trace sampling headers are not sent if the trace is not sampled #4544
Assignees
Comments
6 tasks
Geal
added a commit
that referenced
this issue
Feb 14, 2024
Fix #4544 When a trace is not sampled (due to the filtering layer we use in the telemetry plugin), the `OpenTelemetryLayer` is not called, and so a `TraceId`(the opentelemetry-api one, not the router side one) is never generated, which means that when reaching the header propagation code, the current span context is invalid (trace id = 0 and span id = 0) and so the propagation headers are not sent. We want the propagation headers to still be sent when the trace is not sampled, to let the subgraphs know that they should not sample the trace either. One option was to explicitely set the propagation headers, but that depends a lot on which propagation protocol is used. The trick I use here is generating on the fly a span context with non zero trace id and span id, so that the headers can be generated.
Merged
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
It appears that if the router does not sample a trace (either because the client sets the headers or because there's a ratio sampling configured), then it won't set headers in subgraph requests to indicate if the trace should be sampled or not. It may be related to #3226 (comment)
The text was updated successfully, but these errors were encountered: