Add class ConfigEnvSources to merge stable config and environment variables #6982

mtoffl01 · 2025-11-24T17:57:11Z

Reviewer tips

The majority of code changes are just replacing getEnvironmentVariable with getValueFromEnvSources. Feel free to gloss over those changes once you get the idea from a few, and instead focus on:

packages/dd-trace/src/config-helper.js
packages/dd-trace-/src/config.js
packages/dd-trace-/src/profiling/...

Background

Currently, stable config files and environment variables are only processed when the Config class is instantiated, which happens in tracer.init(). This limits us from earlier access: code that runs before tracer.init() can't access stable config values.
This PR allows us to access stable config values before tracer.init(), when we peek at DD_TRACE env vars.
It also deduplicates configuration sourcing in profiler.

What does this PR do?

Introduces getValueFromEnvSources API in config-helper.js that resolves configuration from local stable config, environment variables, and fleet stable config in ascending priority order, before the Config singleton is initialized. This method can be used instead of getEnvironmentVariable when we want to see whether particular DD_TRACE configs have been set.

Key additions:

config-helper:

getValueFromEnvSources(): Queries for the value at specified config in fleet stable config, env var, and local stable config input, in that order
Comprehensive tests for the new config-helper functionality

profiler

Profiling config now consumes tracer Config fields: profiling/config.js reads options passed down from the main Config singleton, instead of re-reading them directly. For "DD_" configs that are not yet processed by the Config singleton, we use getValueFromEnvSources in order to resolve them from stable config inputs in addition to process.env
Profiling tests updated to mirror runtime behavior: profiling/config.spec.js and profiling/profiler.spec.js now construct profiling Config with a realistic agent URL (and hostname/port when relevant), matching what the tracer Config would provide at runtime, so tests exercise the same code paths the profiler uses in production.

Motivation

All environment variables must be set-able via stable config files: RFC

Note

Not all calls to getEnvironmentVariable were replaced by getResolvedEnv. In some cases, we are really looking for an environment variable that is a heuristic for a particular type of environment. Stable config is not relevant in these cases.

Plugin Checklist

Additional Notes

github-actions · 2025-11-24T17:57:36Z

Overall package size

Self size: 4.43 MB
Deduped: 5.25 MB
No deduping: 5.25 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 2.0.0 | 68.46 kB | 797.03 kB | | dc-polyfill | 0.1.10 | 26.73 kB | 26.73 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

datadog-official · 2025-11-24T17:59:02Z

⚠️ Tests

✨ Fix all issues with Cursor

⚠️ Warnings

❄️ 1 New flaky test detected

cypress@latest esm flaky test retries retries flaky tests from integration-tests/cypress/cypress.spec.js (Datadog) (Fix with Cursor)
Expected values to be strictly equal:

18 !== 10

ℹ️ Info

🧪 All tests passed

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: af99299 | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

codecov · 2025-11-24T18:13:03Z

Codecov Report

❌ Patch coverage is 86.63793% with 31 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.17%. Comparing base (971bdd5) to head (af99299).

Files with missing lines	Patch %	Lines
packages/dd-trace/src/profiling/profiler.js	6.25%	15 Missing ⚠️
packages/dd-trace/src/telemetry/telemetry.js	86.27%	7 Missing ⚠️
...e/src/ci-visibility/exporters/test-worker/index.js	50.00%	2 Missing ⚠️
packages/dd-trace/src/llmobs/sdk.js	33.33%	2 Missing ⚠️
...ility/test-management/get-test-management-tests.js	50.00%	1 Missing ⚠️
packages/dd-trace/src/profiler.js	0.00%	1 Missing ⚠️
packages/dd-trace/src/proxy.js	50.00%	1 Missing ⚠️
packages/dd-trace/src/ritm.js	80.00%	1 Missing ⚠️
packages/dd-trace/src/telemetry/send-data.js	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6982      +/-   ##
==========================================
+ Coverage   85.14%   85.17%   +0.03%     
==========================================
  Files         532      532              
  Lines       22897    22922      +25     
==========================================
+ Hits        19495    19524      +29     
+ Misses       3402     3398       -4

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 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.

pr-commenter · 2025-11-24T18:26:53Z

Benchmarks

Benchmark execution time: 2026-01-20 01:44:41

Comparing candidate commit af99299 in PR branch mtoff/dcfg-getEnv-migration with baseline commit 971bdd5 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 230 metrics, 30 unstable metrics.

packages/dd-trace/src/config_stable.js

packages/dd-trace/src/ci-visibility/exporters/test-worker/index.js

packages/dd-trace/src/config-helper.js

packages/dd-trace/src/config-env-sources.js

packages/dd-trace/src/config-helper.js

packages/dd-trace/src/config/supported-configurations.json

packages/dd-trace/src/config-helper.js

packages/dd-trace/src/profiling/config.js

packages/dd-trace/src/plugin_manager.js

packages/dd-trace/src/plugins/util/ci.js

packages/dd-trace/src/profiling/config.js

watson · 2026-01-07T13:07:55Z

packages/dd-trace/src/config-helper.js

+      localStableConfig: localStableConfig ?? {},
+      fleetStableConfig: fleetStableConfig ?? {},
+      stableConfigWarnings: stableConfigWarnings ?? []


As far as I can see these 3 variables will never be undefined, so this could be written as:

Suggested change

localStableConfig: localStableConfig ?? {},

fleetStableConfig: fleetStableConfig ?? {},

stableConfigWarnings: stableConfigWarnings ?? []

localStableConfig,

fleetStableConfig,

stableConfigWarnings

As you said in some of your other comments, this is not strictly true. In case of a serverless environment, these will be undefined. However, in the code we never actually call this function in that case, so it should work without the undefined check. However, the JSDoc @returns is now technically wrong I guess. But it's all a mess because if you guard the call getStableConfigSources with a check for if we're not in serverless, then they are guaranteed to be objects, so 🤷

Yes, I just checked the overall calls and we guard against calling this in config.js by first checking if the environment is not serverless.

I guess it is a minimal risk to not have the fallback in case a refactoring would ever change that in a weird way. Otherwise this should be good as is. That also applies to the JSDoc as such 😅

I am fine either way. What is your preferred way of handling this?

Feel free to keep it as is

packages/dd-trace/src/config/helper.js

packages/dd-trace/src/telemetry/telemetry.js

packages/dd-trace/src/config.js

watson · 2026-01-08T10:07:30Z

packages/dd-trace/src/config-helper.js

+      localStableConfig: localStableConfig ?? {},
+      fleetStableConfig: fleetStableConfig ?? {},
+      stableConfigWarnings: stableConfigWarnings ?? []


As you said in some of your other comments, this is not strictly true. In case of a serverless environment, these will be undefined. However, in the code we never actually call this function in that case, so it should work without the undefined check. However, the JSDoc @returns is now technically wrong I guess. But it's all a mess because if you guard the call getStableConfigSources with a check for if we're not in serverless, then they are guaranteed to be objects, so 🤷

BridgeAR · 2026-01-08T11:14:52Z

packages/dd-trace/src/exporters/agent/writer.js

      'Datadog-Meta-Lang': 'nodejs',
      'Datadog-Meta-Lang-Version': process.version,
-      'Datadog-Meta-Lang-Interpreter': process.jsEngine || 'v8'
+      'Datadog-Meta-Lang-Interpreter': process.versions.bun ? 'JavaScriptCore' : 'V8'


Note: I believe this is just a value we read, while it could theoretically have an impact on dashboards that look for the lowercase version (most cases would be case insensitive anyway though).

BridgeAR · 2026-01-08T11:16:50Z

packages/dd-trace/src/exporters/agent/writer.js

-    makeRequest(_protocolVersion, data, count, _url, _headers, _lookup, true, (err, res, status) => {
+    makeRequest(_protocolVersion, data, count, _url, _headers, _lookup, (err, res, status) => {
+      // Note that logging will only happen once, regardless of how many times this is called.
+      startupLog(status !== 404 && status !== 200 ? { status, message: err?.message ?? inspect(err) } : undefined)


Note: I am uncertain about the fallback (it should never happen that an error has no message, but just in theory). We would receive the full stacktrace in case it's still a regular error, which would be likely.

BridgeAR · 2026-01-08T12:04:37Z

packages/dd-trace/src/startup-log.js

    errors.agentError = {
-      code: agentError.code ?? '',
-      message: `Agent Error:${agentError.message}`
+      code: agentError.status,


I am actually uncertain, if this is definitely correct. I have to verify that again.

BridgeAR · 2026-01-08T12:06:32Z

packages/dd-trace/src/telemetry/telemetry.js

+  if (errors.agentError) {
+    app.error = errors.agentError
+    errors.agentError = undefined


I am unsure why this was never activated before. I am going to try to verify that before landing.

BridgeAR · 2026-01-08T12:07:15Z

packages/dd-trace/src/telemetry/telemetry.js

-      architecture: os.arch(),
-      os_version: os.version()
-    }
+  if (os.platform() === 'win32') {


Note: This is actually a bug fix.

bengl · 2026-01-13T19:27:20Z

packages/dd-trace/src/config/stable.js

-        fleetConfigPath = '/etc/datadog-agent/managed/datadog-agent/stable/application_monitoring.yaml'
-        break
+  #getStableConfigPaths () {
+    // TODO(BridgeAR): Remove these environment variables once we have a proper way to test the stable config.


As much as we'd like to avoid mocking .... would a filesystem mock suffice here? I think it's sufficiently low level and not mocking dd-trace functionality that it might be appropriate here.

Yes, that would work. I just did not want to make even more changes 😅

simon-id · 2026-01-14T09:08:45Z

packages/dd-trace/src/ci-visibility/exporters/test-worker/index.js

 function getInterprocessTraceCode () {
  if (getEnvironmentVariable('JEST_WORKER_ID')) {
    return JEST_WORKER_TRACE_PAYLOAD_CODE
  }
  if (getEnvironmentVariable('CUCUMBER_WORKER_ID')) {
    return CUCUMBER_WORKER_TRACE_PAYLOAD_CODE
  }
  if (getEnvironmentVariable('MOCHA_WORKER_ID')) {
    return MOCHA_WORKER_TRACE_PAYLOAD_CODE
  }
-  if (getEnvironmentVariable('DD_PLAYWRIGHT_WORKER')) {
+  if (getValueFromEnvSources('DD_PLAYWRIGHT_WORKER')) {
    return PLAYWRIGHT_WORKER_TRACE_PAYLOAD_CODE
  }
  if (getEnvironmentVariable('TINYPOOL_WORKER_ID')) {
    return VITEST_WORKER_TRACE_PAYLOAD_CODE
  }
-  if (getEnvironmentVariable('DD_VITEST_WORKER')) {
+  if (getValueFromEnvSources('DD_VITEST_WORKER')) {
    return VITEST_WORKER_TRACE_PAYLOAD_CODE
  }
  return null


I'd like eyes of @juan-fernandez on the test-viz changes, some of the env vars here are DD_ and some are not. Should we really change it to geTValueFromEnvSources ? Is having a mix of getEnvironementVariable() and getValueFromEnvSources() the behavior we want ?

Maybe having this mix of behaviors depending on the env var name in this function will cause unexpected behavior to customers or even to our own devs.

I am going to check, what our RFCs say about stable config and non DD_ envs. It would only depend on that.

packages/datadog-instrumentations/src/otel-sdk-trace.js

packages/dd-trace/src/ritm.js

fix circular dependency Migrate civis call to use getEnvironmnetVariableSources instead run linter cleanup comments on config-env-sources complete ci/init.js migration migrate otel-sdk-trace.js assert getResolvedEnv behaves just like getEnvironmentVariable when only envs exist migrate register.js migrate DD_TRACE_AWS_SDK_BATCH_PROPAGATION_ENABLED migrate DD_TRACE_AZURE_EVENTHUBS_BATCH_LINKS_ENABLED and DD_TRACE_AZURE_SERVICEBUS_BATCH_LINKS_ENABLED migrate cypress and cucumber DD_CIVISIBILITY_AUTO_INSTRUMENTATION_PROVIDER migrate dd-trace-api, mocha and jest migrate mongodb, playwright and vitest plugins migrate index.js -- specifically for disablement env vars -- and update tests to call resetEnvConfigSources migrate plugin_manager migrate DD_API_KEY in proxy.js Finish bulk migration fix debugger test: reset configenvsources Fix failing tests in ci fix failing lambda tets and aws-sdk tests whoops - include all changes to lambda tests migrate DD_TRACE_ENCODING_DEBUG and DD_TRACE_EXPERIMENTAL_STATE_TRACKING Try out not cachine env vars update config-env-sources tests accordingly Remove calls to resetConfigEnvSources in legacy tests nits restore exporter.spec.js have Config re-use the stable config entries from ConfigEnvSources Add doc for ConfigEnvSources drop config-env-sources; just use config-helper delete config env sources try again to delete config-env-sources Apply getValueFromEnvSources to rest of DD calls; fix serverless.js fix ritm fix more referecnes to config env sources fix another import fix calls to getEnvironmentVariables that need getValueFromEnvSources pass 'config' all the way down into profiler; remove duplicate config resolution logic use getValueFromEnvSources in profiler for DD_ configs leave TODO

Potentially split this into multiple PRs

mtoffl01 added AI Generated Largely based on code generated by an AI or LLM. This label is the same across all dd-trace-* repos core labels Nov 24, 2025

mtoffl01 changed the title ~~Look in StableConfig & Env sources for config pre-init~~ Create class ConfigEnvSources to merge stable config and environment variables Nov 24, 2025

mtoffl01 changed the title ~~Create class ConfigEnvSources to merge stable config and environment variables~~ Add class ConfigEnvSources to merge stable config and environment variables Nov 24, 2025

mtoffl01 force-pushed the mtoff/dcfg-getEnv-migration branch from eacb99d to a532c6a Compare December 4, 2025 17:12

mtoffl01 commented Dec 4, 2025

View reviewed changes

packages/dd-trace/src/config_stable.js Outdated Show resolved Hide resolved

mtoffl01 commented Dec 4, 2025

View reviewed changes

packages/dd-trace/src/ci-visibility/exporters/test-worker/index.js Outdated Show resolved Hide resolved

mtoffl01 marked this pull request as ready for review December 4, 2025 21:14

mtoffl01 requested review from a team as code owners December 4, 2025 21:14

mtoffl01 requested review from BridgeAR and removed request for a team December 4, 2025 21:14

mtoffl01 commented Dec 5, 2025

View reviewed changes

packages/dd-trace/src/config-helper.js Outdated Show resolved Hide resolved

BridgeAR reviewed Dec 17, 2025

View reviewed changes

BridgeAR added the semver-minor label Dec 18, 2025

BridgeAR reviewed Dec 22, 2025

View reviewed changes

packages/dd-trace/src/config/supported-configurations.json Show resolved Hide resolved

BridgeAR reviewed Dec 22, 2025

View reviewed changes

packages/dd-trace/src/config-helper.js Outdated Show resolved Hide resolved

BridgeAR reviewed Dec 22, 2025

View reviewed changes

packages/dd-trace/src/profiling/config.js Show resolved Hide resolved

BridgeAR force-pushed the mtoff/dcfg-getEnv-migration branch 2 times, most recently from 282f094 to 948ddde Compare December 29, 2025 16:35

watson reviewed Jan 7, 2026

View reviewed changes

BridgeAR force-pushed the mtoff/dcfg-getEnv-migration branch 2 times, most recently from 21955bc to 6f3422a Compare January 8, 2026 09:40

watson reviewed Jan 8, 2026

View reviewed changes

BridgeAR reviewed Jan 8, 2026

View reviewed changes

BridgeAR force-pushed the mtoff/dcfg-getEnv-migration branch from c745a69 to b1308bc Compare January 12, 2026 21:38

bengl reviewed Jan 13, 2026

View reviewed changes

simon-id reviewed Jan 14, 2026

View reviewed changes

packages/datadog-instrumentations/src/otel-sdk-trace.js Show resolved Hide resolved

simon-id reviewed Jan 14, 2026

View reviewed changes

packages/dd-trace/src/ritm.js Show resolved Hide resolved

mtoffl01 and others added 2 commits January 20, 2026 02:10

fix review comments and tests & add types & other small fixes

af99299

Potentially split this into multiple PRs

BridgeAR force-pushed the mtoff/dcfg-getEnv-migration branch from b1308bc to af99299 Compare January 20, 2026 01:34

Add class ConfigEnvSources to merge stable config and environment variables #6982

Are you sure you want to change the base?

Add class ConfigEnvSources to merge stable config and environment variables #6982

Conversation

mtoffl01 commented Nov 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Reviewer tips

Background

What does this PR do?

Key additions:

Motivation

Note

Plugin Checklist

Additional Notes

Uh oh!

github-actions bot commented Nov 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Overall package size

Uh oh!

datadog-official bot commented Nov 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

⚠️ Warnings

ℹ️ Info

Uh oh!

codecov bot commented Nov 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

pr-commenter bot commented Nov 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Benchmarks

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

watson Jan 8, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

watson Jan 8, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

mtoffl01 commented Nov 24, 2025 •

edited

Loading

github-actions bot commented Nov 24, 2025 •

edited

Loading

datadog-official bot commented Nov 24, 2025 •

edited

Loading

codecov bot commented Nov 24, 2025 •

edited

Loading

pr-commenter bot commented Nov 24, 2025 •

edited

Loading

watson Jan 8, 2026 •

edited

Loading

watson Jan 8, 2026 •

edited

Loading

BridgeAR Jan 13, 2026 •

edited

Loading

simon-id Jan 14, 2026 •

edited

Loading