Fixes #14241, Fixes #13922: Update the CableRender

[Moehritz]

Fixes: #14241, Fixes: #13922

This commit updates the cable rendering logic to fix both issue #14241 and #13922. Before, objects, terminations and cables where drawn in the svg without context of each other.
Now the following changes are applied:

• Hosts and Terminations are where possible sorted alphabetically
• Terminations and Cables are visually connected, and if necessary not in a vertical line
• Terminations and Hosts are visually aligning
• Cable Tooltips contain more information

Before:

After:

[DanSheps]

I am going to test this and let you know if I come across anything. For now, see my comments below but you can wait until Jeremy pipes in as to whether he wants to take action on those.

This is similar to what I was going to do, but not exactly. Definintely seems like a workable solution though.

[DanSheps]

Traceback (most recent call last):
  File "C:\Development\netbox\venv\lib\site-packages\django\core\handlers\exception.py", line 55, in inner
    response = get_response(request)
  File "C:\Development\netbox\venv\lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Development\netbox\venv\lib\site-packages\django\views\decorators\csrf.py", line 56, in wrapper_view
    return view_func(*args, **kwargs)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\viewsets.py", line 125, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:\Development\netbox\netbox\netbox\netbox\api\viewsets\__init__.py", line 93, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
    raise exc
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "C:\Development\netbox\netbox\netbox\dcim\api\views.py", line 60, in trace
    return HttpResponse(drawing.render().tostring(), content_type='image/svg+xml')
  File "C:\Development\netbox\netbox\netbox\dcim\svg\cables.py", line 405, in render
    start = near[0].bottom_center
IndexError: list index out of range

Repro:

1. Create device
2. Create interfaces (2)
3. Create device
4. Create Rear Ports (2, 1 position)
5. Create Front Ports (2)
6. Connect Int1 to FP1
7. Connect RP1 to RP2
8. Connect FP2 to Int2

This is also reproducable with going through a "proper" panel system (Switch 1 --> Panel 1 --> Panel 2 --> Switch 2

[Moehritz]

Traceback (most recent call last):
  File "C:\Development\netbox\venv\lib\site-packages\django\core\handlers\exception.py", line 55, in inner
    response = get_response(request)
  File "C:\Development\netbox\venv\lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Development\netbox\venv\lib\site-packages\django\views\decorators\csrf.py", line 56, in wrapper_view
    return view_func(*args, **kwargs)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\viewsets.py", line 125, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:\Development\netbox\netbox\netbox\netbox\api\viewsets\__init__.py", line 93, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
    raise exc
  File "C:\Development\netbox\venv\lib\site-packages\rest_framework\views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "C:\Development\netbox\netbox\netbox\dcim\api\views.py", line 60, in trace
    return HttpResponse(drawing.render().tostring(), content_type='image/svg+xml')
  File "C:\Development\netbox\netbox\netbox\dcim\svg\cables.py", line 405, in render
    start = near[0].bottom_center
IndexError: list index out of range

Repro:

1. Create device
2. Create interfaces (2)
3. Create device
4. Create Rear Ports (2, 1 position)
5. Create Front Ports (2)
6. Connect Int1 to FP1
7. Connect RP1 to RP2
8. Connect FP2 to Int2

This is also reproducable with going through a "proper" panel system (Switch 1 --> Panel 1 --> Panel 2 --> Switch 2

This happened due to a_terminations containing the far end and vice-versa.
I did not anticipate this - and corrected for it in a kinda ugly manner (if any of the lists ists empty, redo them backwards). Not sure if there is a better way to solve it right there

[DanSheps]

This happened due to a_terminations containing the far end and vice-versa.
I did not anticipate this - and corrected for it in a kinda ugly manner (if any of the lists ists empty, redo them backwards). Not sure if there is a better way to solve it right there

There might be, I will review when I have time

[DanSheps]

All looks reasonable now to me, but I would like a second set of eyes on this.