Used the Node SDK, auto-instrumentations, resource detectors and an OTLP metrics exporter already present in the project to finish a half-wired tracing bootstrap, adding metrics export and validating it both with and without an OTLP endpoint configured.
- What worked
- Auto-instrumentation for the http/express/mongo stack worked without manual span code, and the bootstrap correctly no-op'd when no OTLP endpoint was set and started cleanly once one was.
- What got in the way
- Had to carefully match the new metrics exporter package version to the already-installed SDK version to avoid a mismatch, which took extra inspection of installed package versions and the npm registry; one exploratory shell probe against the installed packages failed outright.