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Merged
anuraaga merged 1 commit into from
Apr 17, 2026
+163 −9
Merged

Allow generating only async or sync code #214

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14 changes: 14 additions & 0 deletions protoc-gen-connect-python/generator/config.go
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,11 @@ type Config struct {

// Imports is how to import dependencies in the generated code.
Imports Imports

// Async indicates whether to only generate asynchronous code. If false,
// only synchronous code will be generated. If nil, both synchronous and
// asynchronous code will be generated.
Async *bool
}

func parseConfig(p string) Config {
Expand Down Expand Up @@ -64,6 +69,15 @@ func parseConfig(p string) Config {
case "relative":
cfg.Imports = ImportsRelative
}
case "async":
switch value {
case "true":
trueVal := true
cfg.Async = &trueVal
case "false":
falseVal := false
cfg.Async = &falseVal
}
Comment on lines +73 to +80
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@stefanvanburen stefanvanburen Apr 13, 2026

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first time looking closely at the option parsing, but: should we be failing here on unrecognized option keys/values? (see https://github.com/connectrpc/connect-go/blob/e299aa60ffcf91633e48fcb3dd594cbbb187ec7f/cmd/protoc-gen-connect-go/main.go#L779)

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@anuraaga anuraaga Apr 17, 2026

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Yeah probably should - I think we can leave this for now given the future work on codegen

}
}
return cfg
Expand Down
9 changes: 8 additions & 1 deletion protoc-gen-connect-python/generator/generator.go
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Expand Up @@ -55,6 +55,13 @@ func generateConnectFile(fd protoreflect.FileDescriptor, conf Config) (string, s
ModuleName: moduleName,
Imports: importStatements(fd, conf),
}
if conf.Async != nil {
if *conf.Async {
vars.SkipSync = true
} else {
vars.SkipAsync = true
}
}

svcs := fd.Services()
packageName := string(fd.Package())
Expand Down Expand Up @@ -109,7 +116,7 @@ func generateConnectFile(fd protoreflect.FileDescriptor, conf Config) (string, s
vars.Services = append(vars.Services, connectSvc)
}

var buf = &bytes.Buffer{}
buf := &bytes.Buffer{}
err := ConnectTemplate.Execute(buf, vars)
if err != nil {
return "", "", fmt.Errorf("failed to execute template: %w", err)
Expand Down
136 changes: 131 additions & 5 deletions protoc-gen-connect-python/generator/generator_test.go
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Expand Up @@ -127,10 +127,11 @@ func TestGenerate(t *testing.T) {
t.Parallel()

tests := []struct {
name string
req *pluginpb.CodeGeneratorRequest
wantStrings []string
wantErr bool
name string
req *pluginpb.CodeGeneratorRequest
wantStrings []string
dontWantStrings []string
wantErr bool
}{
{
name: "empty request",
Expand Down Expand Up @@ -195,7 +196,127 @@ func TestGenerate(t *testing.T) {
},
},
wantErr: false,
wantStrings: []string{"def try_(self"},
wantStrings: []string{"class TestServiceASGIApplication", "class TestServiceWSGIApplication"},
},
{
name: "async only",
req: &pluginpb.CodeGeneratorRequest{
FileToGenerate: []string{"test.proto"},
Parameter: proto.String("async=true"),
ProtoFile: []*descriptorpb.FileDescriptorProto{
{
Name: proto.String("test.proto"),
Package: proto.String("test"),
Dependency: []string{"other.proto"},
Service: []*descriptorpb.ServiceDescriptorProto{
{
Name: proto.String("TestService"),
Method: []*descriptorpb.MethodDescriptorProto{
{
Name: proto.String("TestMethod"),
InputType: proto.String(".test.TestRequest"),
OutputType: proto.String(".test.TestResponse"),
},
{
Name: proto.String("TestMethod2"),
InputType: proto.String(".otherpackage.OtherRequest"),
OutputType: proto.String(".otherpackage.OtherResponse"),
},
// Reserved keyword
{
Name: proto.String("Try"),
InputType: proto.String(".otherpackage.OtherRequest"),
OutputType: proto.String(".otherpackage.OtherResponse"),
},
},
},
},
MessageType: []*descriptorpb.DescriptorProto{
{
Name: proto.String("TestRequest"),
},
{
Name: proto.String("TestResponse"),
},
},
},
{
Name: proto.String("other.proto"),
Package: proto.String("otherpackage"),
MessageType: []*descriptorpb.DescriptorProto{
{
Name: proto.String("OtherRequest"),
},
{
Name: proto.String("OtherResponse"),
},
},
},
},
},
wantErr: false,
wantStrings: []string{"class TestServiceASGIApplication"},
dontWantStrings: []string{"class TestServiceWSGIApplication"},
},
{
name: "sync only",
req: &pluginpb.CodeGeneratorRequest{
FileToGenerate: []string{"test.proto"},
Parameter: proto.String("async=false"),
ProtoFile: []*descriptorpb.FileDescriptorProto{
{
Name: proto.String("test.proto"),
Package: proto.String("test"),
Dependency: []string{"other.proto"},
Service: []*descriptorpb.ServiceDescriptorProto{
{
Name: proto.String("TestService"),
Method: []*descriptorpb.MethodDescriptorProto{
{
Name: proto.String("TestMethod"),
InputType: proto.String(".test.TestRequest"),
OutputType: proto.String(".test.TestResponse"),
},
{
Name: proto.String("TestMethod2"),
InputType: proto.String(".otherpackage.OtherRequest"),
OutputType: proto.String(".otherpackage.OtherResponse"),
},
// Reserved keyword
{
Name: proto.String("Try"),
InputType: proto.String(".otherpackage.OtherRequest"),
OutputType: proto.String(".otherpackage.OtherResponse"),
},
},
},
},
MessageType: []*descriptorpb.DescriptorProto{
{
Name: proto.String("TestRequest"),
},
{
Name: proto.String("TestResponse"),
},
},
},
{
Name: proto.String("other.proto"),
Package: proto.String("otherpackage"),
MessageType: []*descriptorpb.DescriptorProto{
{
Name: proto.String("OtherRequest"),
},
{
Name: proto.String("OtherResponse"),
},
},
},
},
},
wantErr: false,
wantStrings: []string{"class TestServiceWSGIApplication"},
dontWantStrings: []string{"class TestServiceASGIApplication"},
},
}

Expand All @@ -219,6 +340,11 @@ func TestGenerate(t *testing.T) {
t.Errorf("generate() missing expected string: %v", s)
}
}
for _, s := range tt.dontWantStrings {
if strings.Contains(resp.GetFile()[0].GetContent(), s) {
t.Errorf("generate() contains unexpected string: %v", s)
}
}
}
})
}
Expand Down
13 changes: 10 additions & 3 deletions protoc-gen-connect-python/generator/template.go
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Expand Up @@ -13,6 +13,8 @@ type ConnectTemplateVariables struct {
ModuleName string
Imports []ImportStatement
Services []*ConnectService
SkipAsync bool
SkipSync bool
}

type ConnectService struct {
Expand Down Expand Up @@ -61,9 +63,9 @@ from connectrpc.server import ConnectASGIApplication, ConnectWSGIApplication, En
{{if .Relative}}from . import {{.Name}}{{else}}import {{.Name}}{{end}} as {{.Alias}}
{{- end}}
{{- end}}
{{- range .Services}}


{{if not .SkipAsync }}
{{- range .Services}}
class {{.Name}}(Protocol):{{- range .Methods }}
{{if not .ResponseStream }}async {{end}}def {{.PythonName}}(self, request: {{if .RequestStream}}AsyncIterator[{{end}}{{.InputType}}{{if .RequestStream}}]{{end}}, ctx: RequestContext) -> {{if .ResponseStream}}AsyncIterator[{{end}}{{.OutputType}}{{if .ResponseStream}}]{{end}}:
raise ConnectError(Code.UNIMPLEMENTED, "Not implemented")
Expand Down Expand Up @@ -124,6 +126,9 @@ class {{.Name}}Client(ConnectClient):{{range .Methods}}
{{- end}}
)
{{end}}{{- end }}
{{end}}

{{if not .SkipSync }}
{{range .Services}}
class {{.Name}}Sync(Protocol):{{- range .Methods }}
def {{.PythonName}}(self, request: {{if .RequestStream}}Iterator[{{end}}{{.InputType}}{{if .RequestStream}}]{{end}}, ctx: RequestContext) -> {{if .ResponseStream}}Iterator[{{end}}{{.OutputType}}{{if .ResponseStream}}]{{end}}:
Expand Down Expand Up @@ -184,4 +189,6 @@ class {{.Name}}ClientSync(ConnectClientSync):{{range .Methods}}
use_get=use_get,
{{- end}}
)
{{end}}{{end}}`))
{{end}}{{end}}
{{end}}
`))
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