From 711967ae9639095ce41500bb0e6f80c8b80fab95 Mon Sep 17 00:00:00 2001 From: Stuart Mackie Date: Tue, 25 Jul 2017 10:37:57 -0700 Subject: Contrail charms Change-Id: I2d259d03f63fce38348b8384e26ac23e3fce44a8 Signed-off-by: Stuart Mackie --- .../hooks/charmhelpers/core/hookenv.py | 1068 ++++++++++++++++++++ 1 file changed, 1068 insertions(+) create mode 100644 contrail-analyticsdb/hooks/charmhelpers/core/hookenv.py (limited to 'contrail-analyticsdb/hooks/charmhelpers/core/hookenv.py') diff --git a/contrail-analyticsdb/hooks/charmhelpers/core/hookenv.py b/contrail-analyticsdb/hooks/charmhelpers/core/hookenv.py new file mode 100644 index 0000000..e44e22b --- /dev/null +++ b/contrail-analyticsdb/hooks/charmhelpers/core/hookenv.py @@ -0,0 +1,1068 @@ +# Copyright 2014-2015 Canonical Limited. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +"Interactions with the Juju environment" +# Copyright 2013 Canonical Ltd. +# +# Authors: +# Charm Helpers Developers + +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 ` + or :meth:'@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) + else: + config_cmd_line.append('--all') + 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) + + +def open_ports(start, end, protocol="TCP"): + """Opens a range of service network ports""" + _args = ['open-port'] + _args.append('{}-{}/{}'.format(start, end, protocol)) + subprocess.check_call(_args) + + +def close_ports(start, end, protocol="TCP"): + """Close a range of service network ports""" + _args = ['close-port'] + _args.append('{}-{}/{}'.format(start, end, 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 + + +def application_version_set(version): + """Charm authors may trigger this command from any hook to output what + version of the application is running. This could be a package version, + for instance postgres version 9.5. It could also be a build number or + version control revision identifier, for instance git sha 6fb7ba68. """ + + cmd = ['application-version-set'] + cmd.append(version) + try: + subprocess.check_call(cmd) + except OSError: + log("Application Version: {}".format(version)) + + +@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 and 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 and provided must match a payload that has been previously + registered with juju using payload-register. The 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. + + 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).decode('UTF-8').strip() + + +def add_metric(*args, **kwargs): + """Add metric values. Values may be expressed with keyword arguments. For + metric names containing dashes, these may be expressed as one or more + 'key=value' positional arguments. May only be called from the collect-metrics + hook.""" + _args = ['add-metric'] + _kvpairs = [] + _kvpairs.extend(args) + _kvpairs.extend(['{}={}'.format(k, v) for k, v in kwargs.items()]) + _args.extend(sorted(_kvpairs)) + try: + subprocess.check_call(_args) + return + except EnvironmentError as e: + if e.errno != errno.ENOENT: + raise + log_message = 'add-metric failed: {}'.format(' '.join(_kvpairs)) + log(log_message, level='INFO') + + +def meter_status(): + """Get the meter status, if running in the meter-status-changed hook.""" + return os.environ.get('JUJU_METER_STATUS') + + +def meter_info(): + """Get the meter status information, if running in the meter-status-changed + hook.""" + return os.environ.get('JUJU_METER_INFO') -- cgit 1.2.3-korg