example_test.go

// Copyright (c) The go-grpc-middleware Authors.
// Licensed under the Apache License 2.0.

package zap_test

import (
	"context"
	"fmt"

	"github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
	"go.uber.org/zap"
	"google.golang.org/grpc"
)

// InterceptorLogger adapts zap logger to interceptor logger.
// This code is simple enough to be copied and not imported.
func InterceptorLogger(l *zap.Logger) logging.Logger {
	return logging.LoggerFunc(func(ctx context.Context, lvl logging.Level, msg string, fields ...any) {
		f := make([]zap.Field, 0, len(fields)/2)

		for i := 0; i < len(fields); i += 2 {
			key := fields[i]
			value := fields[i+1]

			switch v := value.(type) {
			case string:
				f = append(f, zap.String(key.(string), v))
			case int:
				f = append(f, zap.Int(key.(string), v))
			case bool:
				f = append(f, zap.Bool(key.(string), v))
			default:
				f = append(f, zap.Any(key.(string), v))
			}
		}

		logger := l.WithOptions(zap.AddCallerSkip(1)).With(f...)

		switch lvl {
		case logging.LevelDebug:
			logger.Debug(msg)
		case logging.LevelInfo:
			logger.Info(msg)
		case logging.LevelWarn:
			logger.Warn(msg)
		case logging.LevelError:
			logger.Error(msg)
		default:
			panic(fmt.Sprintf("unknown level %v", lvl))
		}
	})
}

func ExampleInterceptorLogger() {
	logger := zap.NewExample()

	opts := []logging.Option{
		logging.WithLogOnEvents(logging.StartCall, logging.FinishCall),
		// Add any other option (check functions starting with logging.With).
	}

	// You can now create a server with logging instrumentation that e.g. logs when the unary or stream call is started or finished.
	_ = grpc.NewServer(
		grpc.ChainUnaryInterceptor(
			logging.UnaryServerInterceptor(InterceptorLogger(logger), opts...),
			// Add any other interceptor you want.
		),
		grpc.ChainStreamInterceptor(
			logging.StreamServerInterceptor(InterceptorLogger(logger), opts...),
			// Add any other interceptor you want.
		),
	)
	// ...user server.

	// Similarly you can create client that will log for the unary and stream client started or finished calls.
	_, _ = grpc.Dial(
		"some-target",
		grpc.WithChainUnaryInterceptor(
			logging.UnaryClientInterceptor(InterceptorLogger(logger), opts...),
			// Add any other interceptor you want.
		),
		grpc.WithChainStreamInterceptor(
			logging.StreamClientInterceptor(InterceptorLogger(logger), opts...),
			// Add any other interceptor you want.
		),
	)
	// Output:
}