55 lines
1.5 KiB
Go
55 lines
1.5 KiB
Go
// Copyright 2019, OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package tag
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import (
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"context"
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"runtime/pprof"
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)
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type ctxTagsType struct{}
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var (
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ctxTagsKey = &ctxTagsType{}
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)
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func WithMap(ctx context.Context, m Map) context.Context {
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return context.WithValue(ctx, ctxTagsKey, m)
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}
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func NewContext(ctx context.Context, mutators ...Mutator) context.Context {
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return WithMap(ctx, FromContext(ctx).Apply(MapUpdate{
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MultiMutator: mutators,
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}))
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}
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func FromContext(ctx context.Context) Map {
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if m, ok := ctx.Value(ctxTagsKey).(Map); ok {
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return m
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}
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return NewEmptyMap()
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}
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// Note: the golang pprof.Do API forces this memory allocation, we
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// should file an issue about that. (There's a TODO in the source.)
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func Do(ctx context.Context, f func(ctx context.Context)) {
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m := FromContext(ctx)
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keyvals := make([]string, 0, 2*len(m.m))
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for k, v := range m.m {
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keyvals = append(keyvals, k.Variable.Name, v.value.Emit())
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}
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pprof.Do(ctx, pprof.Labels(keyvals...), f)
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}
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