Context API reference

org.typelevel.otel4s.context.ContextManager[F] reads and restores the active span, baggage, and custom context values. Get it from Otel4s[F].contextManager. OtelJava also provides it on Traces, TracesTestkit, MetricsTestkit, and LogsTestkit.

Member	Result	Description
`current`	`F[Ctx]`	Reads the context when the effect runs.
`scope(context)`	`F ~> F`	Runs effects in the given context. Restores the caller's context on success, failure, or cancellation.
`captureScope`	`F[F ~> F]`	Captures the context when this effect runs. Returns a reusable scope.
`liftTo[G]`	`ContextManager.Aux[G, Ctx]`	Lifts the manager through `LiftKind[F, G]` and keeps the same context type.

Ctx is the backend's context type. Use ContextManager.Aux[F, C] when code needs to name that type. Code that only captures and restores context can use ContextManager[F].

Use ContextManager[F] to summon an implicit manager. Each manager uses its module's context storage. To share context across modules, give them the same local. See Preserve context for deferred work.

import cats.effect.IO
import org.typelevel.otel4s.context.ContextManager
import org.typelevel.otel4s.oteljava.OtelJava

def prepare[A](manager: ContextManager[IO])(effect: IO[A]): IO[IO[A]] =
  manager.captureScope.map(restore => restore(effect))

val program: IO[Unit] =
  OtelJava.autoConfigured[IO]().use { otel4s =>
    prepare(otel4s.contextManager)(IO.unit).flatten
  }

The manager works when tracing is disabled or a span is unsampled. Capturing context does not change a span's lifetime or record telemetry.

Use Otel4s.propagators for propagation.

For deferred effects, resources, and streams, see Preserve context for deferred work. For context storage and fiber inheritance, see How otel4s context propagation works.