/
handler.go
137 lines (118 loc) · 3.07 KB
/
handler.go
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package rpc
import (
"bufio"
"context"
"fmt"
"io"
"os"
"strings"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
"google.golang.org/protobuf/proto"
"google.golang.org/protobuf/reflect/protoreflect"
pb "github.com/sqlc-dev/plugin-sdk-go/plugin"
)
func Handle(server pb.CodegenServiceServer) {
if err := handle(server); err != nil {
fmt.Fprintf(os.Stderr, "error generating output: %s", err)
os.Exit(2)
}
}
func handle(server pb.CodegenServiceServer) error {
handler := newStdioRPCHandler()
pb.RegisterCodegenServiceServer(handler, server)
return handler.Handle()
}
type stdioRPCHandler struct {
services map[string]*serviceInfo
}
func newStdioRPCHandler() *stdioRPCHandler {
return &stdioRPCHandler{services: map[string]*serviceInfo{}}
}
type serviceInfo struct {
serviceImpl any
methods map[string]*grpc.MethodDesc
}
func (s *stdioRPCHandler) RegisterService(sd *grpc.ServiceDesc, ss any) {
// TODO some type checking, see e.g. grpc server.RegisterService()
info := &serviceInfo{
serviceImpl: ss,
methods: make(map[string]*grpc.MethodDesc),
}
for i := range sd.Methods {
d := &sd.Methods[i]
info.methods[d.MethodName] = d
}
s.services[sd.ServiceName] = info
}
func (s *stdioRPCHandler) Handle() error {
var methodArg string
if len(os.Args) < 2 {
// For backwards compatibility with sqlc before v1.24.0
methodArg = fmt.Sprintf("/%s/%s", pb.CodegenService_ServiceDesc.ServiceName, "Generate")
} else {
methodArg = os.Args[1]
}
// Adapted from grpc server handleStream()
sm := methodArg
if sm != "" && sm[0] == '/' {
sm = sm[1:]
}
pos := strings.LastIndex(sm, "/")
if pos == -1 {
errDesc := fmt.Sprintf("malformed method name: %q", methodArg)
return status.Error(codes.Unimplemented, errDesc)
}
service := sm[:pos]
method := sm[pos+1:]
srv, knownService := s.services[service]
if knownService {
if md, ok := srv.methods[method]; ok {
return s.processUnaryRPC(srv, md)
}
}
// Unknown service, or known server unknown method.
var errDesc string
if !knownService {
errDesc = fmt.Sprintf("unknown service %v", service)
} else {
errDesc = fmt.Sprintf("unknown method %v for service %v", method, service)
}
return status.Error(codes.Unimplemented, errDesc)
}
func (s *stdioRPCHandler) processUnaryRPC(srv *serviceInfo, md *grpc.MethodDesc) error {
reqBytes, err := io.ReadAll(os.Stdin)
if err != nil {
return err
}
var resp protoreflect.ProtoMessage
// TODO make this generic
switch md.MethodName {
case "Generate":
var req pb.GenerateRequest
if err := proto.Unmarshal(reqBytes, &req); err != nil {
return err
}
service, ok := srv.serviceImpl.(pb.CodegenServiceServer)
if !ok {
return status.Errorf(codes.Internal, codes.Internal.String())
}
resp, err = service.Generate(context.Background(), &req)
if err != nil {
return err
}
}
respBytes, err := proto.Marshal(resp)
if err != nil {
return err
}
w := bufio.NewWriter(os.Stdout)
if _, err := w.Write(respBytes); err != nil {
return err
}
if err := w.Flush(); err != nil {
return err
}
return nil
}