Introduce interceptor to log client errors (#332)

Here is an example of the logger:
```
2024-12-18T16:17:30.226Z        ERROR   replication     Client Unary RPC Error  {"method": "/xmtp.xmtpv4.payer_api.PayerApi/PublishClientEnvelopes", "duration": 10888708, "code": "Internal", "message": "error publishing group message: rpc error: code = Internal desc = error publishing identity update: timed out"}
```

Fixes #329

pkg/api/server.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"context"
+	"github.com/xmtp/xmtpd/pkg/interceptors/server"
 	"net"
 	"strings"
 	"sync"
@@ -61,6 +62,11 @@ func NewAPIServer(
 		prometheus.EnableHandlingTimeHistogram()
 	})
 
+	loggingInterceptor, err := server.NewLoggingInterceptor(log)
+	if err != nil {
+		return nil, err
+	}
+
 	unary := []grpc.UnaryServerInterceptor{prometheus.UnaryServerInterceptor}
 	stream := []grpc.StreamServerInterceptor{prometheus.StreamServerInterceptor}
 
@@ -75,6 +81,9 @@ func NewAPIServer(
 			PermitWithoutStream: true,
 			MinTime:             15 * time.Second,
 		}),
+		grpc.ChainUnaryInterceptor(loggingInterceptor.Unary()),
+		grpc.ChainStreamInterceptor(loggingInterceptor.Stream()),
+
 		// grpc.MaxRecvMsgSize(s.Config.Options.MaxMsgSize),
 	}
 

pkg/interceptors/server/logging.go

@@ -0,0 +1,81 @@
+package server
+
+import (
+	"context"
+	"fmt"
+	"go.uber.org/zap"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/status"
+)
+
+// LoggingInterceptor logs errors for unary and stream RPCs.
+type LoggingInterceptor struct {
+	logger *zap.Logger
+}
+
+// NewLoggingInterceptor creates a new instance of LoggingInterceptor.
+func NewLoggingInterceptor(logger *zap.Logger) (*LoggingInterceptor, error) {
+	if logger == nil {
+		return nil, fmt.Errorf("logger is required")
+	}
+
+	return &LoggingInterceptor{
+		logger: logger,
+	}, nil
+}
+
+// Unary intercepts unary RPC calls to log errors.
+func (i *LoggingInterceptor) Unary() grpc.UnaryServerInterceptor {
+	return func(
+		ctx context.Context,
+		req interface{},
+		info *grpc.UnaryServerInfo,
+		handler grpc.UnaryHandler,
+	) (interface{}, error) {
+		start := time.Now()
+		resp, err := handler(ctx, req) // Call the actual RPC handler
+		duration := time.Since(start)
+
+		if err != nil {
+			st, _ := status.FromError(err)
+			i.logger.Error(
+				"Client Unary RPC Error",
+				zap.String("method", info.FullMethod),
+				zap.Duration("duration", duration),
+				zap.Any("code", st.Code()),
+				zap.String("message", st.Message()),
+			)
+		}
+
+		return resp, err
+	}
+}
+
+// Stream intercepts stream RPC calls to log errors.
+func (i *LoggingInterceptor) Stream() grpc.StreamServerInterceptor {
+	return func(
+		srv interface{},
+		ss grpc.ServerStream,
+		info *grpc.StreamServerInfo,
+		handler grpc.StreamHandler,
+	) error {
+		start := time.Now()
+		err := handler(srv, ss) // Call the actual stream handler
+		duration := time.Since(start)
+
+		if err != nil {
+			st, _ := status.FromError(err)
+			i.logger.Error(
+				"Stream Client RPC Error",
+				zap.String("method", info.FullMethod),
+				zap.Duration("duration", duration),
+				zap.Any("code", st.Code()),
+				zap.String("message", st.Message()),
+			)
+		}
+
+		return err
+	}
+}

pkg/interceptors/server/logging_test.go

@@ -0,0 +1,107 @@
+package server
+
+import (
+	"context"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	"go.uber.org/zap/zaptest/observer"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"testing"
+)
+
+func createTestLogger() (*zap.Logger, *observer.ObservedLogs) {
+	core, observedLogs := observer.New(zapcore.DebugLevel)
+	logger := zap.New(core)
+	return logger, observedLogs
+}
+
+type mockServerStream struct {
+	grpc.ServerStream
+}
+
+func (m *mockServerStream) Context() context.Context {
+	return context.Background()
+}
+
+func TestUnaryLoggingInterceptor(t *testing.T) {
+	logger, logs := createTestLogger()
+
+	interceptor, err := NewLoggingInterceptor(logger)
+	require.NoError(t, err)
+
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return nil, status.Errorf(codes.Internal, "mock internal error")
+	}
+
+	ctx := context.Background()
+	info := &grpc.UnaryServerInfo{
+		FullMethod: "/test.TestService/TestMethod",
+	}
+	req := struct{}{}
+
+	interceptorUnary := interceptor.Unary()
+	_, err = interceptorUnary(ctx, req, info, handler)
+
+	require.Error(t, err)
+	require.Equal(t, 1, logs.Len(), "expected one log entry but got none")
+
+	logEntry := logs.All()[0]
+
+	require.Equal(t, zapcore.ErrorLevel, logEntry.Level, "expected log level 'Error'")
+	require.Contains(t, logEntry.ContextMap(), "method")
+	require.Equal(
+		t,
+		"/test.TestService/TestMethod",
+		logEntry.ContextMap()["method"],
+		"expected log to contain correct method",
+	)
+	require.Contains(t, logEntry.ContextMap(), "message")
+	require.Equal(
+		t,
+		"mock internal error",
+		logEntry.ContextMap()["message"],
+		"expected log to contain correct error message",
+	)
+}
+func TestStreamLoggingInterceptor(t *testing.T) {
+	logger, logs := createTestLogger()
+	interceptor, err := NewLoggingInterceptor(logger)
+	require.NoError(t, err)
+
+	handler := func(srv interface{}, ss grpc.ServerStream) error {
+		return status.Errorf(codes.NotFound, "mock stream error")
+	}
+
+	info := &grpc.StreamServerInfo{
+		FullMethod: "/test.TestService/TestStream",
+	}
+
+	stream := &mockServerStream{}
+
+	incerceptorStream := interceptor.Stream()
+	err = incerceptorStream(nil, stream, info, handler)
+
+	require.Error(t, err)
+	require.Equal(t, 1, logs.Len(), "expected one log entry but got none")
+
+	logEntry := logs.All()[0]
+
+	require.Equal(t, zapcore.ErrorLevel, logEntry.Level, "expected log level 'Error'")
+	require.Contains(t, logEntry.ContextMap(), "method")
+	require.Equal(
+		t,
+		"/test.TestService/TestStream",
+		logEntry.ContextMap()["method"],
+		"expected log to contain correct method",
+	)
+	require.Contains(t, logEntry.ContextMap(), "message")
+	require.Equal(
+		t,
+		"mock stream error",
+		logEntry.ContextMap()["message"],
+		"expected log to contain correct error message",
+	)
+}