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context.go
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context.go
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// Copyright 2019 Anapaya Systems
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package metrics
import (
"context"
)
type triggerContextKey string
const triggerKey triggerContextKey = "trigger"
// CtxWith returns a new context, based on ctx, that embeds argument trigger.
func CtxWith(ctx context.Context, trigger string) context.Context {
return context.WithValue(ctx, triggerKey, trigger)
}
// FromCtx returns the trigger embedded in ctx if one exists, or the empty
// string otherwise.
func FromCtx(ctx context.Context) string {
if ctx == nil {
return App
}
if trigger := ctx.Value(triggerKey); trigger != nil {
return trigger.(string)
}
return App
}