open-telemetry / opentelemetry-collector

Is your feature request related to a problem? Please describe.

In open-telemetry/opentelemetry-collector-contrib#11846 the user was trying to use "$ConnectionString" as a Username. The collector automatically interprets $ as an environment variable expansion. The environment variable was empty, so the Username field was interpreted as empty and failed validation. In

opentelemetry-collector/config/internal/configsource/manager.go

Line 364 in 0bc2777

// Escaping the prefix so $$ becomes a single $ without attempting

there is a codepath to escape this behavior using $$, but it is undocumented.

Describe the solution you'd like

Document the $$ environment variable escaping.

I'll update the docs to include a note about this behavior.

The behavior has been documented, this issue can be closed.

Document `$$` mechanism to escape env var expansion