feature: Include gRPC status details in error log messages

server.go

@@ -14,11 +14,14 @@ import (
 	"github.com/roadrunner-server/grpc/v6/parser"
 	"github.com/roadrunner-server/grpc/v6/proxy"
 	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/encoding/prototext"
+	"google.golang.org/protobuf/proto"
 )
 
 func (p *Plugin) createGRPCserver(interceptors map[string]api.Interceptor) (*grpc.Server, error) {
@@ -109,7 +112,11 @@ func (p *Plugin) interceptor(ctx context.Context, req any, info *grpc.UnaryServe
 	}()
 
 	if err != nil {
-		p.log.Error("method call was finished with error", "error", err, "method", info.FullMethod, "start", start, "elapsed", time.Since(start).Milliseconds())
+		args := []any{"error", err, "method", info.FullMethod, "start", start, "elapsed", time.Since(start).Milliseconds()}
+		if details := statusDetails(s); len(details) > 0 {
+			args = append(args, "details", details)
+		}
+		p.log.Error("method call was finished with error", args...)
 
 		return nil, err
 	}
@@ -118,6 +125,39 @@ func (p *Plugin) interceptor(ctx context.Context, req any, info *grpc.UnaryServe
 	return resp, nil
 }
 
+// statusDetails renders the well-known google.rpc.* error details attached to s as
+// compact, one-line strings for logging, skipping any other (and potentially large)
+// handler-attached detail. It returns nil when there are no such details.
+func statusDetails(s *status.Status) []string {
+	details := s.Details()
+	if len(details) == 0 {
+		return nil
+	}
+
+	out := make([]string, 0, len(details))
+	for _, d := range details {
+		// Only the standard google.rpc.* error details are logged; arbitrary payloads
+		// a handler may attach are skipped (without touching them), so a failing call
+		// can't dump a large custom message into the logs.
+		switch d.(type) {
+		case *errdetails.BadRequest,
+			*errdetails.ErrorInfo,
+			*errdetails.DebugInfo,
+			*errdetails.Help,
+			*errdetails.LocalizedMessage,
+			*errdetails.PreconditionFailure,
+			*errdetails.QuotaFailure,
+			*errdetails.RequestInfo,
+			*errdetails.ResourceInfo,
+			*errdetails.RetryInfo:
+			m := d.(proto.Message)
+			out = append(out, fmt.Sprintf("%s: %s", m.ProtoReflect().Descriptor().FullName(), prototext.MarshalOptions{}.Format(m)))
+		}
+	}
+
+	return out
+}
+
 func (p *Plugin) serverOptions() ([]grpc.ServerOption, error) {
 	const op = errors.Op("grpc_plugin_server_options")
 

server_test.go

@@ -0,0 +1,75 @@
+package grpc
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/wrapperspb"
+)
+
+func TestStatusDetails_NoDetails_Nil(t *testing.T) {
+	s := status.New(codes.InvalidArgument, "bad arg")
+	assert.Nil(t, statusDetails(s))
+}
+
+func TestStatusDetails_NonStatusError_Nil(t *testing.T) {
+	s, ok := status.FromError(errors.New("boom"))
+	require.False(t, ok)
+	assert.Nil(t, statusDetails(s), "a non-status error carries no details")
+}
+
+func TestStatusDetails_SingleDetail(t *testing.T) {
+	s, err := status.New(codes.InvalidArgument, "bad arg").WithDetails(&errdetails.BadRequest{
+		FieldViolations: []*errdetails.BadRequest_FieldViolation{
+			{Field: "email", Description: "is required"},
+		},
+	})
+	require.NoError(t, err)
+
+	got := statusDetails(s)
+	require.Len(t, got, 1)
+	assert.Contains(t, got[0], "google.rpc.BadRequest", "should name the detail type")
+	assert.Contains(t, got[0], "email", "should include the field value")
+	assert.Contains(t, got[0], "is required")
+}
+
+func TestStatusDetails_MultipleDetails(t *testing.T) {
+	s, err := status.New(codes.FailedPrecondition, "nope").WithDetails(
+		&errdetails.BadRequest{FieldViolations: []*errdetails.BadRequest_FieldViolation{{Field: "x", Description: "y"}}},
+		&errdetails.ErrorInfo{Reason: "QUOTA", Domain: "example.com"},
+	)
+	require.NoError(t, err)
+
+	got := statusDetails(s)
+	require.Len(t, got, 2)
+	joined := got[0] + " | " + got[1]
+	assert.Contains(t, joined, "google.rpc.BadRequest")
+	assert.Contains(t, joined, "google.rpc.ErrorInfo")
+	assert.Contains(t, joined, "QUOTA")
+}
+
+func TestStatusDetails_SkipsNonGoogleRpc(t *testing.T) {
+	// Handlers can attach arbitrary (and potentially large) details; only the
+	// standard google.rpc.* error details should be logged.
+	s, err := status.New(codes.Internal, "boom").WithDetails(&wrapperspb.StringValue{Value: "arbitrary payload"})
+	require.NoError(t, err)
+	assert.Empty(t, statusDetails(s), "non-google.rpc details must be skipped")
+}
+
+func TestStatusDetails_MixedKeepsOnlyGoogleRpc(t *testing.T) {
+	s, err := status.New(codes.InvalidArgument, "bad").WithDetails(
+		&wrapperspb.StringValue{Value: "arbitrary payload"},
+		&errdetails.BadRequest{FieldViolations: []*errdetails.BadRequest_FieldViolation{{Field: "email", Description: "is required"}}},
+	)
+	require.NoError(t, err)
+
+	got := statusDetails(s)
+	require.Len(t, got, 1, "only the google.rpc detail should be kept")
+	assert.Contains(t, got[0], "google.rpc.BadRequest")
+	assert.NotContains(t, got[0], "StringValue")
+}