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Diffstat (limited to 'charms/trusty/ceilometer/charmhelpers/contrib/peerstorage/__init__.py')
| -rw-r--r-- | charms/trusty/ceilometer/charmhelpers/contrib/peerstorage/__init__.py | 269 |
1 files changed, 0 insertions, 269 deletions
diff --git a/charms/trusty/ceilometer/charmhelpers/contrib/peerstorage/__init__.py b/charms/trusty/ceilometer/charmhelpers/contrib/peerstorage/__init__.py deleted file mode 100644 index eafca44..0000000 --- a/charms/trusty/ceilometer/charmhelpers/contrib/peerstorage/__init__.py +++ /dev/null @@ -1,269 +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/>. - -import json -import six - -from charmhelpers.core.hookenv import relation_id as current_relation_id -from charmhelpers.core.hookenv import ( - is_relation_made, - relation_ids, - relation_get as _relation_get, - local_unit, - relation_set as _relation_set, - leader_get as _leader_get, - leader_set, - is_leader, -) - - -""" -This helper provides functions to support use of a peer relation -for basic key/value storage, with the added benefit that all storage -can be replicated across peer units. - -Requirement to use: - -To use this, the "peer_echo()" method has to be called form the peer -relation's relation-changed hook: - -@hooks.hook("cluster-relation-changed") # Adapt the to your peer relation name -def cluster_relation_changed(): - peer_echo() - -Once this is done, you can use peer storage from anywhere: - -@hooks.hook("some-hook") -def some_hook(): - # You can store and retrieve key/values this way: - if is_relation_made("cluster"): # from charmhelpers.core.hookenv - # There are peers available so we can work with peer storage - peer_store("mykey", "myvalue") - value = peer_retrieve("mykey") - print value - else: - print "No peers joind the relation, cannot share key/values :(" -""" - - -def leader_get(attribute=None, rid=None): - """Wrapper to ensure that settings are migrated from the peer relation. - - This is to support upgrading an environment that does not support - Juju leadership election to one that does. - - If a setting is not extant in the leader-get but is on the relation-get - peer rel, it is migrated and marked as such so that it is not re-migrated. - """ - migration_key = '__leader_get_migrated_settings__' - if not is_leader(): - return _leader_get(attribute=attribute) - - settings_migrated = False - leader_settings = _leader_get(attribute=attribute) - previously_migrated = _leader_get(attribute=migration_key) - - if previously_migrated: - migrated = set(json.loads(previously_migrated)) - else: - migrated = set([]) - - try: - if migration_key in leader_settings: - del leader_settings[migration_key] - except TypeError: - pass - - if attribute: - if attribute in migrated: - return leader_settings - - # If attribute not present in leader db, check if this unit has set - # the attribute in the peer relation - if not leader_settings: - peer_setting = _relation_get(attribute=attribute, unit=local_unit(), - rid=rid) - if peer_setting: - leader_set(settings={attribute: peer_setting}) - leader_settings = peer_setting - - if leader_settings: - settings_migrated = True - migrated.add(attribute) - else: - r_settings = _relation_get(unit=local_unit(), rid=rid) - if r_settings: - for key in set(r_settings.keys()).difference(migrated): - # Leader setting wins - if not leader_settings.get(key): - leader_settings[key] = r_settings[key] - - settings_migrated = True - migrated.add(key) - - if settings_migrated: - leader_set(**leader_settings) - - if migrated and settings_migrated: - migrated = json.dumps(list(migrated)) - leader_set(settings={migration_key: migrated}) - - return leader_settings - - -def relation_set(relation_id=None, relation_settings=None, **kwargs): - """Attempt to use leader-set if supported in the current version of Juju, - otherwise falls back on relation-set. - - Note that we only attempt to use leader-set if the provided relation_id is - a peer relation id or no relation id is provided (in which case we assume - we are within the peer relation context). - """ - try: - if relation_id in relation_ids('cluster'): - return leader_set(settings=relation_settings, **kwargs) - else: - raise NotImplementedError - except NotImplementedError: - return _relation_set(relation_id=relation_id, - relation_settings=relation_settings, **kwargs) - - -def relation_get(attribute=None, unit=None, rid=None): - """Attempt to use leader-get if supported in the current version of Juju, - otherwise falls back on relation-get. - - Note that we only attempt to use leader-get if the provided rid is a peer - relation id or no relation id is provided (in which case we assume we are - within the peer relation context). - """ - try: - if rid in relation_ids('cluster'): - return leader_get(attribute, rid) - else: - raise NotImplementedError - except NotImplementedError: - return _relation_get(attribute=attribute, rid=rid, unit=unit) - - -def peer_retrieve(key, relation_name='cluster'): - """Retrieve a named key from peer relation `relation_name`.""" - cluster_rels = relation_ids(relation_name) - if len(cluster_rels) > 0: - cluster_rid = cluster_rels[0] - return relation_get(attribute=key, rid=cluster_rid, - unit=local_unit()) - else: - raise ValueError('Unable to detect' - 'peer relation {}'.format(relation_name)) - - -def peer_retrieve_by_prefix(prefix, relation_name='cluster', delimiter='_', - inc_list=None, exc_list=None): - """ Retrieve k/v pairs given a prefix and filter using {inc,exc}_list """ - inc_list = inc_list if inc_list else [] - exc_list = exc_list if exc_list else [] - peerdb_settings = peer_retrieve('-', relation_name=relation_name) - matched = {} - if peerdb_settings is None: - return matched - for k, v in peerdb_settings.items(): - full_prefix = prefix + delimiter - if k.startswith(full_prefix): - new_key = k.replace(full_prefix, '') - if new_key in exc_list: - continue - if new_key in inc_list or len(inc_list) == 0: - matched[new_key] = v - return matched - - -def peer_store(key, value, relation_name='cluster'): - """Store the key/value pair on the named peer relation `relation_name`.""" - cluster_rels = relation_ids(relation_name) - if len(cluster_rels) > 0: - cluster_rid = cluster_rels[0] - relation_set(relation_id=cluster_rid, - relation_settings={key: value}) - else: - raise ValueError('Unable to detect ' - 'peer relation {}'.format(relation_name)) - - -def peer_echo(includes=None, force=False): - """Echo filtered attributes back onto the same relation for storage. - - This is a requirement to use the peerstorage module - it needs to be called - from the peer relation's changed hook. - - If Juju leader support exists this will be a noop unless force is True. - """ - try: - is_leader() - except NotImplementedError: - pass - else: - if not force: - return # NOOP if leader-election is supported - - # Use original non-leader calls - relation_get = _relation_get - relation_set = _relation_set - - rdata = relation_get() - echo_data = {} - if includes is None: - echo_data = rdata.copy() - for ex in ['private-address', 'public-address']: - if ex in echo_data: - echo_data.pop(ex) - else: - for attribute, value in six.iteritems(rdata): - for include in includes: - if include in attribute: - echo_data[attribute] = value - if len(echo_data) > 0: - relation_set(relation_settings=echo_data) - - -def peer_store_and_set(relation_id=None, peer_relation_name='cluster', - peer_store_fatal=False, relation_settings=None, - delimiter='_', **kwargs): - """Store passed-in arguments both in argument relation and in peer storage. - - It functions like doing relation_set() and peer_store() at the same time, - with the same data. - - @param relation_id: the id of the relation to store the data on. Defaults - to the current relation. - @param peer_store_fatal: Set to True, the function will raise an exception - should the peer sotrage not be avialable.""" - - relation_settings = relation_settings if relation_settings else {} - relation_set(relation_id=relation_id, - relation_settings=relation_settings, - **kwargs) - if is_relation_made(peer_relation_name): - for key, value in six.iteritems(dict(list(kwargs.items()) + - list(relation_settings.items()))): - key_prefix = relation_id or current_relation_id() - peer_store(key_prefix + delimiter + key, - value, - relation_name=peer_relation_name) - else: - if peer_store_fatal: - raise ValueError('Unable to detect ' - 'peer relation {}'.format(peer_relation_name)) |