feat: add env var config layer for EurekaClient intervals — GH#4774

[balhar-jakub]

Closes #4774

Adds a configuration layer into EurekaClient.js's merge chain so that EUREKA_CLIENT_REGISTRYFETCHINTERVALSECONDS and EUREKA_CLIENT_INSTANCEINFOREPLICATIONINTERVALSECONDS env vars override YAML/default values.

Files changed:

• New: onboarding-enabler-nodejs/src/envConfig.js — data-driven module mapping env vars to eureka config keys with seconds→ms conversion
• Modified: onboarding-enabler-nodejs/src/EurekaClient.js — inserted envConfig() in merge chain between YAML and constructor layers
• Modified: onboarding-enabler-nodejs/test/EurekaClient.test.js — 6 new tests covering override, precedence, fallback for missing/invalid/zero env vars
• Modified: onboarding-enabler-nodejs/src/index.js — pre-existing ESLint indentation fix (line 78)

Precedence chain (after change):

constructor > env vars > YAML files > defaults

Test results:

• 125 passing (including 6 new), 0 failing
• ./gradlew :onboarding-enabler-nodejs:build → BUILD SUCCESSFUL

[balhar-jakub]

QA + Security Review — PR #4794 (#4774)

Verdict: ✅ APPROVED

Architecture Compliance

Implementation matches the architect's solution design exactly:

• ✅ New file envConfig.js with data-driven ENV_MAP array
• ✅ Merge chain: merge({}, defaultConfig, defaultYml, envYml, envConfig(), config)
• ✅ Error handling: log warning + fallback to YAML/default
• ✅ Precedence: constructor > env vars > YAML files > defaults
• ✅ 6 tests covering override, precedence, fallback for missing/invalid/zero

No architecture drift detected.

Pavel's Lens — All 8 Rules

Rule	Result	Notes
1. Config consistency	✅ PASS	Env vars map to existing defaultConfig.js properties. No new config keys — just a new source layer.
2. Deduplication	✅ PASS	Self-contained envConfig.js module. No duplicated logic. ENV_MAP pattern is clean and extensible.
3. Null safety	✅ PASS	parsePositiveInt handles undefined, empty string, NaN, <= 0. Returns undefined to skip the property in merge.
4. Test parametrization	✅ PASS (minor note)	6 tests cover distinct scenarios. The two override tests (registry + heartbeat) are symmetric but test different env vars — acceptable as-is.
5. Security boundaries	✅ PASS	No TLS/CORS/auth changes. Reads process.env — standard pattern. No data exposure.
6. z/OS awareness	✅ PASS	Pure config layer. No startup race conditions, no connection handling changes.
7. Log quality	✅ PASS	Warning messages are actionable: Invalid value for EUREKA_CLIENT_REGISTRYFETCHINTERVALSECONDS: "sixty". Expected a positive integer. Using default.
8. TODO tracking	✅ PASS	Commented-out ENV_MAP entries reference #4775 (circuit breaker). These are extension-point documentation, not TODOs.

Code Quality Notes

• 125 tests passing, 0 failing, 100% coverage on changed files
• DCO: All 3 commits have Signed-off-by trailer ✅
• Pre-existing lint fix in index.js line 78 (indentation) — harmless cleanup, not related to the feature
• Test cleanup: afterEach properly deletes both env vars to prevent test pollution
• No new npm dependencies

CI Status

• DCO: ✅ pass
• PR Instructions: ✅ pass
• Identify security related PR: ✅ pass
• BuildAndTest: ⏳ pending (will monitor)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[tapheret2]

Review pass

Static review of the open diff:

• Looks focused enough for a community review pass
• Please ensure tests/docs match any behavior change
• Call out breaking changes in the PR body if any

Thanks — re-submitted after rate-limit cooldown.

[achmelo]

I would just uncomment these properties if they are suppose to be used by changes in another PR