kit

Initialization shows a relatively complex initialization sequence.

package main

import (
	"github.com/go-kit/kit/log"
	middleware "github.com/grpc-ecosystem/go-grpc-middleware"
	"github.com/grpc-ecosystem/go-grpc-middleware/interceptors/logging"
	"github.com/grpc-ecosystem/go-grpc-middleware/interceptors/tags"
	"github.com/grpc-ecosystem/go-grpc-middleware/providers/kit"
	"google.golang.org/grpc"
)

var customFunc logging.CodeToLevel

func main() {
	// Logger is used, allowing pre-definition of certain fields by the user.
	logger := log.NewNopLogger()
	// Shared options for the logger, with a custom gRPC code to log level function.
	opts := []logging.Option{
		logging.WithLevels(customFunc),
	}
	// Create a server, make sure we put the tags context before everything else.
	_ = grpc.NewServer(
		middleware.WithUnaryServerChain(
			tags.UnaryServerInterceptor(tags.WithFieldExtractor(tags.CodeGenRequestFieldExtractor)),
			logging.UnaryServerInterceptor(kit.InterceptorLogger(logger), opts...),
		),
		middleware.WithStreamServerChain(
			tags.StreamServerInterceptor(tags.WithFieldExtractor(tags.CodeGenRequestFieldExtractor)),
			logging.StreamServerInterceptor(kit.InterceptorLogger(logger), opts...),
		),
	)
}

Output:

package main

import (
	"github.com/go-kit/kit/log"
	middleware "github.com/grpc-ecosystem/go-grpc-middleware"
	"github.com/grpc-ecosystem/go-grpc-middleware/interceptors/logging"
	"github.com/grpc-ecosystem/go-grpc-middleware/interceptors/tags"
	"github.com/grpc-ecosystem/go-grpc-middleware/providers/kit"
	"google.golang.org/grpc"
)

var customDurationToFields logging.DurationToFields

func main() {
	// Logger is used, allowing pre-definition of certain fields by the user.
	logger := log.NewNopLogger()
	// Shared options for the logger, with a custom duration to log field function.
	opts := []logging.Option{
		logging.WithDurationField(customDurationToFields),
	}
	// Create a server, make sure we put the tags context before everything else.
	_ = grpc.NewServer(
		middleware.WithUnaryServerChain(
			tags.UnaryServerInterceptor(),
			logging.UnaryServerInterceptor(kit.InterceptorLogger(logger), opts...),
		),
		middleware.WithStreamServerChain(
			tags.StreamServerInterceptor(),
			logging.StreamServerInterceptor(kit.InterceptorLogger(logger), opts...),
		),
	)
}

Output: