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109 lines
2.9 KiB
109 lines
2.9 KiB
// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package trace // import "go.opentelemetry.io/otel/sdk/trace"
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import (
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"errors"
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"fmt"
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"os"
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"strconv"
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"strings"
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)
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const (
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tracesSamplerKey = "OTEL_TRACES_SAMPLER"
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tracesSamplerArgKey = "OTEL_TRACES_SAMPLER_ARG"
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samplerAlwaysOn = "always_on"
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samplerAlwaysOff = "always_off"
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samplerTraceIDRatio = "traceidratio"
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samplerParentBasedAlwaysOn = "parentbased_always_on"
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samplerParsedBasedAlwaysOff = "parentbased_always_off"
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samplerParentBasedTraceIDRatio = "parentbased_traceidratio"
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)
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type errUnsupportedSampler string
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func (e errUnsupportedSampler) Error() string {
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return fmt.Sprintf("unsupported sampler: %s", string(e))
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}
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var (
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errNegativeTraceIDRatio = errors.New("invalid trace ID ratio: less than 0.0")
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errGreaterThanOneTraceIDRatio = errors.New("invalid trace ID ratio: greater than 1.0")
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)
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type samplerArgParseError struct {
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parseErr error
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}
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func (e samplerArgParseError) Error() string {
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return fmt.Sprintf("parsing sampler argument: %s", e.parseErr.Error())
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}
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func (e samplerArgParseError) Unwrap() error {
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return e.parseErr
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}
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func samplerFromEnv() (Sampler, error) {
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sampler, ok := os.LookupEnv(tracesSamplerKey)
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if !ok {
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return nil, nil
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}
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sampler = strings.ToLower(strings.TrimSpace(sampler))
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samplerArg, hasSamplerArg := os.LookupEnv(tracesSamplerArgKey)
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samplerArg = strings.TrimSpace(samplerArg)
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switch sampler {
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case samplerAlwaysOn:
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return AlwaysSample(), nil
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case samplerAlwaysOff:
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return NeverSample(), nil
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case samplerTraceIDRatio:
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if !hasSamplerArg {
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return TraceIDRatioBased(1.0), nil
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}
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return parseTraceIDRatio(samplerArg)
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case samplerParentBasedAlwaysOn:
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return ParentBased(AlwaysSample()), nil
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case samplerParsedBasedAlwaysOff:
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return ParentBased(NeverSample()), nil
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case samplerParentBasedTraceIDRatio:
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if !hasSamplerArg {
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return ParentBased(TraceIDRatioBased(1.0)), nil
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}
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ratio, err := parseTraceIDRatio(samplerArg)
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return ParentBased(ratio), err
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default:
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return nil, errUnsupportedSampler(sampler)
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}
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}
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func parseTraceIDRatio(arg string) (Sampler, error) {
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v, err := strconv.ParseFloat(arg, 64)
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if err != nil {
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return TraceIDRatioBased(1.0), samplerArgParseError{err}
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}
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if v < 0.0 {
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return TraceIDRatioBased(1.0), errNegativeTraceIDRatio
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}
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if v > 1.0 {
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return TraceIDRatioBased(1.0), errGreaterThanOneTraceIDRatio
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}
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return TraceIDRatioBased(v), nil
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}
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