juju/client/facade.py

   1 import argparse
   2 import builtins
   3 import functools
   4 import json
   5 import keyword
   6 from pathlib import Path
   7 import pprint
   8 import textwrap
   9 from typing import Sequence, Mapping, TypeVar, Any, Union
  10 import typing
  11
  12 from . import codegen
  13
  14 _marker = object()
  15
  16 # Map basic types to Python's typing with a callable
  17 SCHEMA_TO_PYTHON = {
  18     'string': str,
  19     'integer': int,
  20     'float': float,
  21     'number': float,
  22     'boolean': bool,
  23     'object': Any,
  24 }
  25
  26
  27 class KindRegistry(dict):
  28     def register(self, name, version, obj):
  29         self[name] = {version: {
  30             "object": obj,
  31         }}
  32
  33     def lookup(self, name, version=None):
  34         """If version is omitted, max version is used"""
  35         versions = self.get(name)
  36         if not versions:
  37             return None
  38         if version:
  39             return versions[version]
  40         return versions[max(versions)]
  41
  42     def getObj(self, name, version=None):
  43         result = self.lookup(name, version)
  44         if result:
  45             obj = result["object"]
  46             return obj
  47         return None
  48
  49
  50 class TypeRegistry(dict):
  51     def get(self, name):
  52         # Two way mapping
  53         refname = Schema.referenceName(name)
  54         if refname not in self:
  55             result = TypeVar(refname)
  56             self[refname] = result
  57             self[result] = refname
  58
  59         return self[refname]
  60
  61 _types = TypeRegistry()
  62 _registry = KindRegistry()
  63 classes = {}
  64
  65
  66 def booler(v):
  67     if isinstance(v, str):
  68         if v == "false":
  69             return False
  70     return bool(v)
  71
  72
  73 def getRefType(ref):
  74     return _types.get(ref)
  75
  76
  77 def refType(obj):
  78     return getRefType(obj["$ref"])
  79
  80
  81 def objType(obj):
  82     kind = obj.get('type')
  83     if not kind:
  84         raise ValueError("%s has no type" % obj)
  85     result = SCHEMA_TO_PYTHON.get(kind)
  86     if not result:
  87         raise ValueError("%s has type %s" % (obj, kind))
  88     return result
  89
  90
  91 basic_types = [str, bool, int, float]
  92
  93
  94 def name_to_py(name):
  95     result = name.replace("-", "_")
  96     result = result.lower()
  97     if keyword.iskeyword(result) or result in dir(builtins):
  98         result += "_"
  99     return result
 100
 101
 102 def strcast(kind, keep_builtins=False):
 103     if issubclass(kind, typing.GenericMeta):
 104         return str(kind)[1:]
 105     if str(kind).startswith('~'):
 106         return str(kind)[1:]
 107     if (kind in basic_types or
 108             type(kind) in basic_types) and keep_builtins is False:
 109         return kind.__name__
 110     return kind
 111
 112
 113 class Args(list):
 114     def __init__(self, defs):
 115         self.defs = defs
 116         if defs:
 117             rtypes = _registry.getObj(_types[defs])
 118             if len(rtypes) == 1:
 119                 if not self.do_explode(rtypes[0][1]):
 120                     for name, rtype in rtypes:
 121                         self.append((name, rtype))
 122             else:
 123                 for name, rtype in rtypes:
 124                     self.append((name, rtype))
 125
 126     def do_explode(self, kind):
 127         if kind in basic_types or type(kind) is typing.TypeVar:
 128             return False
 129         if not issubclass(kind, (typing.Sequence,
 130                                  typing.Mapping)):
 131             self.clear()
 132             self.extend(Args(kind))
 133             return True
 134         return False
 135
 136     def PyToSchemaMapping(self):
 137         m = {}
 138         for n, rt in self:
 139             m[name_to_py(n)] = n
 140         return m
 141
 142     def SchemaToPyMapping(self):
 143         m = {}
 144         for n, tr in self:
 145             m[n] = name_to_py(n)
 146         return m
 147
 148     def _format(self, name, rtype, typed=True):
 149         if typed:
 150             return "{} : {}".format(
 151                 name_to_py(name),
 152                 strcast(rtype)
 153             )
 154         else:
 155             return name_to_py(name)
 156
 157     def _get_arg_str(self, typed=False, joined=", "):
 158         if self:
 159             parts = []
 160             for item in self:
 161                 parts.append(self._format(item[0], item[1], typed))
 162             if joined:
 163                 return joined.join(parts)
 164             return parts
 165         return ''
 166
 167     def as_kwargs(self):
 168         if self:
 169             parts = []
 170             for item in self:
 171                 parts.append('{}=None'.format(name_to_py(item[0])))
 172             return ', '.join(parts)
 173         return ''
 174
 175     def typed(self):
 176         return self._get_arg_str(True)
 177
 178     def __str__(self):
 179         return self._get_arg_str(False)
 180
 181     def get_doc(self):
 182         return self._get_arg_str(True, "\n")
 183
 184
 185 def buildTypes(schema, capture):
 186     global classes
 187     INDENT = "    "
 188     for kind in sorted((k for k in _types if not isinstance(k, str)),
 189                        key=lambda x: str(x)):
 190         name = _types[kind]
 191         if name in classes:
 192             continue
 193         args = Args(kind)
 194         source = ["""
 195 class {}(Type):
 196     _toSchema = {}
 197     _toPy = {}
 198     def __init__(self{}{}):
 199         '''
 200 {}
 201         '''""".format(
 202             name,
 203             args.PyToSchemaMapping(),
 204             args.SchemaToPyMapping(),
 205             ", " if args else "",
 206             args.as_kwargs(),
 207             textwrap.indent(args.get_doc(), INDENT * 2))
 208                   ]
 209         assignments = args._get_arg_str(False, False)
 210
 211         if not args:
 212             source.append("{}pass".format(INDENT * 2))
 213         else:
 214             for arg in args:
 215                 arg_name = name_to_py(arg[0])
 216                 arg_type = arg[1]
 217                 arg_type_name = strcast(arg_type)
 218                 if arg_type in basic_types:
 219                     source.append("{}self.{} = {}".format(INDENT * 2, arg_name, arg_name))
 220                 elif issubclass(arg_type, typing.Sequence):
 221                     value_type = (
 222                         arg_type_name.__parameters__[0]
 223                         if len(arg_type_name.__parameters__)
 224                         else None
 225                     )
 226                     if type(value_type) is typing.TypeVar:
 227                         source.append("{}self.{} = [{}.from_json(o) for o in {} or []]".format(
 228                             INDENT * 2, arg_name, strcast(value_type), arg_name))
 229                     else:
 230                         source.append("{}self.{} = {}".format(INDENT * 2, arg_name, arg_name))
 231                 elif issubclass(arg_type, typing.Mapping):
 232                     value_type = (
 233                         arg_type_name.__parameters__[1]
 234                         if len(arg_type_name.__parameters__) > 1
 235                         else None
 236                     )
 237                     if type(value_type) is typing.TypeVar:
 238                         source.append("{}self.{} = {{k: {}.from_json(v) for k, v in ({} or dict()).items()}}".format(
 239                             INDENT * 2, arg_name, strcast(value_type), arg_name))
 240                     else:
 241                         source.append("{}self.{} = {}".format(INDENT * 2, arg_name, arg_name))
 242                 elif type(arg_type) is typing.TypeVar:
 243                     source.append("{}self.{} = {}.from_json({}) if {} else None".format(
 244                         INDENT * 2, arg_name, arg_type_name, arg_name, arg_name))
 245                 else:
 246                     source.append("{}self.{} = {}".format(INDENT * 2, arg_name, arg_name))
 247
 248         source = "\n".join(source)
 249         capture.write(source)
 250         capture.write("\n\n")
 251         co = compile(source, __name__, "exec")
 252         ns = _getns()
 253         exec(co, ns)
 254         cls = ns[name]
 255         classes[name] = cls
 256
 257
 258 def retspec(defs):
 259     # return specs
 260     # only return 1, so if there is more than one type
 261     # we need to include a union
 262     # In truth there is only 1 return
 263     # Error or the expected Type
 264     if not defs:
 265         return None
 266     rtypes = _registry.getObj(_types[defs])
 267     if not rtypes:
 268         return None
 269     if len(rtypes) > 1:
 270         return Union[tuple([strcast(r[1], True) for r in rtypes])]
 271     return strcast(rtypes[0][1], False)
 272
 273
 274 def return_type(defs):
 275     if not defs:
 276         return None
 277     rtypes = _registry.getObj(_types[defs])
 278     if not rtypes:
 279         return None
 280     if len(rtypes) > 1:
 281         for n, t in rtypes:
 282             if n == "Error":
 283                 continue
 284             return t
 285     return rtypes[0][1]
 286
 287
 288 def type_anno_func(func, defs, is_result=False):
 289     annos = {}
 290     if not defs:
 291         return func
 292     rtypes = _registry.getObj(_types[defs])
 293     if is_result:
 294         kn = "return"
 295         if not rtypes:
 296             annos[kn] = None
 297         elif len(rtypes) > 1:
 298             annos[kn] = Union[tuple([r[1] for r in rtypes])]
 299         else:
 300             annos[kn] = rtypes[0][1]
 301     else:
 302         for name, rtype in rtypes:
 303             name = name_to_py(name)
 304             annos[name] = rtype
 305     func.__annotations__.update(annos)
 306     return func
 307
 308
 309 def ReturnMapping(cls):
 310     # Annotate the method with a return Type
 311     # so the value can be cast
 312     def decorator(f):
 313         @functools.wraps(f)
 314         async def wrapper(*args, **kwargs):
 315             nonlocal cls
 316             reply = await f(*args, **kwargs)
 317             if cls is None:
 318                 return reply
 319             if 'error' in reply:
 320                 cls = classes['Error']
 321             if issubclass(cls, typing.Sequence):
 322                 result = []
 323                 item_cls = cls.__parameters__[0]
 324                 for item in reply:
 325                     result.append(item_cls.from_json(item))
 326                     """
 327                     if 'error' in item:
 328                         cls = classes['Error']
 329                     else:
 330                         cls = item_cls
 331                     result.append(cls.from_json(item))
 332                     """
 333             else:
 334                 result = cls.from_json(reply['response'])
 335
 336             return result
 337         return wrapper
 338     return decorator
 339
 340
 341 def makeFunc(cls, name, params, result, async=True):
 342     INDENT = "    "
 343     args = Args(params)
 344     assignments = []
 345     toschema = args.PyToSchemaMapping()
 346     for arg in args._get_arg_str(False, False):
 347         assignments.append("{}_params[\'{}\'] = {}".format(INDENT,
 348                                                            toschema[arg],
 349                                                            arg))
 350     assignments = "\n".join(assignments)
 351     res = retspec(result)
 352     source = """
 353
 354 @ReturnMapping({rettype})
 355 {async}def {name}(self{argsep}{args}):
 356     '''
 357 {docstring}
 358     Returns -> {res}
 359     '''
 360     # map input types to rpc msg
 361     _params = dict()
 362     msg = dict(type='{cls.name}', request='{name}', version={cls.version}, params=_params)
 363 {assignments}
 364     reply = {await}self.rpc(msg)
 365     return reply
 366
 367 """
 368
 369     fsource = source.format(async="async " if async else "",
 370                             name=name,
 371                             argsep=", " if args else "",
 372                             args=args,
 373                             res=res,
 374                             rettype=result.__name__ if result else None,
 375                             docstring=textwrap.indent(args.get_doc(), INDENT),
 376                             cls=cls,
 377                             assignments=assignments,
 378                             await="await " if async else "")
 379     ns = _getns()
 380     exec(fsource, ns)
 381     func = ns[name]
 382     return func, fsource
 383
 384
 385 def buildMethods(cls, capture):
 386     properties = cls.schema['properties']
 387     for methodname in sorted(properties):
 388         method, source = _buildMethod(cls, methodname)
 389         setattr(cls, methodname, method)
 390         capture.write(source, depth=1)
 391
 392
 393 def _buildMethod(cls, name):
 394     params = None
 395     result = None
 396     method = cls.schema['properties'][name]
 397     if 'properties' in method:
 398         prop = method['properties']
 399         spec = prop.get('Params')
 400         if spec:
 401             params = _types.get(spec['$ref'])
 402         spec = prop.get('Result')
 403         if spec:
 404             result = _types.get(spec['$ref'])
 405     return makeFunc(cls, name, params, result)
 406
 407
 408 def buildFacade(schema):
 409     cls = type(schema.name, (Type,), dict(name=schema.name,
 410                                           version=schema.version,
 411                                           schema=schema))
 412     source = """
 413 class {name}Facade(Type):
 414     name = '{name}'
 415     version = {version}
 416     schema = {schema}
 417     """.format(name=schema.name,
 418                version=schema.version,
 419                schema=textwrap.indent(pprint.pformat(schema), "    "))
 420     return cls, source
 421
 422
 423 class TypeEncoder(json.JSONEncoder):
 424     def default(self, obj):
 425         if isinstance(obj, Type):
 426             return obj.serialize()
 427         return json.JSONEncoder.default(self, obj)
 428
 429
 430 class Type:
 431     def connect(self, connection):
 432         self.connection = connection
 433
 434     async def rpc(self, msg):
 435         result = await self.connection.rpc(msg, encoder=TypeEncoder)
 436         return result
 437
 438     @classmethod
 439     def from_json(cls, data):
 440         if isinstance(data, str):
 441             data = json.loads(data)
 442         d = {}
 443         for k, v in (data or {}).items():
 444             d[cls._toPy.get(k, k)] = v
 445
 446         try:
 447             return cls(**d)
 448         except TypeError:
 449             raise
 450
 451     def serialize(self):
 452         d = {}
 453         for attr, tgt in self._toSchema.items():
 454             d[tgt] = getattr(self, attr)
 455         return d
 456
 457     def to_json(self):
 458         return json.dumps(self.serialize())
 459
 460
 461 class Schema(dict):
 462     def __init__(self, schema):
 463         self.name = schema['Name']
 464         self.version = schema['Version']
 465         self.update(schema['Schema'])
 466
 467     @classmethod
 468     def referenceName(cls, ref):
 469         if ref.startswith("#/definitions/"):
 470             ref = ref.rsplit("/", 1)[-1]
 471         return ref
 472
 473     def resolveDefinition(self, ref):
 474         return self['definitions'][self.referenceName(ref)]
 475
 476     def deref(self, prop, name):
 477         if not isinstance(prop, dict):
 478             raise TypeError(prop)
 479         if "$ref" not in prop:
 480             return prop
 481
 482         target = self.resolveDefinition(prop["$ref"])
 483         return target
 484
 485     def buildDefinitions(self):
 486         # here we are building the types out
 487         # anything in definitions is a type
 488         # but these may contain references themselves
 489         # so we dfs to the bottom and build upwards
 490         # when a types is already in the registry
 491         defs = self.get('definitions')
 492         if not defs:
 493             return
 494         for d, data in defs.items():
 495             if d in _registry:
 496                 continue
 497             node = self.deref(data, d)
 498             kind = node.get("type")
 499             if kind == "object":
 500                 result = self.buildObject(node, d)
 501             elif kind == "array":
 502                 pass
 503             _registry.register(d, self.version, result)
 504             # XXX: This makes sure that the type gets added to the global
 505             # _types dict even if no other type in the schema has a ref
 506             # to it.
 507             getRefType(d)
 508
 509     def buildObject(self, node, name=None, d=0):
 510         # we don't need to build types recursively here
 511         # they are all in definitions already
 512         # we only want to include the type reference
 513         # which we can derive from the name
 514         struct = []
 515         add = struct.append
 516         props = node.get("properties")
 517         pprops = node.get("patternProperties")
 518         if props:
 519             # Sort these so the __init__ arg list for each Type remains
 520             # consistently ordered across regens of client.py
 521             for p in sorted(props):
 522                 prop = props[p]
 523                 if "$ref" in prop:
 524                     add((p, refType(prop)))
 525                 else:
 526                     kind = prop['type']
 527                     if kind == "array":
 528                         add((p, self.buildArray(prop, d + 1)))
 529                     elif kind == "object":
 530                         struct.extend(self.buildObject(prop, p, d + 1))
 531                     else:
 532                         add((p, objType(prop)))
 533         if pprops:
 534             if ".*" not in pprops:
 535                 raise ValueError(
 536                     "Cannot handle actual pattern in patternProperties %s" %
 537                     pprops)
 538             pprop = pprops[".*"]
 539             if "$ref" in pprop:
 540                 add((name, Mapping[str, refType(pprop)]))
 541                 return struct
 542             ppkind = pprop["type"]
 543             if ppkind == "array":
 544                 add((name, self.buildArray(pprop, d + 1)))
 545             else:
 546                 add((name, Mapping[str, SCHEMA_TO_PYTHON[ppkind]]))
 547
 548         if not struct and node.get('additionalProperties', False):
 549             add((name, Mapping[str, SCHEMA_TO_PYTHON['object']]))
 550
 551         return struct
 552
 553     def buildArray(self, obj, d=0):
 554         # return a sequence from an array in the schema
 555         if "$ref" in obj:
 556             return Sequence[refType(obj)]
 557         else:
 558             kind = obj.get("type")
 559             if kind and kind == "array":
 560                 items = obj['items']
 561                 return self.buildArray(items, d + 1)
 562             else:
 563                 return Sequence[objType(obj)]
 564
 565
 566 def _getns():
 567     ns = {'Type': Type,
 568           'typing': typing,
 569           'ReturnMapping': ReturnMapping
 570           }
 571     # Copy our types into the globals of the method
 572     for facade in _registry:
 573         ns[facade] = _registry.getObj(facade)
 574     return ns
 575
 576
 577
 578 def generate_facacdes(options):
 579     global classes
 580     schemas = json.loads(Path(options.schema).read_text("utf-8"))
 581     capture = codegen.CodeWriter()
 582     capture.write(textwrap.dedent("""\
 583         # DO NOT CHANGE THIS FILE! This file is auto-generated by facade.py.
 584         # Changes will be overwritten/lost when the file is regenerated.
 585
 586         from juju.client.facade import Type, ReturnMapping
 587
 588     """))
 589     schemas = [Schema(s) for s in schemas]
 590
 591     for schema in schemas:
 592         schema.buildDefinitions()
 593         buildTypes(schema, capture)
 594
 595     for schema in schemas:
 596         # TODO generate class now with a metaclass that takes the schema
 597         # the generated class has the right name and it in turn uses
 598         # the metaclass to populate cls
 599         cls, source = buildFacade(schema)
 600         capture.write(source)
 601         buildMethods(cls, capture)
 602         classes[schema.name] = cls
 603
 604     return capture
 605
 606 def setup():
 607     parser = argparse.ArgumentParser()
 608     parser.add_argument("-s", "--schema", default="schemas.json")
 609     parser.add_argument("-o", "--output", default="client.py")
 610     options = parser.parse_args()
 611     return options
 612
 613 def main():
 614     options = setup()
 615     capture = generate_facacdes(options)
 616     with open(options.output, "w") as fp:
 617         print(capture, file=fp)
 618
 619
 620
 621 if __name__ == '__main__':
 622     main()