deb-heat/heat/engine/update.py
Oleksii Chuprykov 4e2cfb991a Move Resource exceptions to common module (1)
It is convenient to have all exceptions in exception module.
Also it is reduces namespace cluttering of resource module and decreases
the number of dependencies in other modules (we do not need to import resource
in some cases for now).
UpdateReplace exception is moved in this patch.

Change-Id: Ief441ca2022a0d50e88d709d1a062631479715b7
2015-09-04 14:23:53 +03:00

262 lines
10 KiB
Python

#
# 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.
from oslo_log import log as logging
import six
from heat.common import exception
from heat.common.i18n import _LI
from heat.engine import dependencies
from heat.engine import scheduler
from heat.objects import resource as resource_objects
LOG = logging.getLogger(__name__)
class StackUpdate(object):
"""
A Task to perform the update of an existing stack to a new template.
"""
def __init__(self, existing_stack, new_stack, previous_stack,
rollback=False, error_wait_time=None):
"""Initialise with the existing stack and the new stack."""
self.existing_stack = existing_stack
self.new_stack = new_stack
self.previous_stack = previous_stack
self.rollback = rollback
self.error_wait_time = error_wait_time
self.existing_snippets = dict((n, r.frozen_definition())
for n, r in self.existing_stack.items())
def __repr__(self):
if self.rollback:
return '%s Rollback' % str(self.existing_stack)
else:
return '%s Update' % str(self.existing_stack)
@scheduler.wrappertask
def __call__(self):
"""Return a co-routine that updates the stack."""
cleanup_prev = scheduler.DependencyTaskGroup(
self.previous_stack.dependencies,
self._remove_backup_resource,
reverse=True)
self.updater = scheduler.DependencyTaskGroup(
self.dependencies(),
self._resource_update,
error_wait_time=self.error_wait_time)
if not self.rollback:
yield cleanup_prev()
try:
yield self.updater()
finally:
self.previous_stack.reset_dependencies()
def _resource_update(self, res):
if res.name in self.new_stack and self.new_stack[res.name] is res:
return self._process_new_resource_update(res)
else:
return self._process_existing_resource_update(res)
@scheduler.wrappertask
def _remove_backup_resource(self, prev_res):
if prev_res.state not in ((prev_res.INIT, prev_res.COMPLETE),
(prev_res.DELETE, prev_res.COMPLETE)):
LOG.debug("Deleting backup resource %s" % prev_res.name)
yield prev_res.destroy()
@staticmethod
def _exchange_stacks(existing_res, prev_res):
resource_objects.Resource.exchange_stacks(existing_res.stack.context,
existing_res.id, prev_res.id)
prev_stack, existing_stack = prev_res.stack, existing_res.stack
prev_stack.add_resource(existing_res)
existing_stack.add_resource(prev_res)
@scheduler.wrappertask
def _create_resource(self, new_res):
res_name = new_res.name
# Clean up previous resource
if res_name in self.previous_stack:
prev_res = self.previous_stack[res_name]
if prev_res.state not in ((prev_res.INIT, prev_res.COMPLETE),
(prev_res.DELETE, prev_res.COMPLETE)):
# Swap in the backup resource if it is in a valid state,
# instead of creating a new resource
if prev_res.status == prev_res.COMPLETE:
LOG.debug("Swapping in backup Resource %s" % res_name)
self._exchange_stacks(self.existing_stack[res_name],
prev_res)
return
LOG.debug("Deleting backup Resource %s" % res_name)
yield prev_res.destroy()
# Back up existing resource
if res_name in self.existing_stack:
LOG.debug("Backing up existing Resource %s" % res_name)
existing_res = self.existing_stack[res_name]
self.previous_stack.add_resource(existing_res)
existing_res.state_set(existing_res.UPDATE, existing_res.COMPLETE)
self.existing_stack.add_resource(new_res)
# Save new resource definition to backup stack if it is not
# present in backup stack template already
# it allows to resolve all dependencies that existing resource
# can have if it was copied to backup stack
if (res_name not in
self.previous_stack.t[self.previous_stack.t.RESOURCES]):
LOG.debug("Backing up new Resource %s" % res_name)
definition = new_res.t.reparse(self.previous_stack,
new_res.stack.t)
self.previous_stack.t.add_resource(definition)
self.previous_stack.t.store(self.previous_stack.context)
yield new_res.create()
@scheduler.wrappertask
def _process_new_resource_update(self, new_res):
res_name = new_res.name
res_type = new_res.type()
if (res_name in self.existing_stack and
res_type == self.existing_stack[res_name].type()):
existing_res = self.existing_stack[res_name]
try:
yield self._update_in_place(existing_res,
new_res)
except exception.UpdateReplace:
pass
else:
# Save updated resource definition to backup stack
# cause it allows the backup stack resources to be synchronized
LOG.debug("Backing up updated Resource %s" % res_name)
definition = existing_res.t.reparse(self.previous_stack,
existing_res.stack.t)
self.previous_stack.t.add_resource(definition)
self.previous_stack.t.store(self.previous_stack.context)
LOG.info(_LI("Resource %(res_name)s for stack %(stack_name)s "
"updated"),
{'res_name': res_name,
'stack_name': self.existing_stack.name})
return
yield self._create_resource(new_res)
def _update_in_place(self, existing_res, new_res):
existing_snippet = self.existing_snippets[existing_res.name]
prev_res = self.previous_stack.get(new_res.name)
# Note the new resource snippet is resolved in the context
# of the existing stack (which is the stack being updated)
# but with the template of the new stack (in case the update
# is switching template implementations)
new_snippet = new_res.t.reparse(self.existing_stack,
self.new_stack.t)
return existing_res.update(new_snippet, existing_snippet,
prev_resource=prev_res)
@scheduler.wrappertask
def _process_existing_resource_update(self, existing_res):
res_name = existing_res.name
if res_name in self.previous_stack:
yield self._remove_backup_resource(self.previous_stack[res_name])
if res_name in self.new_stack:
new_res = self.new_stack[res_name]
if new_res.state == (new_res.INIT, new_res.COMPLETE):
# Already updated in-place
return
if existing_res.stack is not self.previous_stack:
yield existing_res.destroy()
if res_name not in self.new_stack:
self.existing_stack.remove_resource(res_name)
def dependencies(self):
'''
Return a Dependencies object representing the dependencies between
update operations to move from an existing stack definition to a new
one.
'''
existing_deps = self.existing_stack.dependencies
new_deps = self.new_stack.dependencies
def edges():
# Create/update the new stack's resources in create order
for e in new_deps.graph().edges():
yield e
# Destroy/cleanup the old stack's resources in delete order
for e in existing_deps.graph(reverse=True).edges():
yield e
# Don't cleanup old resources until after they have been replaced
for name, res in six.iteritems(self.existing_stack):
if name in self.new_stack:
yield (res, self.new_stack[name])
return dependencies.Dependencies(edges())
def preview(self):
upd_keys = set(self.new_stack.resources.keys())
cur_keys = set(self.existing_stack.resources.keys())
common_keys = cur_keys.intersection(upd_keys)
deleted_keys = cur_keys.difference(upd_keys)
added_keys = upd_keys.difference(cur_keys)
updated_keys = []
replaced_keys = []
for key in common_keys:
current_res = self.existing_stack.resources[key]
updated_res = self.new_stack.resources[key]
current_props = current_res.frozen_definition().properties(
current_res.properties_schema, current_res.context)
updated_props = updated_res.frozen_definition().properties(
updated_res.properties_schema, updated_res.context)
try:
if current_res._needs_update(updated_res.frozen_definition(),
current_res.frozen_definition(),
updated_props, current_props,
None, check_init_complete=False):
current_res.update_template_diff_properties(updated_props,
current_props)
updated_keys.append(key)
except exception.UpdateReplace:
replaced_keys.append(key)
return {
'unchanged': list(set(common_keys).difference(
set(updated_keys + replaced_keys))),
'updated': updated_keys,
'replaced': replaced_keys,
'added': added_keys,
'deleted': deleted_keys,
}