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