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.urls import reverse from dcim.choices import * from dcim.constants import * from dcim.fields import PathField from dcim.utils import decompile_path_node, flatten_path, object_to_path_node, path_node_to_object from netbox.models import NetBoxModel from utilities.fields import ColorField from utilities.utils import to_meters from wireless.models import WirelessLink from .devices import Device from .device_components import FrontPort, RearPort __all__ = ( 'Cable', 'CablePath', 'CableTermination', ) # # 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 ) # Cache the associated device (where applicable) for the A and B terminations. This enables filtering of Cables by # their associated Devices. _termination_a_device = models.ForeignKey( to=Device, on_delete=models.CASCADE, related_name='+', blank=True, null=True ) _termination_b_device = models.ForeignKey( to=Device, on_delete=models.CASCADE, related_name='+', blank=True, null=True ) class Meta: ordering = ('pk',) def __init__(self, *args, 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 # Assign associated CableTerminations (if any) if terminations: assert type(terminations) is list assert self.pk is None for t in terminations: t.cable = self self.terminations = terminations else: self.terminations = [] @classmethod def from_db(cls, db, field_names, values): """ Cache the original A and B terminations of existing Cable instances for later reference inside clean(). """ instance = super().from_db(db, field_names, values) instance.terminations = CableTermination.objects.filter(cable=instance) # instance._orig_termination_a_type_id = instance.termination_a_type_id # instance._orig_termination_a_ids = instance.termination_a_ids # instance._orig_termination_b_type_id = instance.termination_b_type_id # instance._orig_termination_b_ids = instance.termination_b_ids return instance 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]) def clean(self): super().clean() # TODO: Is this validation still necessary? # # Check that two connected RearPorts have the same number of positions (if both are >1) # if isinstance(self.termination_a, RearPort) and isinstance(self.termination_b, RearPort): # if self.termination_a.positions > 1 and self.termination_b.positions > 1: # if self.termination_a.positions != self.termination_b.positions: # raise ValidationError( # f"{self.termination_a} has {self.termination_a.positions} position(s) but " # f"{self.termination_b} has {self.termination_b.positions}. " # f"Both terminations must have the same number of positions (if greater than one)." # ) # 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 = '' def save(self, *args, **kwargs): # 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 # TODO: Move to CableTermination # # Store the parent Device for the A and B terminations (if applicable) to enable filtering # if hasattr(self.termination_a[0], 'device'): # self._termination_a_device = self.termination_a[0].device # if hasattr(self.termination_b[0], 'device'): # self._termination_b_device = self.termination_b[0].device 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 def get_status_color(self): return LinkStatusChoices.colors.get(self.status) def get_a_terminations(self): return [ term.termination for term in CableTermination.objects.filter(cable=self, cable_end='A') ] def get_b_terminations(self): return [ term.termination for term in CableTermination.objects.filter(cable=self, cable_end='B') ] 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='+' ) 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' ) class Meta: ordering = ['pk'] constraints = ( models.UniqueConstraint( fields=('termination_type', 'termination_id'), name='unique_termination' ), ) def __str__(self): return f'Cable {self.cable} to {self.termination}' def clean(self): super().clean() # Validate interface type (if applicable) if self.termination_type.model == 'interface' and self.termination.type in NONCONNECTABLE_IFACE_TYPES: raise ValidationError({ 'termination': 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({ 'termination': "Circuit terminations attached to a provider network may not be cabled." }) # TODO # # A front port cannot be connected to its corresponding rear port # if ( # type_a in ['frontport', 'rearport'] and # type_b in ['frontport', 'rearport'] and # ( # getattr(self.termination_a, 'rear_port', None) == self.termination_b or # getattr(self.termination_b, 'rear_port', None) == self.termination_a # ) # ): # raise ValidationError("A front port cannot be connected to it corresponding rear port") # TODO # # Check that termination types are compatible # if type_b not in COMPATIBLE_TERMINATION_TYPES.get(type_a): # raise ValidationError( # f"Incompatible termination types: {self.termination_a_type} and {self.termination_b_type}" # ) class CablePath(models.Model): """ A CablePath instance represents the physical path from an origin to a destination, including all intermediate elements in the path. Every instance must specify an `origin`, whereas `destination` may be null (for paths which do not terminate on a PathEndpoint). `path` contains a list of nodes within the path, each represented by a tuple of (type, ID). The first element in the path must be a Cable instance, followed by a pair of pass-through ports. For example, consider the following topology: 1 2 3 Interface A --- Front Port A | Rear Port A --- Rear Port B | Front Port B --- Interface B This path would be expressed as: CablePath( origin = Interface A destination = Interface B path = [Cable 1, Front Port A, Rear Port A, Cable 2, Rear Port B, Front Port B, Cable 3] ) `is_active` is set to True only if 1) `destination` is not null, and 2) every Cable within the path has a status of "connected". """ 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() class Meta: pass def __str__(self): status = ' (active)' if self.is_active else ' (split)' if self.is_split else '' return f"Path #{self.pk}: {len(self.path)} nodes{status}" def save(self, *args, **kwargs): # Save the flattened nodes list self._nodes = flatten_path(self.path) super().save(*args, **kwargs) # Record a direct reference to this CablePath on its originating object(s) origins = [path_node_to_object(n) for n in self.path[0]] origin_model = origins[0]._meta.model origin_ids = [o.id for o in origins] origin_model.objects.filter(pk__in=origin_ids).update(_path=self.pk) @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 path = [] position_stack = [] is_complete = False is_active = True is_split = False while terminations: # Terminations must all be of the same type and belong to the same parent assert all(isinstance(t, type(terminations[0])) for t in terminations[1:]) assert all(t.parent_object == terminations[0].parent_object for t in terminations[1:]) # 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 assert all(t.link == link for t in terminations[1:]) 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 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)], ]) 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([ path_node_to_object(node) for node in self.path[0] ]) 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) nodes.append(prefetched[ct_id][object_id]) path.append(nodes) return path def get_destination(self): if not self.is_complete: return None return [ path_node_to_object(node) for node in self.path[-1] ] @property def last_nodes(self): """ Return either the destination or the last node within the path. """ return [ path_node_to_object(node) for node in self.path[-1] ] 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. """ rearport = path_node_to_object(self._nodes[-1]) return FrontPort.objects.filter(rear_port=rearport)