add grpc support

go.mod

@@ -4,6 +4,7 @@ go 1.23.4
 
 require (
 	github.com/caarlos0/env/v11 v11.3.1
+	github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.3.1
 	github.com/prometheus/client_golang v1.20.5
 	github.com/rs/zerolog v1.33.0
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.60.0

go.sum

@@ -23,6 +23,8 @@ github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.3.1 h1:KcFzXwzM/kGhIRHvc8jdixfIJjVzuUJdnv+5xsPutog=
+github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.3.1/go.mod h1:qOchhhIlmRcqk/O9uCo/puJlyo07YINaIqdZfZG3Jkc=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.25.1 h1:VNqngBF40hVlDloBruUehVYC3ArSgIyScOAyMRqBxRg=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.25.1/go.mod h1:RBRO7fro65R6tjKzYgLAFo0t1QEXY1Dp+i/bvpRiqiQ=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.0 h1:VD1gqscl4nYs1YxVuSdemTrSgTKrwOWDK0FVFMqm+Cg=

pkg/app/app_types.go

@@ -24,8 +24,10 @@ type App struct {
 }
 
 type AppGRPC struct {
-	Services []*GRPCService
-	GRPCOpts []grpc.ServerOption
+	Services           []*GRPCService
+	UnaryInterceptors  []grpc.UnaryServerInterceptor
+	StreamInterceptors []grpc.StreamServerInterceptor
+	GRPCOpts           []grpc.ServerOption
 }
 
 type GRPCService struct {

pkg/srv/grpc/grpc.go

@@ -3,27 +3,54 @@ package grpc
 import (
 	"context"
 
-	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
+	"github.com/rs/zerolog"
+	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/trace"
-	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	"google.golang.org/grpc"
 
+	appotel "gitea.libretechconsulting.com/rmcguire/go-app/pkg/otel"
 	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/grpc/opts"
 )
 
-type AppGRPCServer struct {
-	ctx    context.Context
-	tracer trace.Tracer
-	meter  metric.Meter
+type appGRPCServer struct {
+	ctx        context.Context
+	tracer     trace.Tracer
+	meter      metric.Meter
+	opts       *opts.GRPCOpts
+	serverOpts []grpc.ServerOption
+	logger     *zerolog.Logger
+	server     *grpc.Server
 }
 
-func InitGRPCServer(ctx context.Context, opts *opts.GRPCOpts) {
-	server := grpc.NewServer()
-
-	stats := otelgrpc.NewServerHandler(otelgrpc.WithTracerProvider(sdktrace.T))
-
-	for _, service := range opts.Services {
-		server.RegisterService(service.Type, service.Service)
+// TODO: This probably needs to pass back an error chan and a shutdown
+// func like the http server does
+func InitGRPCServer(ctx context.Context, opts *opts.GRPCOpts) error {
+	appGRPC := &appGRPCServer{
+		ctx:        ctx,
+		tracer:     appotel.GetTracer(ctx, "grpc"),
+		meter:      appotel.GetMeter(ctx, "grpc"),
+		opts:       opts,
+		serverOpts: make([]grpc.ServerOption, 0),
+		logger:     zerolog.Ctx(ctx),
 	}
+
+	ctx, span := appGRPC.tracer.Start(ctx, "appgrpc.init")
+	defer span.End()
+
+	if err := appGRPC.prepGRPCServer(ctx); err != nil {
+		span.RecordError(err)
+		span.SetStatus(codes.Error, "failed to prepare GRPC Server")
+		return err
+	}
+
+	err := appGRPC.runGRPCServer(ctx)
+	if err != nil {
+		span.RecordError(err)
+		span.SetStatus(codes.Error, "failed to start GRPC Server")
+		return err
+	}
+
+	span.SetStatus(codes.Ok, "")
+	return nil
 }

pkg/srv/grpc/grpc_logger.go

@@ -0,0 +1,51 @@
+package grpc
+
+import (
+	"context"
+
+	grpclogging "github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+// A grpc logging middleware compatible logger
+// implementation using a zerolog logger, either from
+// the global logger or a context logger
+type GRPCLogger struct {
+	logger zerolog.Logger
+}
+
+// Returns a grpcLogger using the global zerolog Logger
+func NewGRPCLogger() *GRPCLogger {
+	return &GRPCLogger{logger: log.Logger}
+}
+
+// Returns a grpcLogger using the zerolog logger in the provided context
+func NewGRPCContextLogger(ctx context.Context) *GRPCLogger {
+	logger := log.Ctx(ctx)
+	return &GRPCLogger{logger: *logger}
+}
+
+// Log logs the fields for given log level. We can assume users (middleware library) will put fields in pairs and
+// those will be unique.
+func (l *GRPCLogger) Log(ctx context.Context, level grpclogging.Level, msg string, fields ...any) {
+	var event *zerolog.Event
+
+	switch level {
+	case grpclogging.LevelDebug:
+		event = l.logger.Debug()
+	case grpclogging.LevelInfo:
+		event = l.logger.Info()
+	case grpclogging.LevelWarn:
+		event = l.logger.Warn()
+	case grpclogging.LevelError:
+		event = l.logger.Error()
+	default:
+		event = l.logger.Warn().
+			Int("unknowngrpcloglevel", int(level))
+	}
+
+	event.Ctx(ctx)
+	event.Fields(fields)
+	event.Msg(msg)
+}

pkg/srv/grpc/grpc_prepare.go

@@ -0,0 +1,96 @@
+package grpc
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	grpclogging "github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
+	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
+)
+
+func (a *appGRPCServer) prepGRPCServer(spanCtx context.Context) error {
+	ctx, span := a.tracer.Start(spanCtx, "appgrpc.init.prepare")
+	defer span.End()
+
+	if len(a.opts.Services) < 1 {
+		err := errors.New("refusing to create grpc server with no services")
+		a.logger.Err(err).Send()
+		span.RecordError(err)
+		span.SetStatus(codes.Error, err.Error())
+		return err
+	}
+
+	// Prepare GRPC Server Opts
+	a.prepareOTEL(ctx)
+	a.prepareLogging(ctx)
+
+	// Chain interceptors for unary RPCs
+	a.serverOpts = append(a.serverOpts,
+		grpc.ChainUnaryInterceptor(a.opts.UnaryInterceptors...))
+	span.SetAttributes(attribute.Int("numUnaryInterceptors",
+		len(a.opts.UnaryInterceptors)))
+
+	// Chain interceptors for streaming RPCs
+	a.serverOpts = append(a.serverOpts,
+		grpc.ChainStreamInterceptor(a.opts.StreamInterceptors...))
+	span.SetAttributes(attribute.Int("numStreamInterceptors",
+		len(a.opts.StreamInterceptors)))
+
+	// Prepare GRPC Server
+	a.server = grpc.NewServer(a.serverOpts...)
+	span.SetAttributes(attribute.Int("numServerOpts", len(a.serverOpts)))
+
+	// Load given services into server registry
+	for _, service := range a.opts.Services {
+		span.AddEvent(fmt.Sprintf("registered %s service", service.Name))
+		a.server.RegisterService(service.Type, service.Service)
+	}
+	span.SetAttributes(attribute.Int("numGRPCServices", len(a.opts.Services)))
+
+	// Enable reflection if desired
+	if a.opts.EnableReflection {
+		reflection.Register(a.server)
+	}
+	span.SetAttributes(attribute.Bool("reflectionEnabled", a.opts.EnableReflection))
+
+	span.SetStatus(codes.Ok, "")
+	return nil
+}
+
+func (a *appGRPCServer) prepareOTEL(spanCtx context.Context) {
+	_, span := a.tracer.Start(spanCtx, "appgrpc.init.prepare.otel", trace.WithAttributes(
+		attribute.Bool("instrumentationEnabled", a.opts.EnableInstrumentation),
+		attribute.String("logLevel", a.logger.GetLevel().String())))
+	defer span.End()
+
+	if a.opts.EnableInstrumentation {
+		a.serverOpts = append(a.serverOpts,
+			grpc.StatsHandler(
+				otelgrpc.NewServerHandler(
+					otelgrpc.WithTracerProvider(otel.GetTracerProvider()),
+					otelgrpc.WithMeterProvider(otel.GetMeterProvider()),
+				)))
+		span.SetStatus(codes.Ok, "")
+	}
+}
+
+func (a *appGRPCServer) prepareLogging(spanCtx context.Context) {
+	_, span := a.tracer.Start(spanCtx, "appgrpc.init.prepare.logging", trace.WithAttributes(
+		attribute.Bool("instrumentationEnabled", a.opts.LogRequests)))
+	defer span.End()
+
+	if a.opts.LogRequests {
+		a.opts.UnaryInterceptors = append(a.opts.UnaryInterceptors,
+			grpclogging.UnaryServerInterceptor(NewGRPCContextLogger(a.ctx)))
+		a.opts.StreamInterceptors = append(a.opts.StreamInterceptors,
+			grpclogging.StreamServerInterceptor(NewGRPCContextLogger(a.ctx)))
+		span.SetStatus(codes.Ok, "")
+	}
+}

pkg/srv/grpc/grpc_run.go

@@ -0,0 +1,11 @@
+package grpc
+
+import "context"
+
+// TODO: Implement
+func (a *appGRPCServer) runGRPCServer(spanCtx context.Context) error {
+	_, span := a.tracer.Start(spanCtx, "appgrpc.init.start")
+	defer span.End()
+
+	return nil
+}