ARSN-601: Promote OTEL SDK packages from optionalDependencies to dependencies

[delthas]

Summary

Move the four OTEL SDK packages — @opentelemetry/sdk-node, sdk-trace-base, resources, exporter-trace-otlp-http — from optionalDependencies to dependencies. ioctl stays optional.

Problem

ARSN-586 classified the SDK packages as optionalDependencies, intending to mean "consumers who don't use tracing skip the ~20 MB install cost". That misuses the npm semantic.

optionalDependencies is for packages that may fail to install (typically native binaries on unsupported platforms) and whose absence the calling code tolerates gracefully. Canonical examples: fsevents, ioctl.

lib/tracing/bootstrap.ts:41 does:

const { NodeSDK } = require('@opentelemetry/sdk-node');

A bare require(). If the SDK is missing, the process crashes — that's regular dependencies semantics, not optional.

The symptom surfaced via CLDSRV-937: cloudserver's production Dockerfile uses yarn install --ignore-optional (added in 2019 during the npm→yarn migration with no commit-message rationale, never revisited). Images built that way ship without the SDK, then crash at startup when ENABLE_OTEL=true:

Error: Cannot find module '@opentelemetry/sdk-node'
Require stack:
- /usr/src/app/node_modules/arsenal/build/lib/tracing/bootstrap.js

Thanks to @DarkIsDude for flagging the optional-dep misclassification in CLDSRV-937's review.

Fix

 "dependencies": {
+    "@opentelemetry/exporter-trace-otlp-http": "^0.219.0",
+    "@opentelemetry/resources": "^2.8.0",
+    "@opentelemetry/sdk-node": "^0.219.0",
+    "@opentelemetry/sdk-trace-base": "^2.8.0",
     ...
 },
 "optionalDependencies": {
-    "@opentelemetry/exporter-trace-otlp-http": "^0.219.0",
-    "@opentelemetry/resources": "^2.8.0",
-    "@opentelemetry/sdk-node": "^0.219.0",
-    "@opentelemetry/sdk-trace-base": "^2.8.0",
     "ioctl": "^2.0.2"
 }

ioctl is the only remaining optionalDependencies entry — its usage at lib/storage/utils.js:46-51 is wrapped in try/catch with a warning fallback, so the optional semantic is honored.

lib/tracing/README.md is updated to reflect the new classification with the rationale.

Precedent in arsenal

Arsenal already ships packages as regular dependencies that not every consumer uses:

• mongodb — some deployments use bucketd, not mongo
• ioredis — some consumers don't use redis
• socket.io, sproxydclient, @aws-sdk/*

There's no in-tree precedent for "opt-in feature SDK as optionalDependencies" — that was a novel (and incorrect) classification introduced by ARSN-586.

Why not the alternatives

• try/catch around the requires in bootstrap.ts: would silently disable tracing when ENABLE_OTEL=true and SDK is missing. Worse UX — operator explicitly asked for tracing; fail-fast is preferable. Also doesn't address --ignore-optional — just papers over it.
• Declare SDK packages in each consumer's package.json: doesn't isolate anything (other arsenal consumers without --ignore-optional already pull them in), adds friction for every future tracing consumer.
• peerDependencies with optional: true: arsenal is git-pinned in consumers via yarn 1, which has rough handling of peer deps for git URLs. Not pragmatic.

Cost

~20 MB to backbeat / vault / sproxyd installs. Acceptable — backbeat already consumes arsenal's kafka.* tracing helpers, and broader OTEL adoption is the direction the stack is moving.

Verification

Sandbox test (yarn install --ignore-optional against this branch via file: dep):

• node_modules/@opentelemetry/sdk-node present ✓ (the fix)
• node_modules/ioctl absent ✓ (still optional, no regression)

Plus locally: yarn build, yarn lint, yarn jest tests/unit/tracing/ all green (71/71).

Relates to: ARSN-586, CLDSRV-937

Issue: ARSN-601

[bert-e]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.03%. Comparing base (5981b88) to head (dc9eb23).

Additional details and impacted files

@@                 Coverage Diff                 @@
##           development/8.4    #2653      +/-   ##
===================================================
+ Coverage            74.00%   74.03%   +0.02%     
===================================================
  Files                  229      229              
  Lines                18503    18503              
  Branches              3820     3845      +25     
===================================================
+ Hits                 13694    13699       +5     
+ Misses                4804     4799       -5     
  Partials                 5        5              

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[delthas]

/approve

[bert-e]

I have successfully merged the changeset of this pull request
into targetted development branches:

• ✔️ development/8.4

• ✔️ development/8.5

The following branches have NOT changed:

• development/6.4
• development/7.10
• development/7.4
• development/7.70
• development/8.1
• development/8.2
• development/8.3

This pull request did not target the following hotfix branch(es) so they
were left untouched:

• hotfix/7.9.0
• hotfix/7.10.4
• hotfix/7.10.46
• hotfix/7.70.14
• hotfix/7.10.57
• hotfix/7.70.4
• hotfix/7.8.0
• hotfix/7.70.20
• hotfix/7.10.29
• hotfix/6.4.7
• hotfix/7.4.7
• hotfix/7.4.4
• hotfix/7.2.0
• hotfix/7.10.1
• hotfix/7.4.2
• hotfix/7.10.36
• hotfix/7.4.5
• hotfix/7.4.1
• hotfix/7.10.31
• hotfix/7.4.0
• hotfix/7.70.25
• hotfix/7.4.8
• hotfix/7.6.0
• hotfix/7.7.0
• hotfix/7.5.0
• hotfix/7.10.47
• hotfix/7.4.9
• hotfix/7.10.3
• hotfix/7.10.43
• hotfix/7.10.2
• hotfix/7.4.3
• hotfix/7.4.10
• hotfix/7.10.0
• hotfix/7.4.6

Please check the status of the associated issue ARSN-601.

Goodbye delthas.

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