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mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2024-12-12 10:04:29 +02:00
opentelemetry-go/internal/baggage/context.go
Tyler Yahn 4bf6150fa9
Add baggage implementation based on the W3C and OpenTelemetry specification (#1967)
* Rename baggage context file

* Initial baggage implementation

* Initial tests

* More tests

* Update baggage context functionality

* Add New method to baggage pkg

* Update namedtracer example

* URL encode baggage values

* Refactor and use internal baggage pkg

* Update OpenTracing bridge

* Update baggage propagator

* Fix lint and test errors

* Add changes to changelog

* Apply suggestions from code review

* Rename testcase field per suggestion

* Update test to verify last-one-wins semantics

* Explicitly seed random numbers with static seed in tests

* Parse Member key/value with string split

* Add test for member parse with equal signs in value

* Trim whitespaces for member key/value
2021-06-08 08:06:37 -07:00

96 lines
2.6 KiB
Go

// Copyright The OpenTelemetry Authors
//
// 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 baggage
import "context"
type baggageContextKeyType int
const baggageKey baggageContextKeyType = iota
// SetHookFunc is a callback called when storing baggage in the context.
type SetHookFunc func(context.Context, List) context.Context
// GetHookFunc is a callback called when getting baggage from the context.
type GetHookFunc func(context.Context, List) List
type baggageState struct {
list List
setHook SetHookFunc
getHook GetHookFunc
}
// ContextWithSetHook returns a copy of parent with hook configured to be
// invoked every time ContextWithBaggage is called.
//
// Passing nil SetHookFunc creates a context with no set hook to call.
func ContextWithSetHook(parent context.Context, hook SetHookFunc) context.Context {
var s baggageState
switch v := parent.Value(baggageKey).(type) {
case baggageState:
s = v
}
s.setHook = hook
return context.WithValue(parent, baggageKey, s)
}
// ContextWithGetHook returns a copy of parent with hook configured to be
// invoked every time FromContext is called.
//
// Passing nil GetHookFunc creates a context with no get hook to call.
func ContextWithGetHook(parent context.Context, hook GetHookFunc) context.Context {
var s baggageState
switch v := parent.Value(baggageKey).(type) {
case baggageState:
s = v
}
s.getHook = hook
return context.WithValue(parent, baggageKey, s)
}
// ContextWithList returns a copy of parent with baggage. Passing nil list
// returns a context without any baggage.
func ContextWithList(parent context.Context, list List) context.Context {
var s baggageState
switch v := parent.Value(baggageKey).(type) {
case baggageState:
s = v
}
s.list = list
ctx := context.WithValue(parent, baggageKey, s)
if s.setHook != nil {
ctx = s.setHook(ctx, list)
}
return ctx
}
// ListFromContext returns the baggage contained in ctx.
func ListFromContext(ctx context.Context) List {
switch v := ctx.Value(baggageKey).(type) {
case baggageState:
if v.getHook != nil {
return v.getHook(ctx, v.list)
}
return v.list
default:
return nil
}
}