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Merged
raphael merged 1 commit into from
Oct 16, 2025
Merged

Add gRPC support to mains plugin #215

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110 changes: 101 additions & 9 deletions mains/generate.go
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,8 @@ type srvInfo struct {
APIPkg string
Services []*service.Data
HasWS bool
HasHTTP bool
HasGRPC bool
ServerName string
}

Expand All @@ -43,7 +45,11 @@ type svcT struct {
SrvVar string
GenPkg string
GenHTTPPkg string
GenGRPCPkg string
GenGRPCPbPkg string
HasWebSocket bool
HasHTTP bool
HasGRPC bool
}

// Register the plugin for the example phase.
Expand Down Expand Up @@ -109,21 +115,32 @@ func generateExample(genpkg string, roots []eval.Root, files []*codegen.File) ([
apipkg := apiPkgAlias(genpkg, roots)
if info, ok := srvMap[dir]; ok {
info.HasWS = hasWS
info.HasHTTP = true
if info.APIPkg == "" { info.APIPkg = apipkg }
} else {
srvMap[dir] = &srvInfo{Dir: dir, APIPkg: apipkg, Services: svcs, HasWS: hasWS}
srvMap[dir] = &srvInfo{Dir: dir, APIPkg: apipkg, Services: svcs, HasWS: hasWS, HasHTTP: true}
}
}
// Detect gRPC servers from grpc.go files
for _, f := range files {
if filepath.Base(f.Path) != "grpc.go" { continue }
segs := strings.Split(filepath.ToSlash(f.Path), "/")
if len(segs) < 3 || segs[0] != "cmd" { continue }
dir := segs[1]
if info, ok := srvMap[dir]; ok {
info.HasGRPC = true
}
}

if len(srvMap) == 0 {
return files, nil
}

// Filter out default example mains and http.go; we'll add our own mains.
// Filter out default example mains, http.go, and grpc.go; we'll add our own mains.
var out []*codegen.File
for _, f := range files {
base := filepath.Base(f.Path)
if strings.HasPrefix(f.Path, "cmd/") && (base == "main.go" || base == "http.go") {
if strings.HasPrefix(f.Path, "cmd/") && (base == "main.go" || base == "http.go" || base == "grpc.go") {
continue
}
out = append(out, f)
Expand Down Expand Up @@ -156,6 +173,14 @@ func generateExample(genpkg string, roots []eval.Root, files []*codegen.File) ([
codegen.GoaNamedImport("http", "goahttp"),
{Path: "google.golang.org/grpc/credentials/insecure"},
}
if info.HasGRPC {
specs = append(specs,
&codegen.ImportSpec{Path: "net"},
&codegen.ImportSpec{Path: "google.golang.org/grpc"},
&codegen.ImportSpec{Path: "google.golang.org/grpc/reflection"},
&codegen.ImportSpec{Path: "go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"},
)
}
if info.HasWS {
specs = append(specs, &codegen.ImportSpec{Path: "github.com/gorilla/websocket"})
}
Expand All @@ -164,19 +189,45 @@ func generateExample(genpkg string, roots []eval.Root, files []*codegen.File) ([

scope := codegen.NewNameScope()
var svcsData []svcT
httpBySvc := httpServicesByName(roots)
grpcBySvc := grpcServicesByName(roots)
wsBySvc := httpWebSocketByService(roots)
hasAnyWS := false
hasAnyHTTP := false
hasAnyGRPC := false
for _, sd := range info.Services {
genAlias := scope.Unique(sd.PkgName, "svc")
httpAlias := scope.Unique(sd.PkgName+"svr", "svr")
specs = append(specs,
&codegen.ImportSpec{Path: path.Join(genpkg, sd.PathName), Name: genAlias},
&codegen.ImportSpec{Path: path.Join(genpkg, "http", sd.PathName, "server"), Name: httpAlias},
)
hasHTTP := httpBySvc[sd.Name]
hasGRPC := grpcBySvc[sd.Name]
hws := wsBySvc[sd.Name]

var httpAlias, grpcAlias, grpcPbAlias string

// Always add the base service package
specs = append(specs, &codegen.ImportSpec{Path: path.Join(genpkg, sd.PathName), Name: genAlias})

// Conditionally add HTTP server imports
if hasHTTP {
httpAlias = scope.Unique(sd.PkgName+"svr", "svr")
specs = append(specs, &codegen.ImportSpec{Path: path.Join(genpkg, "http", sd.PathName, "server"), Name: httpAlias})
hasAnyHTTP = true
}

// Conditionally add gRPC server imports
if hasGRPC {
grpcAlias = scope.Unique(sd.PkgName+"grpc", "grpcsvc")
grpcPbAlias = scope.Unique(sd.PkgName+"pb", "pb")
specs = append(specs,
&codegen.ImportSpec{Path: path.Join(genpkg, "grpc", sd.PathName, "server"), Name: grpcAlias},
&codegen.ImportSpec{Path: path.Join(genpkg, "grpc", sd.PathName, "pb"), Name: grpcPbAlias},
)
hasAnyGRPC = true
}

if hws {
hasAnyWS = true
}

svcsData = append(svcsData, svcT{
Name: sd.Name,
StructName: sd.StructName,
Expand All @@ -185,7 +236,11 @@ func generateExample(genpkg string, roots []eval.Root, files []*codegen.File) ([
SrvVar: sd.VarName + "Server",
GenPkg: genAlias,
GenHTTPPkg: httpAlias,
GenGRPCPkg: grpcAlias,
GenGRPCPbPkg: grpcPbAlias,
HasWebSocket: hws,
HasHTTP: hasHTTP,
HasGRPC: hasGRPC,
})
}

Expand All @@ -195,6 +250,8 @@ func generateExample(genpkg string, roots []eval.Root, files []*codegen.File) ([
"APIPkg": info.APIPkg,
"Services": svcsData,
"HasAnyWebSocket": hasAnyWS,
"HasHTTP": hasAnyHTTP,
"HasGRPC": hasAnyGRPC,
"ServiceCount": len(svcsData),
"ServerLabel": serverLabel(roots),
}},
Expand Down Expand Up @@ -265,7 +322,8 @@ func httpWebSocketByService(roots []eval.Root) map[string]bool {
if e.SSE != nil {
continue
}
if e.MethodExpr != nil && e.MethodExpr.Stream != expr.NoStreamKind {
// Stream is 0 when no streaming is defined, and >= NoStreamKind (1) when streaming is used
if e.MethodExpr != nil && e.MethodExpr.Stream != 0 {
hasWS[svc.Name()] = true
break
}
Expand All @@ -286,3 +344,37 @@ func rootServer(roots []eval.Root) *expr.ServerExpr {
}
return nil
}

// httpServicesByName returns map of service names that have HTTP endpoints.
func httpServicesByName(roots []eval.Root) map[string]bool {
hasHTTP := map[string]bool{}
for _, r := range roots {
root, ok := r.(*expr.RootExpr)
if !ok || root.API == nil || root.API.HTTP == nil {
continue
}
for _, svc := range root.API.HTTP.Services {
if len(svc.HTTPEndpoints) > 0 {
hasHTTP[svc.Name()] = true
}
}
}
return hasHTTP
}

// grpcServicesByName returns map of service names that have gRPC endpoints.
func grpcServicesByName(roots []eval.Root) map[string]bool {
hasGRPC := map[string]bool{}
for _, r := range roots {
root, ok := r.(*expr.RootExpr)
if !ok || root.API == nil || root.API.GRPC == nil {
continue
}
for _, svc := range root.API.GRPC.Services {
if len(svc.GRPCEndpoints) > 0 {
hasGRPC[svc.Name()] = true
}
}
}
return hasGRPC
}
88 changes: 57 additions & 31 deletions mains/templates/main.go.tpl
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,35 +1,11 @@
package main

import (
"context"
"flag"
"fmt"
"net/http"
"net/http/httptrace"
"os"
"os/signal"
"sync"
"syscall"
"time"

"go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace"
"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
"goa.design/clue/clue"
"goa.design/clue/debug"
"goa.design/clue/health"
"goa.design/clue/log"
goahttp "goa.design/goa/v3/http"
{{- if .HasAnyWebSocket }}
"github.com/gorilla/websocket"
{{- end }}
"google.golang.org/grpc/credentials/insecure"
)

func main() {
var (
{{- if .HasHTTP }}
httpaddr = flag.String("http-addr", ":8080", "HTTP listen address")
{{- end }}
{{- if .HasGRPC }}
grpcaddr = flag.String("grpc-addr", ":9090", "gRPC listen address")
{{- end }}
metricsAddr = flag.String("metrics-addr", ":8081", "metrics listen address")
coladdr = flag.String("otel-addr", ":4317", "OpenTelemetry collector listen address")
debugf = flag.Bool("debug", false, "Enable debug logs")
Expand Down Expand Up @@ -126,6 +102,7 @@ func main() {
{{ .EpVar }}.Use(log.Endpoint)
{{- end }}

{{- if .HasHTTP }}
// 6. Create HTTP transport
mux := goahttp.NewMuxer()
debug.MountDebugLogEnabler(debug.Adapt(mux))
Expand All @@ -139,6 +116,7 @@ func main() {
{{- end }}

{{- range .Services }}
{{- if .HasHTTP }}
// {{ .Name }} HTTP server
{{- if .HasWebSocket }}
{{ .SrvVar }} := {{ .GenHTTPPkg }}.New({{ .EpVar }}, mux, goahttp.RequestDecoder, goahttp.ResponseEncoder, nil, nil, upgrader, nil)
Expand All @@ -150,10 +128,37 @@ func main() {
log.Print(ctx, log.KV{K: "method", V: m.Method}, log.KV{K: "endpoint", V: m.Verb + " " + m.Pattern})
}
{{- end }}
{{- end }}

httpServer := &http.Server{Addr: *httpaddr, Handler: handler}
{{- end }}

{{- if .HasGRPC }}
// 6b. Create gRPC server with interceptors
var grpcServerOpts []grpc.ServerOption
grpcServerOpts = append(grpcServerOpts, grpc.StatsHandler(otelgrpc.NewServerHandler()))
grpcServerOpts = append(grpcServerOpts, grpc.ChainUnaryInterceptor(
log.UnaryServerInterceptor(ctx),
debug.UnaryServerInterceptor(),
))
grpcServerOpts = append(grpcServerOpts, grpc.ChainStreamInterceptor(
log.StreamServerInterceptor(ctx),
debug.StreamServerInterceptor(),
))
grpcServer := grpc.NewServer(grpcServerOpts...)

{{- range .Services }}
{{- if .HasGRPC }}
// {{ .Name }} gRPC server
{{ .SvcVar }}GRPCServer := {{ .GenGRPCPkg }}.New({{ .EpVar }}, nil)
{{ .GenGRPCPbPkg }}.Register{{ .StructName }}Server(grpcServer, {{ .SvcVar }}GRPCServer)
{{- end }}
{{- end }}

// 7. Start HTTP servers (graceful shutdown)
reflection.Register(grpcServer)
{{- end }}

// 7. Start servers (graceful shutdown)
errc := make(chan error)
go func() {
c := make(chan os.Signal, 1)
Expand All @@ -167,18 +172,32 @@ func main() {
go func() {
defer wg.Done()

{{- if .HasHTTP }}
go func() {
log.Printf(ctx, "HTTP server listening on %s", *httpaddr)
errc <- httpServer.ListenAndServe()
}()
{{- end }}

{{- if .HasGRPC }}
go func() {
lis, err := net.Listen("tcp", *grpcaddr)
if err != nil {
errc <- err
return
}
log.Printf(ctx, "gRPC server listening on %s", *grpcaddr)
errc <- grpcServer.Serve(lis)
}()
{{- end }}

go func() {
log.Printf(ctx, "Metrics server listening on %s", *metricsAddr)
errc <- metricsServer.ListenAndServe()
}()

<-ctx.Done()
log.Printf(ctx, "shutting down HTTP servers")
log.Printf(ctx, "shutting down servers")

// Shutdown gracefully with a 30s timeout.
sctx, scancel := context.WithTimeout(context.Background(), 30*time.Second)
Expand All @@ -192,9 +211,16 @@ func main() {
}
{{- end }}

{{- if .HasHTTP }}
if err := httpServer.Shutdown(sctx); err != nil {
log.Errorf(sctx, err, "failed to shutdown HTTP server")
}
{{- end }}

{{- if .HasGRPC }}
grpcServer.GracefulStop()
{{- end }}

if err := metricsServer.Shutdown(sctx); err != nil {
log.Errorf(sctx, err, "failed to shutdown metrics server")
}
Expand Down
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