diff options
Diffstat (limited to 'cloudinit/sources/__init__.py')
| -rw-r--r-- | cloudinit/sources/__init__.py | 78 |
1 files changed, 77 insertions, 1 deletions
diff --git a/cloudinit/sources/__init__.py b/cloudinit/sources/__init__.py index 90d74575..f424316a 100644 --- a/cloudinit/sources/__init__.py +++ b/cloudinit/sources/__init__.py @@ -19,6 +19,7 @@ from cloudinit.atomic_helper import write_json from cloudinit import importer from cloudinit import log as logging from cloudinit import net +from cloudinit.event import EventType from cloudinit import type_utils from cloudinit import user_data as ud from cloudinit import util @@ -102,6 +103,25 @@ class DataSource(object): url_timeout = 10 # timeout for each metadata url read attempt url_retries = 5 # number of times to retry url upon 404 + # The datasource defines a list of supported EventTypes during which + # the datasource can react to changes in metadata and regenerate + # network configuration on metadata changes. + # A datasource which supports writing network config on each system boot + # would set update_events = {'network': [EventType.BOOT]} + + # Default: generate network config on new instance id (first boot). + update_events = {'network': [EventType.BOOT_NEW_INSTANCE]} + + # N-tuple listing default values for any metadata-related class + # attributes cached on an instance by a process_data runs. These attribute + # values are reset via clear_cached_attrs during any update_metadata call. + cached_attr_defaults = ( + ('ec2_metadata', UNSET), ('network_json', UNSET), + ('metadata', {}), ('userdata', None), ('userdata_raw', None), + ('vendordata', None), ('vendordata_raw', None)) + + _dirty_cache = False + def __init__(self, sys_cfg, distro, paths, ud_proc=None): self.sys_cfg = sys_cfg self.distro = distro @@ -134,11 +154,31 @@ class DataSource(object): 'region': self.region, 'availability-zone': self.availability_zone}} + def clear_cached_attrs(self, attr_defaults=()): + """Reset any cached metadata attributes to datasource defaults. + + @param attr_defaults: Optional tuple of (attr, value) pairs to + set instead of cached_attr_defaults. + """ + if not self._dirty_cache: + return + if attr_defaults: + attr_values = attr_defaults + else: + attr_values = self.cached_attr_defaults + + for attribute, value in attr_values: + if hasattr(self, attribute): + setattr(self, attribute, value) + if not attr_defaults: + self._dirty_cache = False + def get_data(self): """Datasources implement _get_data to setup metadata and userdata_raw. Minimally, the datasource should return a boolean True on success. """ + self._dirty_cache = True return_value = self._get_data() json_file = os.path.join(self.paths.run_dir, INSTANCE_JSON_FILE) if not return_value: @@ -174,6 +214,7 @@ class DataSource(object): return return_value def _get_data(self): + """Walk metadata sources, process crawled data and save attributes.""" raise NotImplementedError( 'Subclasses of DataSource must implement _get_data which' ' sets self.metadata, vendordata_raw and userdata_raw.') @@ -416,6 +457,41 @@ class DataSource(object): def get_package_mirror_info(self): return self.distro.get_package_mirror_info(data_source=self) + def update_metadata(self, source_event_types): + """Refresh cached metadata if the datasource supports this event. + + The datasource has a list of update_events which + trigger refreshing all cached metadata as well as refreshing the + network configuration. + + @param source_event_types: List of EventTypes which may trigger a + metadata update. + + @return True if the datasource did successfully update cached metadata + due to source_event_type. + """ + supported_events = {} + for event in source_event_types: + for update_scope, update_events in self.update_events.items(): + if event in update_events: + if not supported_events.get(update_scope): + supported_events[update_scope] = [] + supported_events[update_scope].append(event) + for scope, matched_events in supported_events.items(): + LOG.debug( + "Update datasource metadata and %s config due to events: %s", + scope, ', '.join(matched_events)) + # Each datasource has a cached config property which needs clearing + # Once cleared that config property will be regenerated from + # current metadata. + self.clear_cached_attrs((('_%s_config' % scope, UNSET),)) + if supported_events: + self.clear_cached_attrs() + result = self.get_data() + if result: + return True + return False + def check_instance_id(self, sys_cfg): # quickly (local check only) if self.instance_id is still return False @@ -520,7 +596,7 @@ def find_source(sys_cfg, distro, paths, ds_deps, cfg_list, pkg_list, reporter): with myrep: LOG.debug("Seeing if we can get any data from %s", cls) s = cls(sys_cfg, distro, paths) - if s.get_data(): + if s.update_metadata([EventType.BOOT_NEW_INSTANCE]): myrep.message = "found %s data from %s" % (mode, name) return (s, type_utils.obj_name(cls)) except Exception: |