| commit | author | age | ||
| e4c057 | 1 | import itertools |
| MM | 2 | import operator |
| 3 | import sys | |
| 4 | ||
| 5 | from pyramid.compat import reraise | |
| 6 | ||
| 7 | from pyramid.config.util import ActionInfo | |
| 8 | ||
| 9 | from pyramid.exceptions import ( | |
| 10 | ConfigurationConflictError, | |
| 11 | ConfigurationError, | |
| 12 | ConfigurationExecutionError, | |
| 13 | ) | |
| 14 | ||
| 15 | from pyramid.registry import undefer | |
| 16 | ||
| 17 | ||
| 18 | class ActionConfiguratorMixin(object): | |
| 19 | @property | |
| 20 | def action_info(self): | |
| 21 | info = self.info # usually a ZCML action (ParserInfo) if self.info | |
| 22 | if not info: | |
| 23 | # Try to provide more accurate info for conflict reports | |
| 24 | if self._ainfo: | |
| 25 | info = self._ainfo[0] | |
| 26 | else: | |
| 27 | info = ActionInfo(None, 0, '', '') | |
| 28 | return info | |
| 29 | ||
| 30 | def action( | |
| 31 | self, | |
| 32 | discriminator, | |
| 33 | callable=None, | |
| 34 | args=(), | |
| 35 | kw=None, | |
| 36 | order=0, | |
| 37 | introspectables=(), | |
| 38 | **extra | |
| 39 | ): | |
| 40 | """ Register an action which will be executed when | |
| 41 | :meth:`pyramid.config.Configurator.commit` is called (or executed | |
| 42 | immediately if ``autocommit`` is ``True``). | |
| 43 | ||
| 44 | .. warning:: This method is typically only used by :app:`Pyramid` | |
| 45 | framework extension authors, not by :app:`Pyramid` application | |
| 46 | developers. | |
| 47 | ||
| 48 | The ``discriminator`` uniquely identifies the action. It must be | |
| 49 | given, but it can be ``None``, to indicate that the action never | |
| 50 | conflicts. It must be a hashable value. | |
| 51 | ||
| 52 | The ``callable`` is a callable object which performs the task | |
| 53 | associated with the action when the action is executed. It is | |
| 54 | optional. | |
| 55 | ||
| 56 | ``args`` and ``kw`` are tuple and dict objects respectively, which | |
| 57 | are passed to ``callable`` when this action is executed. Both are | |
| 58 | optional. | |
| 59 | ||
| 60 | ``order`` is a grouping mechanism; an action with a lower order will | |
| 61 | be executed before an action with a higher order (has no effect when | |
| 62 | autocommit is ``True``). | |
| 63 | ||
| 64 | ``introspectables`` is a sequence of :term:`introspectable` objects | |
| 65 | (or the empty sequence if no introspectable objects are associated | |
| 66 | with this action). If this configurator's ``introspection`` | |
| 67 | attribute is ``False``, these introspectables will be ignored. | |
| 68 | ||
| 69 | ``extra`` provides a facility for inserting extra keys and values | |
| 70 | into an action dictionary. | |
| 71 | """ | |
| 72 | # catch nonhashable discriminators here; most unit tests use | |
| 73 | # autocommit=False, which won't catch unhashable discriminators | |
| 74 | assert hash(discriminator) | |
| 75 | ||
| 76 | if kw is None: | |
| 77 | kw = {} | |
| 78 | ||
| 79 | autocommit = self.autocommit | |
| 80 | action_info = self.action_info | |
| 81 | ||
| 82 | if not self.introspection: | |
| 83 | # if we're not introspecting, ignore any introspectables passed | |
| 84 | # to us | |
| 85 | introspectables = () | |
| 86 | ||
| 87 | if autocommit: | |
| 88 | # callables can depend on the side effects of resolving a | |
| 89 | # deferred discriminator | |
| 90 | self.begin() | |
| 91 | try: | |
| 92 | undefer(discriminator) | |
| 93 | if callable is not None: | |
| 94 | callable(*args, **kw) | |
| 95 | for introspectable in introspectables: | |
| 96 | introspectable.register(self.introspector, action_info) | |
| 97 | finally: | |
| 98 | self.end() | |
| 99 | ||
| 100 | else: | |
| 101 | action = extra | |
| 102 | action.update( | |
| 103 | dict( | |
| 104 | discriminator=discriminator, | |
| 105 | callable=callable, | |
| 106 | args=args, | |
| 107 | kw=kw, | |
| 108 | order=order, | |
| 109 | info=action_info, | |
| 110 | includepath=self.includepath, | |
| 111 | introspectables=introspectables, | |
| 112 | ) | |
| 113 | ) | |
| 114 | self.action_state.action(**action) | |
| 115 | ||
| 116 | def _get_action_state(self): | |
| 117 | registry = self.registry | |
| 118 | try: | |
| 119 | state = registry.action_state | |
| 120 | except AttributeError: | |
| 121 | state = ActionState() | |
| 122 | registry.action_state = state | |
| 123 | return state | |
| 124 | ||
| 125 | def _set_action_state(self, state): | |
| 126 | self.registry.action_state = state | |
| 127 | ||
| 128 | action_state = property(_get_action_state, _set_action_state) | |
| 129 | ||
| 130 | _ctx = action_state # bw compat | |
| 131 | ||
| 132 | def commit(self): | |
| 133 | """ | |
| 134 | Commit any pending configuration actions. If a configuration | |
| 135 | conflict is detected in the pending configuration actions, this method | |
| 136 | will raise a :exc:`ConfigurationConflictError`; within the traceback | |
| 137 | of this error will be information about the source of the conflict, | |
| 138 | usually including file names and line numbers of the cause of the | |
| 139 | configuration conflicts. | |
| 140 | ||
| 141 | .. warning:: | |
| 142 | You should think very carefully before manually invoking | |
| 143 | ``commit()``. Especially not as part of any reusable configuration | |
| 144 | methods. Normally it should only be done by an application author at | |
| 145 | the end of configuration in order to override certain aspects of an | |
| 146 | addon. | |
| 147 | ||
| 148 | """ | |
| 149 | self.begin() | |
| 150 | try: | |
| 151 | self.action_state.execute_actions(introspector=self.introspector) | |
| 152 | finally: | |
| 153 | self.end() | |
| 154 | self.action_state = ActionState() # old actions have been processed | |
| 155 | ||
| 156 | # this class is licensed under the ZPL (stolen from Zope) | |
| 157 | class ActionState(object): | |
| 158 | def __init__(self): | |
| 159 | # NB "actions" is an API, dep'd upon by pyramid_zcml's load_zcml func | |
| 160 | self.actions = [] | |
| 161 | self._seen_files = set() | |
| 162 | ||
| 163 | def processSpec(self, spec): | |
| 164 | """Check whether a callable needs to be processed. The ``spec`` | |
| 165 | refers to a unique identifier for the callable. | |
| 166 | ||
| 167 | Return True if processing is needed and False otherwise. If | |
| 168 | the callable needs to be processed, it will be marked as | |
| 169 | processed, assuming that the caller will procces the callable if | |
| 170 | it needs to be processed. | |
| 171 | """ | |
| 172 | if spec in self._seen_files: | |
| 173 | return False | |
| 174 | self._seen_files.add(spec) | |
| 175 | return True | |
| 176 | ||
| 177 | def action( | |
| 178 | self, | |
| 179 | discriminator, | |
| 180 | callable=None, | |
| 181 | args=(), | |
| 182 | kw=None, | |
| 183 | order=0, | |
| 184 | includepath=(), | |
| 185 | info=None, | |
| 186 | introspectables=(), | |
| 187 | **extra | |
| 188 | ): | |
| 189 | """Add an action with the given discriminator, callable and arguments | |
| 190 | """ | |
| 191 | if kw is None: | |
| 192 | kw = {} | |
| 193 | action = extra | |
| 194 | action.update( | |
| 195 | dict( | |
| 196 | discriminator=discriminator, | |
| 197 | callable=callable, | |
| 198 | args=args, | |
| 199 | kw=kw, | |
| 200 | includepath=includepath, | |
| 201 | info=info, | |
| 202 | order=order, | |
| 203 | introspectables=introspectables, | |
| 204 | ) | |
| 205 | ) | |
| 206 | self.actions.append(action) | |
| 207 | ||
| 208 | def execute_actions(self, clear=True, introspector=None): | |
| 209 | """Execute the configuration actions | |
| 210 | ||
| 211 | This calls the action callables after resolving conflicts | |
| 212 | ||
| 213 | For example: | |
| 214 | ||
| 215 | >>> output = [] | |
| 216 | >>> def f(*a, **k): | |
| 217 | ... output.append(('f', a, k)) | |
| 218 | >>> context = ActionState() | |
| 219 | >>> context.actions = [ | |
| 220 | ... (1, f, (1,)), | |
| 221 | ... (1, f, (11,), {}, ('x', )), | |
| 222 | ... (2, f, (2,)), | |
| 223 | ... ] | |
| 224 | >>> context.execute_actions() | |
| 225 | >>> output | |
| 226 | [('f', (1,), {}), ('f', (2,), {})] | |
| 227 | ||
| 228 | If the action raises an error, we convert it to a | |
| 229 | ConfigurationExecutionError. | |
| 230 | ||
| 231 | >>> output = [] | |
| 232 | >>> def bad(): | |
| 233 | ... bad.xxx | |
| 234 | >>> context.actions = [ | |
| 235 | ... (1, f, (1,)), | |
| 236 | ... (1, f, (11,), {}, ('x', )), | |
| 237 | ... (2, f, (2,)), | |
| 238 | ... (3, bad, (), {}, (), 'oops') | |
| 239 | ... ] | |
| 240 | >>> try: | |
| 241 | ... v = context.execute_actions() | |
| 242 | ... except ConfigurationExecutionError, v: | |
| 243 | ... pass | |
| 244 | >>> print(v) | |
| 245 | exceptions.AttributeError: 'function' object has no attribute 'xxx' | |
| 246 | in: | |
| 247 | oops | |
| 248 | ||
| 249 | Note that actions executed before the error still have an effect: | |
| 250 | ||
| 251 | >>> output | |
| 252 | [('f', (1,), {}), ('f', (2,), {})] | |
| 253 | ||
| 254 | The execution is re-entrant such that actions may be added by other | |
| 255 | actions with the one caveat that the order of any added actions must | |
| 256 | be equal to or larger than the current action. | |
| 257 | ||
| 258 | >>> output = [] | |
| 259 | >>> def f(*a, **k): | |
| 260 | ... output.append(('f', a, k)) | |
| 261 | ... context.actions.append((3, g, (8,), {})) | |
| 262 | >>> def g(*a, **k): | |
| 263 | ... output.append(('g', a, k)) | |
| 264 | >>> context.actions = [ | |
| 265 | ... (1, f, (1,)), | |
| 266 | ... ] | |
| 267 | >>> context.execute_actions() | |
| 268 | >>> output | |
| 269 | [('f', (1,), {}), ('g', (8,), {})] | |
| 270 | ||
| 271 | """ | |
| 272 | try: | |
| 273 | all_actions = [] | |
| 274 | executed_actions = [] | |
| 275 | action_iter = iter([]) | |
| 276 | conflict_state = ConflictResolverState() | |
| 277 | ||
| 278 | while True: | |
| 279 | # We clear the actions list prior to execution so if there | |
| 280 | # are some new actions then we add them to the mix and resolve | |
| 281 | # conflicts again. This orders the new actions as well as | |
| 282 | # ensures that the previously executed actions have no new | |
| 283 | # conflicts. | |
| 284 | if self.actions: | |
| 285 | all_actions.extend(self.actions) | |
| 286 | action_iter = resolveConflicts( | |
| 287 | self.actions, state=conflict_state | |
| 288 | ) | |
| 289 | self.actions = [] | |
| 290 | ||
| 291 | action = next(action_iter, None) | |
| 292 | if action is None: | |
| 293 | # we are done! | |
| 294 | break | |
| 295 | ||
| 296 | callable = action['callable'] | |
| 297 | args = action['args'] | |
| 298 | kw = action['kw'] | |
| 299 | info = action['info'] | |
| 300 | # we use "get" below in case an action was added via a ZCML | |
| 301 | # directive that did not know about introspectables | |
| 302 | introspectables = action.get('introspectables', ()) | |
| 303 | ||
| 304 | try: | |
| 305 | if callable is not None: | |
| 306 | callable(*args, **kw) | |
| 307 | except Exception: | |
| 308 | t, v, tb = sys.exc_info() | |
| 309 | try: | |
| 310 | reraise( | |
| 311 | ConfigurationExecutionError, | |
| 312 | ConfigurationExecutionError(t, v, info), | |
| 313 | tb, | |
| 314 | ) | |
| 315 | finally: | |
| 316 | del t, v, tb | |
| 317 | ||
| 318 | if introspector is not None: | |
| 319 | for introspectable in introspectables: | |
| 320 | introspectable.register(introspector, info) | |
| 321 | ||
| 322 | executed_actions.append(action) | |
| 323 | ||
| 324 | self.actions = all_actions | |
| 325 | return executed_actions | |
| 326 | ||
| 327 | finally: | |
| 328 | if clear: | |
| 329 | self.actions = [] | |
| 330 | ||
| 331 | ||
| 332 | class ConflictResolverState(object): | |
| 333 | def __init__(self): | |
| 334 | # keep a set of resolved discriminators to test against to ensure | |
| 335 | # that a new action does not conflict with something already executed | |
| 336 | self.resolved_ainfos = {} | |
| 337 | ||
| 338 | # actions left over from a previous iteration | |
| 339 | self.remaining_actions = [] | |
| 340 | ||
| 341 | # after executing an action we memoize its order to avoid any new | |
| 342 | # actions sending us backward | |
| 343 | self.min_order = None | |
| 344 | ||
| 345 | # unique tracks the index of the action so we need it to increase | |
| 346 | # monotonically across invocations to resolveConflicts | |
| 347 | self.start = 0 | |
| 348 | ||
| 349 | ||
| 350 | # this function is licensed under the ZPL (stolen from Zope) | |
| 351 | def resolveConflicts(actions, state=None): | |
| 352 | """Resolve conflicting actions | |
| 353 | ||
| 354 | Given an actions list, identify and try to resolve conflicting actions. | |
| 355 | Actions conflict if they have the same non-None discriminator. | |
| 356 | ||
| 357 | Conflicting actions can be resolved if the include path of one of | |
| 358 | the actions is a prefix of the includepaths of the other | |
| 359 | conflicting actions and is unequal to the include paths in the | |
| 360 | other conflicting actions. | |
| 361 | ||
| 362 | Actions are resolved on a per-order basis because some discriminators | |
| 363 | cannot be computed until earlier actions have executed. An action in an | |
| 364 | earlier order may execute successfully only to find out later that it was | |
| 365 | overridden by another action with a smaller include path. This will result | |
| 366 | in a conflict as there is no way to revert the original action. | |
| 367 | ||
| 368 | ``state`` may be an instance of ``ConflictResolverState`` that | |
| 369 | can be used to resume execution and resolve the new actions against the | |
| 370 | list of executed actions from a previous call. | |
| 371 | ||
| 372 | """ | |
| 373 | if state is None: | |
| 374 | state = ConflictResolverState() | |
| 375 | ||
| 376 | # pick up where we left off last time, but track the new actions as well | |
| 377 | state.remaining_actions.extend(normalize_actions(actions)) | |
| 378 | actions = state.remaining_actions | |
| 379 | ||
| 380 | def orderandpos(v): | |
| 381 | n, v = v | |
| 382 | return (v['order'] or 0, n) | |
| 383 | ||
| 384 | def orderonly(v): | |
| 385 | n, v = v | |
| 386 | return v['order'] or 0 | |
| 387 | ||
| 388 | sactions = sorted(enumerate(actions, start=state.start), key=orderandpos) | |
| 389 | for order, actiongroup in itertools.groupby(sactions, orderonly): | |
| 390 | # "order" is an integer grouping. Actions in a lower order will be | |
| 391 | # executed before actions in a higher order. All of the actions in | |
| 392 | # one grouping will be executed (its callable, if any will be called) | |
| 393 | # before any of the actions in the next. | |
| 394 | output = [] | |
| 395 | unique = {} | |
| 396 | ||
| 397 | # error out if we went backward in order | |
| 398 | if state.min_order is not None and order < state.min_order: | |
| 399 | r = [ | |
| 400 | 'Actions were added to order={0} after execution had moved ' | |
| 401 | 'on to order={1}. Conflicting actions: '.format( | |
| 402 | order, state.min_order | |
| 403 | ) | |
| 404 | ] | |
| 405 | for i, action in actiongroup: | |
| 406 | for line in str(action['info']).rstrip().split('\n'): | |
| 407 | r.append(" " + line) | |
| 408 | raise ConfigurationError('\n'.join(r)) | |
| 409 | ||
| 410 | for i, action in actiongroup: | |
| 411 | # Within an order, actions are executed sequentially based on | |
| 412 | # original action ordering ("i"). | |
| 413 | ||
| 414 | # "ainfo" is a tuple of (i, action) where "i" is an integer | |
| 415 | # expressing the relative position of this action in the action | |
| 416 | # list being resolved, and "action" is an action dictionary. The | |
| 417 | # purpose of an ainfo is to associate an "i" with a particular | |
| 418 | # action; "i" exists for sorting after conflict resolution. | |
| 419 | ainfo = (i, action) | |
| 420 | ||
| 421 | # wait to defer discriminators until we are on their order because | |
| 422 | # the discriminator may depend on state from a previous order | |
| 423 | discriminator = undefer(action['discriminator']) | |
| 424 | action['discriminator'] = discriminator | |
| 425 | ||
| 426 | if discriminator is None: | |
| 427 | # The discriminator is None, so this action can never conflict. | |
| 428 | # We can add it directly to the result. | |
| 429 | output.append(ainfo) | |
| 430 | continue | |
| 431 | ||
| 432 | L = unique.setdefault(discriminator, []) | |
| 433 | L.append(ainfo) | |
| 434 | ||
| 435 | # Check for conflicts | |
| 436 | conflicts = {} | |
| 437 | for discriminator, ainfos in unique.items(): | |
| 438 | # We use (includepath, i) as a sort key because we need to | |
| 439 | # sort the actions by the paths so that the shortest path with a | |
| 440 | # given prefix comes first. The "first" action is the one with the | |
| 441 | # shortest include path. We break sorting ties using "i". | |
| 442 | def bypath(ainfo): | |
| 443 | path, i = ainfo[1]['includepath'], ainfo[0] | |
| 444 | return path, order, i | |
| 445 | ||
| 446 | ainfos.sort(key=bypath) | |
| 447 | ainfo, rest = ainfos[0], ainfos[1:] | |
| 448 | _, action = ainfo | |
| 449 | ||
| 450 | # ensure this new action does not conflict with a previously | |
| 451 | # resolved action from an earlier order / invocation | |
| 452 | prev_ainfo = state.resolved_ainfos.get(discriminator) | |
| 453 | if prev_ainfo is not None: | |
| 454 | _, paction = prev_ainfo | |
| 455 | basepath, baseinfo = paction['includepath'], paction['info'] | |
| 456 | includepath = action['includepath'] | |
| 457 | # if the new action conflicts with the resolved action then | |
| 458 | # note the conflict, otherwise drop the action as it's | |
| 459 | # effectively overriden by the previous action | |
| 460 | if ( | |
| 461 | includepath[: len(basepath)] != basepath | |
| 462 | or includepath == basepath | |
| 463 | ): | |
| 464 | L = conflicts.setdefault(discriminator, [baseinfo]) | |
| 465 | L.append(action['info']) | |
| 466 | ||
| 467 | else: | |
| 468 | output.append(ainfo) | |
| 469 | ||
| 470 | basepath, baseinfo = action['includepath'], action['info'] | |
| 471 | for _, action in rest: | |
| 472 | includepath = action['includepath'] | |
| 473 | # Test whether path is a prefix of opath | |
| 474 | if ( | |
| 475 | includepath[: len(basepath)] != basepath | |
| 476 | or includepath == basepath # not a prefix | |
| 477 | ): | |
| 478 | L = conflicts.setdefault(discriminator, [baseinfo]) | |
| 479 | L.append(action['info']) | |
| 480 | ||
| 481 | if conflicts: | |
| 482 | raise ConfigurationConflictError(conflicts) | |
| 483 | ||
| 484 | # sort resolved actions by "i" and yield them one by one | |
| 485 | for i, action in sorted(output, key=operator.itemgetter(0)): | |
| 486 | # do not memoize the order until we resolve an action inside it | |
| 487 | state.min_order = action['order'] | |
| 488 | state.start = i + 1 | |
| 489 | state.remaining_actions.remove(action) | |
| 490 | state.resolved_ainfos[action['discriminator']] = (i, action) | |
| 491 | yield action | |
| 492 | ||
| 493 | ||
| 494 | def normalize_actions(actions): | |
| 495 | """Convert old-style tuple actions to new-style dicts.""" | |
| 496 | result = [] | |
| 497 | for v in actions: | |
| 498 | if not isinstance(v, dict): | |
| 499 | v = expand_action_tuple(*v) | |
| 500 | result.append(v) | |
| 501 | return result | |
| 502 | ||
| 503 | ||
| 504 | def expand_action_tuple( | |
| 505 | discriminator, | |
| 506 | callable=None, | |
| 507 | args=(), | |
| 508 | kw=None, | |
| 509 | includepath=(), | |
| 510 | info=None, | |
| 511 | order=0, | |
| 512 | introspectables=(), | |
| 513 | ): | |
| 514 | if kw is None: | |
| 515 | kw = {} | |
| 516 | return dict( | |
| 517 | discriminator=discriminator, | |
| 518 | callable=callable, | |
| 519 | args=args, | |
| 520 | kw=kw, | |
| 521 | includepath=includepath, | |
| 522 | info=info, | |
| 523 | order=order, | |
| 524 | introspectables=introspectables, | |
| 525 | ) | |
