Add support for the zerolog logging provider (#299)

Makefile

@@ -32,6 +32,7 @@ test: vet
 	cd ./providers/kit/ && go test -v -race ./...
 	cd ./providers/logrus/ && go test -v -race ./...
 	cd ./providers/zap/ && go test -v -race ./...
+	cd ./providers/zerolog/ && go test -v -race ./...
 	./scripts/test_all.sh
 
 .PHONY: all test

README.md

@@ -16,7 +16,7 @@
 ## Middleware
 
 [gRPC Go](https://github.com/grpc/grpc-go) recently acquired support for
-Interceptors, i.e. [middleware](https://medium.com/@matryer/writing-middleware-in-golang-and-how-go-makes-it-so-much-fun-4375c1246e81#.gv7tdlghs) 
+Interceptors, i.e. [middleware](https://medium.com/@matryer/writing-middleware-in-golang-and-how-go-makes-it-so-much-fun-4375c1246e81#.gv7tdlghs)
 that is executed either on the gRPC Server before the request is passed onto the user's application logic, or on the gRPC client either around the user call. It is a perfect way to implement
 common patterns: auth, logging, message, validation, retries or monitoring.
 
@@ -54,13 +54,14 @@ myServer := grpc.NewServer(
 *Please send a PR to add new interceptors or middleware to this list*
 
 #### Auth
-   * [`auth`](auth) - a customizable (via `AuthFunc`) piece of auth middleware 
+   * [`auth`](auth) - a customizable (via `AuthFunc`) piece of auth middleware
 
 #### Logging
    * [`tags`](interceptors/tags) - a library that adds a `Tag` map to context, with data populated from request body
    * [`zap`](providers/zap) - integration of [zap](https://github.com/uber-go/zap) logging library into gRPC handlers.
    * [`logrus`](providers/logrus) - integration of [logrus](https://github.com/sirupsen/logrus) logging library into gRPC handlers.
    * [`kit`](providers/kit) - integration of [go-kit](https://github.com/go-kit/kit/tree/master/log) logging library into gRPC handlers.
+   * [`zerolog`](providers/zerolog) - integration of [zerolog](https://github.com/rs/zerolog) logging Library into gRPC handlers.
 
 #### Monitoring
    * [`grpc_prometheus`⚡](https://github.com/grpc-ecosystem/go-grpc-prometheus) - Prometheus client-side and server-side monitoring middleware

interceptors/logging/doc.go

@@ -29,6 +29,7 @@ Implementations:
 * providers/logrus
 * providers/zap
 * providers/kit
+* providers/zerolog
 
 See relevant packages below.
 */

providers/zerolog/doc.go

@@ -0,0 +1,5 @@
+/*
+Package zerolog provides a small adapter required to use zerolog in logging gRPC middlewares.
+Please see examples for examples of use.
+*/
+package zerolog

providers/zerolog/examples_test.go

@@ -0,0 +1,136 @@
+package zerolog_test
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/rs/zerolog"
+	"google.golang.org/grpc"
+
+	middleware "github.com/grpc-ecosystem/go-grpc-middleware/v2"
+	"github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
+	"github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/tags"
+	grpczerolog "github.com/grpc-ecosystem/go-grpc-middleware/v2/providers/zerolog"
+)
+
+var (
+	customFunc             logging.CodeToLevel
+	customDurationToFields logging.DurationToFields
+)
+
+func Example_initializationWithCustomLevels() {
+	// Logger is used, allowing pre-definition of certain fields by the user.
+	logger := zerolog.New(os.Stderr)
+	// 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(),
+			logging.UnaryServerInterceptor(grpczerolog.InterceptorLogger(logger), opts...),
+		),
+		middleware.WithStreamServerChain(
+			tags.StreamServerInterceptor(),
+			logging.StreamServerInterceptor(grpczerolog.InterceptorLogger(logger), opts...),
+		),
+	)
+}
+
+func Example_initializationWithDurationFieldOverride() {
+	// Logger is used, allowing pre-definition of certain fields by the user.
+	logger := zerolog.New(os.Stderr)
+	// 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(grpczerolog.InterceptorLogger(logger), opts...),
+		),
+		middleware.WithStreamServerChain(
+			tags.StreamServerInterceptor(),
+			logging.StreamServerInterceptor(grpczerolog.InterceptorLogger(logger), opts...),
+		),
+	)
+}
+
+func Example_initializationWithCodeGenRequestFieldExtractor() {
+	// Logger is used, allowing pre-definition of certain fields by the user.
+	logger := zerolog.New(os.Stderr)
+	// 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(grpczerolog.InterceptorLogger(logger)),
+		),
+		middleware.WithStreamServerChain(
+			tags.StreamServerInterceptor(tags.WithFieldExtractor(tags.CodeGenRequestFieldExtractor)),
+			logging.StreamServerInterceptor(grpczerolog.InterceptorLogger(logger)),
+		),
+	)
+}
+
+func ExampleWithDecider() {
+	// Logger is used, allowing pre-definition of certain fields by the user.
+	logger := zerolog.New(os.Stderr)
+	// Shared options for the logger, with a custom decider that log everything except successful
+	// calls from "/blah.foo.healthcheck/Check" method.
+	opts := []logging.Option{
+		logging.WithDecider(func(methodFullName string, err error) bool {
+			// will not log gRPC calls if it was a call to healthcheck and no error was raised
+			if err == nil && methodFullName == "/blah.foo.healthcheck/Check" {
+				return false
+			}
+
+			// by default you will log all calls
+			return true
+		}),
+	}
+	// Create a server, make sure we put the tags context before everything else.
+	_ = []grpc.ServerOption{
+		middleware.WithUnaryServerChain(
+			tags.UnaryServerInterceptor(),
+			logging.UnaryServerInterceptor(grpczerolog.InterceptorLogger(logger), opts...),
+		),
+		middleware.WithStreamServerChain(
+			tags.StreamServerInterceptor(),
+			logging.StreamServerInterceptor(grpczerolog.InterceptorLogger(logger), opts...),
+		),
+	}
+}
+
+func ExampleWithPayloadLogging() {
+	// Logger is used, allowing pre-definition of certain fields by the user.
+	logger := zerolog.New(os.Stderr)
+	// Expect payload from  "/blah.foo.healthcheck/Check" call to be logged.
+	payloadDecider := func(ctx context.Context, fullMethodName string, servingObject interface{}) bool {
+		return fullMethodName == "/blah.foo.healthcheck/Check"
+	}
+
+	// Create a server, make sure we put the tags context before everything else.
+	_ = []grpc.ServerOption{
+		middleware.WithUnaryServerChain(
+			tags.UnaryServerInterceptor(),
+			logging.UnaryServerInterceptor(grpczerolog.InterceptorLogger(logger)),
+			logging.PayloadUnaryServerInterceptor(grpczerolog.InterceptorLogger(logger), payloadDecider),
+		),
+		middleware.WithStreamServerChain(
+			tags.StreamServerInterceptor(),
+			logging.StreamServerInterceptor(grpczerolog.InterceptorLogger(logger)),
+			logging.PayloadStreamServerInterceptor(grpczerolog.InterceptorLogger(logger), payloadDecider),
+		),
+	}
+}
+
+func TestExamplesBuildable(t *testing.T) {
+	Example_initializationWithCustomLevels()
+	Example_initializationWithDurationFieldOverride()
+	Example_initializationWithCodeGenRequestFieldExtractor()
+	ExampleWithDecider()
+	ExampleWithPayloadLogging()
+}

providers/zerolog/go.mod

@@ -0,0 +1,9 @@
+module github.com/grpc-ecosystem/go-grpc-middleware/v2/providers/zerolog
+
+go 1.14
+
+require (
+	github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.0.0-20200501113911-9a95f0fdbfea
+	github.com/rs/zerolog v1.19.0
+	google.golang.org/grpc v1.19.0
+)

providers/zerolog/go.sum

@@ -0,0 +1,80 @@
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providers/zerolog/logger.go

@@ -0,0 +1,50 @@
+package zerolog
+
+import (
+	"fmt"
+
+	"github.com/rs/zerolog"
+
+	"github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
+)
+
+// Compatibility check.
+var _ logging.Logger = &Logger{}
+
+// Logger is a zerolog logging adapter compatible with logging middlewares.
+type Logger struct {
+	zerolog.Context
+}
+
+// InterceptorLogger is a zerolog.Logger to Logger adapter.
+func InterceptorLogger(logger zerolog.Logger) *Logger {
+	return &Logger{logger.With()}
+}
+
+// Log implements the logging.Logger interface.
+func (l *Logger) Log(lvl logging.Level, msg string) {
+	cl := l.Logger()
+	switch lvl {
+	case logging.DEBUG:
+		cl.Debug().Msg(msg)
+	case logging.INFO:
+		cl.Info().Msg(msg)
+	case logging.WARNING:
+		cl.Warn().Msg(msg)
+	case logging.ERROR:
+		cl.Error().Msg(msg)
+	default:
+		// TODO(kb): Perhaps this should be a logged warning, defaulting to ERROR to get attention
+		// without interrupting code flow?
+		panic(fmt.Sprintf("zerolog: unknown level %s", lvl))
+	}
+}
+
+// With implements the logging.Logger interface.
+func (l *Logger) With(fields ...string) logging.Logger {
+	vals := make(map[string]interface{}, len(fields)/2)
+	for i := 0; i < len(fields); i += 2 {
+		vals[fields[i]] = fields[i+1]
+	}
+	return InterceptorLogger(l.Fields(vals).Logger())
+}