grpc/grpc-go · error

extproc: failed to unmarshal config %v: %v

Error message

extproc: failed to unmarshal config %v: %v

What it means

Raised by ParseFilterConfig (ext_proc.go:116) when the ExternalProcessor Any's bytes cannot be deserialized into envoy.extensions.filters.http.ext_proc.v3.ExternalProcessor. The ext_proc counterpart to error 360: structurally invalid wire data for the declared type causes the LDS resource to be NACKed.

Source

Thrown at internal/xds/httpfilter/extproc/ext_proc.go:116

		return fmt.Errorf("extproc: invalid request body mode %v: want %q or %q", m, "NONE", "GRPC")
	}
	if m := mode.GetResponseBodyMode(); m != v3procfilterpb.ProcessingMode_NONE && m != v3procfilterpb.ProcessingMode_GRPC {
		return fmt.Errorf("extproc: invalid response body mode %v: want %q or %q", m, "NONE", "GRPC")
	}
	if mode.GetResponseBodyMode() == v3procfilterpb.ProcessingMode_GRPC && mode.GetResponseTrailerMode() != v3procfilterpb.ProcessingMode_SEND {
		return fmt.Errorf("extproc: invalid response trailer mode %v: must be %q when response body mode is %q", mode.GetResponseTrailerMode(), "SEND", "GRPC")
	}
	return nil
}

func (builder) ParseFilterConfig(cfg proto.Message) (httpfilter.FilterConfig, error) {
	m, ok := cfg.(*anypb.Any)
	if !ok {
		return nil, fmt.Errorf("extproc: error parsing config %v: unknown type %T, want *anypb.Any", cfg, cfg)
	}
	msg := new(v3procfilterpb.ExternalProcessor)
	if err := m.UnmarshalTo(msg); err != nil {
		return nil, fmt.Errorf("extproc: failed to unmarshal config %v: %v", cfg, err)
	}
	if msg.GetProcessingMode() == nil {
		return nil, fmt.Errorf("extproc: missing processing_mode in config %v", cfg)
	}
	if err := validateBodyProcessingMode(msg.GetProcessingMode()); err != nil {
		return nil, err
	}

	if msg.GetGrpcService() == nil {
		return nil, fmt.Errorf("extproc: empty grpc_service provided in config %v", cfg)
	}
	server, err := iextproc.ParseGRPCServiceConfig(msg.GetGrpcService())
	if err != nil {
		return nil, fmt.Errorf("extproc: failed to parse grpc_service %v", err)
	}

	mutationRules, err := httpfilter.HeaderMutationRulesFromProto(msg.GetMutationRules())
	if err != nil {

View on GitHub (pinned to 03255a9237)

Solutions

1. Read the wrapped %v for the protobuf-level cause (unexpected EOF = truncation; unknown field = version skew).
2. Confirm type_url is 'type.googleapis.com/envoy.extensions.filters.http.ext_proc.v3.ExternalProcessor' and the body decodes as that exact message.
3. Decode Any.value with protoc against the v3 ExternalProcessor descriptor; re-emit a correct resource.

Example fix

// before: Any payload is not a valid ExternalProcessor
//
// after: marshal the real v3 ExternalProcessor into the Any
import (
  "google.golang.org/protobuf/types/known/anypb"
  v3procfilterpb "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/http/ext_proc/v3"
)
ep := &v3procfilterpb.ExternalProcessor{
  GrpcService:    &v3corepb.GrpcService{ /* google_grpc... */ },
  ProcessingMode: &v3procfilterpb.ProcessingMode{ /* NONE/GRPC only */ },
}
anyCfg, err := anypb.New(ep)

// Validate an ExternalProcessor Any before publishing (ext_proc.go:114-116).
func validateExtProcAny(a *anypb.Any) error {
    if a == nil || a.TypeUrl != "type.googleapis.com/envoy.extensions.filters.http.ext_proc.v3.ExternalProcessor" {
        return fmt.Errorf("wrong/nil type_url for ExternalProcessor")
    }
    msg := new(v3procfilterpb.ExternalProcessor)
    if err := a.UnmarshalTo(msg); err != nil {
        return fmt.Errorf("ExternalProcessor payload invalid: %w", err)
    }
    return nil
}

When it happens

Trigger: cfg is a valid *anypb.Any but m.UnmarshalTo(new(v3procfilterpb.ExternalProcessor)) at ext_proc.go:115 returns a non-nil error — corrupt/truncated bytes, or payload serialized from a different message than the type_url claims.

Common situations: Control plane emitted a malformed ExternalProcessor config; type_url says ExternalProcessor but the body is a different proto; v2/v3 or go-control-plane version mismatch.

Related errors

• rls_csp: error parsing config %v: %v
• extauthz: failed to unmarshal config: %v
• extauthz: failed to unmarshal override config %v: %v
• extproc: invalid request body mode %v: want %q or %q
• extproc: invalid response body mode %v: want %q or %q

AI-assisted analysis of grpc/grpc-go@03255a9237 (2026-08-07). Data as JSON: /api/errors/b7495d130a375bc2. Report an issue: GitHub.