feat(gl): add structured grpc observability

interface/grpc/server.go

@@ -4,13 +4,17 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log/slog"
 	"net"
+	"runtime/debug"
 	"time"
 
 	ledgerv1 "gl/gen/ledger/v1"
 
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/reflection"
+	"google.golang.org/grpc/status"
 )
 
 type ServerConfig struct {
@@ -30,7 +34,7 @@ func Run(ctx context.Context, cfg ServerConfig, handler ledgerv1.GeneralLedgerSe
 func runWithListener(ctx context.Context, shutdownTimeout time.Duration, listener net.Listener, handler ledgerv1.GeneralLedgerServiceServer) error {
 	defer listener.Close()
 
-	server := grpc.NewServer()
+	server := grpc.NewServer(grpc.ChainUnaryInterceptor(structuredUnaryLogger(), panicRecovery()))
 	ledgerv1.RegisterGeneralLedgerServiceServer(server, handler)
 	reflection.Register(server)
 
@@ -67,3 +71,39 @@ func runWithListener(ctx context.Context, shutdownTimeout time.Duration, listene
 	}
 	return nil
 }
+
+func structuredUnaryLogger() grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
+		started := time.Now()
+		response, err := handler(ctx, req)
+		code := status.Code(err)
+		level := slog.LevelInfo
+		if code != codes.OK {
+			level = slog.LevelError
+		}
+		slog.Log(ctx, level, "grpc call finished",
+			"component", "grpc_server",
+			"grpc_method", info.FullMethod,
+			"grpc_code", code.String(),
+			"duration_ms", float64(time.Since(started).Microseconds())/1000,
+		)
+		return response, err
+	}
+}
+
+func panicRecovery() grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (response any, err error) {
+		defer func() {
+			if recovered := recover(); recovered != nil {
+				slog.ErrorContext(ctx, "grpc panic recovered",
+					"component", "grpc_server",
+					"grpc_method", info.FullMethod,
+					"panic", recovered,
+					"stack", string(debug.Stack()),
+				)
+				err = status.Error(codes.Internal, "internal server error")
+			}
+		}()
+		return handler(ctx, req)
+	}
+}