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opentelemetry-go/sdk/trace/trace.go
rghetia 0f32efcdaa
Trace sdk (#65)
* trace sdk initial commit.

* fix imports and comments.

* remove tracestate

* split trace.go

* add attribute over limit test.

* add comments and restructure span.go and tracer.go

* refactor MessageEvent

* defer unlock

* some more cleanup in span.go

* rename *MessageEvent* to *Event*

* cleanup comments in trace_test.go

* fix typos.

* return full string ID for traceID and spanID.
2019-08-02 13:52:55 -07:00

76 lines
2.0 KiB
Go

// Copyright 2019, 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 trace
import (
"context"
crand "crypto/rand"
"encoding/binary"
"math/rand"
"sync"
"sync/atomic"
apitrace "go.opentelemetry.io/api/trace"
)
var config atomic.Value // access atomically
func init() {
gen := &defaultIDGenerator{}
// initialize traceID and spanID generators.
var rngSeed int64
for _, p := range []interface{}{
&rngSeed, &gen.traceIDAdd, &gen.nextSpanID, &gen.spanIDInc,
} {
_ = binary.Read(crand.Reader, binary.LittleEndian, p)
}
gen.traceIDRand = rand.New(rand.NewSource(rngSeed))
gen.spanIDInc |= 1
config.Store(&Config{
DefaultSampler: ProbabilitySampler(defaultSamplingProbability),
IDGenerator: gen,
MaxAttributesPerSpan: DefaultMaxAttributesPerSpan,
MaxEventsPerSpan: DefaultMaxEventsPerSpan,
MaxLinksPerSpan: DefaultMaxLinksPerSpan,
})
}
var tr *tracer
var registerOnce sync.Once
// Register registers tracer implementation as default Tracer.
// It creates single instance of tracer and registers it once.
// Recommended use is to call Register in main() of an
// application before calling any tracing api.
func Register() apitrace.Tracer {
registerOnce.Do(func() {
tr = &tracer{}
apitrace.SetGlobalTracer(tr)
})
return tr
}
type contextKey struct{}
func fromContext(ctx context.Context) *span {
s, _ := ctx.Value(contextKey{}).(*span)
return s
}
func newContext(parent context.Context, s *span) context.Context {
return context.WithValue(parent, contextKey{}, s)
}