def resolveConflicts(actions):
"""Resolve conflicting actions
Given an actions list, identify and try to resolve conflicting actions.
Actions conflict if they have the same non-None discriminator.
Conflicting actions can be resolved if the include path of one of
the actions is a prefix of the includepaths of the other
conflicting actions and is unequal to the include paths in the
other conflicting actions.
"""
def orderandpos(v):
n, v = v
if not isinstance(v, dict):
# old-style tuple action
v = expand_action(*v)
return (v['order'] or 0, n)
sactions = sorted(enumerate(actions), key=orderandpos)
def orderonly(v):
n, v = v
if not isinstance(v, dict):
# old-style tuple action
v = expand_action(*v)
return v['order'] or 0
for order, actiongroup in itertools.groupby(sactions, orderonly):
# "order" is an integer grouping. Actions in a lower order will be
# executed before actions in a higher order. All of the actions in
# one grouping will be executed (its callable, if any will be called)
# before any of the actions in the next.
unique = {}
output = []
for i, action in actiongroup:
# Within an order, actions are executed sequentially based on
# original action ordering ("i").
if not isinstance(action, dict):
# old-style tuple action
action = expand_action(*action)
# "ainfo" is a tuple of (order, i, action) where "order" is a
# user-supplied grouping, "i" is an integer expressing the relative
# position of this action in the action list being resolved, and
# "action" is an action dictionary. The purpose of an ainfo is to
# associate an "order" and an "i" with a particular action; "order"
# and "i" exist for sorting purposes after conflict resolution.
ainfo = (order, i, action)
discriminator = undefer(action['discriminator'])
action['discriminator'] = discriminator
if discriminator is None:
# The discriminator is None, so this action can never conflict.
# We can add it directly to the result.
output.append(ainfo)
continue
L = unique.setdefault(discriminator, [])
L.append(ainfo)
# Check for conflicts
conflicts = {}
for discriminator, ainfos in unique.items():
# We use (includepath, order, i) as a sort key because we need to
# sort the actions by the paths so that the shortest path with a
# given prefix comes first. The "first" action is the one with the
# shortest include path. We break sorting ties using "order", then
# "i".
def bypath(ainfo):
path, order, i = ainfo[2]['includepath'], ainfo[0], ainfo[1]
return path, order, i
ainfos.sort(key=bypath)
ainfo, rest = ainfos[0], ainfos[1:]
output.append(ainfo)
_, _, action = ainfo
basepath, baseinfo, discriminator = (
action['includepath'],
action['info'],
action['discriminator'],
)
for _, _, action in rest:
includepath = action['includepath']
# Test whether path is a prefix of opath
if (includepath[:len(basepath)] != basepath # not a prefix
or includepath == basepath):
L = conflicts.setdefault(discriminator, [baseinfo])
L.append(action['info'])
if conflicts:
raise ConfigurationConflictError(conflicts)
# sort conflict-resolved actions by (order, i) and yield them one by one
for a in [x[2] for x in sorted(output, key=operator.itemgetter(0, 1))]:
yield a
def _makeOne(self, conflicts):
from pyramid.exceptions import ConfigurationConflictError
return ConfigurationConflictError(conflicts)
def resolveConflicts(actions, state=None):
"""Resolve conflicting actions
Given an actions list, identify and try to resolve conflicting actions.
Actions conflict if they have the same non-None discriminator.
Conflicting actions can be resolved if the include path of one of
the actions is a prefix of the includepaths of the other
conflicting actions and is unequal to the include paths in the
other conflicting actions.
Actions are resolved on a per-order basis because some discriminators
cannot be computed until earlier actions have executed. An action in an
earlier order may execute successfully only to find out later that it was
overridden by another action with a smaller include path. This will result
in a conflict as there is no way to revert the original action.
``state`` may be an instance of ``ConflictResolverState`` that
can be used to resume execution and resolve the new actions against the
list of executed actions from a previous call.
"""
if state is None:
state = ConflictResolverState()
# pick up where we left off last time, but track the new actions as well
state.remaining_actions.extend(normalize_actions(actions))
actions = state.remaining_actions
def orderandpos(v):
n, v = v
return (v['order'] or 0, n)
def orderonly(v):
n, v = v
return v['order'] or 0
sactions = sorted(enumerate(actions, start=state.start), key=orderandpos)
for order, actiongroup in itertools.groupby(sactions, orderonly):
# "order" is an integer grouping. Actions in a lower order will be
# executed before actions in a higher order. All of the actions in
# one grouping will be executed (its callable, if any will be called)
# before any of the actions in the next.
output = []
unique = {}
# error out if we went backward in order
if state.min_order is not None and order < state.min_order:
r = [
'Actions were added to order={0} after execution had moved '
'on to order={1}. Conflicting actions: '.format(
order, state.min_order)
]
for i, action in actiongroup:
for line in str(action['info']).rstrip().split('\n'):
r.append(" " + line)
raise ConfigurationError('\n'.join(r))
for i, action in actiongroup:
# Within an order, actions are executed sequentially based on
# original action ordering ("i").
# "ainfo" is a tuple of (i, action) where "i" is an integer
# expressing the relative position of this action in the action
# list being resolved, and "action" is an action dictionary. The
# purpose of an ainfo is to associate an "i" with a particular
# action; "i" exists for sorting after conflict resolution.
ainfo = (i, action)
# wait to defer discriminators until we are on their order because
# the discriminator may depend on state from a previous order
discriminator = undefer(action['discriminator'])
action['discriminator'] = discriminator
if discriminator is None:
# The discriminator is None, so this action can never conflict.
# We can add it directly to the result.
output.append(ainfo)
continue
L = unique.setdefault(discriminator, [])
L.append(ainfo)
# Check for conflicts
conflicts = {}
for discriminator, ainfos in unique.items():
# We use (includepath, i) as a sort key because we need to
# sort the actions by the paths so that the shortest path with a
# given prefix comes first. The "first" action is the one with the
# shortest include path. We break sorting ties using "i".
def bypath(ainfo):
path, i = ainfo[1]['includepath'], ainfo[0]
return path, order, i
ainfos.sort(key=bypath)
ainfo, rest = ainfos[0], ainfos[1:]
_, action = ainfo
# ensure this new action does not conflict with a previously
# resolved action from an earlier order / invocation
prev_ainfo = state.resolved_ainfos.get(discriminator)
if prev_ainfo is not None:
_, paction = prev_ainfo
basepath, baseinfo = paction['includepath'], paction['info']
includepath = action['includepath']
# if the new action conflicts with the resolved action then
# note the conflict, otherwise drop the action as it's
# effectively overriden by the previous action
if (includepath[:len(basepath)] != basepath
or includepath == basepath):
L = conflicts.setdefault(discriminator, [baseinfo])
L.append(action['info'])
else:
output.append(ainfo)
basepath, baseinfo = action['includepath'], action['info']
for _, action in rest:
includepath = action['includepath']
# Test whether path is a prefix of opath
if (includepath[:len(basepath)] != basepath
or includepath == basepath # not a prefix
):
L = conflicts.setdefault(discriminator, [baseinfo])
L.append(action['info'])
if conflicts:
raise ConfigurationConflictError(conflicts)
# sort resolved actions by "i" and yield them one by one
for i, action in sorted(output, key=operator.itemgetter(0)):
# do not memoize the order until we resolve an action inside it
state.min_order = action['order']
state.start = i + 1
state.remaining_actions.remove(action)
state.resolved_ainfos[action['discriminator']] = (i, action)
yield action
def resolveConflicts(actions):
"""Resolve conflicting actions
Given an actions list, identify and try to resolve conflicting actions.
Actions conflict if they have the same non-null discriminator.
Conflicting actions can be resolved if the include path of one of
the actions is a prefix of the includepaths of the other
conflicting actions and is unequal to the include paths in the
other conflicting actions.
Here are some examples to illustrate how this works:
>>> from zope.configmachine.tests.directives import f
>>> from pprint import PrettyPrinter
>>> pprint=PrettyPrinter(width=60).pprint
>>> pprint(resolveConflicts([
... (None, f),
... (1, f, (1,), {}, (), 'first'),
... (1, f, (2,), {}, ('x',), 'second'),
... (1, f, (3,), {}, ('y',), 'third'),
... (4, f, (4,), {}, ('y',), 'should be last', 99999),
... (3, f, (3,), {}, ('y',)),
... (None, f, (5,), {}, ('y',)),
... ]))
[(None, f),
(1, f, (1,), {}, (), 'first'),
(3, f, (3,), {}, ('y',)),
(None, f, (5,), {}, ('y',)),
(4, f, (4,), {}, ('y',), 'should be last')]
>>> try:
... v = resolveConflicts([
... (None, f),
... (1, f, (2,), {}, ('x',), 'eek'),
... (1, f, (3,), {}, ('y',), 'ack'),
... (4, f, (4,), {}, ('y',)),
... (3, f, (3,), {}, ('y',)),
... (None, f, (5,), {}, ('y',)),
... ])
... except ConfigurationConflictError, v:
... pass
>>> print v
Conflicting configuration actions
For: 1
eek
ack
"""
# organize actions by discriminators
unique = {}
output = []
for i in range(len(actions)):
(discriminator, callable, args, kw, includepath, info,
order) = expand_action(*(actions[i]))
order = order or i
if discriminator is None:
# The discriminator is None, so this directive can
# never conflict. We can add it directly to the
# configuration actions.
output.append(
(order, discriminator, callable, args, kw, includepath, info))
continue
a = unique.setdefault(discriminator, [])
a.append((includepath, order, callable, args, kw, info))
# Check for conflicts
conflicts = {}
for discriminator, dups in unique.items():
# We need to sort the actions by the paths so that the shortest
# path with a given prefix comes first:
dups.sort()
(basepath, i, callable, args, kw, baseinfo) = dups[0]
output.append(
(i, discriminator, callable, args, kw, basepath, baseinfo))
for includepath, i, callable, args, kw, info in dups[1:]:
# Test whether path is a prefix of opath
if (includepath[:len(basepath)] != basepath # not a prefix
or (includepath == basepath)):
if discriminator not in conflicts:
conflicts[discriminator] = [baseinfo]
conflicts[discriminator].append(info)
if conflicts:
raise ConfigurationConflictError(conflicts)
# Now put the output back in the original order, and return it:
output.sort()
r = []
for o in output:
action = o[1:]
while len(action) > 2 and not action[-1]:
action = action[:-1]
r.append(action)
return r