prometheus/vendor/github.com/opentracing/opentracing-go/noop.go
beorn7 ddefee52dc Update dependencies
Note that by just running `make update-go-deps`, the K8s Go client was
set to `k8s.io/client-go v11.0.0+incompatible`. However, that doesn't
play well with `k8s.io/apimachinery v0.18.5`. I the manually changed
the Go client line to `k8s.io/client-go v0.18.5`, which made
everything work. I guess Go Modules got confused by the ginormous
v11.0.0 version tag. Or it is a problem that pulling k8s.io/client-go
with git results in a rather old repo without the v0.18.5
tag. github.com/kubernetes/client-go has all the right tags. I
actually don't understand how Go Modules still correctly figures out
the source from the `k8s.io/client-go v0.18.5` line.

If one of the reviewers could enlighten me, I'd much appreciate it.

Signed-off-by: beorn7 <beorn@grafana.com>
2020-07-11 00:42:05 +02:00

65 lines
2.6 KiB
Go

package opentracing
import "github.com/opentracing/opentracing-go/log"
// A NoopTracer is a trivial, minimum overhead implementation of Tracer
// for which all operations are no-ops.
//
// The primary use of this implementation is in libraries, such as RPC
// frameworks, that make tracing an optional feature controlled by the
// end user. A no-op implementation allows said libraries to use it
// as the default Tracer and to write instrumentation that does
// not need to keep checking if the tracer instance is nil.
//
// For the same reason, the NoopTracer is the default "global" tracer
// (see GlobalTracer and SetGlobalTracer functions).
//
// WARNING: NoopTracer does not support baggage propagation.
type NoopTracer struct{}
type noopSpan struct{}
type noopSpanContext struct{}
var (
defaultNoopSpanContext SpanContext = noopSpanContext{}
defaultNoopSpan Span = noopSpan{}
defaultNoopTracer Tracer = NoopTracer{}
)
const (
emptyString = ""
)
// noopSpanContext:
func (n noopSpanContext) ForeachBaggageItem(handler func(k, v string) bool) {}
// noopSpan:
func (n noopSpan) Context() SpanContext { return defaultNoopSpanContext }
func (n noopSpan) SetBaggageItem(key, val string) Span { return n }
func (n noopSpan) BaggageItem(key string) string { return emptyString }
func (n noopSpan) SetTag(key string, value interface{}) Span { return n }
func (n noopSpan) LogFields(fields ...log.Field) {}
func (n noopSpan) LogKV(keyVals ...interface{}) {}
func (n noopSpan) Finish() {}
func (n noopSpan) FinishWithOptions(opts FinishOptions) {}
func (n noopSpan) SetOperationName(operationName string) Span { return n }
func (n noopSpan) Tracer() Tracer { return defaultNoopTracer }
func (n noopSpan) LogEvent(event string) {}
func (n noopSpan) LogEventWithPayload(event string, payload interface{}) {}
func (n noopSpan) Log(data LogData) {}
// StartSpan belongs to the Tracer interface.
func (n NoopTracer) StartSpan(operationName string, opts ...StartSpanOption) Span {
return defaultNoopSpan
}
// Inject belongs to the Tracer interface.
func (n NoopTracer) Inject(sp SpanContext, format interface{}, carrier interface{}) error {
return nil
}
// Extract belongs to the Tracer interface.
func (n NoopTracer) Extract(format interface{}, carrier interface{}) (SpanContext, error) {
return nil, ErrSpanContextNotFound
}