pkg/trace/scheduler_tracer.go

/*
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you 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 (
	"io"
	"sync"

	"github.com/opentracing/opentracing-go"

	"github.com/apache/yunikorn-core/pkg/log"
)

// SchedulerTracer defines minimum interface for tracing
type SchedulerTracer interface {
	NewTraceContext() SchedulerTraceContext
	Close()
}

var _ SchedulerTracer = &SchedulerTracerImpl{}

type SchedulerTracerImpl struct {
	Tracer opentracing.Tracer
	Closer io.Closer
	sync.RWMutex
	*SchedulerTracerImplParams
}

type SchedulerTracerImplParams struct {
	Mode       string
	FilterTags map[string]interface{}
}

const (
	Sampling        = "Sampling"
	Debug           = "Debug"
	DebugWithFilter = "DebugWithFilter"
)

var DefaultSchedulerTracerImplParams = &SchedulerTracerImplParams{
	Mode:       Sampling,
	FilterTags: nil,
}

// SetParams set runtime parameter for tracer
func (s *SchedulerTracerImpl) SetParams(params *SchedulerTracerImplParams) {
	if params == nil {
		return
	}
	if params.Mode == DebugWithFilter && len(params.FilterTags) == 0 {
		log.Log(log.OpenTracing).Warn("FilterTags is empty while trying to run in DebugWithFilter mode." +
			" Please use Debug mode instead.")
	}
	s.Lock()
	defer s.Unlock()
	s.SchedulerTracerImplParams = params
}

// NewTraceContext create SchedulerTraceContext based on parameter settings
func (s *SchedulerTracerImpl) NewTraceContext() SchedulerTraceContext {
	s.RLock()
	defer s.RUnlock()
	switch s.Mode {
	case Sampling:
		return &SchedulerTraceContextImpl{
			Tracer:       s.Tracer,
			SpanStack:    []opentracing.Span{},
			OnDemandFlag: false,
		}
	case Debug:
		return &SchedulerTraceContextImpl{
			Tracer:       s.Tracer,
			SpanStack:    []opentracing.Span{},
			OnDemandFlag: true,
		}
	case DebugWithFilter:
		return &DelaySchedulerTraceContextImpl{
			Tracer:     s.Tracer,
			Spans:      []*DelaySpan{},
			FilterTags: s.FilterTags,
		}
	default:
		return nil
	}
}

// Close calls tracer's closer if exists
func (s *SchedulerTracerImpl) Close() {
	if s.Closer != nil {
		s.Closer.Close()
	}
}

// NewSchedulerTracer creates new tracer instance with params
// params is set to default sampling mode if it is nil
func NewSchedulerTracer(params *SchedulerTracerImplParams) (SchedulerTracer, error) {
	if params == nil {
		params = DefaultSchedulerTracerImplParams
	}

	tracer, closer, err := NewTracerFromEnv("yunikorn-core-scheduler")
	if err != nil {
		return nil, err
	}

	return &SchedulerTracerImpl{
		Tracer:                    tracer,
		Closer:                    closer,
		SchedulerTracerImplParams: params,
	}, nil
}