1 // Copyright 2017 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
12 // runtime_setProfLabel is defined in runtime/proflabel.go.
13 func runtime_setProfLabel(labels unsafe.Pointer)
15 // runtime_getProfLabel is defined in runtime/proflabel.go.
16 func runtime_getProfLabel() unsafe.Pointer
18 // SetGoroutineLabels sets the current goroutine's labels to match ctx.
19 // A new goroutine inherits the labels of the goroutine that created it.
20 // This is a lower-level API than Do, which should be used instead when possible.
21 func SetGoroutineLabels(ctx context.Context) {
22 ctxLabels, _ := ctx.Value(labelContextKey{}).(*labelMap)
23 runtime_setProfLabel(unsafe.Pointer(ctxLabels))
26 // Do calls f with a copy of the parent context with the
27 // given labels added to the parent's label map.
28 // Goroutines spawned while executing f will inherit the augmented label-set.
29 // Each key/value pair in labels is inserted into the label map in the
30 // order provided, overriding any previous value for the same key.
31 // The augmented label map will be set for the duration of the call to f
32 // and restored once f returns.
33 func Do(ctx context.Context, labels LabelSet, f func(context.Context)) {
34 defer SetGoroutineLabels(ctx)
35 ctx = WithLabels(ctx, labels)
36 SetGoroutineLabels(ctx)