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// Copyright (c) 2017 Uber Technologies, Inc.
//
// 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 jaeger
import (
"time"
"github.com/uber/jaeger-client-go/log"
)
// SamplerOption is a function that sets some option on the sampler
type SamplerOption func(options *samplerOptions)
// SamplerOptions is a factory for all available SamplerOption's.
var SamplerOptions SamplerOptionsFactory
// SamplerOptionsFactory is a factory for all available SamplerOption's.
// The type acts as a namespace for factory functions. It is public to
// make the functions discoverable via godoc. Recommended to be used
// via global SamplerOptions variable.
type SamplerOptionsFactory struct{}
type samplerOptions struct {
metrics *Metrics
sampler SamplerV2
logger log.DebugLogger
samplingServerURL string
samplingRefreshInterval time.Duration
samplingFetcher SamplingStrategyFetcher
samplingParser SamplingStrategyParser
updaters []SamplerUpdater
posParams PerOperationSamplerParams
}
// Metrics creates a SamplerOption that initializes Metrics on the sampler,
// which is used to emit statistics.
func (SamplerOptionsFactory) Metrics(m *Metrics) SamplerOption {
return func(o *samplerOptions) {
o.metrics = m
}
}
// MaxOperations creates a SamplerOption that sets the maximum number of
// operations the sampler will keep track of.
func (SamplerOptionsFactory) MaxOperations(maxOperations int) SamplerOption {
return func(o *samplerOptions) {
o.posParams.MaxOperations = maxOperations
}
}
// OperationNameLateBinding creates a SamplerOption that sets the respective
// field in the PerOperationSamplerParams.
func (SamplerOptionsFactory) OperationNameLateBinding(enable bool) SamplerOption {
return func(o *samplerOptions) {
o.posParams.OperationNameLateBinding = enable
}
}
// InitialSampler creates a SamplerOption that sets the initial sampler
// to use before a remote sampler is created and used.
func (SamplerOptionsFactory) InitialSampler(sampler Sampler) SamplerOption {
return func(o *samplerOptions) {
o.sampler = samplerV1toV2(sampler)
}
}
// Logger creates a SamplerOption that sets the logger used by the sampler.
func (SamplerOptionsFactory) Logger(logger Logger) SamplerOption {
return func(o *samplerOptions) {
o.logger = log.DebugLogAdapter(logger)
}
}
// SamplingServerURL creates a SamplerOption that sets the sampling server url
// of the local agent that contains the sampling strategies.
func (SamplerOptionsFactory) SamplingServerURL(samplingServerURL string) SamplerOption {
return func(o *samplerOptions) {
o.samplingServerURL = samplingServerURL
}
}
// SamplingRefreshInterval creates a SamplerOption that sets how often the
// sampler will poll local agent for the appropriate sampling strategy.
func (SamplerOptionsFactory) SamplingRefreshInterval(samplingRefreshInterval time.Duration) SamplerOption {
return func(o *samplerOptions) {
o.samplingRefreshInterval = samplingRefreshInterval
}
}
// SamplingStrategyFetcher creates a SamplerOption that initializes sampling strategy fetcher.
func (SamplerOptionsFactory) SamplingStrategyFetcher(fetcher SamplingStrategyFetcher) SamplerOption {
return func(o *samplerOptions) {
o.samplingFetcher = fetcher
}
}
// SamplingStrategyParser creates a SamplerOption that initializes sampling strategy parser.
func (SamplerOptionsFactory) SamplingStrategyParser(parser SamplingStrategyParser) SamplerOption {
return func(o *samplerOptions) {
o.samplingParser = parser
}
}
// Updaters creates a SamplerOption that initializes sampler updaters.
func (SamplerOptionsFactory) Updaters(updaters ...SamplerUpdater) SamplerOption {
return func(o *samplerOptions) {
o.updaters = updaters
}
}
func (o *samplerOptions) applyOptionsAndDefaults(opts ...SamplerOption) *samplerOptions {
for _, option := range opts {
option(o)
}
if o.sampler == nil {
o.sampler = newProbabilisticSampler(0.001)
}
if o.logger == nil {
o.logger = log.NullLogger
}
if o.samplingServerURL == "" {
o.samplingServerURL = DefaultSamplingServerURL
}
if o.metrics == nil {
o.metrics = NewNullMetrics()
}
if o.samplingRefreshInterval <= 0 {
o.samplingRefreshInterval = defaultSamplingRefreshInterval
}
if o.samplingFetcher == nil {
o.samplingFetcher = &httpSamplingStrategyFetcher{
serverURL: o.samplingServerURL,
logger: o.logger,
}
}
if o.samplingParser == nil {
o.samplingParser = new(samplingStrategyParser)
}
if o.updaters == nil {
o.updaters = []SamplerUpdater{
&AdaptiveSamplerUpdater{
MaxOperations: o.posParams.MaxOperations,
OperationNameLateBinding: o.posParams.OperationNameLateBinding,
},
new(ProbabilisticSamplerUpdater),
new(RateLimitingSamplerUpdater),
}
}
return o
}