juju/model.py

   1 import asyncio
   2 import collections
   3 import json
   4 import logging
   5 import os
   6 import re
   7 import stat
   8 import tempfile
   9 import weakref
  10 import zipfile
  11 from concurrent.futures import CancelledError
  12 from functools import partial
  13 from pathlib import Path
  14
  15 import yaml
  16 import theblues.charmstore
  17 import theblues.errors
  18
  19 from .client import client
  20 from .client import watcher
  21 from .client import connection
  22 from .constraints import parse as parse_constraints, normalize_key
  23 from .delta import get_entity_delta
  24 from .delta import get_entity_class
  25 from .exceptions import DeadEntityException
  26 from .errors import JujuError, JujuAPIError
  27 from .placement import parse as parse_placement
  28
  29 log = logging.getLogger(__name__)
  30
  31
  32 class _Observer(object):
  33     """Wrapper around an observer callable.
  34
  35     This wrapper allows filter criteria to be associated with the
  36     callable so that it's only called for changes that meet the criteria.
  37
  38     """
  39     def __init__(self, callable_, entity_type, action, entity_id, predicate):
  40         self.callable_ = callable_
  41         self.entity_type = entity_type
  42         self.action = action
  43         self.entity_id = entity_id
  44         self.predicate = predicate
  45         if self.entity_id:
  46             self.entity_id = str(self.entity_id)
  47             if not self.entity_id.startswith('^'):
  48                 self.entity_id = '^' + self.entity_id
  49             if not self.entity_id.endswith('$'):
  50                 self.entity_id += '$'
  51
  52     async def __call__(self, delta, old, new, model):
  53         await self.callable_(delta, old, new, model)
  54
  55     def cares_about(self, delta):
  56         """Return True if this observer "cares about" (i.e. wants to be
  57         called) for a this delta.
  58
  59         """
  60         if (self.entity_id and delta.get_id() and
  61                 not re.match(self.entity_id, str(delta.get_id()))):
  62             return False
  63
  64         if self.entity_type and self.entity_type != delta.entity:
  65             return False
  66
  67         if self.action and self.action != delta.type:
  68             return False
  69
  70         if self.predicate and not self.predicate(delta):
  71             return False
  72
  73         return True
  74
  75
  76 class ModelObserver(object):
  77     async def __call__(self, delta, old, new, model):
  78         handler_name = 'on_{}_{}'.format(delta.entity, delta.type)
  79         method = getattr(self, handler_name, self.on_change)
  80         await method(delta, old, new, model)
  81
  82     async def on_change(self, delta, old, new, model):
  83         """Generic model-change handler.
  84
  85         :param delta: :class:`juju.client.overrides.Delta`
  86         :param old: :class:`juju.model.ModelEntity`
  87         :param new: :class:`juju.model.ModelEntity`
  88         :param model: :class:`juju.model.Model`
  89
  90         """
  91         pass
  92
  93
  94 class ModelState(object):
  95     """Holds the state of the model, including the delta history of all
  96     entities in the model.
  97
  98     """
  99     def __init__(self, model):
 100         self.model = model
 101         self.state = dict()
 102
 103     def _live_entity_map(self, entity_type):
 104         """Return an id:Entity map of all the living entities of
 105         type ``entity_type``.
 106
 107         """
 108         return {
 109             entity_id: self.get_entity(entity_type, entity_id)
 110             for entity_id, history in self.state.get(entity_type, {}).items()
 111             if history[-1] is not None
 112         }
 113
 114     @property
 115     def applications(self):
 116         """Return a map of application-name:Application for all applications
 117         currently in the model.
 118
 119         """
 120         return self._live_entity_map('application')
 121
 122     @property
 123     def machines(self):
 124         """Return a map of machine-id:Machine for all machines currently in
 125         the model.
 126
 127         """
 128         return self._live_entity_map('machine')
 129
 130     @property
 131     def units(self):
 132         """Return a map of unit-id:Unit for all units currently in
 133         the model.
 134
 135         """
 136         return self._live_entity_map('unit')
 137
 138     def entity_history(self, entity_type, entity_id):
 139         """Return the history deque for an entity.
 140
 141         """
 142         return self.state[entity_type][entity_id]
 143
 144     def entity_data(self, entity_type, entity_id, history_index):
 145         """Return the data dict for an entity at a specific index of its
 146         history.
 147
 148         """
 149         return self.entity_history(entity_type, entity_id)[history_index]
 150
 151     def apply_delta(self, delta):
 152         """Apply delta to our state and return a copy of the
 153         affected object as it was before and after the update, e.g.:
 154
 155             old_obj, new_obj = self.apply_delta(delta)
 156
 157         old_obj may be None if the delta is for the creation of a new object,
 158         e.g. a new application or unit is deployed.
 159
 160         new_obj will never be None, but may be dead (new_obj.dead == True)
 161         if the object was deleted as a result of the delta being applied.
 162
 163         """
 164         history = (
 165             self.state
 166             .setdefault(delta.entity, {})
 167             .setdefault(delta.get_id(), collections.deque())
 168         )
 169
 170         history.append(delta.data)
 171         if delta.type == 'remove':
 172             history.append(None)
 173
 174         entity = self.get_entity(delta.entity, delta.get_id())
 175         return entity.previous(), entity
 176
 177     def get_entity(
 178             self, entity_type, entity_id, history_index=-1, connected=True):
 179         """Return an object instance for the given entity_type and id.
 180
 181         By default the object state matches the most recent state from
 182         Juju. To get an instance of the object in an older state, pass
 183         history_index, an index into the history deque for the entity.
 184
 185         """
 186
 187         if history_index < 0 and history_index != -1:
 188             history_index += len(self.entity_history(entity_type, entity_id))
 189             if history_index < 0:
 190                 return None
 191
 192         try:
 193             self.entity_data(entity_type, entity_id, history_index)
 194         except IndexError:
 195             return None
 196
 197         entity_class = get_entity_class(entity_type)
 198         return entity_class(
 199             entity_id, self.model, history_index=history_index,
 200             connected=connected)
 201
 202
 203 class ModelEntity(object):
 204     """An object in the Model tree"""
 205
 206     def __init__(self, entity_id, model, history_index=-1, connected=True):
 207         """Initialize a new entity
 208
 209         :param entity_id str: The unique id of the object in the model
 210         :param model: The model instance in whose object tree this
 211             entity resides
 212         :history_index int: The index of this object's state in the model's
 213             history deque for this entity
 214         :connected bool: Flag indicating whether this object gets live updates
 215             from the model.
 216
 217         """
 218         self.entity_id = entity_id
 219         self.model = model
 220         self._history_index = history_index
 221         self.connected = connected
 222         self.connection = model.connection
 223
 224     def __repr__(self):
 225         return '<{} entity_id="{}">'.format(type(self).__name__,
 226                                             self.entity_id)
 227
 228     def __getattr__(self, name):
 229         """Fetch object attributes from the underlying data dict held in the
 230         model.
 231
 232         """
 233         return self.safe_data[name]
 234
 235     def __bool__(self):
 236         return bool(self.data)
 237
 238     def on_change(self, callable_):
 239         """Add a change observer to this entity.
 240
 241         """
 242         self.model.add_observer(
 243             callable_, self.entity_type, 'change', self.entity_id)
 244
 245     def on_remove(self, callable_):
 246         """Add a remove observer to this entity.
 247
 248         """
 249         self.model.add_observer(
 250             callable_, self.entity_type, 'remove', self.entity_id)
 251
 252     @property
 253     def entity_type(self):
 254         """A string identifying the entity type of this object, e.g.
 255         'application' or 'unit', etc.
 256
 257         """
 258         return self.__class__.__name__.lower()
 259
 260     @property
 261     def current(self):
 262         """Return True if this object represents the current state of the
 263         entity in the underlying model.
 264
 265         This will be True except when the object represents an entity at a
 266         non-latest state in history, e.g. if the object was obtained by calling
 267         .previous() on another object.
 268
 269         """
 270         return self._history_index == -1
 271
 272     @property
 273     def dead(self):
 274         """Returns True if this entity no longer exists in the underlying
 275         model.
 276
 277         """
 278         return (
 279             self.data is None or
 280             self.model.state.entity_data(
 281                 self.entity_type, self.entity_id, -1) is None
 282         )
 283
 284     @property
 285     def alive(self):
 286         """Returns True if this entity still exists in the underlying
 287         model.
 288
 289         """
 290         return not self.dead
 291
 292     @property
 293     def data(self):
 294         """The data dictionary for this entity.
 295
 296         """
 297         return self.model.state.entity_data(
 298             self.entity_type, self.entity_id, self._history_index)
 299
 300     @property
 301     def safe_data(self):
 302         """The data dictionary for this entity.
 303
 304         If this `ModelEntity` points to the dead state, it will
 305         raise `DeadEntityException`.
 306
 307         """
 308         if self.data is None:
 309             raise DeadEntityException(
 310                 "Entity {}:{} is dead - its attributes can no longer be "
 311                 "accessed. Use the .previous() method on this object to get "
 312                 "a copy of the object at its previous state.".format(
 313                     self.entity_type, self.entity_id))
 314         return self.data
 315
 316     def previous(self):
 317         """Return a copy of this object as was at its previous state in
 318         history.
 319
 320         Returns None if this object is new (and therefore has no history).
 321
 322         The returned object is always "disconnected", i.e. does not receive
 323         live updates.
 324
 325         """
 326         return self.model.state.get_entity(
 327             self.entity_type, self.entity_id, self._history_index - 1,
 328             connected=False)
 329
 330     def next(self):
 331         """Return a copy of this object at its next state in
 332         history.
 333
 334         Returns None if this object is already the latest.
 335
 336         The returned object is "disconnected", i.e. does not receive
 337         live updates, unless it is current (latest).
 338
 339         """
 340         if self._history_index == -1:
 341             return None
 342
 343         new_index = self._history_index + 1
 344         connected = (
 345             new_index == len(self.model.state.entity_history(
 346                 self.entity_type, self.entity_id)) - 1
 347         )
 348         return self.model.state.get_entity(
 349             self.entity_type, self.entity_id, self._history_index - 1,
 350             connected=connected)
 351
 352     def latest(self):
 353         """Return a copy of this object at its current state in the model.
 354
 355         Returns self if this object is already the latest.
 356
 357         The returned object is always "connected", i.e. receives
 358         live updates from the model.
 359
 360         """
 361         if self._history_index == -1:
 362             return self
 363
 364         return self.model.state.get_entity(self.entity_type, self.entity_id)
 365
 366
 367 class Model(object):
 368     def __init__(self, loop=None):
 369         """Instantiate a new connected Model.
 370
 371         :param loop: an asyncio event loop
 372
 373         """
 374         self.loop = loop or asyncio.get_event_loop()
 375         self.connection = None
 376         self.observers = weakref.WeakValueDictionary()
 377         self.state = ModelState(self)
 378         self.info = None
 379         self._watcher_task = None
 380         self._watch_shutdown = asyncio.Event(loop=self.loop)
 381         self._watch_received = asyncio.Event(loop=self.loop)
 382         self._charmstore = CharmStore(self.loop)
 383
 384     async def connect(self, *args, **kw):
 385         """Connect to an arbitrary Juju model.
 386
 387         args and kw are passed through to Connection.connect()
 388
 389         """
 390         if 'loop' not in kw:
 391             kw['loop'] = self.loop
 392         self.connection = await connection.Connection.connect(*args, **kw)
 393         await self._after_connect()
 394
 395     async def connect_current(self):
 396         """Connect to the current Juju model.
 397
 398         """
 399         self.connection = await connection.Connection.connect_current(
 400             self.loop)
 401         await self._after_connect()
 402
 403     async def connect_model(self, model_name):
 404         """Connect to a specific Juju model by name.
 405
 406         :param model_name:  Format [controller:][user/]model
 407
 408         """
 409         self.connection = await connection.Connection.connect_model(model_name,
 410                                                                     self.loop)
 411         await self._after_connect()
 412
 413     async def _after_connect(self):
 414         """Run initialization steps after connecting to websocket.
 415
 416         """
 417         self._watch()
 418         await self._watch_received.wait()
 419         await self.get_info()
 420
 421     async def disconnect(self):
 422         """Shut down the watcher task and close websockets.
 423
 424         """
 425         self._stop_watching()
 426         if self.connection and self.connection.is_open:
 427             await self._watch_shutdown.wait()
 428             log.debug('Closing model connection')
 429             await self.connection.close()
 430             self.connection = None
 431
 432     async def add_local_charm_dir(self, charm_dir, series):
 433         """Upload a local charm to the model.
 434
 435         This will automatically generate an archive from
 436         the charm dir.
 437
 438         :param charm_dir: Path to the charm directory
 439         :param series: Charm series
 440
 441         """
 442         fh = tempfile.NamedTemporaryFile()
 443         CharmArchiveGenerator(charm_dir).make_archive(fh.name)
 444         with fh:
 445             func = partial(
 446                 self.add_local_charm, fh, series, os.stat(fh.name).st_size)
 447             charm_url = await self.loop.run_in_executor(None, func)
 448
 449         log.debug('Uploaded local charm: %s -> %s', charm_dir, charm_url)
 450         return charm_url
 451
 452     def add_local_charm(self, charm_file, series, size=None):
 453         """Upload a local charm archive to the model.
 454
 455         Returns the 'local:...' url that should be used to deploy the charm.
 456
 457         :param charm_file: Path to charm zip archive
 458         :param series: Charm series
 459         :param size: Size of the archive, in bytes
 460         :return str: 'local:...' url for deploying the charm
 461         :raises: :class:`JujuError` if the upload fails
 462
 463         Uses an https endpoint at the same host:port as the wss.
 464         Supports large file uploads.
 465
 466         .. warning::
 467
 468            This method will block. Consider using :meth:`add_local_charm_dir`
 469            instead.
 470
 471         """
 472         conn, headers, path_prefix = self.connection.https_connection()
 473         path = "%s/charms?series=%s" % (path_prefix, series)
 474         headers['Content-Type'] = 'application/zip'
 475         if size:
 476             headers['Content-Length'] = size
 477         conn.request("POST", path, charm_file, headers)
 478         response = conn.getresponse()
 479         result = response.read().decode()
 480         if not response.status == 200:
 481             raise JujuError(result)
 482         result = json.loads(result)
 483         return result['charm-url']
 484
 485     def all_units_idle(self):
 486         """Return True if all units are idle.
 487
 488         """
 489         for unit in self.units.values():
 490             unit_status = unit.data['agent-status']['current']
 491             if unit_status != 'idle':
 492                 return False
 493         return True
 494
 495     async def reset(self, force=False):
 496         """Reset the model to a clean state.
 497
 498         :param bool force: Force-terminate machines.
 499
 500         This returns only after the model has reached a clean state. "Clean"
 501         means no applications or machines exist in the model.
 502
 503         """
 504         log.debug('Resetting model')
 505         for app in self.applications.values():
 506             await app.destroy()
 507         for machine in self.machines.values():
 508             await machine.destroy(force=force)
 509         await self.block_until(
 510             lambda: len(self.machines) == 0
 511         )
 512
 513     async def block_until(self, *conditions, timeout=None, wait_period=0.5):
 514         """Return only after all conditions are true.
 515
 516         """
 517         async def _block():
 518             while not all(c() for c in conditions):
 519                 await asyncio.sleep(wait_period, loop=self.loop)
 520         await asyncio.wait_for(_block(), timeout, loop=self.loop)
 521
 522     @property
 523     def applications(self):
 524         """Return a map of application-name:Application for all applications
 525         currently in the model.
 526
 527         """
 528         return self.state.applications
 529
 530     @property
 531     def machines(self):
 532         """Return a map of machine-id:Machine for all machines currently in
 533         the model.
 534
 535         """
 536         return self.state.machines
 537
 538     @property
 539     def units(self):
 540         """Return a map of unit-id:Unit for all units currently in
 541         the model.
 542
 543         """
 544         return self.state.units
 545
 546     async def get_info(self):
 547         """Return a client.ModelInfo object for this Model.
 548
 549         Retrieves latest info for this Model from the api server. The
 550         return value is cached on the Model.info attribute so that the
 551         valued may be accessed again without another api call, if
 552         desired.
 553
 554         This method is called automatically when the Model is connected,
 555         resulting in Model.info being initialized without requiring an
 556         explicit call to this method.
 557
 558         """
 559         facade = client.ClientFacade()
 560         facade.connect(self.connection)
 561
 562         self.info = await facade.ModelInfo()
 563         log.debug('Got ModelInfo: %s', vars(self.info))
 564
 565         return self.info
 566
 567     def add_observer(
 568             self, callable_, entity_type=None, action=None, entity_id=None,
 569             predicate=None):
 570         """Register an "on-model-change" callback
 571
 572         Once the model is connected, ``callable_``
 573         will be called each time the model changes. ``callable_`` should
 574         be Awaitable and accept the following positional arguments:
 575
 576             delta - An instance of :class:`juju.delta.EntityDelta`
 577                 containing the raw delta data recv'd from the Juju
 578                 websocket.
 579
 580             old_obj - If the delta modifies an existing object in the model,
 581                 old_obj will be a copy of that object, as it was before the
 582                 delta was applied. Will be None if the delta creates a new
 583                 entity in the model.
 584
 585             new_obj - A copy of the new or updated object, after the delta
 586                 is applied. Will be None if the delta removes an entity
 587                 from the model.
 588
 589             model - The :class:`Model` itself.
 590
 591         Events for which ``callable_`` is called can be specified by passing
 592         entity_type, action, and/or entitiy_id filter criteria, e.g.::
 593
 594             add_observer(
 595                 myfunc,
 596                 entity_type='application', action='add', entity_id='ubuntu')
 597
 598         For more complex filtering conditions, pass a predicate function. It
 599         will be called with a delta as its only argument. If the predicate
 600         function returns True, the ``callable_`` will be called.
 601
 602         """
 603         observer = _Observer(
 604             callable_, entity_type, action, entity_id, predicate)
 605         self.observers[observer] = callable_
 606
 607     def _watch(self):
 608         """Start an asynchronous watch against this model.
 609
 610         See :meth:`add_observer` to register an onchange callback.
 611
 612         """
 613         async def _start_watch():
 614             self._watch_shutdown.clear()
 615             try:
 616                 allwatcher = watcher.AllWatcher()
 617                 self._watch_conn = await self.connection.clone()
 618                 allwatcher.connect(self._watch_conn)
 619                 while True:
 620                     results = await allwatcher.Next()
 621                     for delta in results.deltas:
 622                         delta = get_entity_delta(delta)
 623                         old_obj, new_obj = self.state.apply_delta(delta)
 624                         # XXX: Might not want to shield at this level
 625                         # We are shielding because when the watcher is
 626                         # canceled (on disconnect()), we don't want all of
 627                         # its children (every observer callback) to be
 628                         # canceled with it. So we shield them. But this means
 629                         # they can *never* be canceled.
 630                         await asyncio.shield(
 631                             self._notify_observers(delta, old_obj, new_obj),
 632                             loop=self.loop)
 633                     self._watch_received.set()
 634             except CancelledError:
 635                 log.debug('Closing watcher connection')
 636                 await self._watch_conn.close()
 637                 self._watch_shutdown.set()
 638                 self._watch_conn = None
 639
 640         log.debug('Starting watcher task')
 641         self._watcher_task = self.loop.create_task(_start_watch())
 642
 643     def _stop_watching(self):
 644         """Stop the asynchronous watch against this model.
 645
 646         """
 647         log.debug('Stopping watcher task')
 648         if self._watcher_task:
 649             self._watcher_task.cancel()
 650
 651     async def _notify_observers(self, delta, old_obj, new_obj):
 652         """Call observing callbacks, notifying them of a change in model state
 653
 654         :param delta: The raw change from the watcher
 655             (:class:`juju.client.overrides.Delta`)
 656         :param old_obj: The object in the model that this delta updates.
 657             May be None.
 658         :param new_obj: The object in the model that is created or updated
 659             by applying this delta.
 660
 661         """
 662         if new_obj and not old_obj:
 663             delta.type = 'add'
 664
 665         log.debug(
 666             'Model changed: %s %s %s',
 667             delta.entity, delta.type, delta.get_id())
 668
 669         for o in self.observers:
 670             if o.cares_about(delta):
 671                 asyncio.ensure_future(o(delta, old_obj, new_obj, self),
 672                                       loop=self.loop)
 673
 674     async def _wait(self, entity_type, entity_id, action, predicate=None):
 675         """
 676         Block the calling routine until a given action has happened to the
 677         given entity
 678
 679         :param entity_type: The entity's type.
 680         :param entity_id: The entity's id.
 681         :param action: the type of action (e.g., 'add', 'change', or 'remove')
 682         :param predicate: optional callable that must take as an
 683             argument a delta, and must return a boolean, indicating
 684             whether the delta contains the specific action we're looking
 685             for. For example, you might check to see whether a 'change'
 686             has a 'completed' status. See the _Observer class for details.
 687
 688         """
 689         q = asyncio.Queue(loop=self.loop)
 690
 691         async def callback(delta, old, new, model):
 692             await q.put(delta.get_id())
 693
 694         self.add_observer(callback, entity_type, action, entity_id, predicate)
 695         entity_id = await q.get()
 696         # object might not be in the entity_map if we were waiting for a
 697         # 'remove' action
 698         return self.state._live_entity_map(entity_type).get(entity_id)
 699
 700     async def _wait_for_new(self, entity_type, entity_id=None, predicate=None):
 701         """Wait for a new object to appear in the Model and return it.
 702
 703         Waits for an object of type ``entity_type`` with id ``entity_id``.
 704         If ``entity_id`` is ``None``, it will wait for the first new entity
 705         of the correct type.
 706
 707         This coroutine blocks until the new object appears in the model.
 708
 709         """
 710         # if the entity is already in the model, just return it
 711         if entity_id in self.state._live_entity_map(entity_type):
 712             return self.state._live_entity_map(entity_type)[entity_id]
 713         # if we know the entity_id, we can trigger on any action that puts
 714         # the enitty into the model; otherwise, we have to watch for the
 715         # next "add" action on that entity_type
 716         action = 'add' if entity_id is None else None
 717         return await self._wait(entity_type, entity_id, action, predicate)
 718
 719     async def wait_for_action(self, action_id):
 720         """Given an action, wait for it to complete."""
 721
 722         if action_id.startswith("action-"):
 723             # if we've been passed action.tag, transform it into the
 724             # id that the api deltas will use.
 725             action_id = action_id[7:]
 726
 727         def predicate(delta):
 728             return delta.data['status'] in ('completed', 'failed')
 729
 730         return await self._wait('action', action_id, 'change', predicate)
 731
 732     async def add_machine(
 733             self, spec=None, constraints=None, disks=None, series=None):
 734         """Start a new, empty machine and optionally a container, or add a
 735         container to a machine.
 736
 737         :param str spec: Machine specification
 738             Examples::
 739
 740                 (None) - starts a new machine
 741                 'lxd' - starts a new machine with one lxd container
 742                 'lxd:4' - starts a new lxd container on machine 4
 743                 'ssh:user@10.10.0.3' - manually provisions a machine with ssh
 744                 'zone=us-east-1a' - starts a machine in zone us-east-1s on AWS
 745                 'maas2.name' - acquire machine maas2.name on MAAS
 746
 747         :param dict constraints: Machine constraints
 748             Example::
 749
 750                 constraints={
 751                     'mem': 256 * MB,
 752                 }
 753
 754         :param list disks: List of disk constraint dictionaries
 755             Example::
 756
 757                 disks=[{
 758                     'pool': 'rootfs',
 759                     'size': 10 * GB,
 760                     'count': 1,
 761                 }]
 762
 763         :param str series: Series, e.g. 'xenial'
 764
 765         Supported container types are: lxd, kvm
 766
 767         When deploying a container to an existing machine, constraints cannot
 768         be used.
 769
 770         """
 771         params = client.AddMachineParams()
 772         params.jobs = ['JobHostUnits']
 773
 774         if spec:
 775             placement = parse_placement(spec)
 776             if placement:
 777                 params.placement = placement[0]
 778
 779         if constraints:
 780             params.constraints = client.Value.from_json(constraints)
 781
 782         if disks:
 783             params.disks = [
 784                 client.Constraints.from_json(o) for o in disks]
 785
 786         if series:
 787             params.series = series
 788
 789         # Submit the request.
 790         client_facade = client.ClientFacade()
 791         client_facade.connect(self.connection)
 792         results = await client_facade.AddMachines([params])
 793         error = results.machines[0].error
 794         if error:
 795             raise ValueError("Error adding machine: %s", error.message)
 796         machine_id = results.machines[0].machine
 797         log.debug('Added new machine %s', machine_id)
 798         return await self._wait_for_new('machine', machine_id)
 799
 800     async def add_relation(self, relation1, relation2):
 801         """Add a relation between two applications.
 802
 803         :param str relation1: '<application>[:<relation_name>]'
 804         :param str relation2: '<application>[:<relation_name>]'
 805
 806         """
 807         app_facade = client.ApplicationFacade()
 808         app_facade.connect(self.connection)
 809
 810         log.debug(
 811             'Adding relation %s <-> %s', relation1, relation2)
 812
 813         try:
 814             result = await app_facade.AddRelation([relation1, relation2])
 815         except JujuAPIError as e:
 816             if 'relation already exists' not in e.message:
 817                 raise
 818             log.debug(
 819                 'Relation %s <-> %s already exists', relation1, relation2)
 820             # TODO: if relation already exists we should return the
 821             # Relation ModelEntity here
 822             return None
 823
 824         def predicate(delta):
 825             endpoints = {}
 826             for endpoint in delta.data['endpoints']:
 827                 endpoints[endpoint['application-name']] = endpoint['relation']
 828             return endpoints == result.endpoints
 829
 830         return await self._wait_for_new('relation', None, predicate)
 831
 832     def add_space(self, name, *cidrs):
 833         """Add a new network space.
 834
 835         Adds a new space with the given name and associates the given
 836         (optional) list of existing subnet CIDRs with it.
 837
 838         :param str name: Name of the space
 839         :param \*cidrs: Optional list of existing subnet CIDRs
 840
 841         """
 842         raise NotImplementedError()
 843
 844     def add_ssh_key(self, key):
 845         """Add a public SSH key to this model.
 846
 847         :param str key: The public ssh key
 848
 849         """
 850         raise NotImplementedError()
 851     add_ssh_keys = add_ssh_key
 852
 853     def add_subnet(self, cidr_or_id, space, *zones):
 854         """Add an existing subnet to this model.
 855
 856         :param str cidr_or_id: CIDR or provider ID of the existing subnet
 857         :param str space: Network space with which to associate
 858         :param str \*zones: Zone(s) in which the subnet resides
 859
 860         """
 861         raise NotImplementedError()
 862
 863     def get_backups(self):
 864         """Retrieve metadata for backups in this model.
 865
 866         """
 867         raise NotImplementedError()
 868
 869     def block(self, *commands):
 870         """Add a new block to this model.
 871
 872         :param str \*commands: The commands to block. Valid values are
 873             'all-changes', 'destroy-model', 'remove-object'
 874
 875         """
 876         raise NotImplementedError()
 877
 878     def get_blocks(self):
 879         """List blocks for this model.
 880
 881         """
 882         raise NotImplementedError()
 883
 884     def get_cached_images(self, arch=None, kind=None, series=None):
 885         """Return a list of cached OS images.
 886
 887         :param str arch: Filter by image architecture
 888         :param str kind: Filter by image kind, e.g. 'lxd'
 889         :param str series: Filter by image series, e.g. 'xenial'
 890
 891         """
 892         raise NotImplementedError()
 893
 894     def create_backup(self, note=None, no_download=False):
 895         """Create a backup of this model.
 896
 897         :param str note: A note to store with the backup
 898         :param bool no_download: Do not download the backup archive
 899         :return str: Path to downloaded archive
 900
 901         """
 902         raise NotImplementedError()
 903
 904     def create_storage_pool(self, name, provider_type, **pool_config):
 905         """Create or define a storage pool.
 906
 907         :param str name: Name to give the storage pool
 908         :param str provider_type: Pool provider type
 909         :param \*\*pool_config: key/value pool configuration pairs
 910
 911         """
 912         raise NotImplementedError()
 913
 914     def debug_log(
 915             self, no_tail=False, exclude_module=None, include_module=None,
 916             include=None, level=None, limit=0, lines=10, replay=False,
 917             exclude=None):
 918         """Get log messages for this model.
 919
 920         :param bool no_tail: Stop after returning existing log messages
 921         :param list exclude_module: Do not show log messages for these logging
 922             modules
 923         :param list include_module: Only show log messages for these logging
 924             modules
 925         :param list include: Only show log messages for these entities
 926         :param str level: Log level to show, valid options are 'TRACE',
 927             'DEBUG', 'INFO', 'WARNING', 'ERROR,
 928         :param int limit: Return this many of the most recent (possibly
 929             filtered) lines are shown
 930         :param int lines: Yield this many of the most recent lines, and keep
 931             yielding
 932         :param bool replay: Yield the entire log, and keep yielding
 933         :param list exclude: Do not show log messages for these entities
 934
 935         """
 936         raise NotImplementedError()
 937
 938     async def deploy(
 939             self, entity_url, application_name=None, bind=None, budget=None,
 940             channel=None, config=None, constraints=None, force=False,
 941             num_units=1, plan=None, resources=None, series=None, storage=None,
 942             to=None):
 943         """Deploy a new service or bundle.
 944
 945         :param str entity_url: Charm or bundle url
 946         :param str application_name: Name to give the service
 947         :param dict bind: <charm endpoint>:<network space> pairs
 948         :param dict budget: <budget name>:<limit> pairs
 949         :param str channel: Charm store channel from which to retrieve
 950             the charm or bundle, e.g. 'development'
 951         :param dict config: Charm configuration dictionary
 952         :param constraints: Service constraints
 953         :type constraints: :class:`juju.Constraints`
 954         :param bool force: Allow charm to be deployed to a machine running
 955             an unsupported series
 956         :param int num_units: Number of units to deploy
 957         :param str plan: Plan under which to deploy charm
 958         :param dict resources: <resource name>:<file path> pairs
 959         :param str series: Series on which to deploy
 960         :param dict storage: Storage constraints TODO how do these look?
 961         :param to: Placement directive as a string. For example:
 962
 963             '23' - place on machine 23
 964             'lxd:7' - place in new lxd container on machine 7
 965             '24/lxd/3' - place in container 3 on machine 24
 966
 967             If None, a new machine is provisioned.
 968
 969
 970         TODO::
 971
 972             - application_name is required; fill this in automatically if not
 973               provided by caller
 974             - series is required; how do we pick a default?
 975
 976         """
 977         if storage:
 978             storage = {
 979                 k: client.Constraints(**v)
 980                 for k, v in storage.items()
 981             }
 982
 983         is_local = (
 984             entity_url.startswith('local:') or
 985             os.path.isdir(entity_url)
 986         )
 987         entity_id = await self.charmstore.entityId(entity_url) \
 988             if not is_local else entity_url
 989
 990         client_facade = client.ClientFacade()
 991         client_facade.connect(self.connection)
 992
 993         is_bundle = ((is_local and
 994                       (Path(entity_id) / 'bundle.yaml').exists()) or
 995                      (not is_local and 'bundle/' in entity_id))
 996
 997         if is_bundle:
 998             handler = BundleHandler(self)
 999             await handler.fetch_plan(entity_id)
1000             await handler.execute_plan()
1001             extant_apps = {app for app in self.applications}
1002             pending_apps = set(handler.applications) - extant_apps
1003             if pending_apps:
1004                 # new apps will usually be in the model by now, but if some
1005                 # haven't made it yet we'll need to wait on them to be added
1006                 await asyncio.gather(*[
1007                     asyncio.ensure_future(
1008                         self._wait_for_new('application', app_name),
1009                         loop=self.loop)
1010                     for app_name in pending_apps
1011                 ], loop=self.loop)
1012             return [app for name, app in self.applications.items()
1013                     if name in handler.applications]
1014         else:
1015             if not is_local:
1016                 parts = entity_id[3:].split('/')
1017                 if parts[0].startswith('~'):
1018                     parts.pop(0)
1019                 if not application_name:
1020                     application_name = parts[-1].split('-')[0]
1021                 if not series:
1022                     if len(parts) > 1:
1023                         series = parts[0]
1024                     else:
1025                         entity = await self.charmstore.entity(entity_id)
1026                         ss = entity['Meta']['supported-series']
1027                         series = ss['SupportedSeries'][0]
1028                 await client_facade.AddCharm(channel, entity_id)
1029             elif not entity_id.startswith('local:'):
1030                 # We have a local charm dir that needs to be uploaded
1031                 charm_dir = os.path.abspath(
1032                     os.path.expanduser(entity_id))
1033                 series = series or get_charm_series(charm_dir)
1034                 if not series:
1035                     raise JujuError(
1036                         "Couldn't determine series for charm at {}. "
1037                         "Pass a 'series' kwarg to Model.deploy().".format(
1038                             charm_dir))
1039                 entity_id = await self.add_local_charm_dir(charm_dir, series)
1040             return await self._deploy(
1041                 charm_url=entity_id,
1042                 application=application_name,
1043                 series=series,
1044                 config=config or {},
1045                 constraints=constraints,
1046                 endpoint_bindings=bind,
1047                 resources=resources,
1048                 storage=storage,
1049                 channel=channel,
1050                 num_units=num_units,
1051                 placement=parse_placement(to),
1052             )
1053
1054     async def _deploy(self, charm_url, application, series, config,
1055                       constraints, endpoint_bindings, resources, storage,
1056                       channel=None, num_units=None, placement=None):
1057             log.info('Deploying %s', charm_url)
1058
1059             # stringify all config values for API, and convert to YAML
1060             config = {k: str(v) for k, v in config.items()}
1061             config = yaml.dump({application: config},
1062                                default_flow_style=False)
1063
1064             app_facade = client.ApplicationFacade()
1065             app_facade.connect(self.connection)
1066
1067             app = client.ApplicationDeploy(
1068                 charm_url=charm_url,
1069                 application=application,
1070                 series=series,
1071                 channel=channel,
1072                 config_yaml=config,
1073                 constraints=parse_constraints(constraints),
1074                 endpoint_bindings=endpoint_bindings,
1075                 num_units=num_units,
1076                 resources=resources,
1077                 storage=storage,
1078                 placement=placement,
1079             )
1080
1081             result = await app_facade.Deploy([app])
1082             errors = [r.error.message for r in result.results if r.error]
1083             if errors:
1084                 raise JujuError('\n'.join(errors))
1085             return await self._wait_for_new('application', application)
1086
1087     def destroy(self):
1088         """Terminate all machines and resources for this model.
1089
1090         """
1091         raise NotImplementedError()
1092
1093     async def destroy_unit(self, *unit_names):
1094         """Destroy units by name.
1095
1096         """
1097         app_facade = client.ApplicationFacade()
1098         app_facade.connect(self.connection)
1099
1100         log.debug(
1101             'Destroying unit%s %s',
1102             's' if len(unit_names) == 1 else '',
1103             ' '.join(unit_names))
1104
1105         return await app_facade.DestroyUnits(list(unit_names))
1106     destroy_units = destroy_unit
1107
1108     def get_backup(self, archive_id):
1109         """Download a backup archive file.
1110
1111         :param str archive_id: The id of the archive to download
1112         :return str: Path to the archive file
1113
1114         """
1115         raise NotImplementedError()
1116
1117     def enable_ha(
1118             self, num_controllers=0, constraints=None, series=None, to=None):
1119         """Ensure sufficient controllers exist to provide redundancy.
1120
1121         :param int num_controllers: Number of controllers to make available
1122         :param constraints: Constraints to apply to the controller machines
1123         :type constraints: :class:`juju.Constraints`
1124         :param str series: Series of the controller machines
1125         :param list to: Placement directives for controller machines, e.g.::
1126
1127             '23' - machine 23
1128             'lxc:7' - new lxc container on machine 7
1129             '24/lxc/3' - lxc container 3 or machine 24
1130
1131             If None, a new machine is provisioned.
1132
1133         """
1134         raise NotImplementedError()
1135
1136     def get_config(self):
1137         """Return the configuration settings for this model.
1138
1139         """
1140         raise NotImplementedError()
1141
1142     def get_constraints(self):
1143         """Return the machine constraints for this model.
1144
1145         """
1146         raise NotImplementedError()
1147
1148     def grant(self, username, acl='read'):
1149         """Grant a user access to this model.
1150
1151         :param str username: Username
1152         :param str acl: Access control ('read' or 'write')
1153
1154         """
1155         raise NotImplementedError()
1156
1157     def import_ssh_key(self, identity):
1158         """Add a public SSH key from a trusted indentity source to this model.
1159
1160         :param str identity: User identity in the form <lp|gh>:<username>
1161
1162         """
1163         raise NotImplementedError()
1164     import_ssh_keys = import_ssh_key
1165
1166     def get_machines(self, machine, utc=False):
1167         """Return list of machines in this model.
1168
1169         :param str machine: Machine id, e.g. '0'
1170         :param bool utc: Display time as UTC in RFC3339 format
1171
1172         """
1173         raise NotImplementedError()
1174
1175     def get_shares(self):
1176         """Return list of all users with access to this model.
1177
1178         """
1179         raise NotImplementedError()
1180
1181     def get_spaces(self):
1182         """Return list of all known spaces, including associated subnets.
1183
1184         """
1185         raise NotImplementedError()
1186
1187     def get_ssh_key(self):
1188         """Return known SSH keys for this model.
1189
1190         """
1191         raise NotImplementedError()
1192     get_ssh_keys = get_ssh_key
1193
1194     def get_storage(self, filesystem=False, volume=False):
1195         """Return details of storage instances.
1196
1197         :param bool filesystem: Include filesystem storage
1198         :param bool volume: Include volume storage
1199
1200         """
1201         raise NotImplementedError()
1202
1203     def get_storage_pools(self, names=None, providers=None):
1204         """Return list of storage pools.
1205
1206         :param list names: Only include pools with these names
1207         :param list providers: Only include pools for these providers
1208
1209         """
1210         raise NotImplementedError()
1211
1212     def get_subnets(self, space=None, zone=None):
1213         """Return list of known subnets.
1214
1215         :param str space: Only include subnets in this space
1216         :param str zone: Only include subnets in this zone
1217
1218         """
1219         raise NotImplementedError()
1220
1221     def remove_blocks(self):
1222         """Remove all blocks from this model.
1223
1224         """
1225         raise NotImplementedError()
1226
1227     def remove_backup(self, backup_id):
1228         """Delete a backup.
1229
1230         :param str backup_id: The id of the backup to remove
1231
1232         """
1233         raise NotImplementedError()
1234
1235     def remove_cached_images(self, arch=None, kind=None, series=None):
1236         """Remove cached OS images.
1237
1238         :param str arch: Architecture of the images to remove
1239         :param str kind: Image kind to remove, e.g. 'lxd'
1240         :param str series: Image series to remove, e.g. 'xenial'
1241
1242         """
1243         raise NotImplementedError()
1244
1245     def remove_machine(self, *machine_ids):
1246         """Remove a machine from this model.
1247
1248         :param str \*machine_ids: Ids of the machines to remove
1249
1250         """
1251         raise NotImplementedError()
1252     remove_machines = remove_machine
1253
1254     def remove_ssh_key(self, *keys):
1255         """Remove a public SSH key(s) from this model.
1256
1257         :param str \*keys: Keys to remove
1258
1259         """
1260         raise NotImplementedError()
1261     remove_ssh_keys = remove_ssh_key
1262
1263     def restore_backup(
1264             self, bootstrap=False, constraints=None, archive=None,
1265             backup_id=None, upload_tools=False):
1266         """Restore a backup archive to a new controller.
1267
1268         :param bool bootstrap: Bootstrap a new state machine
1269         :param constraints: Model constraints
1270         :type constraints: :class:`juju.Constraints`
1271         :param str archive: Path to backup archive to restore
1272         :param str backup_id: Id of backup to restore
1273         :param bool upload_tools: Upload tools if bootstrapping a new machine
1274
1275         """
1276         raise NotImplementedError()
1277
1278     def retry_provisioning(self):
1279         """Retry provisioning for failed machines.
1280
1281         """
1282         raise NotImplementedError()
1283
1284     def revoke(self, username, acl='read'):
1285         """Revoke a user's access to this model.
1286
1287         :param str username: Username to revoke
1288         :param str acl: Access control ('read' or 'write')
1289
1290         """
1291         raise NotImplementedError()
1292
1293     def run(self, command, timeout=None):
1294         """Run command on all machines in this model.
1295
1296         :param str command: The command to run
1297         :param int timeout: Time to wait before command is considered failed
1298
1299         """
1300         raise NotImplementedError()
1301
1302     def set_config(self, **config):
1303         """Set configuration keys on this model.
1304
1305         :param \*\*config: Config key/values
1306
1307         """
1308         raise NotImplementedError()
1309
1310     def set_constraints(self, constraints):
1311         """Set machine constraints on this model.
1312
1313         :param :class:`juju.Constraints` constraints: Machine constraints
1314
1315         """
1316         raise NotImplementedError()
1317
1318     def get_action_output(self, action_uuid, wait=-1):
1319         """Get the results of an action by ID.
1320
1321         :param str action_uuid: Id of the action
1322         :param int wait: Time in seconds to wait for action to complete
1323
1324         """
1325         raise NotImplementedError()
1326
1327     def get_action_status(self, uuid_or_prefix=None, name=None):
1328         """Get the status of all actions, filtered by ID, ID prefix, or action name.
1329
1330         :param str uuid_or_prefix: Filter by action uuid or prefix
1331         :param str name: Filter by action name
1332
1333         """
1334         raise NotImplementedError()
1335
1336     def get_budget(self, budget_name):
1337         """Get budget usage info.
1338
1339         :param str budget_name: Name of budget
1340
1341         """
1342         raise NotImplementedError()
1343
1344     async def get_status(self, filters=None, utc=False):
1345         """Return the status of the model.
1346
1347         :param str filters: Optional list of applications, units, or machines
1348             to include, which can use wildcards ('*').
1349         :param bool utc: Display time as UTC in RFC3339 format
1350
1351         """
1352         client_facade = client.ClientFacade()
1353         client_facade.connect(self.connection)
1354         return await client_facade.FullStatus(filters)
1355
1356     def sync_tools(
1357             self, all_=False, destination=None, dry_run=False, public=False,
1358             source=None, stream=None, version=None):
1359         """Copy Juju tools into this model.
1360
1361         :param bool all_: Copy all versions, not just the latest
1362         :param str destination: Path to local destination directory
1363         :param bool dry_run: Don't do the actual copy
1364         :param bool public: Tools are for a public cloud, so generate mirrors
1365             information
1366         :param str source: Path to local source directory
1367         :param str stream: Simplestreams stream for which to sync metadata
1368         :param str version: Copy a specific major.minor version
1369
1370         """
1371         raise NotImplementedError()
1372
1373     def unblock(self, *commands):
1374         """Unblock an operation that would alter this model.
1375
1376         :param str \*commands: The commands to unblock. Valid values are
1377             'all-changes', 'destroy-model', 'remove-object'
1378
1379         """
1380         raise NotImplementedError()
1381
1382     def unset_config(self, *keys):
1383         """Unset configuration on this model.
1384
1385         :param str \*keys: The keys to unset
1386
1387         """
1388         raise NotImplementedError()
1389
1390     def upgrade_gui(self):
1391         """Upgrade the Juju GUI for this model.
1392
1393         """
1394         raise NotImplementedError()
1395
1396     def upgrade_juju(
1397             self, dry_run=False, reset_previous_upgrade=False,
1398             upload_tools=False, version=None):
1399         """Upgrade Juju on all machines in a model.
1400
1401         :param bool dry_run: Don't do the actual upgrade
1402         :param bool reset_previous_upgrade: Clear the previous (incomplete)
1403             upgrade status
1404         :param bool upload_tools: Upload local version of tools
1405         :param str version: Upgrade to a specific version
1406
1407         """
1408         raise NotImplementedError()
1409
1410     def upload_backup(self, archive_path):
1411         """Store a backup archive remotely in Juju.
1412
1413         :param str archive_path: Path to local archive
1414
1415         """
1416         raise NotImplementedError()
1417
1418     @property
1419     def charmstore(self):
1420         return self._charmstore
1421
1422     async def get_metrics(self, *tags):
1423         """Retrieve metrics.
1424
1425         :param str \*tags: Tags of entities from which to retrieve metrics.
1426             No tags retrieves the metrics of all units in the model.
1427         :return: Dictionary of unit_name:metrics
1428
1429         """
1430         log.debug("Retrieving metrics for %s",
1431                   ', '.join(tags) if tags else "all units")
1432
1433         metrics_facade = client.MetricsDebugFacade()
1434         metrics_facade.connect(self.connection)
1435
1436         entities = [client.Entity(tag) for tag in tags]
1437         metrics_result = await metrics_facade.GetMetrics(entities)
1438
1439         metrics = collections.defaultdict(list)
1440
1441         for entity_metrics in metrics_result.results:
1442             error = entity_metrics.error
1443             if error:
1444                 if "is not a valid tag" in error:
1445                     raise ValueError(error.message)
1446                 else:
1447                     raise Exception(error.message)
1448
1449             for metric in entity_metrics.metrics:
1450                 metrics[metric.unit].append(vars(metric))
1451
1452         return metrics
1453
1454
1455 def get_charm_series(path):
1456     """Inspects the charm directory at ``path`` and returns a default
1457     series from its metadata.yaml (the first item in the 'series' list).
1458
1459     Returns None if no series can be determined.
1460
1461     """
1462     md = Path(path) / "metadata.yaml"
1463     if not md.exists():
1464         return None
1465     data = yaml.load(md.open())
1466     series = data.get('series')
1467     return series[0] if series else None
1468
1469
1470 class BundleHandler(object):
1471     """
1472     Handle bundles by using the API to translate bundle YAML into a plan of
1473     steps and then dispatching each of those using the API.
1474     """
1475     def __init__(self, model):
1476         self.model = model
1477         self.charmstore = model.charmstore
1478         self.plan = []
1479         self.references = {}
1480         self._units_by_app = {}
1481         for unit_name, unit in model.units.items():
1482             app_units = self._units_by_app.setdefault(unit.application, [])
1483             app_units.append(unit_name)
1484         self.client_facade = client.ClientFacade()
1485         self.client_facade.connect(model.connection)
1486         self.app_facade = client.ApplicationFacade()
1487         self.app_facade.connect(model.connection)
1488         self.ann_facade = client.AnnotationsFacade()
1489         self.ann_facade.connect(model.connection)
1490
1491     async def _handle_local_charms(self, bundle):
1492         """Search for references to local charms (i.e. filesystem paths)
1493         in the bundle. Upload the local charms to the model, and replace
1494         the filesystem paths with appropriate 'local:' paths in the bundle.
1495
1496         Return the modified bundle.
1497
1498         :param dict bundle: Bundle dictionary
1499         :return: Modified bundle dictionary
1500
1501         """
1502         apps, args = [], []
1503
1504         default_series = bundle.get('series')
1505         for app_name in self.applications:
1506             app_dict = bundle['services'][app_name]
1507             charm_dir = os.path.abspath(os.path.expanduser(app_dict['charm']))
1508             if not os.path.isdir(charm_dir):
1509                 continue
1510             series = (
1511                 app_dict.get('series') or
1512                 default_series or
1513                 get_charm_series(charm_dir)
1514             )
1515             if not series:
1516                 raise JujuError(
1517                     "Couldn't determine series for charm at {}. "
1518                     "Add a 'series' key to the bundle.".format(charm_dir))
1519
1520             # Keep track of what we need to update. We keep a list of apps
1521             # that need to be updated, and a corresponding list of args
1522             # needed to update those apps.
1523             apps.append(app_name)
1524             args.append((charm_dir, series))
1525
1526         if apps:
1527             # If we have apps to update, spawn all the coroutines concurrently
1528             # and wait for them to finish.
1529             charm_urls = await asyncio.gather(*[
1530                 self.model.add_local_charm_dir(*params)
1531                 for params in args
1532             ], loop=self.model.loop)
1533             # Update the 'charm:' entry for each app with the new 'local:' url.
1534             for app_name, charm_url in zip(apps, charm_urls):
1535                 bundle['services'][app_name]['charm'] = charm_url
1536
1537         return bundle
1538
1539     async def fetch_plan(self, entity_id):
1540         is_local = not entity_id.startswith('cs:') and os.path.isdir(entity_id)
1541         if is_local:
1542             bundle_yaml = (Path(entity_id) / "bundle.yaml").read_text()
1543         else:
1544             bundle_yaml = await self.charmstore.files(entity_id,
1545                                                       filename='bundle.yaml',
1546                                                       read_file=True)
1547         self.bundle = yaml.safe_load(bundle_yaml)
1548         self.bundle = await self._handle_local_charms(self.bundle)
1549
1550         self.plan = await self.client_facade.GetBundleChanges(
1551             yaml.dump(self.bundle))
1552
1553         if self.plan.errors:
1554             raise JujuError('\n'.join(self.plan.errors))
1555
1556     async def execute_plan(self):
1557         for step in self.plan.changes:
1558             method = getattr(self, step.method)
1559             result = await method(*step.args)
1560             self.references[step.id_] = result
1561
1562     @property
1563     def applications(self):
1564         return list(self.bundle['services'].keys())
1565
1566     def resolve(self, reference):
1567         if reference and reference.startswith('$'):
1568             reference = self.references[reference[1:]]
1569         return reference
1570
1571     async def addCharm(self, charm, series):
1572         """
1573         :param charm string:
1574             Charm holds the URL of the charm to be added.
1575
1576         :param series string:
1577             Series holds the series of the charm to be added
1578             if the charm default is not sufficient.
1579         """
1580         # We don't add local charms because they've already been added
1581         # by self._handle_local_charms
1582         if charm.startswith('local:'):
1583             return charm
1584
1585         entity_id = await self.charmstore.entityId(charm)
1586         log.debug('Adding %s', entity_id)
1587         await self.client_facade.AddCharm(None, entity_id)
1588         return entity_id
1589
1590     async def addMachines(self, params=None):
1591         """
1592         :param params dict:
1593             Dictionary specifying the machine to add. All keys are optional.
1594             Keys include:
1595
1596             series: string specifying the machine OS series.
1597
1598             constraints: string holding machine constraints, if any. We'll
1599                 parse this into the json friendly dict that the juju api
1600                 expects.
1601
1602             container_type: string holding the type of the container (for
1603                 instance ""lxd" or kvm"). It is not specified for top level
1604                 machines.
1605
1606             parent_id: string holding a placeholder pointing to another
1607                 machine change or to a unit change. This value is only
1608                 specified in the case this machine is a container, in
1609                 which case also ContainerType is set.
1610
1611         """
1612         params = params or {}
1613
1614         # Normalize keys
1615         params = {normalize_key(k): params[k] for k in params.keys()}
1616
1617         # Fix up values, as necessary.
1618         if 'parent_id' in params:
1619             params['parent_id'] = self.resolve(params['parent_id'])
1620
1621         params['constraints'] = parse_constraints(
1622             params.get('constraints'))
1623         params['jobs'] = params.get('jobs', ['JobHostUnits'])
1624
1625         if params.get('container_type') == 'lxc':
1626             log.warning('Juju 2.0 does not support lxc containers. '
1627                         'Converting containers to lxd.')
1628             params['container_type'] = 'lxd'
1629
1630         # Submit the request.
1631         params = client.AddMachineParams(**params)
1632         results = await self.client_facade.AddMachines([params])
1633         error = results.machines[0].error
1634         if error:
1635             raise ValueError("Error adding machine: %s", error.message)
1636         machine = results.machines[0].machine
1637         log.debug('Added new machine %s', machine)
1638         return machine
1639
1640     async def addRelation(self, endpoint1, endpoint2):
1641         """
1642         :param endpoint1 string:
1643         :param endpoint2 string:
1644             Endpoint1 and Endpoint2 hold relation endpoints in the
1645             "application:interface" form, where the application is always a
1646             placeholder pointing to an application change, and the interface is
1647             optional. Examples are "$deploy-42:web" or just "$deploy-42".
1648         """
1649         endpoints = [endpoint1, endpoint2]
1650         # resolve indirect references
1651         for i in range(len(endpoints)):
1652             parts = endpoints[i].split(':')
1653             parts[0] = self.resolve(parts[0])
1654             endpoints[i] = ':'.join(parts)
1655
1656         log.info('Relating %s <-> %s', *endpoints)
1657         return await self.model.add_relation(*endpoints)
1658
1659     async def deploy(self, charm, series, application, options, constraints,
1660                      storage, endpoint_bindings, resources):
1661         """
1662         :param charm string:
1663             Charm holds the URL of the charm to be used to deploy this
1664             application.
1665
1666         :param series string:
1667             Series holds the series of the application to be deployed
1668             if the charm default is not sufficient.
1669
1670         :param application string:
1671             Application holds the application name.
1672
1673         :param options map[string]interface{}:
1674             Options holds application options.
1675
1676         :param constraints string:
1677             Constraints holds the optional application constraints.
1678
1679         :param storage map[string]string:
1680             Storage holds the optional storage constraints.
1681
1682         :param endpoint_bindings map[string]string:
1683             EndpointBindings holds the optional endpoint bindings
1684
1685         :param resources map[string]int:
1686             Resources identifies the revision to use for each resource
1687             of the application's charm.
1688         """
1689         # resolve indirect references
1690         charm = self.resolve(charm)
1691         await self.model._deploy(
1692             charm_url=charm,
1693             application=application,
1694             series=series,
1695             config=options,
1696             constraints=constraints,
1697             endpoint_bindings=endpoint_bindings,
1698             resources=resources,
1699             storage=storage,
1700         )
1701         return application
1702
1703     async def addUnit(self, application, to):
1704         """
1705         :param application string:
1706             Application holds the application placeholder name for which a unit
1707             is added.
1708
1709         :param to string:
1710             To holds the optional location where to add the unit, as a
1711             placeholder pointing to another unit change or to a machine change.
1712         """
1713         application = self.resolve(application)
1714         placement = self.resolve(to)
1715         if self._units_by_app.get(application):
1716             # enough units for this application already exist;
1717             # claim one, and carry on
1718             # NB: this should probably honor placement, but the juju client
1719             # doesn't, so we're not bothering, either
1720             unit_name = self._units_by_app[application].pop()
1721             log.debug('Reusing unit %s for %s', unit_name, application)
1722             return self.model.units[unit_name]
1723
1724         log.debug('Adding new unit for %s%s', application,
1725                   ' to %s' % placement if placement else '')
1726         return await self.model.applications[application].add_unit(
1727             count=1,
1728             to=placement,
1729         )
1730
1731     async def expose(self, application):
1732         """
1733         :param application string:
1734             Application holds the placeholder name of the application that must
1735             be exposed.
1736         """
1737         application = self.resolve(application)
1738         log.info('Exposing %s', application)
1739         return await self.model.applications[application].expose()
1740
1741     async def setAnnotations(self, id_, entity_type, annotations):
1742         """
1743         :param id_ string:
1744             Id is the placeholder for the application or machine change
1745             corresponding to the entity to be annotated.
1746
1747         :param entity_type EntityType:
1748             EntityType holds the type of the entity, "application" or
1749             "machine".
1750
1751         :param annotations map[string]string:
1752             Annotations holds the annotations as key/value pairs.
1753         """
1754         entity_id = self.resolve(id_)
1755         try:
1756             entity = self.model.state.get_entity(entity_type, entity_id)
1757         except KeyError:
1758             entity = await self.model._wait_for_new(entity_type, entity_id)
1759         return await entity.set_annotations(annotations)
1760
1761
1762 class CharmStore(object):
1763     """
1764     Async wrapper around theblues.charmstore.CharmStore
1765     """
1766     def __init__(self, loop):
1767         self.loop = loop
1768         self._cs = theblues.charmstore.CharmStore(timeout=5)
1769
1770     def __getattr__(self, name):
1771         """
1772         Wrap method calls in coroutines that use run_in_executor to make them
1773         async.
1774         """
1775         attr = getattr(self._cs, name)
1776         if not callable(attr):
1777             wrapper = partial(getattr, self._cs, name)
1778             setattr(self, name, wrapper)
1779         else:
1780             async def coro(*args, **kwargs):
1781                 method = partial(attr, *args, **kwargs)
1782                 for attempt in range(1, 4):
1783                     try:
1784                         return await self.loop.run_in_executor(None, method)
1785                     except theblues.errors.ServerError:
1786                         if attempt == 3:
1787                             raise
1788                         await asyncio.sleep(1, loop=self.loop)
1789             setattr(self, name, coro)
1790             wrapper = coro
1791         return wrapper
1792
1793
1794 class CharmArchiveGenerator(object):
1795     def __init__(self, path):
1796         self.path = os.path.abspath(os.path.expanduser(path))
1797
1798     def make_archive(self, path):
1799         """Create archive of directory and write to ``path``.
1800
1801         :param path: Path to archive
1802
1803         Ignored::
1804
1805             * build/\* - This is used for packing the charm itself and any
1806                           similar tasks.
1807             * \*/.\*    - Hidden files are all ignored for now.  This will most
1808                           likely be changed into a specific ignore list
1809                           (.bzr, etc)
1810
1811         """
1812         zf = zipfile.ZipFile(path, 'w', zipfile.ZIP_DEFLATED)
1813         for dirpath, dirnames, filenames in os.walk(self.path):
1814             relative_path = dirpath[len(self.path) + 1:]
1815             if relative_path and not self._ignore(relative_path):
1816                 zf.write(dirpath, relative_path)
1817             for name in filenames:
1818                 archive_name = os.path.join(relative_path, name)
1819                 if not self._ignore(archive_name):
1820                     real_path = os.path.join(dirpath, name)
1821                     self._check_type(real_path)
1822                     if os.path.islink(real_path):
1823                         self._check_link(real_path)
1824                         self._write_symlink(
1825                             zf, os.readlink(real_path), archive_name)
1826                     else:
1827                         zf.write(real_path, archive_name)
1828         zf.close()
1829         return path
1830
1831     def _check_type(self, path):
1832         """Check the path
1833         """
1834         s = os.stat(path)
1835         if stat.S_ISDIR(s.st_mode) or stat.S_ISREG(s.st_mode):
1836             return path
1837         raise ValueError("Invalid Charm at % %s" % (
1838             path, "Invalid file type for a charm"))
1839
1840     def _check_link(self, path):
1841         link_path = os.readlink(path)
1842         if link_path[0] == "/":
1843             raise ValueError(
1844                 "Invalid Charm at %s: %s" % (
1845                     path, "Absolute links are invalid"))
1846         path_dir = os.path.dirname(path)
1847         link_path = os.path.join(path_dir, link_path)
1848         if not link_path.startswith(os.path.abspath(self.path)):
1849             raise ValueError(
1850                 "Invalid charm at %s %s" % (
1851                     path, "Only internal symlinks are allowed"))
1852
1853     def _write_symlink(self, zf, link_target, link_path):
1854         """Package symlinks with appropriate zipfile metadata."""
1855         info = zipfile.ZipInfo()
1856         info.filename = link_path
1857         info.create_system = 3
1858         # Magic code for symlinks / py2/3 compat
1859         # 27166663808 = (stat.S_IFLNK | 0755) << 16
1860         info.external_attr = 2716663808
1861         zf.writestr(info, link_target)
1862
1863     def _ignore(self, path):
1864         if path == "build" or path.startswith("build/"):
1865             return True
1866         if path.startswith('.'):
1867             return True