httpheader extension: Expose HTTP headers as ClientInfo.Auth

extension/httpheaderextension/README.md

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+# HTTP Header Extension
+
+Exposes incoming HTTP headers as fields in the Auth context using [configauth](https://github.com/open-telemetry/opentelemetry-collector/tree/main/config/configauth).
+
+# Credits
+
+- [oidcauthextension](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/extension/oidcauthextension)
+- [Issue #4400](https://github.com/open-telemetry/opentelemetry-collector/issues/4440)

extension/httpheaderextension/authdata.go

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+package httpheaderextension
+
+import "go.opentelemetry.io/collector/client"
+
+var _ client.AuthData = (*authData)(nil)
+
+type authData struct {
+	headers map[string][]string
+}
+
+func (a *authData) GetAttribute(name string) interface{} {
+	v, ok := a.headers[name]
+	if !ok {
+		return nil
+	}
+	if len(v) == 0 {
+		return ""
+	}
+	return v[len(v)-1] // return last
+}
+
+func (a *authData) GetAttributeNames() []string {
+	list := make([]string, len(a.headers))
+	i := 0
+	for k := range a.headers {
+		list[i] = k
+		i++
+	}
+	return list
+}

extension/httpheaderextension/config.go

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+package httpheaderextension
+
+import "go.opentelemetry.io/collector/config"
+
+// Config has the configuration for the HTTP Header extension.
+type Config struct {
+	config.ExtensionSettings `mapstructure:",squash"` // squash ensures fields are correctly decoded in embedded struct
+}

extension/httpheaderextension/extension.go

@@ -0,0 +1,68 @@
+package httpheaderextension
+
+import (
+	"context"
+	"net/http"
+
+	"go.opentelemetry.io/collector/client"
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/configauth"
+	"go.uber.org/zap"
+	"google.golang.org/grpc"
+)
+
+type httpheaderExtension struct {
+	cfg               *Config
+	unaryInterceptor  configauth.GRPCUnaryInterceptorFunc
+	streamInterceptor configauth.GRPCStreamInterceptorFunc
+	httpInterceptor   configauth.HTTPInterceptorFunc
+
+	logger *zap.Logger
+}
+
+var (
+	_ configauth.ServerAuthenticator = (*httpheaderExtension)(nil)
+)
+
+func newExtension(cfg *Config, logger *zap.Logger) (*httpheaderExtension, error) {
+	return &httpheaderExtension{
+		cfg:               cfg,
+		logger:            logger,
+		unaryInterceptor:  configauth.DefaultGRPCUnaryServerInterceptor,
+		streamInterceptor: configauth.DefaultGRPCStreamServerInterceptor,
+		httpInterceptor:   configauth.DefaultHTTPInterceptor,
+	}, nil
+}
+
+func (e *httpheaderExtension) Start(_ context.Context, _ component.Host) error {
+	return nil
+}
+
+// Shutdown is invoked during service shutdown.
+func (e *httpheaderExtension) Shutdown(context.Context) error {
+	return nil
+}
+
+// Authenticate checks whether the given context contains valid auth data. Successfully authenticated calls will always return a nil error and a context with the auth data.
+func (e *httpheaderExtension) Authenticate(ctx context.Context, headers map[string][]string) (context.Context, error) {
+	cl := client.FromContext(ctx)
+	cl.Auth = &authData{
+		headers: headers,
+	}
+	return client.NewContext(ctx, cl), nil
+}
+
+// GRPCUnaryServerInterceptor is a helper method to provide a gRPC-compatible UnaryInterceptor, typically calling the authenticator's Authenticate method.
+func (e *httpheaderExtension) GRPCUnaryServerInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+	return e.unaryInterceptor(ctx, req, info, handler, e.Authenticate)
+}
+
+// GRPCStreamServerInterceptor is a helper method to provide a gRPC-compatible StreamInterceptor, typically calling the authenticator's Authenticate method.
+func (e *httpheaderExtension) GRPCStreamServerInterceptor(srv interface{}, str grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+	return e.streamInterceptor(srv, str, info, handler, e.Authenticate)
+}
+
+// GRPCStreamServerInterceptor is a helper method to provide a gRPC-compatible StreamInterceptor, typically calling the authenticator's Authenticate method.
+func (e *httpheaderExtension) HTTPInterceptor(next http.Handler) http.Handler {
+	return e.httpInterceptor(next, e.Authenticate)
+}

extension/httpheaderextension/factory.go

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+package httpheaderextension
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/extension/extensionhelper"
+)
+
+const (
+	// The value of extension "type" in configuration.
+	typeStr = "httpheader"
+)
+
+// NewFactory creates a factory for the OIDC Authenticator extension.
+func NewFactory() component.ExtensionFactory {
+	return extensionhelper.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		createExtension)
+}
+
+func createDefaultConfig() config.Extension {
+	return &Config{
+		ExtensionSettings: config.NewExtensionSettings(config.NewComponentID(typeStr)),
+	}
+}
+
+func createExtension(_ context.Context, set component.ExtensionCreateSettings, cfg config.Extension) (component.Extension, error) {
+	return newExtension(cfg.(*Config), set.Logger)
+}

extension/httpheaderextension/go.mod

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+module github.com/open-telemetry/opentelemetry-collector-contrib/extension/httpheaderextension
+
+go 1.17
+
+require (
+	go.opentelemetry.io/collector v0.41.1-0.20211210184707-4dcb3388a168
+	go.uber.org/zap v1.19.1
+	google.golang.org/grpc v1.42.0
+)
+
+require (
+	github.com/fsnotify/fsnotify v1.4.9 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/knadh/koanf v1.3.2 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/mapstructure v1.4.2 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/spf13/cast v1.4.1 // indirect
+	go.opentelemetry.io/collector/model v0.40.0 // indirect
+	go.opentelemetry.io/otel v1.2.0 // indirect
+	go.opentelemetry.io/otel/metric v0.25.0 // indirect
+	go.opentelemetry.io/otel/trace v1.2.0 // indirect
+	go.uber.org/atomic v1.9.0 // indirect
+	go.uber.org/multierr v1.7.0 // indirect
+	golang.org/x/net v0.0.0-20210614182718-04defd469f4e // indirect
+	golang.org/x/sys v0.0.0-20211013075003-97ac67df715c // indirect
+	golang.org/x/text v0.3.6 // indirect
+	google.golang.org/genproto v0.0.0-20210604141403-392c879c8b08 // indirect
+	google.golang.org/protobuf v1.27.1 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+)