v1.41.0

Summary

This release introduces rule based span sampling for the tracer which can be configured through the env var DD_SPAN_SAMPLING_RULES. For configuration details, see the docs.
Additionally it is now possible to propagate an HTTP request's user id across services when using the SetUser() tracer function, thanks to the WithPropagation() option.
Also, the tracer now flushes trace stats when stopping, and some changes to contribs were also made:

• For net/http the RoundTripper has a new option to ignore outgoing requests
• For segmentio/kafka.go.v0 the message's topic name is used when the writer's topic name is unavailable
• For 99designs/gqlgen, basic support was added for tracing GraphQL functions

The profiler fixed a bug which caused the first minute of activity to be missing from profiles. The profiler now respects the DD_TRACE_STARTUP_LOGS environment variable, which can be set to false to turn off start-up logging. Profiles are now tagged with the seq_id tag, which counts how many profiles have been uploaded so far.

Some more improvements and fixes can also be found in the list of changes below.

Changes

Tracer

• contrib/net/http: Add new option to RoundTripper to ignore outgoing request (#1403)
• contrib/segmentio: reading topic name from message if writer topic is empty (#1400)
• contrib: support tracing for GraphQL (#1380)
• ddtrace/tracer: add an option to propagate user id over services (#1387)
• ddtrace/tracer: add support for single span matching (#1357)
• ddtrace/tracer: force trace stats flush on Stop, thanks @Kyle-Verhoog (#1393)

Profiler

• profiler: implement profile_seq tag (#1391)
• profiler: respect DD_TRACE_STARTUP_LOGS environment variable (#1385)
• profiler: start collecting profiles immediately (#1417)

Full Changelog: v1.40.1...v1.41.0