buildctl: revert trace shutdown timeout

This partially reverts the buildctl tracer shutdown change from #6757.

The 50ms shutdown context can expire while delegated traces are flushed over a slow but healthy connhelper transport. Restore the previous buildctl shutdown behavior so that this telemetry cleanup path does not fail an otherwise successful command.

Keep the daemon-side telemetry shutdown bounds and trace forwarder changes from #6757 intact.

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

cmd/buildctl/common/trace.go

@@ -3,12 +3,10 @@ package common
 import (
 	"context"
 	"os"
-	"time"
 
 	"github.com/moby/buildkit/util/appcontext"
 	"github.com/moby/buildkit/util/tracing/delegated"
 	"github.com/moby/buildkit/util/tracing/detect"
-	"github.com/pkg/errors"
 	"github.com/urfave/cli/v3"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"
@@ -16,8 +14,6 @@ import (
 	"go.opentelemetry.io/otel/trace"
 )
 
-const exportTimeout = 50 * time.Millisecond
-
 func AttachAppContext(app *cli.Command) error {
 	baseCtx := appcontext.Context()
 
@@ -79,13 +75,7 @@ func AttachAppContext(app *cli.Command) error {
 			span.End()
 		}
 
-		// Set a rather aggressive timeout for shutting down the tracer provider
-		// to ensure we don't stall on a non-responsive tracing endpoint for too long
-		// on shutdown.
-		ctx, cancel := context.WithTimeoutCause(appcontext.Shutdown(), exportTimeout, errors.WithStack(context.DeadlineExceeded))
-		defer cancel()
-
-		return tp.Shutdown(ctx)
+		return tp.Shutdown(context.TODO())
 	}
 	return nil
 }