87 lines
2.4 KiB
Go
87 lines
2.4 KiB
Go
// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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//go:generate mdatagen metadata.yaml
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package envprovider // import "go.opentelemetry.io/collector/confmap/provider/envprovider"
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import (
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"context"
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"fmt"
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"os"
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"strings"
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"go.uber.org/zap"
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"go.opentelemetry.io/collector/confmap"
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"go.opentelemetry.io/collector/confmap/internal/envvar"
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)
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const (
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schemeName = "env"
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)
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type provider struct {
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logger *zap.Logger
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}
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// NewFactory returns a factory for a confmap.Provider that reads the configuration from the given environment variable.
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//
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// This Provider supports "env" scheme, and can be called with a selector:
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// `env:NAME_OF_ENVIRONMENT_VARIABLE`
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//
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// A default value for unset variable can be provided after :- suffix, for example:
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// `env:NAME_OF_ENVIRONMENT_VARIABLE:-default_value`
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//
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// See also: https://opentelemetry.io/docs/specs/otel/configuration/data-model/#environment-variable-substitution
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func NewFactory() confmap.ProviderFactory {
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return confmap.NewProviderFactory(newProvider)
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}
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func newProvider(ps confmap.ProviderSettings) confmap.Provider {
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return &provider{
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logger: ps.Logger,
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}
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}
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func (emp *provider) Retrieve(_ context.Context, uri string, _ confmap.WatcherFunc) (*confmap.Retrieved, error) {
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if !strings.HasPrefix(uri, schemeName+":") {
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return nil, fmt.Errorf("%q uri is not supported by %q provider", uri, schemeName)
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}
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envVarName, defaultValuePtr := parseEnvVarURI(uri[len(schemeName)+1:])
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if !envvar.ValidationRegexp.MatchString(envVarName) {
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return nil, fmt.Errorf("environment variable %q has invalid name: must match regex %s", envVarName, envvar.ValidationPattern)
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}
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val, exists := os.LookupEnv(envVarName)
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if !exists {
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if defaultValuePtr != nil {
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val = *defaultValuePtr
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} else {
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emp.logger.Warn("Configuration references unset environment variable", zap.String("name", envVarName))
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}
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} else if val == "" {
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emp.logger.Info("Configuration references empty environment variable", zap.String("name", envVarName))
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}
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return confmap.NewRetrievedFromYAML([]byte(val))
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}
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func (*provider) Scheme() string {
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return schemeName
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}
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func (*provider) Shutdown(context.Context) error {
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return nil
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}
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// returns (var name, default value)
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func parseEnvVarURI(uri string) (string, *string) {
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const defaultSuffix = ":-"
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name, defaultValue, hasDefault := strings.Cut(uri, defaultSuffix)
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if hasDefault {
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return name, &defaultValue
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}
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return uri, nil
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}
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