import itertools from collections import defaultdict from django.contrib.contenttypes.fields import GenericForeignKey from django.contrib.contenttypes.models import ContentType from django.core.exceptions import ValidationError from django.db import models from django.db.models import Sum from django.dispatch import Signal from django.urls import reverse from dcim.choices import * from dcim.constants import * from dcim.fields import PathField from dcim.utils import decompile_path_node, object_to_path_node, path_node_to_object from netbox.models import NetBoxModel from utilities.fields import ColorField from utilities.querysets import RestrictedQuerySet from utilities.utils import to_meters from wireless.models import WirelessLink from .device_components import FrontPort, RearPort __all__ = ( 'Cable', 'CablePath', 'CableTermination', ) trace_paths = Signal() # # Cables # class Cable(NetBoxModel): """ A physical connection between two endpoints. """ type = models.CharField( max_length=50, choices=CableTypeChoices, blank=True ) status = models.CharField( max_length=50, choices=LinkStatusChoices, default=LinkStatusChoices.STATUS_CONNECTED ) tenant = models.ForeignKey( to='tenancy.Tenant', on_delete=models.PROTECT, related_name='cables', blank=True, null=True ) label = models.CharField( max_length=100, blank=True ) color = ColorField( blank=True ) length = models.DecimalField( max_digits=8, decimal_places=2, blank=True, null=True ) length_unit = models.CharField( max_length=50, choices=CableLengthUnitChoices, blank=True, ) # Stores the normalized length (in meters) for database ordering _abs_length = models.DecimalField( max_digits=10, decimal_places=4, blank=True, null=True ) class Meta: ordering = ('pk',) def __init__(self, *args, a_terminations=None, b_terminations=None, **kwargs): super().__init__(*args, **kwargs) # A copy of the PK to be used by __str__ in case the object is deleted self._pk = self.pk # Cache the original status so we can check later if it's been changed self._orig_status = self.status self._terminations_modified = False # Assign or retrieve A/B terminations if a_terminations: self.a_terminations = a_terminations if b_terminations: self.b_terminations = b_terminations def __str__(self): pk = self.pk or self._pk return self.label or f'#{pk}' def get_absolute_url(self): return reverse('dcim:cable', args=[self.pk]) @property def a_terminations(self): if hasattr(self, '_a_terminations'): return self._a_terminations # Query self.terminations.all() to leverage cached results return [ ct.termination for ct in self.terminations.all() if ct.cable_end == CableEndChoices.SIDE_A ] @a_terminations.setter def a_terminations(self, value): self._terminations_modified = True self._a_terminations = value @property def b_terminations(self): if hasattr(self, '_b_terminations'): return self._b_terminations # Query self.terminations.all() to leverage cached results return [ ct.termination for ct in self.terminations.all() if ct.cable_end == CableEndChoices.SIDE_B ] @b_terminations.setter def b_terminations(self, value): self._terminations_modified = True self._b_terminations = value def clean(self): super().clean() # Validate length and length_unit if self.length is not None and not self.length_unit: raise ValidationError("Must specify a unit when setting a cable length") elif self.length is None: self.length_unit = '' if self.pk is None and (not self.a_terminations or not self.b_terminations): raise ValidationError("Must define A and B terminations when creating a new cable.") if self._terminations_modified: # Check that all termination objects for either end are of the same type for terms in (self.a_terminations, self.b_terminations): if len(terms) > 1 and not all(isinstance(t, type(terms[0])) for t in terms[1:]): raise ValidationError("Cannot connect different termination types to same end of cable.") # Check that termination types are compatible if self.a_terminations and self.b_terminations: a_type = self.a_terminations[0]._meta.model_name b_type = self.b_terminations[0]._meta.model_name if b_type not in COMPATIBLE_TERMINATION_TYPES.get(a_type): raise ValidationError(f"Incompatible termination types: {a_type} and {b_type}") # Run clean() on any new CableTerminations for termination in self.a_terminations: CableTermination(cable=self, cable_end='A', termination=termination).clean() for termination in self.b_terminations: CableTermination(cable=self, cable_end='B', termination=termination).clean() def save(self, *args, **kwargs): _created = self.pk is None # Store the given length (if any) in meters for use in database ordering if self.length and self.length_unit: self._abs_length = to_meters(self.length, self.length_unit) else: self._abs_length = None super().save(*args, **kwargs) # Update the private pk used in __str__ in case this is a new object (i.e. just got its pk) self._pk = self.pk # Retrieve existing A/B terminations for the Cable a_terminations = {ct.termination: ct for ct in self.terminations.filter(cable_end='A')} b_terminations = {ct.termination: ct for ct in self.terminations.filter(cable_end='B')} # Delete stale CableTerminations if self._terminations_modified: for termination, ct in a_terminations.items(): if termination.pk and termination not in self.a_terminations: ct.delete() for termination, ct in b_terminations.items(): if termination.pk and termination not in self.b_terminations: ct.delete() # Save new CableTerminations (if any) if self._terminations_modified: for termination in self.a_terminations: if not termination.pk or termination not in a_terminations: CableTermination(cable=self, cable_end='A', termination=termination).save() for termination in self.b_terminations: if not termination.pk or termination not in b_terminations: CableTermination(cable=self, cable_end='B', termination=termination).save() trace_paths.send(Cable, instance=self, created=_created) def get_status_color(self): return LinkStatusChoices.colors.get(self.status) class CableTermination(models.Model): """ A mapping between side A or B of a Cable and a terminating object (e.g. an Interface or CircuitTermination). """ cable = models.ForeignKey( to='dcim.Cable', on_delete=models.CASCADE, related_name='terminations' ) cable_end = models.CharField( max_length=1, choices=CableEndChoices, verbose_name='End' ) termination_type = models.ForeignKey( to=ContentType, limit_choices_to=CABLE_TERMINATION_MODELS, on_delete=models.PROTECT, related_name='+' ) termination_id = models.PositiveBigIntegerField() termination = GenericForeignKey( ct_field='termination_type', fk_field='termination_id' ) # Cached associations to enable efficient filtering _device = models.ForeignKey( to='dcim.Device', on_delete=models.CASCADE, blank=True, null=True ) _rack = models.ForeignKey( to='dcim.Rack', on_delete=models.CASCADE, blank=True, null=True ) _location = models.ForeignKey( to='dcim.Location', on_delete=models.CASCADE, blank=True, null=True ) _site = models.ForeignKey( to='dcim.Site', on_delete=models.CASCADE, blank=True, null=True ) objects = RestrictedQuerySet.as_manager() class Meta: ordering = ('cable', 'cable_end', 'pk') constraints = ( models.UniqueConstraint( fields=('termination_type', 'termination_id'), name='dcim_cable_termination_unique_termination' ), ) def __str__(self): return f'Cable {self.cable} to {self.termination}' def clean(self): super().clean() # Check for existing termination existing_termination = CableTermination.objects.exclude(cable=self.cable).filter( termination_type=self.termination_type, termination_id=self.termination_id ).first() if existing_termination is not None: raise ValidationError( f"Duplicate termination found for {self.termination_type.app_label}.{self.termination_type.model} " f"{self.termination_id}: cable {existing_termination.cable.pk}" ) # Validate interface type (if applicable) if self.termination_type.model == 'interface' and self.termination.type in NONCONNECTABLE_IFACE_TYPES: raise ValidationError(f"Cables cannot be terminated to {self.termination.get_type_display()} interfaces") # A CircuitTermination attached to a ProviderNetwork cannot have a Cable if self.termination_type.model == 'circuittermination' and self.termination.provider_network is not None: raise ValidationError("Circuit terminations attached to a provider network may not be cabled.") def save(self, *args, **kwargs): # Cache objects associated with the terminating object (for filtering) self.cache_related_objects() super().save(*args, **kwargs) # Set the cable on the terminating object termination_model = self.termination._meta.model termination_model.objects.filter(pk=self.termination_id).update( cable=self.cable, cable_end=self.cable_end ) def delete(self, *args, **kwargs): # Delete the cable association on the terminating object termination_model = self.termination._meta.model termination_model.objects.filter(pk=self.termination_id).update( cable=None, cable_end='' ) super().delete(*args, **kwargs) def cache_related_objects(self): """ Cache objects related to the termination (e.g. device, rack, site) directly on the object to enable efficient filtering. """ assert self.termination is not None # Device components if getattr(self.termination, 'device', None): self._device = self.termination.device self._rack = self.termination.device.rack self._location = self.termination.device.location self._site = self.termination.device.site # Power feeds elif getattr(self.termination, 'rack', None): self._rack = self.termination.rack self._location = self.termination.rack.location self._site = self.termination.rack.site # Circuit terminations elif getattr(self.termination, 'site', None): self._site = self.termination.site class CablePath(models.Model): """ A CablePath instance represents the physical path from a set of origin nodes to a set of destination nodes, including all intermediate elements. `path` contains the ordered set of nodes, arranged in lists of (type, ID) tuples. (Each cable in the path can terminate to one or more objects.) For example, consider the following topology: A B C Interface 1 --- Front Port 1 | Rear Port 1 --- Rear Port 2 | Front Port 3 --- Interface 2 Front Port 2 Front Port 4 This path would be expressed as: CablePath( path = [ [Interface 1], [Cable A], [Front Port 1, Front Port 2], [Rear Port 1], [Cable B], [Rear Port 2], [Front Port 3, Front Port 4], [Cable C], [Interface 2], ] ) `is_active` is set to True only if every Cable within the path has a status of "connected". `is_complete` is True if the instance represents a complete end-to-end path from origin(s) to destination(s). `is_split` is True if the path diverges across multiple cables. `_nodes` retains a flattened list of all nodes within the path to enable simple filtering. """ path = models.JSONField( default=list ) is_active = models.BooleanField( default=False ) is_complete = models.BooleanField( default=False ) is_split = models.BooleanField( default=False ) _nodes = PathField() def __str__(self): return f"Path #{self.pk}: {len(self.path)} hops" def save(self, *args, **kwargs): # Save the flattened nodes list self._nodes = list(itertools.chain(*self.path)) super().save(*args, **kwargs) # Record a direct reference to this CablePath on its originating object(s) origin_model = self.origin_type.model_class() origin_ids = [decompile_path_node(node)[1] for node in self.path[0]] origin_model.objects.filter(pk__in=origin_ids).update(_path=self.pk) @property def origin_type(self): if self.path: ct_id, _ = decompile_path_node(self.path[0][0]) return ContentType.objects.get_for_id(ct_id) @property def destination_type(self): if self.is_complete: ct_id, _ = decompile_path_node(self.path[-1][0]) return ContentType.objects.get_for_id(ct_id) @property def path_objects(self): """ Cache and return the complete path as lists of objects, derived from their annotation within the path. """ if not hasattr(self, '_path_objects'): self._path_objects = self._get_path() return self._path_objects @property def origins(self): """ Return the list of originating objects. """ return self.path_objects[0] @property def destinations(self): """ Return the list of destination objects, if the path is complete. """ if not self.is_complete: return [] return self.path_objects[-1] @property def segment_count(self): return int(len(self.path) / 3) @classmethod def from_origin(cls, terminations): """ Create a new CablePath instance as traced from the given termination objects. These can be any object to which a Cable or WirelessLink connects (interfaces, console ports, circuit termination, etc.). All terminations must be of the same type and must belong to the same parent object. """ from circuits.models import CircuitTermination if not terminations: return None # Ensure all originating terminations are attached to the same link if len(terminations) > 1: assert all(t.link == terminations[0].link for t in terminations[1:]) path = [] position_stack = [] is_complete = False is_active = True is_split = False while terminations: # Terminations must all be of the same type assert all(isinstance(t, type(terminations[0])) for t in terminations[1:]) # Check for a split path (e.g. rear port fanning out to multiple front ports with # different cables attached) if len(set(t.link for t in terminations)) > 1: is_split = True break # Step 1: Record the near-end termination object(s) path.append([ object_to_path_node(t) for t in terminations ]) # Step 2: Determine the attached link (Cable or WirelessLink), if any link = terminations[0].link if link is None and len(path) == 1: # If this is the start of the path and no link exists, return None return None elif link is None: # Otherwise, halt the trace if no link exists break assert type(link) in (Cable, WirelessLink) # Step 3: Record the link and update path status if not "connected" path.append([object_to_path_node(link)]) if hasattr(link, 'status') and link.status != LinkStatusChoices.STATUS_CONNECTED: is_active = False # Step 4: Determine the far-end terminations if isinstance(link, Cable): termination_type = ContentType.objects.get_for_model(terminations[0]) local_cable_terminations = CableTermination.objects.filter( termination_type=termination_type, termination_id__in=[t.pk for t in terminations] ) # Terminations must all belong to same end of Cable local_cable_end = local_cable_terminations[0].cable_end assert all(ct.cable_end == local_cable_end for ct in local_cable_terminations[1:]) remote_cable_terminations = CableTermination.objects.filter( cable=link, cable_end='A' if local_cable_end == 'B' else 'B' ) remote_terminations = [ct.termination for ct in remote_cable_terminations] else: # WirelessLink remote_terminations = [link.interface_b] if link.interface_a is terminations[0] else [link.interface_a] # Step 5: Record the far-end termination object(s) path.append([ object_to_path_node(t) for t in remote_terminations ]) # Step 6: Determine the "next hop" terminations, if applicable if not remote_terminations: break if isinstance(remote_terminations[0], FrontPort): # Follow FrontPorts to their corresponding RearPorts rear_ports = RearPort.objects.filter( pk__in=[t.rear_port_id for t in remote_terminations] ) if len(rear_ports) > 1: assert all(rp.positions == 1 for rp in rear_ports) elif rear_ports[0].positions > 1: position_stack.append([fp.rear_port_position for fp in remote_terminations]) terminations = rear_ports elif isinstance(remote_terminations[0], RearPort): if len(remote_terminations) > 1 or remote_terminations[0].positions == 1: front_ports = FrontPort.objects.filter( rear_port_id__in=[rp.pk for rp in remote_terminations], rear_port_position=1 ) elif position_stack: front_ports = FrontPort.objects.filter( rear_port_id=remote_terminations[0].pk, rear_port_position__in=position_stack.pop() ) else: # No position indicated: path has split, so we stop at the RearPorts is_split = True break terminations = front_ports elif isinstance(remote_terminations[0], CircuitTermination): # Follow a CircuitTermination to its corresponding CircuitTermination (A to Z or vice versa) term_side = remote_terminations[0].term_side assert all(ct.term_side == term_side for ct in remote_terminations[1:]) circuit_termination = CircuitTermination.objects.filter( circuit=remote_terminations[0].circuit, term_side='Z' if term_side == 'A' else 'A' ).first() if circuit_termination is None: break elif circuit_termination.provider_network: # Circuit terminates to a ProviderNetwork path.extend([ [object_to_path_node(circuit_termination)], [object_to_path_node(circuit_termination.provider_network)], ]) is_complete = True break elif circuit_termination.site and not circuit_termination.cable: # Circuit terminates to a Site path.extend([ [object_to_path_node(circuit_termination)], [object_to_path_node(circuit_termination.site)], ]) break terminations = [circuit_termination] # Anything else marks the end of the path else: is_complete = True break return cls( path=path, is_complete=is_complete, is_active=is_active, is_split=is_split ) def retrace(self): """ Retrace the path from the currently-defined originating termination(s) """ _new = self.from_origin(self.origins) if _new: self.path = _new.path self.is_complete = _new.is_complete self.is_active = _new.is_active self.is_split = _new.is_split self.save() else: self.delete() def _get_path(self): """ Return the path as a list of prefetched objects. """ # Compile a list of IDs to prefetch for each type of model in the path to_prefetch = defaultdict(list) for node in self._nodes: ct_id, object_id = decompile_path_node(node) to_prefetch[ct_id].append(object_id) # Prefetch path objects using one query per model type. Prefetch related devices where appropriate. prefetched = {} for ct_id, object_ids in to_prefetch.items(): model_class = ContentType.objects.get_for_id(ct_id).model_class() queryset = model_class.objects.filter(pk__in=object_ids) if hasattr(model_class, 'device'): queryset = queryset.prefetch_related('device') prefetched[ct_id] = { obj.id: obj for obj in queryset } # Replicate the path using the prefetched objects. path = [] for step in self.path: nodes = [] for node in step: ct_id, object_id = decompile_path_node(node) try: nodes.append(prefetched[ct_id][object_id]) except KeyError: # Ignore stale (deleted) object IDs pass path.append(nodes) return path def get_cable_ids(self): """ Return all Cable IDs within the path. """ cable_ct = ContentType.objects.get_for_model(Cable).pk cable_ids = [] for node in self._nodes: ct, id = decompile_path_node(node) if ct == cable_ct: cable_ids.append(id) return cable_ids def get_total_length(self): """ Return a tuple containing the sum of the length of each cable in the path and a flag indicating whether the length is definitive. """ cable_ids = self.get_cable_ids() cables = Cable.objects.filter(id__in=cable_ids, _abs_length__isnull=False) total_length = cables.aggregate(total=Sum('_abs_length'))['total'] is_definitive = len(cables) == len(cable_ids) return total_length, is_definitive def get_split_nodes(self): """ Return all available next segments in a split cable path. """ nodes = self.path_objects[-1] # RearPort splitting to multiple FrontPorts with no stack position if type(nodes[0]) is RearPort: return FrontPort.objects.filter(rear_port__in=nodes) # Cable terminating to multiple FrontPorts mapped to different # RearPorts connected to different cables elif type(nodes[0]) is FrontPort: return RearPort.objects.filter(pk__in=[fp.rear_port_id for fp in nodes])