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 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 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 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