| commit | author | age | ||
| d579f2 | 1 | import functools |
| e4c057 | 2 | import itertools |
| MM | 3 | import operator |
| 4 | import sys | |
| d579f2 | 5 | import traceback |
| MM | 6 | from zope.interface import implementer |
| e4c057 | 7 | |
| MM | 8 | from pyramid.compat import reraise |
| 9 | from pyramid.exceptions import ( | |
| 10 | ConfigurationConflictError, | |
| 11 | ConfigurationError, | |
| 12 | ConfigurationExecutionError, | |
| 13 | ) | |
| d579f2 | 14 | from pyramid.interfaces import IActionInfo |
| e4c057 | 15 | from pyramid.registry import undefer |
| d579f2 | 16 | from pyramid.util import is_nonstr_iter |
| e4c057 | 17 | |
| MM | 18 | |
| 19 | class ActionConfiguratorMixin(object): | |
| 20 | @property | |
| 21 | def action_info(self): | |
| 22 | info = self.info # usually a ZCML action (ParserInfo) if self.info | |
| 23 | if not info: | |
| 24 | # Try to provide more accurate info for conflict reports | |
| 25 | if self._ainfo: | |
| 26 | info = self._ainfo[0] | |
| 27 | else: | |
| 28 | info = ActionInfo(None, 0, '', '') | |
| 29 | return info | |
| 30 | ||
| 31 | def action( | |
| 32 | self, | |
| 33 | discriminator, | |
| 34 | callable=None, | |
| 35 | args=(), | |
| 36 | kw=None, | |
| 37 | order=0, | |
| 38 | introspectables=(), | |
| 39 | **extra | |
| 40 | ): | |
| 41 | """ Register an action which will be executed when | |
| 42 | :meth:`pyramid.config.Configurator.commit` is called (or executed | |
| 43 | immediately if ``autocommit`` is ``True``). | |
| 44 | ||
| 45 | .. warning:: This method is typically only used by :app:`Pyramid` | |
| 46 | framework extension authors, not by :app:`Pyramid` application | |
| 47 | developers. | |
| 48 | ||
| 49 | The ``discriminator`` uniquely identifies the action. It must be | |
| 50 | given, but it can be ``None``, to indicate that the action never | |
| 51 | conflicts. It must be a hashable value. | |
| 52 | ||
| 53 | The ``callable`` is a callable object which performs the task | |
| 54 | associated with the action when the action is executed. It is | |
| 55 | optional. | |
| 56 | ||
| 57 | ``args`` and ``kw`` are tuple and dict objects respectively, which | |
| 58 | are passed to ``callable`` when this action is executed. Both are | |
| 59 | optional. | |
| 60 | ||
| 61 | ``order`` is a grouping mechanism; an action with a lower order will | |
| 62 | be executed before an action with a higher order (has no effect when | |
| 63 | autocommit is ``True``). | |
| 64 | ||
| 65 | ``introspectables`` is a sequence of :term:`introspectable` objects | |
| 66 | (or the empty sequence if no introspectable objects are associated | |
| 67 | with this action). If this configurator's ``introspection`` | |
| 68 | attribute is ``False``, these introspectables will be ignored. | |
| 69 | ||
| 70 | ``extra`` provides a facility for inserting extra keys and values | |
| 71 | into an action dictionary. | |
| 72 | """ | |
| 73 | # catch nonhashable discriminators here; most unit tests use | |
| 74 | # autocommit=False, which won't catch unhashable discriminators | |
| 75 | assert hash(discriminator) | |
| 76 | ||
| 77 | if kw is None: | |
| 78 | kw = {} | |
| 79 | ||
| 80 | autocommit = self.autocommit | |
| 81 | action_info = self.action_info | |
| 82 | ||
| 83 | if not self.introspection: | |
| 84 | # if we're not introspecting, ignore any introspectables passed | |
| 85 | # to us | |
| 86 | introspectables = () | |
| 87 | ||
| 88 | if autocommit: | |
| 89 | # callables can depend on the side effects of resolving a | |
| 90 | # deferred discriminator | |
| 91 | self.begin() | |
| 92 | try: | |
| 93 | undefer(discriminator) | |
| 94 | if callable is not None: | |
| 95 | callable(*args, **kw) | |
| 96 | for introspectable in introspectables: | |
| 97 | introspectable.register(self.introspector, action_info) | |
| 98 | finally: | |
| 99 | self.end() | |
| 100 | ||
| 101 | else: | |
| 102 | action = extra | |
| 103 | action.update( | |
| 104 | dict( | |
| 105 | discriminator=discriminator, | |
| 106 | callable=callable, | |
| 107 | args=args, | |
| 108 | kw=kw, | |
| 109 | order=order, | |
| 110 | info=action_info, | |
| 111 | includepath=self.includepath, | |
| 112 | introspectables=introspectables, | |
| 113 | ) | |
| 114 | ) | |
| 115 | self.action_state.action(**action) | |
| 116 | ||
| 117 | def _get_action_state(self): | |
| 118 | registry = self.registry | |
| 119 | try: | |
| 120 | state = registry.action_state | |
| 121 | except AttributeError: | |
| 122 | state = ActionState() | |
| 123 | registry.action_state = state | |
| 124 | return state | |
| 125 | ||
| 126 | def _set_action_state(self, state): | |
| 127 | self.registry.action_state = state | |
| 128 | ||
| 129 | action_state = property(_get_action_state, _set_action_state) | |
| 130 | ||
| 131 | _ctx = action_state # bw compat | |
| 132 | ||
| 133 | def commit(self): | |
| 134 | """ | |
| 135 | Commit any pending configuration actions. If a configuration | |
| 136 | conflict is detected in the pending configuration actions, this method | |
| 137 | will raise a :exc:`ConfigurationConflictError`; within the traceback | |
| 138 | of this error will be information about the source of the conflict, | |
| 139 | usually including file names and line numbers of the cause of the | |
| 140 | configuration conflicts. | |
| 141 | ||
| 142 | .. warning:: | |
| 143 | You should think very carefully before manually invoking | |
| 144 | ``commit()``. Especially not as part of any reusable configuration | |
| 145 | methods. Normally it should only be done by an application author at | |
| 146 | the end of configuration in order to override certain aspects of an | |
| 147 | addon. | |
| 148 | ||
| 149 | """ | |
| 150 | self.begin() | |
| 151 | try: | |
| 152 | self.action_state.execute_actions(introspector=self.introspector) | |
| 153 | finally: | |
| 154 | self.end() | |
| 155 | self.action_state = ActionState() # old actions have been processed | |
| d579f2 | 156 | |
| e4c057 | 157 | |
| MM | 158 | # this class is licensed under the ZPL (stolen from Zope) |
| 159 | class ActionState(object): | |
| 160 | def __init__(self): | |
| 161 | # NB "actions" is an API, dep'd upon by pyramid_zcml's load_zcml func | |
| 162 | self.actions = [] | |
| 163 | self._seen_files = set() | |
| 164 | ||
| 165 | def processSpec(self, spec): | |
| 166 | """Check whether a callable needs to be processed. The ``spec`` | |
| 167 | refers to a unique identifier for the callable. | |
| 168 | ||
| 169 | Return True if processing is needed and False otherwise. If | |
| 170 | the callable needs to be processed, it will be marked as | |
| 171 | processed, assuming that the caller will procces the callable if | |
| 172 | it needs to be processed. | |
| 173 | """ | |
| 174 | if spec in self._seen_files: | |
| 175 | return False | |
| 176 | self._seen_files.add(spec) | |
| 177 | return True | |
| 178 | ||
| 179 | def action( | |
| 180 | self, | |
| 181 | discriminator, | |
| 182 | callable=None, | |
| 183 | args=(), | |
| 184 | kw=None, | |
| 185 | order=0, | |
| 186 | includepath=(), | |
| 187 | info=None, | |
| 188 | introspectables=(), | |
| 189 | **extra | |
| 190 | ): | |
| 191 | """Add an action with the given discriminator, callable and arguments | |
| 192 | """ | |
| 193 | if kw is None: | |
| 194 | kw = {} | |
| 195 | action = extra | |
| 196 | action.update( | |
| 197 | dict( | |
| 198 | discriminator=discriminator, | |
| 199 | callable=callable, | |
| 200 | args=args, | |
| 201 | kw=kw, | |
| 202 | includepath=includepath, | |
| 203 | info=info, | |
| 204 | order=order, | |
| 205 | introspectables=introspectables, | |
| 206 | ) | |
| 207 | ) | |
| 208 | self.actions.append(action) | |
| 209 | ||
| 210 | def execute_actions(self, clear=True, introspector=None): | |
| 211 | """Execute the configuration actions | |
| 212 | ||
| 213 | This calls the action callables after resolving conflicts | |
| 214 | ||
| 215 | For example: | |
| 216 | ||
| 217 | >>> output = [] | |
| 218 | >>> def f(*a, **k): | |
| 219 | ... output.append(('f', a, k)) | |
| 220 | >>> context = ActionState() | |
| 221 | >>> context.actions = [ | |
| 222 | ... (1, f, (1,)), | |
| 223 | ... (1, f, (11,), {}, ('x', )), | |
| 224 | ... (2, f, (2,)), | |
| 225 | ... ] | |
| 226 | >>> context.execute_actions() | |
| 227 | >>> output | |
| 228 | [('f', (1,), {}), ('f', (2,), {})] | |
| 229 | ||
| 230 | If the action raises an error, we convert it to a | |
| 231 | ConfigurationExecutionError. | |
| 232 | ||
| 233 | >>> output = [] | |
| 234 | >>> def bad(): | |
| 235 | ... bad.xxx | |
| 236 | >>> context.actions = [ | |
| 237 | ... (1, f, (1,)), | |
| 238 | ... (1, f, (11,), {}, ('x', )), | |
| 239 | ... (2, f, (2,)), | |
| 240 | ... (3, bad, (), {}, (), 'oops') | |
| 241 | ... ] | |
| 242 | >>> try: | |
| 243 | ... v = context.execute_actions() | |
| 244 | ... except ConfigurationExecutionError, v: | |
| 245 | ... pass | |
| 246 | >>> print(v) | |
| 247 | exceptions.AttributeError: 'function' object has no attribute 'xxx' | |
| 248 | in: | |
| 249 | oops | |
| 250 | ||
| 251 | Note that actions executed before the error still have an effect: | |
| 252 | ||
| 253 | >>> output | |
| 254 | [('f', (1,), {}), ('f', (2,), {})] | |
| 255 | ||
| 256 | The execution is re-entrant such that actions may be added by other | |
| 257 | actions with the one caveat that the order of any added actions must | |
| 258 | be equal to or larger than the current action. | |
| 259 | ||
| 260 | >>> output = [] | |
| 261 | >>> def f(*a, **k): | |
| 262 | ... output.append(('f', a, k)) | |
| 263 | ... context.actions.append((3, g, (8,), {})) | |
| 264 | >>> def g(*a, **k): | |
| 265 | ... output.append(('g', a, k)) | |
| 266 | >>> context.actions = [ | |
| 267 | ... (1, f, (1,)), | |
| 268 | ... ] | |
| 269 | >>> context.execute_actions() | |
| 270 | >>> output | |
| 271 | [('f', (1,), {}), ('g', (8,), {})] | |
| 272 | ||
| 273 | """ | |
| 274 | try: | |
| 275 | all_actions = [] | |
| 276 | executed_actions = [] | |
| 277 | action_iter = iter([]) | |
| 278 | conflict_state = ConflictResolverState() | |
| 279 | ||
| 280 | while True: | |
| 281 | # We clear the actions list prior to execution so if there | |
| 282 | # are some new actions then we add them to the mix and resolve | |
| 283 | # conflicts again. This orders the new actions as well as | |
| 284 | # ensures that the previously executed actions have no new | |
| 285 | # conflicts. | |
| 286 | if self.actions: | |
| 287 | all_actions.extend(self.actions) | |
| 288 | action_iter = resolveConflicts( | |
| 289 | self.actions, state=conflict_state | |
| 290 | ) | |
| 291 | self.actions = [] | |
| 292 | ||
| 293 | action = next(action_iter, None) | |
| 294 | if action is None: | |
| 295 | # we are done! | |
| 296 | break | |
| 297 | ||
| 298 | callable = action['callable'] | |
| 299 | args = action['args'] | |
| 300 | kw = action['kw'] | |
| 301 | info = action['info'] | |
| 302 | # we use "get" below in case an action was added via a ZCML | |
| 303 | # directive that did not know about introspectables | |
| 304 | introspectables = action.get('introspectables', ()) | |
| 305 | ||
| 306 | try: | |
| 307 | if callable is not None: | |
| 308 | callable(*args, **kw) | |
| 309 | except Exception: | |
| 310 | t, v, tb = sys.exc_info() | |
| 311 | try: | |
| 312 | reraise( | |
| 313 | ConfigurationExecutionError, | |
| 314 | ConfigurationExecutionError(t, v, info), | |
| 315 | tb, | |
| 316 | ) | |
| 317 | finally: | |
| 318 | del t, v, tb | |
| 319 | ||
| 320 | if introspector is not None: | |
| 321 | for introspectable in introspectables: | |
| 322 | introspectable.register(introspector, info) | |
| 323 | ||
| 324 | executed_actions.append(action) | |
| 325 | ||
| 326 | self.actions = all_actions | |
| 327 | return executed_actions | |
| 328 | ||
| 329 | finally: | |
| 330 | if clear: | |
| 331 | self.actions = [] | |
| 332 | ||
| 333 | ||
| 334 | class ConflictResolverState(object): | |
| 335 | def __init__(self): | |
| 336 | # keep a set of resolved discriminators to test against to ensure | |
| 337 | # that a new action does not conflict with something already executed | |
| 338 | self.resolved_ainfos = {} | |
| 339 | ||
| 340 | # actions left over from a previous iteration | |
| 341 | self.remaining_actions = [] | |
| 342 | ||
| 343 | # after executing an action we memoize its order to avoid any new | |
| 344 | # actions sending us backward | |
| 345 | self.min_order = None | |
| 346 | ||
| 347 | # unique tracks the index of the action so we need it to increase | |
| 348 | # monotonically across invocations to resolveConflicts | |
| 349 | self.start = 0 | |
| 350 | ||
| 351 | ||
| 352 | # this function is licensed under the ZPL (stolen from Zope) | |
| 353 | def resolveConflicts(actions, state=None): | |
| 354 | """Resolve conflicting actions | |
| 355 | ||
| 356 | Given an actions list, identify and try to resolve conflicting actions. | |
| 357 | Actions conflict if they have the same non-None discriminator. | |
| 358 | ||
| 359 | Conflicting actions can be resolved if the include path of one of | |
| 360 | the actions is a prefix of the includepaths of the other | |
| 361 | conflicting actions and is unequal to the include paths in the | |
| 362 | other conflicting actions. | |
| 363 | ||
| 364 | Actions are resolved on a per-order basis because some discriminators | |
| 365 | cannot be computed until earlier actions have executed. An action in an | |
| 366 | earlier order may execute successfully only to find out later that it was | |
| 367 | overridden by another action with a smaller include path. This will result | |
| 368 | in a conflict as there is no way to revert the original action. | |
| 369 | ||
| 370 | ``state`` may be an instance of ``ConflictResolverState`` that | |
| 371 | can be used to resume execution and resolve the new actions against the | |
| 372 | list of executed actions from a previous call. | |
| 373 | ||
| 374 | """ | |
| 375 | if state is None: | |
| 376 | state = ConflictResolverState() | |
| 377 | ||
| 378 | # pick up where we left off last time, but track the new actions as well | |
| 379 | state.remaining_actions.extend(normalize_actions(actions)) | |
| 380 | actions = state.remaining_actions | |
| 381 | ||
| 382 | def orderandpos(v): | |
| 383 | n, v = v | |
| 384 | return (v['order'] or 0, n) | |
| 385 | ||
| 386 | def orderonly(v): | |
| 387 | n, v = v | |
| 388 | return v['order'] or 0 | |
| 389 | ||
| 390 | sactions = sorted(enumerate(actions, start=state.start), key=orderandpos) | |
| 391 | for order, actiongroup in itertools.groupby(sactions, orderonly): | |
| 392 | # "order" is an integer grouping. Actions in a lower order will be | |
| 393 | # executed before actions in a higher order. All of the actions in | |
| 394 | # one grouping will be executed (its callable, if any will be called) | |
| 395 | # before any of the actions in the next. | |
| 396 | output = [] | |
| 397 | unique = {} | |
| 398 | ||
| 399 | # error out if we went backward in order | |
| 400 | if state.min_order is not None and order < state.min_order: | |
| 401 | r = [ | |
| 402 | 'Actions were added to order={0} after execution had moved ' | |
| 403 | 'on to order={1}. Conflicting actions: '.format( | |
| 404 | order, state.min_order | |
| 405 | ) | |
| 406 | ] | |
| 407 | for i, action in actiongroup: | |
| 408 | for line in str(action['info']).rstrip().split('\n'): | |
| 409 | r.append(" " + line) | |
| 410 | raise ConfigurationError('\n'.join(r)) | |
| 411 | ||
| 412 | for i, action in actiongroup: | |
| 413 | # Within an order, actions are executed sequentially based on | |
| 414 | # original action ordering ("i"). | |
| 415 | ||
| 416 | # "ainfo" is a tuple of (i, action) where "i" is an integer | |
| 417 | # expressing the relative position of this action in the action | |
| 418 | # list being resolved, and "action" is an action dictionary. The | |
| 419 | # purpose of an ainfo is to associate an "i" with a particular | |
| 420 | # action; "i" exists for sorting after conflict resolution. | |
| 421 | ainfo = (i, action) | |
| 422 | ||
| 423 | # wait to defer discriminators until we are on their order because | |
| 424 | # the discriminator may depend on state from a previous order | |
| 425 | discriminator = undefer(action['discriminator']) | |
| 426 | action['discriminator'] = discriminator | |
| 427 | ||
| 428 | if discriminator is None: | |
| 429 | # The discriminator is None, so this action can never conflict. | |
| 430 | # We can add it directly to the result. | |
| 431 | output.append(ainfo) | |
| 432 | continue | |
| 433 | ||
| 434 | L = unique.setdefault(discriminator, []) | |
| 435 | L.append(ainfo) | |
| 436 | ||
| 437 | # Check for conflicts | |
| 438 | conflicts = {} | |
| 439 | for discriminator, ainfos in unique.items(): | |
| 440 | # We use (includepath, i) as a sort key because we need to | |
| 441 | # sort the actions by the paths so that the shortest path with a | |
| 442 | # given prefix comes first. The "first" action is the one with the | |
| 443 | # shortest include path. We break sorting ties using "i". | |
| 444 | def bypath(ainfo): | |
| 445 | path, i = ainfo[1]['includepath'], ainfo[0] | |
| 446 | return path, order, i | |
| 447 | ||
| 448 | ainfos.sort(key=bypath) | |
| 449 | ainfo, rest = ainfos[0], ainfos[1:] | |
| 450 | _, action = ainfo | |
| 451 | ||
| 452 | # ensure this new action does not conflict with a previously | |
| 453 | # resolved action from an earlier order / invocation | |
| 454 | prev_ainfo = state.resolved_ainfos.get(discriminator) | |
| 455 | if prev_ainfo is not None: | |
| 456 | _, paction = prev_ainfo | |
| 457 | basepath, baseinfo = paction['includepath'], paction['info'] | |
| 458 | includepath = action['includepath'] | |
| 459 | # if the new action conflicts with the resolved action then | |
| 460 | # note the conflict, otherwise drop the action as it's | |
| 461 | # effectively overriden by the previous action | |
| 462 | if ( | |
| 463 | includepath[: len(basepath)] != basepath | |
| 464 | or includepath == basepath | |
| 465 | ): | |
| 466 | L = conflicts.setdefault(discriminator, [baseinfo]) | |
| 467 | L.append(action['info']) | |
| 468 | ||
| 469 | else: | |
| 470 | output.append(ainfo) | |
| 471 | ||
| 472 | basepath, baseinfo = action['includepath'], action['info'] | |
| 473 | for _, action in rest: | |
| 474 | includepath = action['includepath'] | |
| 475 | # Test whether path is a prefix of opath | |
| 476 | if ( | |
| 477 | includepath[: len(basepath)] != basepath | |
| 478 | or includepath == basepath # not a prefix | |
| 479 | ): | |
| 480 | L = conflicts.setdefault(discriminator, [baseinfo]) | |
| 481 | L.append(action['info']) | |
| 482 | ||
| 483 | if conflicts: | |
| 484 | raise ConfigurationConflictError(conflicts) | |
| 485 | ||
| 486 | # sort resolved actions by "i" and yield them one by one | |
| 487 | for i, action in sorted(output, key=operator.itemgetter(0)): | |
| 488 | # do not memoize the order until we resolve an action inside it | |
| 489 | state.min_order = action['order'] | |
| 490 | state.start = i + 1 | |
| 491 | state.remaining_actions.remove(action) | |
| 492 | state.resolved_ainfos[action['discriminator']] = (i, action) | |
| 493 | yield action | |
| 494 | ||
| 495 | ||
| 496 | def normalize_actions(actions): | |
| 497 | """Convert old-style tuple actions to new-style dicts.""" | |
| 498 | result = [] | |
| 499 | for v in actions: | |
| 500 | if not isinstance(v, dict): | |
| 501 | v = expand_action_tuple(*v) | |
| 502 | result.append(v) | |
| 503 | return result | |
| 504 | ||
| 505 | ||
| 506 | def expand_action_tuple( | |
| 507 | discriminator, | |
| 508 | callable=None, | |
| 509 | args=(), | |
| 510 | kw=None, | |
| 511 | includepath=(), | |
| 512 | info=None, | |
| 513 | order=0, | |
| 514 | introspectables=(), | |
| 515 | ): | |
| 516 | if kw is None: | |
| 517 | kw = {} | |
| 518 | return dict( | |
| 519 | discriminator=discriminator, | |
| 520 | callable=callable, | |
| 521 | args=args, | |
| 522 | kw=kw, | |
| 523 | includepath=includepath, | |
| 524 | info=info, | |
| 525 | order=order, | |
| 526 | introspectables=introspectables, | |
| 527 | ) | |
| d579f2 | 528 | |
| MM | 529 | |
| 530 | @implementer(IActionInfo) | |
| 531 | class ActionInfo(object): | |
| 532 | def __init__(self, file, line, function, src): | |
| 533 | self.file = file | |
| 534 | self.line = line | |
| 535 | self.function = function | |
| 536 | self.src = src | |
| 537 | ||
| 538 | def __str__(self): | |
| 539 | srclines = self.src.split('\n') | |
| 540 | src = '\n'.join(' %s' % x for x in srclines) | |
| 541 | return 'Line %s of file %s:\n%s' % (self.line, self.file, src) | |
| 542 | ||
| 543 | ||
| 544 | def action_method(wrapped): | |
| 545 | """ Wrapper to provide the right conflict info report data when a method | |
| 546 | that calls Configurator.action calls another that does the same. Not a | |
| 547 | documented API but used by some external systems.""" | |
| 548 | ||
| 549 | def wrapper(self, *arg, **kw): | |
| 550 | if self._ainfo is None: | |
| 551 | self._ainfo = [] | |
| 552 | info = kw.pop('_info', None) | |
| 553 | # backframes for outer decorators to actionmethods | |
| 554 | backframes = kw.pop('_backframes', 0) + 2 | |
| 555 | if is_nonstr_iter(info) and len(info) == 4: | |
| 556 | # _info permitted as extract_stack tuple | |
| 557 | info = ActionInfo(*info) | |
| 558 | if info is None: | |
| 559 | try: | |
| 560 | f = traceback.extract_stack(limit=4) | |
| 561 | ||
| 562 | # Work around a Python 3.5 issue whereby it would insert an | |
| 563 | # extra stack frame. This should no longer be necessary in | |
| 564 | # Python 3.5.1 | |
| 565 | last_frame = ActionInfo(*f[-1]) | |
| 566 | if last_frame.function == 'extract_stack': # pragma: no cover | |
| 567 | f.pop() | |
| 568 | info = ActionInfo(*f[-backframes]) | |
| 569 | except Exception: # pragma: no cover | |
| 570 | info = ActionInfo(None, 0, '', '') | |
| 571 | self._ainfo.append(info) | |
| 572 | try: | |
| 573 | result = wrapped(self, *arg, **kw) | |
| 574 | finally: | |
| 575 | self._ainfo.pop() | |
| 576 | return result | |
| 577 | ||
| 578 | if hasattr(wrapped, '__name__'): | |
| 579 | functools.update_wrapper(wrapper, wrapped) | |
| 580 | wrapper.__docobj__ = wrapped | |
| 581 | return wrapper | |
