# Copyright 2015 OpenStack Foundation # All Rights Reserved. # # 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. import glance_store as store_api from glance_store import backend from oslo_config import cfg from oslo_log import log as logging from oslo_utils import encodeutils import six from taskflow.patterns import linear_flow as lf from taskflow import retry from taskflow import task from glance.common import exception from glance.common.scripts.image_import import main as image_import from glance.common.scripts import utils as script_utils from glance.i18n import _, _LE, _LI LOG = logging.getLogger(__name__) CONF = cfg.CONF # TODO(jokke): We should refactor the task implementations so that we do not # need to duplicate what we have already for example in base_import.py. class _DeleteFromFS(task.Task): def __init__(self, task_id, task_type): self.task_id = task_id self.task_type = task_type super(_DeleteFromFS, self).__init__( name='%s-DeleteFromFS-%s' % (task_type, task_id)) def execute(self, file_path): """Remove file from the backend :param file_path: path to the file being deleted """ store_api.delete_from_backend(file_path) class _VerifyStaging(task.Task): # NOTE(jokke): This could be also for example "staging_path" but to # keep this compatible with other flows we want to stay consistent # with base_import default_provides = 'file_path' def __init__(self, task_id, task_type, task_repo, uri): self.task_id = task_id self.task_type = task_type self.task_repo = task_repo self.uri = uri super(_VerifyStaging, self).__init__( name='%s-ConfigureStaging-%s' % (task_type, task_id)) # NOTE(jokke): If we want to use other than 'file' store in the # future, this is one thing that needs to change. try: uri.index('file:///', 0) except ValueError: msg = (_("%(task_id)s of %(task_type)s not configured " "properly. Value of node_staging_uri must be " " in format 'file://'") % {'task_id': self.task_id, 'task_type': self.task_type}) raise exception.BadTaskConfiguration(msg) # NOTE(jokke): We really don't need the store for anything but # verifying that we actually can build the store will allow us to # fail the flow early with clear message why that happens. self._build_store() def _build_store(self): # NOTE(jokke): If we want to use some other store for staging, we can # implement the logic more general here. For now this should do. # NOTE(flaper87): Due to the nice glance_store api (#sarcasm), we're # forced to build our own config object, register the required options # (and by required I mean *ALL* of them, even the ones we don't want), # and create our own store instance by calling a private function. # This is certainly unfortunate but it's the best we can do until the # glance_store refactor is done. A good thing is that glance_store is # under our team's management and it gates on Glance so changes to # this API will (should?) break task's tests. conf = cfg.ConfigOpts() backend.register_opts(conf) conf.set_override('filesystem_store_datadir', CONF.node_staging_uri[7:], group='glance_store') # NOTE(flaper87): Do not even try to judge me for this... :( # With the glance_store refactor, this code will change, until # that happens, we don't have a better option and this is the # least worst one, IMHO. store = backend._load_store(conf, 'file') try: store.configure() except AttributeError: msg = (_("%(task_id)s of %(task_type)s not configured " "properly. Could not load the filesystem store") % {'task_id': self.task_id, 'task_type': self.task_type}) raise exception.BadTaskConfiguration(msg) def execute(self): """Test the backend store and return the 'file_path'""" return self.uri class _ImportToStore(task.Task): def __init__(self, task_id, task_type, image_repo, uri): self.task_id = task_id self.task_type = task_type self.image_repo = image_repo self.uri = uri super(_ImportToStore, self).__init__( name='%s-ImportToStore-%s' % (task_type, task_id)) def execute(self, image_id, file_path=None): """Bringing the imported image to back end store :param image_id: Glance Image ID :param file_path: path to the image file """ # NOTE(flaper87): There are a couple of interesting bits in the # interaction between this task and the `_ImportToFS` one. I'll try # to cover them in this comment. # # NOTE(jokke): We do not have _ImportToFS currently in this flow but # I will leave Flavio's comments here as we will utilize it or fork # of it after MVP. # # NOTE(flaper87): # `_ImportToFS` downloads the image to a dedicated `work_dir` which # needs to be configured in advance (please refer to the config option # docs for more info). The motivation behind this is also explained in # the `_ImportToFS.execute` method. # # Due to the fact that we have an `_ImportToFS` task which downloads # the image data already, we need to be as smart as we can in this task # to avoid downloading the data several times and reducing the copy or # write times. There are several scenarios where the interaction # between this task and `_ImportToFS` could be improved. All these # scenarios assume the `_ImportToFS` task has been executed before # and/or in a more abstract scenario, that `file_path` is being # provided. # # Scenario 1: FS Store is Remote, introspection enabled, # conversion disabled # # In this scenario, the user would benefit from having the scratch path # being the same path as the fs store. Only one write would happen and # an extra read will happen in order to introspect the image. Note that # this read is just for the image headers and not the entire file. # # Scenario 2: FS Store is remote, introspection enabled, # conversion enabled # # In this scenario, the user would benefit from having a *local* store # into which the image can be converted. This will require downloading # the image locally, converting it and then copying the converted image # to the remote store. # # Scenario 3: FS Store is local, introspection enabled, # conversion disabled # Scenario 4: FS Store is local, introspection enabled, # conversion enabled # # In both these scenarios the user shouldn't care if the FS # store path and the work dir are the same, therefore probably # benefit, about the scratch path and the FS store being the # same from a performance perspective. Space wise, regardless # of the scenario, the user will have to account for it in # advance. # # Lets get to it and identify the different scenarios in the # implementation image = self.image_repo.get(image_id) image.status = 'importing' self.image_repo.save(image) # NOTE(flaper87): Let's dance... and fall # # Unfortunatelly, because of the way our domain layers work and # the checks done in the FS store, we can't simply rename the file # and set the location. To do that, we'd have to duplicate the logic # of every and each of the domain factories (quota, location, etc) # and we'd also need to hack the FS store to prevent it from raising # a "duplication path" error. I'd rather have this task copying the # image bits one more time than duplicating all that logic. # # Since I don't think this should be the definitive solution, I'm # leaving the code below as a reference for what should happen here # once the FS store and domain code will be able to handle this case. # # if file_path is None: # image_import.set_image_data(image, self.uri, None) # return # NOTE(flaper87): Don't assume the image was stored in the # work_dir. Think in the case this path was provided by another task. # Also, lets try to neither assume things nor create "logic" # dependencies between this task and `_ImportToFS` # # base_path = os.path.dirname(file_path.split("file://")[-1]) # NOTE(flaper87): Hopefully just scenarios #3 and #4. I say # hopefully because nothing prevents the user to use the same # FS store path as a work dir # # image_path = os.path.join(base_path, image_id) # # if (base_path == CONF.glance_store.filesystem_store_datadir or # base_path in CONF.glance_store.filesystem_store_datadirs): # os.rename(file_path, image_path) # # image_import.set_image_data(image, image_path, None) # NOTE(jokke): The different options here are kind of pointless as we # will need the file path anyways for our delete workflow for now. # For future proofing keeping this as is. image_import.set_image_data(image, file_path or self.uri, self.task_id) # NOTE(flaper87): We need to save the image again after the locations # have been set in the image. self.image_repo.save(image) class _SaveImage(task.Task): def __init__(self, task_id, task_type, image_repo): self.task_id = task_id self.task_type = task_type self.image_repo = image_repo super(_SaveImage, self).__init__( name='%s-SaveImage-%s' % (task_type, task_id)) def execute(self, image_id): """Transition image status to active :param image_id: Glance Image ID """ new_image = self.image_repo.get(image_id) if new_image.status == 'saving': # NOTE(flaper87): THIS IS WRONG! # we should be doing atomic updates to avoid # race conditions. This happens in other places # too. new_image.status = 'active' self.image_repo.save(new_image) class _CompleteTask(task.Task): def __init__(self, task_id, task_type, task_repo): self.task_id = task_id self.task_type = task_type self.task_repo = task_repo super(_CompleteTask, self).__init__( name='%s-CompleteTask-%s' % (task_type, task_id)) def execute(self, image_id): """Finishing the task flow :param image_id: Glance Image ID """ task = script_utils.get_task(self.task_repo, self.task_id) if task is None: return try: task.succeed({'image_id': image_id}) except Exception as e: # Note: The message string contains Error in it to indicate # in the task.message that it's a error message for the user. # TODO(nikhil): need to bring back save_and_reraise_exception when # necessary log_msg = _LE("Task ID %(task_id)s failed. Error: %(exc_type)s: " "%(e)s") LOG.exception(log_msg, {'exc_type': six.text_type(type(e)), 'e': encodeutils.exception_to_unicode(e), 'task_id': task.task_id}) err_msg = _("Error: %(exc_type)s: %(e)s") task.fail(err_msg % {'exc_type': six.text_type(type(e)), 'e': encodeutils.exception_to_unicode(e)}) finally: self.task_repo.save(task) LOG.info(_LI("%(task_id)s of %(task_type)s completed"), {'task_id': self.task_id, 'task_type': self.task_type}) def get_flow(**kwargs): """Return task flow :param task_id: Task ID :param task_type: Type of the task :param task_repo: Task repo :param image_repo: Image repository used :param image_id: ID of the Image to be processed :param uri: uri for the image file """ task_id = kwargs.get('task_id') task_type = kwargs.get('task_type') task_repo = kwargs.get('task_repo') image_repo = kwargs.get('image_repo') image_id = kwargs.get('image_id') uri = kwargs.get('uri') if not uri: separator = '' if not CONF.node_staging_uri.endsWith('/'): separator = '/' uri = separator.join((CONF.node_staging_uri, str(image_id))) flow = lf.flow(task_type, retry=retry.AlwaysRevert()) flow.add(_VerifyStaging(task_id, task_type, uri)) # TODO(jokke): For the pluggable tasks like image verification or # image conversion we need to implement the plugin logic here. import_to_store = _ImportToStore(task_id, task_type, image_repo, uri, rebind_args={'image_id': image_id}) flow.add(import_to_store) delete_task = lf.Flow(task_type).add(_DeleteFromFS(task_id, task_type)) flow.add(delete_task) save_task = _SaveImage(task_id, task_type, image_repo, rebind_args={'image_id': image_id}) flow.add(save_task) complete_task = _CompleteTask(task_id, task_type, task_repo, rebind_args={'image_id': image_id}) flow.add(complete_task) return flow