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move span, trace and event implementation to sdk. (#27)
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* move event to sdk.

* move trace and span implementation to sdk.
- also added noop implementation of span and trace.

* fix review comments.
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rghetia authored Jun 27, 2019
1 parent 541621c commit 521a6c4
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Showing 14 changed files with 1,120 additions and 105 deletions.
28 changes: 0 additions & 28 deletions api/event/event.go
Original file line number Diff line number Diff line change
Expand Up @@ -15,17 +15,10 @@
package event

import (
"fmt"

"github.com/open-telemetry/opentelemetry-go/api/core"
)

type (
event struct {
message string
attributes []core.KeyValue
}

// Event interface provides methods to retrieve Event properties.
Event interface {

Expand All @@ -36,24 +29,3 @@ type (
Attributes() []core.KeyValue
}
)

var _ Event = (*event)(nil)

// WithAttr creates an Event with Attributes and a message.
// Attributes are immutable.
func WithAttr(msg string, attributes ...core.KeyValue) Event {
return event{message: msg, attributes: attributes}
}

// WithString creates an Event with formatted string.
func WithString(f string, args ...interface{}) Event {
return event{message: fmt.Sprint(f, args), attributes: nil}
}

func (e event) Message() string {
return e.message
}

func (e event) Attributes() []core.KeyValue {
return append(e.attributes[:0:0], e.attributes...)
}
83 changes: 61 additions & 22 deletions api/trace/api.go
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ package trace

import (
"context"
"sync/atomic"
"time"

"google.golang.org/grpc/codes"
Expand All @@ -31,14 +32,21 @@ type (
Tracer interface {
Start(context.Context, string, ...SpanOption) (context.Context, Span)

// WithSpan wraps the execution of the function body with a span.
// It starts a new span and sets it as an active span in the context.
// It then executes the body. It closes the span before returning the execution result.
// TODO: Should it restore the previous span?
WithSpan(
ctx context.Context,
operation string,
body func(ctx context.Context) error,
) error

// TODO: Do we need WithService and WithComponent?
WithService(name string) Tracer
WithComponent(name string) Tracer

// WithResources attaches resource attributes to the Tracer.
WithResources(res ...core.KeyValue) Tracer

// Note: see https://github.com/opentracing/opentracing-go/issues/127
Expand All @@ -53,39 +61,50 @@ type (

stats.Interface

SetError(bool)

// Tracer returns tracer used to create this span. Tracer cannot be nil.
Tracer() Tracer

// Finish completes the span. No updates are allowed to span after it
// finishes. The only exception is setting status of the span.
Finish()

// AddEvent adds an event to the span.
AddEvent(ctx context.Context, event event.Event)

// IsRecordingEvents returns true is the span is active and recording events is enabled.
// IsRecordingEvents returns true if the span is active and recording events is enabled.
IsRecordingEvents() bool

// SpancContext returns span context of the span. Return SpanContext is usable
// even after the span is finished.
SpanContext() core.SpanContext

// SetStatus sets the status of the span. The status of the span can be updated
// even after span is finished.
SetStatus(codes.Code)
}

Injector interface {
// Inject serializes span context and tag.Map and inserts them in to
// carrier associated with the injector. For example in case of http request,
// span context could added to the request (carrier) as W3C Trace context header.
Inject(core.SpanContext, tag.Map)
}

// SpanOption apply changes to SpanOptions.
SpanOption func(*SpanOptions)

// SpanOptions provides options to set properties of span at the time of starting
// a new span.
SpanOptions struct {
attributes []core.KeyValue
startTime time.Time
reference Reference
recordEvent bool
Attributes []core.KeyValue
StartTime time.Time
Reference Reference
RecordEvent bool
}

// Reference is used to establish relationship between newly created span and the
// other span. The other span could be related as a parent or linked or any other
// future relationship type.
Reference struct {
core.SpanContext
RelationshipType
Expand All @@ -94,39 +113,49 @@ type (
RelationshipType int
)

var (
// The process global tracer could have process-wide resource
// tags applied directly, or we can have a SetGlobal tracer to
// install a default tracer w/ resources.
global atomic.Value

// TODO: create NOOP Tracer and register it instead of creating empty tracer here.
nt = &noopTracer{}
)

const (
ChildOfRelationship RelationshipType = iota
FollowsFromRelationship
)

// GlobalTracer return tracer registered with global registry.
// If no tracer is registered then an instance of noop Tracer is returned.
func GlobalTracer() Tracer {
if t := global.Load(); t != nil {
return t.(Tracer)
}
return empty
return nt
}

// SetGlobalTracer sets provided tracer as a global tracer.
func SetGlobalTracer(t Tracer) {
global.Store(t)
}

// Start starts a new span using registered global tracer.
func Start(ctx context.Context, name string, opts ...SpanOption) (context.Context, Span) {
return GlobalTracer().Start(ctx, name, opts...)
}

// Active returns current span from the context.
func Active(ctx context.Context) Span {
span, _ := scope.Active(ctx).(*span)
span, _ := scope.Active(ctx).(Span)
return span
}

func WithSpan(ctx context.Context, name string, body func(context.Context) error) error {
return GlobalTracer().WithSpan(ctx, name, body)
}

func SetError(ctx context.Context, v bool) {
Active(ctx).SetError(v)
}

// Inject is convenient function to inject current span context using injector.
// Injector is expected to serialize span context and inject it in to a carrier.
// An example of a carrier is http request.
func Inject(ctx context.Context, injector Injector) {
span := Active(ctx)
if span == nil {
Expand All @@ -136,36 +165,46 @@ func Inject(ctx context.Context, injector Injector) {
span.Tracer().Inject(ctx, span, injector)
}

// WithStartTime sets the start time of the span to provided time t, when it is started.
// In absensce of this option, wall clock time is used as start time.
// This option is typically used when starting of the span is delayed.
func WithStartTime(t time.Time) SpanOption {
return func(o *SpanOptions) {
o.startTime = t
o.StartTime = t
}
}

// WithAttributes sets attributes to span. These attributes provides additional
// data about the span.
func WithAttributes(attrs ...core.KeyValue) SpanOption {
return func(o *SpanOptions) {
o.attributes = attrs
o.Attributes = attrs
}
}

// WithRecordEvents enables recording of the events while the span is active.
// In the absence of this option, RecordEvent is set to false, disabling any recording of
// the events.
func WithRecordEvents() SpanOption {
return func(o *SpanOptions) {
o.recordEvent = true
o.RecordEvent = true
}
}

// ChildOf. TODO: do we need this?.
func ChildOf(sc core.SpanContext) SpanOption {
return func(o *SpanOptions) {
o.reference = Reference{
o.Reference = Reference{
SpanContext: sc,
RelationshipType: ChildOfRelationship,
}
}
}

// FollowsFrom. TODO: do we need this?.
func FollowsFrom(sc core.SpanContext) SpanOption {
return func(o *SpanOptions) {
o.reference = Reference{
o.Reference = Reference{
SpanContext: sc,
RelationshipType: FollowsFromRelationship,
}
Expand Down
93 changes: 93 additions & 0 deletions api/trace/noop_span.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,93 @@
// 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"

"google.golang.org/grpc/codes"

"github.com/open-telemetry/opentelemetry-go/api/core"
"github.com/open-telemetry/opentelemetry-go/api/event"
)

var _ Span = (*noopSpan)(nil)

// SpancContext returns an invalid span context.
func (sp *noopSpan) SpanContext() core.SpanContext {
return core.INVALID_SPAN_CONTEXT
}

// IsRecordingEvents always returns false for noopSpan.
func (sp *noopSpan) IsRecordingEvents() bool {
return false
}

// SetStatus does nothing.
func (sp *noopSpan) SetStatus(status codes.Code) {
return
}

// ScopeID returns and empty ScopeID.
func (sp *noopSpan) ScopeID() core.ScopeID {
return core.ScopeID{}
}

// SetError does nothing.
func (sp *noopSpan) SetError(v bool) {
return
}

// SetAttribute does nothing.
func (sp *noopSpan) SetAttribute(attribute core.KeyValue) {
return
}

// SetAttributes does nothing.
func (sp *noopSpan) SetAttributes(attributes ...core.KeyValue) {
return
}

// ModifyAttribute does nothing.
func (sp *noopSpan) ModifyAttribute(mutator core.Mutator) {
return
}

// ModifyAttributes does nothing.
func (sp *noopSpan) ModifyAttributes(mutators ...core.Mutator) {
return
}

// Finish does nothing.
func (sp *noopSpan) Finish() {
return
}

// Tracer returns noop implementation of Tracer.
func (sp *noopSpan) Tracer() Tracer {
return t
}

// AddEvent does nothing.
func (sp *noopSpan) AddEvent(ctx context.Context, event event.Event) {
}

// Record does nothing.
func (sp *noopSpan) Record(ctx context.Context, m ...core.Measurement) {
}

// RecordSingle does nothing.
func (sp *noopSpan) RecordSingle(ctx context.Context, m core.Measurement) {
}
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