79 lines
2.6 KiB
Go
79 lines
2.6 KiB
Go
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// 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 autoexport // import "go.opentelemetry.io/contrib/exporters/autoexport"
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import (
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"context"
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"errors"
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"fmt"
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"sync"
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)
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const otelExporterOTLPProtoEnvKey = "OTEL_EXPORTER_OTLP_PROTOCOL"
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// registry maintains a map of exporter names to exporter factories
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// func(context.Context) (T, error) that is safe for concurrent use by multiple
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// goroutines without additional locking or coordination.
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type registry[T any] struct {
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mu sync.Mutex
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names map[string]func(context.Context) (T, error)
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}
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var (
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// errUnknownExporter is returned when an unknown exporter name is used in
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// the OTEL_*_EXPORTER environment variables.
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errUnknownExporter = errors.New("unknown exporter")
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// errInvalidOTLPProtocol is returned when an invalid protocol is used in
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// the OTEL_EXPORTER_OTLP_PROTOCOL environment variable.
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errInvalidOTLPProtocol = errors.New("invalid OTLP protocol - should be one of ['grpc', 'http/protobuf']")
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// errDuplicateRegistration is returned when an duplicate registration is detected.
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errDuplicateRegistration = errors.New("duplicate registration")
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)
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// load returns tries to find the exporter factory with the key and
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// then execute the factory, returning the created SpanExporter.
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// errUnknownExporter is returned if the registration is missing and the error from
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// executing the factory if not nil.
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func (r *registry[T]) load(ctx context.Context, key string) (T, error) {
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r.mu.Lock()
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defer r.mu.Unlock()
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factory, ok := r.names[key]
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if !ok {
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var zero T
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return zero, errUnknownExporter
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}
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return factory(ctx)
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}
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// store sets the factory for a key if is not already in the registry. errDuplicateRegistration
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// is returned if the registry already contains key.
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func (r *registry[T]) store(key string, factory func(context.Context) (T, error)) error {
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r.mu.Lock()
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defer r.mu.Unlock()
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if _, ok := r.names[key]; ok {
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return fmt.Errorf("%w: %q", errDuplicateRegistration, key)
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}
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r.names[key] = factory
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return nil
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}
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func must(err error) {
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if err != nil {
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panic(err)
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}
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}
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