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Diffstat (limited to 'charms/trusty/ceilometer/charmhelpers/contrib/charmsupport/volumes.py')
| -rw-r--r-- | charms/trusty/ceilometer/charmhelpers/contrib/charmsupport/volumes.py | 175 |
1 files changed, 0 insertions, 175 deletions
diff --git a/charms/trusty/ceilometer/charmhelpers/contrib/charmsupport/volumes.py b/charms/trusty/ceilometer/charmhelpers/contrib/charmsupport/volumes.py deleted file mode 100644 index 320961b..0000000 --- a/charms/trusty/ceilometer/charmhelpers/contrib/charmsupport/volumes.py +++ /dev/null @@ -1,175 +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/>. - -''' -Functions for managing volumes in juju units. One volume is supported per unit. -Subordinates may have their own storage, provided it is on its own partition. - -Configuration stanzas:: - - volume-ephemeral: - type: boolean - default: true - description: > - If false, a volume is mounted as sepecified in "volume-map" - If true, ephemeral storage will be used, meaning that log data - will only exist as long as the machine. YOU HAVE BEEN WARNED. - volume-map: - type: string - default: {} - description: > - YAML map of units to device names, e.g: - "{ rsyslog/0: /dev/vdb, rsyslog/1: /dev/vdb }" - Service units will raise a configure-error if volume-ephemeral - is 'true' and no volume-map value is set. Use 'juju set' to set a - value and 'juju resolved' to complete configuration. - -Usage:: - - from charmsupport.volumes import configure_volume, VolumeConfigurationError - from charmsupport.hookenv import log, ERROR - def post_mount_hook(): - stop_service('myservice') - def post_mount_hook(): - start_service('myservice') - - if __name__ == '__main__': - try: - configure_volume(before_change=pre_mount_hook, - after_change=post_mount_hook) - except VolumeConfigurationError: - log('Storage could not be configured', ERROR) - -''' - -# XXX: Known limitations -# - fstab is neither consulted nor updated - -import os -from charmhelpers.core import hookenv -from charmhelpers.core import host -import yaml - - -MOUNT_BASE = '/srv/juju/volumes' - - -class VolumeConfigurationError(Exception): - '''Volume configuration data is missing or invalid''' - pass - - -def get_config(): - '''Gather and sanity-check volume configuration data''' - volume_config = {} - config = hookenv.config() - - errors = False - - if config.get('volume-ephemeral') in (True, 'True', 'true', 'Yes', 'yes'): - volume_config['ephemeral'] = True - else: - volume_config['ephemeral'] = False - - try: - volume_map = yaml.safe_load(config.get('volume-map', '{}')) - except yaml.YAMLError as e: - hookenv.log("Error parsing YAML volume-map: {}".format(e), - hookenv.ERROR) - errors = True - if volume_map is None: - # probably an empty string - volume_map = {} - elif not isinstance(volume_map, dict): - hookenv.log("Volume-map should be a dictionary, not {}".format( - type(volume_map))) - errors = True - - volume_config['device'] = volume_map.get(os.environ['JUJU_UNIT_NAME']) - if volume_config['device'] and volume_config['ephemeral']: - # asked for ephemeral storage but also defined a volume ID - hookenv.log('A volume is defined for this unit, but ephemeral ' - 'storage was requested', hookenv.ERROR) - errors = True - elif not volume_config['device'] and not volume_config['ephemeral']: - # asked for permanent storage but did not define volume ID - hookenv.log('Ephemeral storage was requested, but there is no volume ' - 'defined for this unit.', hookenv.ERROR) - errors = True - - unit_mount_name = hookenv.local_unit().replace('/', '-') - volume_config['mountpoint'] = os.path.join(MOUNT_BASE, unit_mount_name) - - if errors: - return None - return volume_config - - -def mount_volume(config): - if os.path.exists(config['mountpoint']): - if not os.path.isdir(config['mountpoint']): - hookenv.log('Not a directory: {}'.format(config['mountpoint'])) - raise VolumeConfigurationError() - else: - host.mkdir(config['mountpoint']) - if os.path.ismount(config['mountpoint']): - unmount_volume(config) - if not host.mount(config['device'], config['mountpoint'], persist=True): - raise VolumeConfigurationError() - - -def unmount_volume(config): - if os.path.ismount(config['mountpoint']): - if not host.umount(config['mountpoint'], persist=True): - raise VolumeConfigurationError() - - -def managed_mounts(): - '''List of all mounted managed volumes''' - return filter(lambda mount: mount[0].startswith(MOUNT_BASE), host.mounts()) - - -def configure_volume(before_change=lambda: None, after_change=lambda: None): - '''Set up storage (or don't) according to the charm's volume configuration. - Returns the mount point or "ephemeral". before_change and after_change - are optional functions to be called if the volume configuration changes. - ''' - - config = get_config() - if not config: - hookenv.log('Failed to read volume configuration', hookenv.CRITICAL) - raise VolumeConfigurationError() - - if config['ephemeral']: - if os.path.ismount(config['mountpoint']): - before_change() - unmount_volume(config) - after_change() - return 'ephemeral' - else: - # persistent storage - if os.path.ismount(config['mountpoint']): - mounts = dict(managed_mounts()) - if mounts.get(config['mountpoint']) != config['device']: - before_change() - unmount_volume(config) - mount_volume(config) - after_change() - else: - before_change() - mount_volume(config) - after_change() - return config['mountpoint'] |