Performance: Make `NodeSDK` instrumentation + `body` attributes opt-in

[heiwen]

What is the problem this feature would solve?

Right now the opentelemetry plugin:

• Initializes the OpenTelemetry NodeSDK by default
• Automatically records request/response body + sizes, which requires body/stream transformations

Both add noticeable overhead and make it hard to run lightweight or custom OTel setups (Bun, edge, manual SDK, etc), especially with larger streaming calls (e.g. proxying LLM calls). It also kind of goes against the performance spirit of Elysia.

Per the OTel HTTP semantic conventions, body size attributes are opt-in and should only be recorded when explicitly enabled or already known (e.g. via content-length):

https://opentelemetry.io/docs/specs/semconv/http/http-spans/

Specifically:

• http.request.body
• http.request.body.size
• http.response.body
• http.response.body.size

What is the feature you are proposing to solve the problem?

1. Make NodeSDK initialisation opt-in:

new Elysia()
  .use(
    opentelemetry({
      // default to empty array
      instrumentations: [getNodeAutoInstrumentations()]
    })
  )

2. Make body + size capture opt-in:

new Elysia()
  .use(
    opentelemetry({
      // default to false
      captureBodies: true
    })
  )

3. Less performance critical, but to align with OTEL spec conventions, headers should also be opt-in for security reasons.

This would probably also allow to reduce the dependencies from @opentelemetry/sdk-node to @opentelemetry/sdk-trace-base.

[mtt-artis]

Less performance critical, but to align with OTEL spec conventions, headers should also be opt-in for security reasons.

Agreed, I have developed a custom plugin to overwrite authorisation or / and cookies attributes