go/internal/telemetry/event/key.go

40 lines
1.2 KiB
Go

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package event
import (
"context"
)
// Key is used as the identity of a Tag.
// Keys are intended to be compared by pointer only, the name should be unique
// for communicating with external systems, but it is not required or enforced.
type Key struct {
Name string
Description string
}
// TagOf returns a Tag for a key and value.
// This is a trivial helper that makes common logging easier to read.
func TagOf(name string, value interface{}) Tag {
return Tag{Key: &Key{Name: name}, Value: value}
}
// Of creates a new Tag with this key and the supplied value.
// You can use this when building a tag list.
func (k *Key) Of(v interface{}) Tag {
return Tag{Key: k, Value: v}
}
// From can be used to get a tag for the key from a context.
func (k *Key) From(ctx context.Context) Tag {
return Tag{Key: k, Value: ctx.Value(k)}
}
// With is a wrapper over the Label package level function for just this key.
func (k *Key) With(ctx context.Context, v interface{}) context.Context {
return Label(ctx, Tag{Key: k, Value: v})
}