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opentelemetry-go/internal/internaltest/text_map_propagator.go
Tyler Yahn 7f10ef72d4
Remove propagation testing types from oteltest (#2116)
* Add propagationtest package

* Update internal/global to use propagationtest

* Move propagationtest into internal
2021-07-22 08:16:57 -07:00

113 lines
3.3 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 internaltest
import (
"context"
"fmt"
"strconv"
"strings"
"testing"
"go.opentelemetry.io/otel/propagation"
)
type ctxKeyType string
type state struct {
Injections uint64
Extractions uint64
}
func newState(encoded string) state {
if encoded == "" {
return state{}
}
split := strings.SplitN(encoded, ",", 2)
injects, _ := strconv.ParseUint(split[0], 10, 64)
extracts, _ := strconv.ParseUint(split[1], 10, 64)
return state{
Injections: injects,
Extractions: extracts,
}
}
func (s state) String() string {
return fmt.Sprintf("%d,%d", s.Injections, s.Extractions)
}
// TextMapPropagator is a propagation.TextMapPropagator used for testing.
type TextMapPropagator struct {
name string
ctxKey ctxKeyType
}
var _ propagation.TextMapPropagator = (*TextMapPropagator)(nil)
// NewTextMapPropagator returns a new TextMapPropagator for testing. It will
// use name as the key it injects into a TextMapCarrier when Inject is called.
func NewTextMapPropagator(name string) *TextMapPropagator {
return &TextMapPropagator{name: name, ctxKey: ctxKeyType(name)}
}
func (p *TextMapPropagator) stateFromContext(ctx context.Context) state {
if v := ctx.Value(p.ctxKey); v != nil {
if s, ok := v.(state); ok {
return s
}
}
return state{}
}
func (p *TextMapPropagator) stateFromCarrier(carrier propagation.TextMapCarrier) state {
return newState(carrier.Get(p.name))
}
// Inject sets cross-cutting concerns for p from ctx into carrier.
func (p *TextMapPropagator) Inject(ctx context.Context, carrier propagation.TextMapCarrier) {
s := p.stateFromContext(ctx)
s.Injections++
carrier.Set(p.name, s.String())
}
// InjectedN tests if p has made n injections to carrier.
func (p *TextMapPropagator) InjectedN(t *testing.T, carrier *TextMapCarrier, n int) bool {
if actual := p.stateFromCarrier(carrier).Injections; actual != uint64(n) {
t.Errorf("TextMapPropagator{%q} injected %d times, not %d", p.name, actual, n)
return false
}
return true
}
// Extract reads cross-cutting concerns for p from carrier into ctx.
func (p *TextMapPropagator) Extract(ctx context.Context, carrier propagation.TextMapCarrier) context.Context {
s := p.stateFromCarrier(carrier)
s.Extractions++
return context.WithValue(ctx, p.ctxKey, s)
}
// ExtractedN tests if p has made n extractions from the lineage of ctx.
// nolint (context is not first arg)
func (p *TextMapPropagator) ExtractedN(t *testing.T, ctx context.Context, n int) bool {
if actual := p.stateFromContext(ctx).Extractions; actual != uint64(n) {
t.Errorf("TextMapPropagator{%q} extracted %d time, not %d", p.name, actual, n)
return false
}
return true
}
// Fields returns the name of p as the key who's value is set with Inject.
func (p *TextMapPropagator) Fields() []string { return []string{p.name} }