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opentelemetry-go/sdk/trace/trace.go

144 lines
4.0 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"
"math/rand"
"github.com/open-telemetry/opentelemetry-go/api/core"
"github.com/open-telemetry/opentelemetry-go/api/scope"
"github.com/open-telemetry/opentelemetry-go/api/tag"
apitrace "github.com/open-telemetry/opentelemetry-go/api/trace"
"github.com/open-telemetry/opentelemetry-go/exporter/observer"
"github.com/open-telemetry/opentelemetry-go/sdk/event"
)
type tracer struct {
resources core.EventID
}
var (
ServiceKey = tag.New("service")
ComponentKey = tag.New("component")
ErrorKey = tag.New("error")
SpanIDKey = tag.New("span_id")
TraceIDKey = tag.New("trace_id")
MessageKey = tag.New("message",
tag.WithDescription("message text: info, error, etc"),
)
)
var t = &tracer{}
// Register registers tracer to global registry and returns the registered tracer.
func Register() apitrace.Tracer {
apitrace.SetGlobalTracer(t)
return t
}
func (t *tracer) ScopeID() core.ScopeID {
return t.resources.Scope()
}
func (t *tracer) WithResources(attributes ...core.KeyValue) apitrace.Tracer {
s := scope.New(t.resources.Scope(), attributes...)
return &tracer{
resources: s.ScopeID().EventID,
}
}
func (t *tracer) WithComponent(name string) apitrace.Tracer {
return t.WithResources(ComponentKey.String(name))
}
func (t *tracer) WithService(name string) apitrace.Tracer {
return t.WithResources(ServiceKey.String(name))
}
func (t *tracer) WithSpan(ctx context.Context, name string, body func(context.Context) error) error {
// TODO: use runtime/trace.WithRegion for execution tracer support
// TODO: use runtime/pprof.Do for profile tags support
ctx, span := t.Start(ctx, name)
defer span.Finish()
if err := body(ctx); err != nil {
span.SetAttribute(ErrorKey.Bool(true))
span.AddEvent(ctx, event.WithAttr("span error", MessageKey.String(err.Error())))
return err
}
return nil
}
// Start starts a new span with provided name and span options.
// If parent span reference is provided in the span option then it is used as as parent.
// Otherwise, parent span reference is retrieved from current context.
// The new span uses the same TraceID as parent.
// If no parent is found then a root span is created and started with random TraceID.
// TODO: Add sampling logic.
func (t *tracer) Start(ctx context.Context, name string, opts ...apitrace.SpanOption) (context.Context, apitrace.Span) {
var child core.SpanContext
child.SpanID = rand.Uint64()
o := &apitrace.SpanOptions{}
for _, opt := range opts {
opt(o)
}
var parentScope core.ScopeID
if o.Reference.HasTraceID() {
parentScope = o.Reference.Scope()
} else {
parentSpan, _ := apitrace.Active(ctx).(*span)
parentScope = parentSpan.ScopeID()
}
if parentScope.HasTraceID() {
parent := parentScope.SpanContext
child.TraceIDHigh = parent.TraceIDHigh
child.TraceIDLow = parent.TraceIDLow
} else {
child.TraceIDHigh = rand.Uint64()
child.TraceIDLow = rand.Uint64()
}
childScope := core.ScopeID{
SpanContext: child,
EventID: t.resources,
}
span := &span{
spanContext: child,
tracer: t,
recordEvent: o.RecordEvent,
eventID: observer.Record(observer.Event{
Time: o.StartTime,
Type: observer.START_SPAN,
Scope: scope.New(childScope, o.Attributes...).ScopeID(),
Context: ctx,
Parent: parentScope,
String: name,
}),
}
return scope.SetActive(ctx, span), span
}
func (t *tracer) Inject(ctx context.Context, span apitrace.Span, injector apitrace.Injector) {
injector.Inject(span.ScopeID().SpanContext, tag.FromContext(ctx))
}