We were digging into Cloud Functions and OpenTelemetry and ran into an issue with getting the traceparent header to ensure tracing context is propagated. We noticed that the problem was that Cloud Functions sets the header name to Traceparent, but OpenTelemetry looks for a header named traceparent.

Ideally, this should not matter, given that headers should be treated without case sensitivity, per RFC 7320 Section 3.2. However, com.google.cloud.functions.HttpRequest.getFirstHeader seems to care about casing.

Would it make sense to change the implementation to treat headers without case sensitivity? At the moment, we are planning to use a workaround (See gist for an example)