path: root/vendor/go.opencensus.io/trace/config.go

// Copyright 2018, OpenCensus 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 (
    "sync"

    "go.opencensus.io/trace/internal"
)

// Config represents the global tracing configuration.
type Config struct {
    // DefaultSampler is the default sampler used when creating new spans.
    DefaultSampler Sampler

    // IDGenerator is for internal use only.
    IDGenerator internal.IDGenerator

    // MaxAnnotationEventsPerSpan is max number of annotation events per span
    MaxAnnotationEventsPerSpan int

    // MaxMessageEventsPerSpan is max number of message events per span
    MaxMessageEventsPerSpan int

    // MaxAnnotationEventsPerSpan is max number of attributes per span
    MaxAttributesPerSpan int

    // MaxLinksPerSpan is max number of links per span
    MaxLinksPerSpan int
}

var configWriteMu sync.Mutex

const (
    // DefaultMaxAnnotationEventsPerSpan is default max number of annotation events per span
    DefaultMaxAnnotationEventsPerSpan = 32

    // DefaultMaxMessageEventsPerSpan is default max number of message events per span
    DefaultMaxMessageEventsPerSpan = 128

    // DefaultMaxAttributesPerSpan is default max number of attributes per span
    DefaultMaxAttributesPerSpan = 32

    // DefaultMaxLinksPerSpan is default max number of links per span
    DefaultMaxLinksPerSpan = 32
)

// ApplyConfig applies changes to the global tracing configuration.
//
// Fields not provided in the given config are going to be preserved.
func ApplyConfig(cfg Config) {
    configWriteMu.Lock()
    defer configWriteMu.Unlock()
    c := *config.Load().(*Config)
    if cfg.DefaultSampler != nil {
        c.DefaultSampler = cfg.DefaultSampler
    }
    if cfg.IDGenerator != nil {
        c.IDGenerator = cfg.IDGenerator
    }
    if cfg.MaxAnnotationEventsPerSpan > 0 {
        c.MaxAnnotationEventsPerSpan = cfg.MaxAnnotationEventsPerSpan
    }
    if cfg.MaxMessageEventsPerSpan > 0 {
        c.MaxMessageEventsPerSpan = cfg.MaxMessageEventsPerSpan
    }
    if cfg.MaxAttributesPerSpan > 0 {
        c.MaxAttributesPerSpan = cfg.MaxAttributesPerSpan
    }
    if cfg.MaxLinksPerSpan > 0 {
        c.MaxLinksPerSpan = cfg.MaxLinksPerSpan
    }
    config.Store(&c)
}