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opentelemetry-go/oteltest/text_map_propagator.go

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// 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 oteltest // import "go.opentelemetry.io/otel/oteltest"
import (
"context"
"fmt"
"strconv"
"strings"
"sync"
"testing"
"go.opentelemetry.io/otel"
)
type ctxKeyType string
// TextMapCarrier provides a testing storage medium to for a
// TextMapPropagator. It records all the operations it performs.
type TextMapCarrier struct {
mtx sync.Mutex
gets []string
sets [][2]string
data map[string]string
}
// NewTextMapCarrier returns a new *TextMapCarrier populated with data.
func NewTextMapCarrier(data map[string]string) *TextMapCarrier {
copied := make(map[string]string, len(data))
for k, v := range data {
copied[k] = v
}
return &TextMapCarrier{data: copied}
}
// Get returns the value associated with the passed key.
func (c *TextMapCarrier) Get(key string) string {
c.mtx.Lock()
defer c.mtx.Unlock()
c.gets = append(c.gets, key)
return c.data[key]
}
// GotKey tests if c.Get has been called for key.
func (c *TextMapCarrier) GotKey(t *testing.T, key string) bool {
c.mtx.Lock()
defer c.mtx.Unlock()
for _, k := range c.gets {
if k == key {
return true
}
}
t.Errorf("TextMapCarrier.Get(%q) has not been called", key)
return false
}
// GotN tests if n calls to c.Get have been made.
func (c *TextMapCarrier) GotN(t *testing.T, n int) bool {
c.mtx.Lock()
defer c.mtx.Unlock()
if len(c.gets) != n {
t.Errorf("TextMapCarrier.Get was called %d times, not %d", len(c.gets), n)
return false
}
return true
}
// Set stores the key-value pair.
func (c *TextMapCarrier) Set(key, value string) {
c.mtx.Lock()
defer c.mtx.Unlock()
c.sets = append(c.sets, [2]string{key, value})
c.data[key] = value
}
// SetKeyValue tests if c.Set has been called for the key-value pair.
func (c *TextMapCarrier) SetKeyValue(t *testing.T, key, value string) bool {
c.mtx.Lock()
defer c.mtx.Unlock()
var vals []string
for _, pair := range c.sets {
if key == pair[0] {
if value == pair[1] {
return true
}
vals = append(vals, pair[1])
}
}
if len(vals) > 0 {
t.Errorf("TextMapCarrier.Set called with %q and %v values, but not %s", key, vals, value)
}
t.Errorf("TextMapCarrier.Set(%q,%q) has not been called", key, value)
return false
}
// SetN tests if n calls to c.Set have been made.
func (c *TextMapCarrier) SetN(t *testing.T, n int) bool {
c.mtx.Lock()
defer c.mtx.Unlock()
if len(c.sets) != n {
t.Errorf("TextMapCarrier.Set was called %d times, not %d", len(c.sets), n)
return false
}
return true
}
// Reset zeros out the internal state recording of c.
func (c *TextMapCarrier) Reset() {
c.mtx.Lock()
defer c.mtx.Unlock()
c.gets = nil
c.sets = nil
c.data = make(map[string]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)
}
type TextMapPropagator struct {
Name string
ctxKey ctxKeyType
}
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 otel.TextMapCarrier) state {
return newState(carrier.Get(p.Name))
}
// Inject set cross-cutting concerns for p from the Context into the carrier.
func (p *TextMapPropagator) Inject(ctx context.Context, carrier otel.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 the carrier into a Context.
func (p *TextMapPropagator) Extract(ctx context.Context, carrier otel.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 p.Name as the key who's value is set with Inject.
func (p *TextMapPropagator) Fields() []string { return []string{p.Name} }