Rendered config , jinja not fully setting values in loops

[NetworkHow]

Hello All,

I am attempting to work on configuration against a switch that does vlan ranges per interface. I am filtering through the tagged list to allow this to work and create the needed list.
This part itself works fine however it does it per line and attempting to add it to a range.

environment:
docker pull NetBox Community v4.1.6 (2024-10-31)

goal is to have output such as

interface Ethernet 1/1/1 
no shutdown 
switchport mode trunk 
switchport access vlan 101 
switchport trunk allowed vlan 1011-1014 
flowcontrol receive off 

config render jinja template, with debug drop ins:

{% for interface in device.interfaces.all() %}
{% if interface.mgmt_only == false %}
interface {{ interface.name }}
{%- if interface.enabled == false %}
 shutdown
{%- elif interface.enabled == true %}
 no shutdown
{%- endif -%}
{%- if interface.mode == "access" -%}
 switchport mode access
 switchport access vlan {{ interface.untagged_vlan.vid }}
{% elif interface.mode == "tagged" %}
 switchport mode trunk
 switchport access vlan {{ interface.untagged_vlan.vid }}
{%- set vlan_list = [] %}
{%- for vlan in interface.tagged_vlans.all() %}
{%- if vlan.vid != interface.untagged_vlan.vid %}
{%- set _ = vlan_list.append(vlan.vid) %}
{%- endif %}
{%- endfor %}
printing vlan list 
{{vlan_list}}
end of vlan list
{%- set vlan_list = vlan_list|sort %}
{%- set ranges = [] %}
{%- set start = vlan_list[0] %}
{%- set end = vlan_list[0] %}
{%- if vlan_list|length > 0 %}

{%- for i in range(1, vlan_list|length) %}
printing loop id : {{i}}
printing vlan length: {{vlan_list|length}}
printing start value: {{start}}
printing end value: {{end}}
printing vlan list id: {{vlan_list[i]}}
  {%- if vlan_list[i] == end + 1 %}
--i hit main if in vlan list, if must match {{end + 1}}, vlanid is {{vlan_list[i] }}, start is now {{start}}, end is now {{end}}, before set option

    {%- set end = vlan_list[i] %}
end is now after set {{end}}
  {%- else %}
--i hit else in vlan list, vlanid is {{vlan_list[i] }}, matching against {{end + 1}}, start is now {{start}}, end is now {{end}}, before sets
    {%- set _ = ranges.append((start, end)) %}
    {%- set start = vlan_list[i] %}
    {%- set end = vlan_list[i] %}
end is now after set {{end}}
  {%- endif %}
--
after if loop, vlanid is {{vlan_list }}, start is now {{start}}, end is now {{end}}
---
{%- endfor %}
--
after for loop, vlanid is {{vlan_list }}, range is {{ranges }}, start is now {{start}}, end is now {{end}}
---
{%- set _ = ranges.append((start, end)) %}
printing new ranges list {{ranges}}
 switchport trunk allowed vlan 
{%- for range in ranges %}
  {%- if range[0] == range[1] %}
    {{ range[0] }}
  {%- else %}
    {{ range[0] }}-{{ range[1] }}
  {%- endif %}
  {%- if not loop.last %},{% endif %}
{%- endfor %}
{%- endif %}
{%- endif %}
 flowcontrol receive off
{% endif %}
{% endfor %}

This config rendering though just loops fine but within the loop it seems to keep partly resetting itself to inital value and not keeping the 'end' value set options thoughout the loop itself.

i have changed and edited the below to differnet locations within the script but have yet to find a way to keep it.

{%- set start = vlan_list[0] %}
{%- set end = vlan_list[0] %}

below is the example rendering.

interface Ethernet 1/1/1
 no shutdown
 switchport mode trunk
 switchport access vlan 101
printing vlan list 
[1011, 1012, 1013, 1014]
end of vlan list
printing loop id : 1
printing vlan length: 4
printing start value: 1011
printing end value: 1011
printing vlan list id: 1012
--i hit main if in vlan list, if must match 1012, vlanid is 1012, start is now 1011, end is now 1011, before set option
end is now after set 1012
--
after if loop, vlanid is [1011, 1012, 1013, 1014], start is now 1011, end is now 1012
---
printing loop id : 2
printing vlan length: 4
printing start value: 1011
printing end value: 1011
printing vlan list id: 1013
--i hit else in vlan list, vlanid is 1013, matching against 1012, start is now 1011, end is now 1011, before sets
end is now after set 1013
--
after if loop, vlanid is [1011, 1012, 1013, 1014], start is now 1013, end is now 1013
---
printing loop id : 3
printing vlan length: 4
printing start value: 1011
printing end value: 1011
printing vlan list id: 1014
--i hit else in vlan list, vlanid is 1014, matching against 1012, start is now 1011, end is now 1011, before sets
end is now after set 1014
--
after if loop, vlanid is [1011, 1012, 1013, 1014], start is now 1014, end is now 1014
---
--
after for loop, vlanid is [1011, 1012, 1013, 1014], range is [(1011, 1011), (1011, 1011)], start is now 1011, end is now 1011
---
printing new ranges list [(1011, 1011), (1011, 1011), (1011, 1011)]
 switchport trunk allowed vlan
    1011,
    1011,
    1011
 flowcontrol receive off

Any ideas why it would be resetting the end variable after the loop?

[pl0xym0r]

Various ideas:

• {%- for i in range(1, vlan_list|length) %}
  printing loop id : {{i}}
  printing vlan list id: {{vlan_list[i]}}
  --> list start at 0, you should maybe use : i-1

• what happens if you have multiple discontinuous ranges ?

• should a jinja_filter (in python) reasonable?

• last and least : switchport trunk allowed vlan 1011,1012,1013,1014 ?

[NetworkHow]

the i-1 does make sense and did allow some of the outputs to show more expected values but it is now cutting off last item, believe as the inital value is set to 0 we can ignore this as loop is just comparing current to 1 already. .
added the below i-1 into it to reset all values to match the start of 0 count. This did result in the print vlan list id output in the debug to show some items that were a bit off though so matching seemed to have broken

{%- for i in range(1, vlan_list|length) %}
{%- set i= i-1 %}

i did test with stand alone and another range. new list is
[50, 400, 401, 1011, 1012, 1013, 1014]

however it still only ever uses the first value it finds in the start / end vars when setting the range values.

---
printing vlan list 
[50, 400, 401, 1011, 1012, 1013, 1014]
end of vlan list
printing loop id : 1
printing vlan length: 7
printing start value: 50
printing end value: 50
printing vlan list id: 400
--i hit else in vlan list, vlanid is 400, matching against 51, start is now 50, end is now 50, before sets, ranges is current []
end is now after set 400, ranges is current [(50, 50)]
--
after if loop, vlanid is [50, 400, 401, 1011, 1012, 1013, 1014], start is now 400, end is now 400, ranges is current [(50, 50)]
---
printing loop id : 2
printing vlan length: 7
printing start value: 50
printing end value: 50
printing vlan list id: 401
--i hit else in vlan list, vlanid is 401, matching against 51, start is now 50, end is now 50, before sets, ranges is current [(50, 50)]
end is now after set 401, ranges is current [(50, 50), (50, 50)]
--
after if loop, vlanid is [50, 400, 401, 1011, 1012, 1013, 1014], start is now 401, end is now 401, ranges is current [(50, 50), (50, 50)]
---

jinja_filter for python unsure how would implament that in this context as not really filtering said list just trying to compress it.

The issue why cannot have multiple lines is attempting to follow an intent/actual compare and using multiple lines or incorrect , that dont exactly match will result in mismatches on every port during compares.

[pl0xym0r]

jinja_filter for python unsure how would implament that in this context as not really filtering said list just trying to compress it.

you enter a data with special format and it "translates" to whatever you want --> a string in your case like "100 - 105" but you write the code in python (easier than jinja) otherwise, do a macro in jinja to do it : parse an ordered list, then "extract" to range value.
I think you could find ideas/tempaltes on internet, i don't remember if ttl255 did it.

[NetworkHow]

I was talking with someone else and confirmed Jinja does not store variables globally by default. this was the issue that was happening. This required using namespaces.
once edited vars to use ns.name the items stuck the way i was expecting.

{%- set ns = namespace(ranges=[], start=vlan_list[0], end=vlan_list[0]) %}

cleaned up code that will keep var in loops:

{% for interface in device.interfaces.all() %}
{% if interface.mgmt_only == false %}
interface {{ interface.name }}
{%- if interface.enabled == false %}
 shutdown
{%- elif interface.enabled == true %}
 no shutdown
{%- endif -%}
{%- if interface.mode == "access" -%}
 switchport mode access
 switchport access vlan {{ interface.untagged_vlan.vid }}
{% elif interface.mode == "tagged" %}
 switchport mode trunk
 switchport access vlan {{ interface.untagged_vlan.vid }}
{%- set vlan_list = [] %}
{%- for vlan in interface.tagged_vlans.all() %}
{%- if vlan.vid != interface.untagged_vlan.vid %}
{%- set _ = vlan_list.append(vlan.vid) %}
{%- endif %}
{%- endfor %}
{%- set vlan_list = vlan_list|sort %}
{%- set ns = namespace(ranges=[], start=vlan_list[0], end=vlan_list[0]) %}
{%- if vlan_list|length > 0 %}
{%- for i in range(1, vlan_list|length) %}
  {%- if vlan_list[i] == ns.end + 1 %}
    {%- set ns.end = vlan_list[i] %}
  {%- else %}
    {%- set _ = ns.ranges.append((ns.start, ns.end)) %}
    {%- set ns.start = vlan_list[i] %}
    {%- set ns.end = vlan_list[i] %}
  {%- endif %}
{%- endfor %}
{%- set _ = ns.ranges.append((ns.start, ns.end)) %}
 switchport trunk allowed vlan {% for range in ns.ranges -%}   {%- if range[0] == range[1] -%}     {{ range[0] }}   {%- else -%}     {{ range[0] }}-{{ range[1] }}   {%- endif -%}   {%- if not loop.last -%},{%- endif -%}
{%- endfor -%}
{%- endif %}
{%- endif %}
 flowcontrol receive off
{% endif %}
{% endfor %}