Enhancement: Value validaions

[dudu579]

Is it platform specific

generic

Importance or Severity

Critical

Description of the enhancement

SONiC 03/24/2026 meeting:
Alibaba wants value validations happen before data was transferred in SAI.

Current Behavior

To implement platform-based yang-model leaf range customization, I want to separate this requirement in three use cases:

• Static range: mgmt-framework installs debian package sonic-otn-platform-schema to deviation yang-model leaves.
• Identity/enum: Directly write sonic-mgmt-common sonic-yang.
• Dynamic range/complexed logic: Directly extended sonic-yang though sonic-ext:custom-validation.

Proposed Behavior

None.

[dudu579]

CVL Range Validation Developer Guide

1. Overview

Two ways to enforce numeric ranges on OTN CONFIG_DB leaves before they reach Redis:

Type	When to Use	Enforced By
Static range — same bounds for all deployments	e.g., target-gain-tilt has a fixed platform limit	YANG deviate replace + libyang
Dynamic range — per-instance bounds from CONFIG_DB	e.g., target-gain varies per amplifier configuration	Go custom CVL validator

---

2. Files to Create or Modify

For Static Range (YANG Deviation)

New file — write the platform range here:

device/<vendor>/<platform>/cvl-yang/sonic-otn-config-validation.yang

deviation "/sopt-amp:sonic-optical-amplifier/.../sopt-amp:target-gain-tilt" {
    deviate replace {
        type decimal64 {
            fraction-digits 2;
            range "-2.00..0.00";   // ← your platform range
        }
    }
}

At container startup, cvl-gen-yin.sh reads YANG files from /usr/share/sonic/platform/cvl-yang/ and compiles them to YINs under schema/platform/<platform_asic>/ so CVL can load them.

---

For Dynamic Range (Custom Go Validator)

Modify — add sonic-ext:custom-validation annotation to the leaf and add bound leaves:

sonic-mgmt-common/models/yang/sonic/sonic-optical-amplifier.yang

import sonic-extension { prefix sonic-ext; }   // must be in this file, not a deviation

leaf target-gain {
    type decimal64 { fraction-digits 2; }
    sonic-ext:custom-validation "ValidateOtnGain";
}
leaf min-gain {
    type decimal64 { fraction-digits 2; }
    units "dBm";
}
leaf max-gain {
    type decimal64 { fraction-digits 2; }
    units "dBm";
}

New file — implement the validator:

sonic-mgmt-common/cvl/custom_validation/otn_validations.go

The method name must exactly match the string in custom-validation "...". Read bounds from CONFIG_DB: OTN_OA|<name> (fields min-gain / max-gain). Return CVL_SUCCESS if either field is absent (permissive).

3. Testing

# Static range test (target-gain-tilt, range -2.00..0.00)
# Out-of-range → expect error
curl -k -X PATCH https://localhost/restconf/data/openconfig-optical-amplifier:optical-amplifier/amplifiers/amplifier=OA0-0/config \
  -H "Content-Type: application/yang-data+json" -u admin:PASSWORD \
  -d '{"openconfig-optical-amplifier:config": {"name": "OA0-0", "target-gain-tilt": "3.00"}}'

# In-range
curl -k -X PATCH https://localhost/restconf/data/openconfig-optical-amplifier:optical-amplifier/amplifiers/amplifier=OA0-0/config \
  -H "Content-Type: application/yang-data+json" -u admin:PASSWORD \
  -d '{"openconfig-optical-amplifier:config": {"name": "OA0-0", "target-gain-tilt": "-1.00"}}'

# Seed CONFIG_DB bounds for dynamic range
config otn-oa update OA0-0 --min-gain 15.0
config otn-oa update OA0-0 --max-gain 25.0

# Out-of-range → expect error with constraint message
curl -k -X PATCH https://localhost/restconf/data/openconfig-optical-amplifier:optical-amplifier/amplifiers/amplifier=OA0-0/config \
  -H "Content-Type: application/yang-data+json" -u admin:PASSWORD \
  -d '{"openconfig-optical-amplifier:config": {"name": "OA0-0", "target-gain": "30.00"}}'

# In-range
curl -k -X PATCH https://localhost/restconf/data/openconfig-optical-amplifier:optical-amplifier/amplifiers/amplifier=OA0-0/config \
  -H "Content-Type: application/yang-data+json" -u admin:PASSWORD \
  -d '{"openconfig-optical-amplifier:config": {"name": "OA0-0", "target-gain": "20.00"}}'

[dudu579]

@jjin62 Above are developer guide for CVL extension. Developer only needs to modify sonic-buildimage/device/molex/x86_64-otn-kvm_x86_64-r0/cvl-yang/sonic-otn-config-validation.yang to define yang-model leaf ranges.

Generated Yin

root@sonic:/usr/sbin/schema/platform/otn-kvm# pwd
/usr/sbin/schema/platform/otn-kvm
root@sonic:/usr/sbin/schema/platform/otn-kvm# cat sonic-otn-config-validation.yin
<?xml version="1.0" encoding="UTF-8"?>
<module name="sonic-otn-config-validation"
        xmlns="urn:ietf:params:xml:ns:yang:yin:1"
        xmlns:sonic-otn-cv="http://github.com/Azure/sonic-otn-config-validation"
        xmlns:sopt-amp="http://github.com/Azure/sonic-optical-amplifier">
  <namespace uri="http://github.com/Azure/sonic-otn-config-validation"/>
  <prefix value="sonic-otn-cv"/>
  <import module="sonic-optical-amplifier">
    <prefix value="sopt-amp"/>
  </import>
  <revision date="2026-04-29">
    <description>
      <text>Add range constraints to OTN optical amplifier leaves.</text>
    </description>
  </revision>
  <deviation target-node="/sopt-amp:sonic-optical-amplifier/sopt-amp:OTN_OA/sopt-amp:OTN_OA_LIST/sopt-amp:target-gain-tilt">
    <deviate value="replace">
      <type name="decimal64">
        <fraction-digits value="2"/>
        <range value="-2.00..0.00"/>
      </type>
    </deviate>
  </deviation>
</module>

[dudu579]

Improvements

• Check platform_asic in every device folder to avoid every device's cvl yang-models are injected at debian build-time.
• Rename debian package from sonic-otn-config-validation to sonic-config-validation
• Replace dynamic range example from target-tilt to target-gain. Min&Max are got from Redis CONFIG_DB. sonic-yang has these two nodes. (Need to consider different components may have different Min&Max)

Proposal

For improvement 1, I found that mgmt-framework does have device-level folder mirror and it originally has pyang tool. This means before mgmt-framework load all yins, I can generate device-level yins and create the device-level folder within /usr/sbin/schema. All yins will be loaded together.

[dudu579]

@jjin62 I finished above improvements. Please help me take a review.