SNMP: Cisco Catalyst serial_number fallback when stack MIB serial is absent

[ian28223]

Summary

Catalyst device metadata serial_number should use chassisSerialNumberString (CISCO-STACK-MIB) when that OID is present. This change only adds a second source: entPhysicalSerialNum at ENTITY-MIB 1.3.6.1.2.1.47.1.1.1.1.11.1 (index 1) so the Agent can still populate serial_number when chassisSerialNumberString does not exist on the device.

Implementation: _cisco-catalyst.yaml uses an ordered symbols: list (stack OID first, ENTITY OID second). The Agent uses the first symbol that returns a value at collection time.

Scope

• snmp/datadog_checks/snmp/data/default_profiles/_cisco-catalyst.yaml only, plus snmp/changelog.d/23369.fixed.

Testing

• ddev --no-interactive test snmp (or targeted metadata tests) before ready for review.

[datadog-prod-us1-4]

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 95.38% (+8.24%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 1c6cd04 | Docs | Datadog PR Page | Give us feedback!}

[dd-octo-sts]

Validation Report

All 20 validations passed.

Show details

Validation	Description	Status
agent-reqs	Verify check versions match the Agent requirements file	✅
ci	Validate CI configuration and Codecov settings	✅
codeowners	Validate every integration has a CODEOWNERS entry	✅
config	Validate default configuration files against spec.yaml	✅
dep	Verify dependency pins are consistent and Agent-compatible	✅
http	Validate integrations use the HTTP wrapper correctly	✅
imports	Validate check imports do not use deprecated modules	✅
integration-style	Validate check code style conventions	✅
jmx-metrics	Validate JMX metrics definition files and config	✅
labeler	Validate PR labeler config matches integration directories	✅
legacy-signature	Validate no integration uses the legacy Agent check signature	✅
license-headers	Validate Python files have proper license headers	✅
licenses	Validate third-party license attribution list	✅
metadata	Validate metadata.csv metric definitions	✅
models	Validate configuration data models match spec.yaml	✅
openmetrics	Validate OpenMetrics integrations disable the metric limit	✅
package	Validate Python package metadata and naming	✅
readmes	Validate README files have required sections	✅
saved-views	Validate saved view JSON file structure and fields	✅
version	Validate version consistency between package and changelog	✅

View full run

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.01%. Comparing base (47ac5cc) to head (1c6cd04).
⚠️ Report is 92 commits behind head on master.

Additional details and impacted files

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[victorsprengel]

Could we also add coverage for the fallback oid in the existing unit tests?

[victorsprengel]

Can we keep MIB: field for both symbols?

[ian28223]

I could but why? symbol/symbols does not have a MIB field - they are just silently ignored. It was not mentioned in https://datadoghq.dev/integrations-core/tutorials/snmp/profile-format/#value-from-multiple-oids-symbols

If only for reference/documentation purposes, I did leave the MIB as a comment.

https://github.com/DataDog/datadog-agent/blob/9f24ee816b26464ca4db0e1e2b56b5deb6ca6893/pkg/networkdevice/profile/profiledefinition/metrics.go#L66-L88