, 'w') as f: - json.dump(self, f) - - def _implicit_save(self): - if self.implicit_save: - self.save() - - -@cached -def config(scope=None): - """Juju charm configuration""" - config_cmd_line = ['config-get'] - if scope is not None: - config_cmd_line.append(scope) - config_cmd_line.append('--format=json') - try: - config_data = json.loads( - subprocess.check_output(config_cmd_line).decode('UTF-8')) - if scope is not None: - return config_data - return Config(config_data) - except ValueError: - return None - - -@cached -def relation_get(attribute=None, unit=None, rid=None): - """Get relation information""" - _args = ['relation-get', '--format=json'] - if rid: - _args.append('-r') - _args.append(rid) - _args.append(attribute or '-') - if unit: - _args.append(unit) - try: - return json.loads(subprocess.check_output(_args).decode('UTF-8')) - except ValueError: - return None - except CalledProcessError as e: - if e.returncode == 2: - return None - raise - - -def relation_set(relation_id=None, relation_settings=None, **kwargs): - """Set relation information for the current unit""" - relation_settings = relation_settings if relation_settings else {} - relation_cmd_line = ['relation-set'] - accepts_file = "--file" in subprocess.check_output( - relation_cmd_line + ["--help"], universal_newlines=True) - if relation_id is not None: - relation_cmd_line.extend(('-r', relation_id)) - settings = relation_settings.copy() - settings.update(kwargs) - for key, value in settings.items(): - # Force value to be a string: it always should, but some call - # sites pass in things like dicts or numbers. - if value is not None: - settings[key] = "{}".format(value) - if accepts_file: - # --file was introduced in Juju 1.23.2. Use it by default if - # available, since otherwise we'll break if the relation data is - # too big. Ideally we should tell relation-set to read the data from - # stdin, but that feature is broken in 1.23.2: Bug #1454678. - with tempfile.NamedTemporaryFile(delete=False) as settings_file: - settings_file.write(yaml.safe_dump(settings).encode("utf-8")) - subprocess.check_call( - relation_cmd_line + ["--file", settings_file.name]) - os.remove(settings_file.name) - else: - for key, value in settings.items(): - if value is None: - relation_cmd_line.append('{}='.format(key)) - else: - relation_cmd_line.append('{}={}'.format(key, value)) - subprocess.check_call(relation_cmd_line) - # Flush cache of any relation-gets for local unit - flush(local_unit()) - - -def relation_clear(r_id=None): - ''' Clears any relation data already set on relation r_id ''' - settings = relation_get(rid=r_id, - unit=local_unit()) - for setting in settings: - if setting not in ['public-address', 'private-address']: - settings[setting] = None - relation_set(relation_id=r_id, - **settings) - - -@cached -def relation_ids(reltype=None): - """A list of relation_ids""" - reltype = reltype or relation_type() - relid_cmd_line = ['relation-ids', '--format=json'] - if reltype is not None: - relid_cmd_line.append(reltype) - return json.loads( - subprocess.check_output(relid_cmd_line).decode('UTF-8')) or [] - return [] - - -@cached -def related_units(relid=None): - """A list of related units""" - relid = relid or relation_id() - units_cmd_line = ['relation-list', '--format=json'] - if relid is not None: - units_cmd_line.extend(('-r', relid)) - return json.loads( - subprocess.check_output(units_cmd_line).decode('UTF-8')) or [] - - -@cached -def relation_for_unit(unit=None, rid=None): - """Get the json represenation of a unit's relation""" - unit = unit or remote_unit() - relation = relation_get(unit=unit, rid=rid) - for key in relation: - if key.endswith('-list'): - relation[key] = relation[key].split() - relation['__unit__'] = unit - return relation - - -@cached -def relations_for_id(relid=None): - """Get relations of a specific relation ID""" - relation_data = [] - relid = relid or relation_ids() - for unit in related_units(relid): - unit_data = relation_for_unit(unit, relid) - unit_data['__relid__'] = relid - relation_data.append(unit_data) - return relation_data - - -@cached -def relations_of_type(reltype=None): - """Get relations of a specific type""" - relation_data = [] - reltype = reltype or relation_type() - for relid in relation_ids(reltype): - for relation in relations_for_id(relid): - relation['__relid__'] = relid - relation_data.append(relation) - return relation_data - - -@cached -def metadata(): - """Get the current charm metadata.yaml contents as a python object""" - with open(os.path.join(charm_dir(), 'metadata.yaml')) as md: - return yaml.safe_load(md) - - -@cached -def relation_types(): - """Get a list of relation types supported by this charm""" - rel_types = [] - md = metadata() - for key in ('provides', 'requires', 'peers'): - section = md.get(key) - if section: - rel_types.extend(section.keys()) - return rel_types - - -@cached -def peer_relation_id(): - '''Get the peers relation id if a peers relation has been joined, else None.''' - md = metadata() - section = md.get('peers') - if section: - for key in section: - relids = relation_ids(key) - if relids: - return relids[0] - return None - - -@cached -def relation_to_interface(relation_name): - """ - Given the name of a relation, return the interface that relation uses. - - :returns: The interface name, or ``None``. - """ - return relation_to_role_and_interface(relation_name)[1] - - -@cached -def relation_to_role_and_interface(relation_name): - """ - Given the name of a relation, return the role and the name of the interface - that relation uses (where role is one of ``provides``, ``requires``, or ``peers``). - - :returns: A tuple containing ``(role, interface)``, or ``(None, None)``. - """ - _metadata = metadata() - for role in ('provides', 'requires', 'peers'): - interface = _metadata.get(role, {}).get(relation_name, {}).get('interface') - if interface: - return role, interface - return None, None - - -@cached -def role_and_interface_to_relations(role, interface_name): - """ - Given a role and interface name, return a list of relation names for the - current charm that use that interface under that role (where role is one - of ``provides``, ``requires``, or ``peers``). - - :returns: A list of relation names. - """ - _metadata = metadata() - results = [] - for relation_name, relation in _metadata.get(role, {}).items(): - if relation['interface'] == interface_name: - results.append(relation_name) - return results - - -@cached -def interface_to_relations(interface_name): - """ - Given an interface, return a list of relation names for the current - charm that use that interface. - - :returns: A list of relation names. - """ - results = [] - for role in ('provides', 'requires', 'peers'): - results.extend(role_and_interface_to_relations(role, interface_name)) - return results - - -@cached -def charm_name(): - """Get the name of the current charm as is specified on metadata.yaml""" - return metadata().get('name') - - -@cached -def relations(): - """Get a nested dictionary of relation data for all related units""" - rels = {} - for reltype in relation_types(): - relids = {} - for relid in relation_ids(reltype): - units = {local_unit(): relation_get(unit=local_unit(), rid=relid)} - for unit in related_units(relid): - reldata = relation_get(unit=unit, rid=relid) - units[unit] = reldata - relids[relid] = units - rels[reltype] = relids - return rels - - -@cached -def is_relation_made(relation, keys='private-address'): - ''' - Determine whether a relation is established by checking for - presence of key(s). If a list of keys is provided, they - must all be present for the relation to be identified as made - ''' - if isinstance(keys, str): - keys = [keys] - for r_id in relation_ids(relation): - for unit in related_units(r_id): - context = {} - for k in keys: - context[k] = relation_get(k, rid=r_id, - unit=unit) - if None not in context.values(): - return True - return False - - -def open_port(port, protocol="TCP"): - """Open a service network port""" - _args = ['open-port'] - _args.append('{}/{}'.format(port, protocol)) - subprocess.check_call(_args) - - -def close_port(port, protocol="TCP"): - """Close a service network port""" - _args = ['close-port'] - _args.append('{}/{}'.format(port, protocol)) - subprocess.check_call(_args) - - -@cached -def unit_get(attribute): - """Get the unit ID for the remote unit""" - _args = ['unit-get', '--format=json', attribute] - try: - return json.loads(subprocess.check_output(_args).decode('UTF-8')) - except ValueError: - return None - - -def unit_public_ip(): - """Get this unit's public IP address""" - return unit_get('public-address') - - -def unit_private_ip(): - """Get this unit's private IP address""" - return unit_get('private-address') - - -@cached -def storage_get(attribute=None, storage_id=None): - """Get storage attributes""" - _args = ['storage-get', '--format=json'] - if storage_id: - _args.extend(('-s', storage_id)) - if attribute: - _args.append(attribute) - try: - return json.loads(subprocess.check_output(_args).decode('UTF-8')) - except ValueError: - return None - - -@cached -def storage_list(storage_name=None): - """List the storage IDs for the unit""" - _args = ['storage-list', '--format=json'] - if storage_name: - _args.append(storage_name) - try: - return json.loads(subprocess.check_output(_args).decode('UTF-8')) - except ValueError: - return None - except OSError as e: - import errno - if e.errno == errno.ENOENT: - # storage-list does not exist - return [] - raise - - -class UnregisteredHookError(Exception): - """Raised when an undefined hook is called""" - pass - - -class Hooks(object): - """A convenient handler for hook functions. - - Example:: - - hooks = Hooks() - - # register a hook, taking its name from the function name - @hooks.hook() - def install(): - pass # your code here - - # register a hook, providing a custom hook name - @hooks.hook("config-changed") - def config_changed(): - pass # your code here - - if __name__ == "__main__": - # execute a hook based on the name the program is called by - hooks.execute(sys.argv) - """ - - def __init__(self, config_save=None): - super(Hooks, self).__init__() - self._hooks = {} - - # For unknown reasons, we allow the Hooks constructor to override - # config().implicit_save. - if config_save is not None: - config().implicit_save = config_save - - def register(self, name, function): - """Register a hook""" - self._hooks[name] = function - - def execute(self, args): - """Execute a registered hook based on args[0]""" - _run_atstart() - hook_name = os.path.basename(args[0]) - if hook_name in self._hooks: - try: - self._hooks[hook_name]() - except SystemExit as x: - if x.code is None or x.code == 0: - _run_atexit() - raise - _run_atexit() - else: - raise UnregisteredHookError(hook_name) - - def hook(self, *hook_names): - """Decorator, registering them as hooks""" - def wrapper(decorated): - for hook_name in hook_names: - self.register(hook_name, decorated) - else: - self.register(decorated.__name__, decorated) - if '_' in decorated.__name__: - self.register( - decorated.__name__.replace('_', '-'), decorated) - return decorated - return wrapper - - -def charm_dir(): - """Return the root directory of the current charm""" - return os.environ.get('CHARM_DIR') - - -@cached -def action_get(key=None): - """Gets the value of an action parameter, or all key/value param pairs""" - cmd = ['action-get'] - if key is not None: - cmd.append(key) - cmd.append('--format=json') - action_data = json.loads(subprocess.check_output(cmd).decode('UTF-8')) - return action_data - - -def action_set(values): - """Sets the values to be returned after the action finishes""" - cmd = ['action-set'] - for k, v in list(values.items()): - cmd.append('{}={}'.format(k, v)) - subprocess.check_call(cmd) - - -def action_fail(message): - """Sets the action status to failed and sets the error message. - - The results set by action_set are preserved.""" - subprocess.check_call(['action-fail', message]) - - -def action_name(): - """Get the name of the currently executing action.""" - return os.environ.get('JUJU_ACTION_NAME') - - -def action_uuid(): - """Get the UUID of the currently executing action.""" - return os.environ.get('JUJU_ACTION_UUID') - - -def action_tag(): - """Get the tag for the currently executing action.""" - return os.environ.get('JUJU_ACTION_TAG') - - -def status_set(workload_state, message): - """Set the workload state with a message - - Use status-set to set the workload state with a message which is visible - to the user via juju status. If the status-set command is not found then - assume this is juju < 1.23 and juju-log the message unstead. - - workload_state -- valid juju workload state. - message -- status update message - """ - valid_states = ['maintenance', 'blocked', 'waiting', 'active'] - if workload_state not in valid_states: - raise ValueError( - '{!r} is not a valid workload state'.format(workload_state) - ) - cmd = ['status-set', workload_state, message] - try: - ret = subprocess.call(cmd) - if ret == 0: - return - except OSError as e: - if e.errno != errno.ENOENT: - raise - log_message = 'status-set failed: {} {}'.format(workload_state, - message) - log(log_message, level='INFO') - - -def status_get(): - """Retrieve the previously set juju workload state and message - - If the status-get command is not found then assume this is juju < 1.23 and - return 'unknown', "" - - """ - cmd = ['status-get', "--format=json", "--include-data"] - try: - raw_status = subprocess.check_output(cmd) - except OSError as e: - if e.errno == errno.ENOENT: - return ('unknown', "") - else: - raise - else: - status = json.loads(raw_status.decode("UTF-8")) - return (status["status"], status["message"]) - - -def translate_exc(from_exc, to_exc): - def inner_translate_exc1(f): - @wraps(f) - def inner_translate_exc2(*args, **kwargs): - try: - return f(*args, **kwargs) - except from_exc: - raise to_exc - - return inner_translate_exc2 - - return inner_translate_exc1 - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def is_leader(): - """Does the current unit hold the juju leadership - - Uses juju to determine whether the current unit is the leader of its peers - """ - cmd = ['is-leader', '--format=json'] - return json.loads(subprocess.check_output(cmd).decode('UTF-8')) - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def leader_get(attribute=None): - """Juju leader get value(s)""" - cmd = ['leader-get', '--format=json'] + [attribute or '-'] - return json.loads(subprocess.check_output(cmd).decode('UTF-8')) - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def leader_set(settings=None, **kwargs): - """Juju leader set value(s)""" - # Don't log secrets. - # log("Juju leader-set '%s'" % (settings), level=DEBUG) - cmd = ['leader-set'] - settings = settings or {} - settings.update(kwargs) - for k, v in settings.items(): - if v is None: - cmd.append('{}='.format(k)) - else: - cmd.append('{}={}'.format(k, v)) - subprocess.check_call(cmd) - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def payload_register(ptype, klass, pid): - """ is used while a hook is running to let Juju know that a - payload has been started.""" - cmd = ['payload-register'] - for x in [ptype, klass, pid]: - cmd.append(x) - subprocess.check_call(cmd) - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def payload_unregister(klass, pid): - """ is used while a hook is running to let Juju know - that a payload has been manually stopped. The <class> and <id> provided - must match a payload that has been previously registered with juju using - payload-register.""" - cmd = ['payload-unregister'] - for x in [klass, pid]: - cmd.append(x) - subprocess.check_call(cmd) - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def payload_status_set(klass, pid, status): - """is used to update the current status of a registered payload. - The <class> and <id> provided must match a payload that has been previously - registered with juju using payload-register. The <status> must be one of the - follow: starting, started, stopping, stopped""" - cmd = ['payload-status-set'] - for x in [klass, pid, status]: - cmd.append(x) - subprocess.check_call(cmd) - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def resource_get(name): - """used to fetch the resource path of the given name. - - <name> must match a name of defined resource in metadata.yaml - - returns either a path or False if resource not available - """ - if not name: - return False - - cmd = ['resource-get', name] - try: - return subprocess.check_output(cmd).decode('UTF-8') - except subprocess.CalledProcessError: - return False - - -@cached -def juju_version(): - """Full version string (eg. '1.23.3.1-trusty-amd64')""" - # Per https://bugs.launchpad.net/juju-core/+bug/1455368/comments/1 - jujud = glob.glob('/var/lib/juju/tools/machine-*/jujud')[0] - return subprocess.check_output([jujud, 'version'], - universal_newlines=True).strip() - - -@cached -def has_juju_version(minimum_version): - """Return True if the Juju version is at least the provided version""" - return LooseVersion(juju_version()) >= LooseVersion(minimum_version) - - -_atexit = [] -_atstart = [] - - -def atstart(callback, *args, **kwargs): - '''Schedule a callback to run before the main hook. - - Callbacks are run in the order they were added. - - This is useful for modules and classes to perform initialization - and inject behavior. In particular: - - - Run common code before all of your hooks, such as logging - the hook name or interesting relation data. - - Defer object or module initialization that requires a hook - context until we know there actually is a hook context, - making testing easier. - - Rather than requiring charm authors to include boilerplate to - invoke your helper's behavior, have it run automatically if - your object is instantiated or module imported. - - This is not at all useful after your hook framework as been launched. - ''' - global _atstart - _atstart.append((callback, args, kwargs)) - - -def atexit(callback, *args, **kwargs): - '''Schedule a callback to run on successful hook completion. - - Callbacks are run in the reverse order that they were added.''' - _atexit.append((callback, args, kwargs)) - - -def _run_atstart(): - '''Hook frameworks must invoke this before running the main hook body.''' - global _atstart - for callback, args, kwargs in _atstart: - callback(*args, **kwargs) - del _atstart[:] - - -def _run_atexit(): - '''Hook frameworks must invoke this after the main hook body has - successfully completed. Do not invoke it if the hook fails.''' - global _atexit - for callback, args, kwargs in reversed(_atexit): - callback(*args, **kwargs) - del _atexit[:] - - -@translate_exc(from_exc=OSError, to_exc=NotImplementedError) -def network_get_primary_address(binding): - ''' - Retrieve the primary network address for a named binding - - :param binding: string. The name of a relation of extra-binding - :return: string. The primary IP address for the named binding - :raise: NotImplementedError if run on Juju < 2.0 - ''' - cmd = ['network-get', '--primary-address', binding] - return subprocess.check_output(cmd).strip() |