Add stream support

cmd/mobyextgen/descriptor.go

@@ -80,11 +80,18 @@ func fileDescriptor(pt point) (*descriptorpb.FileDescriptorProto, error) {
 
 	svc := &descriptorpb.ServiceDescriptorProto{Name: new(pt.service)}
 	for _, m := range pt.methods {
-		svc.Method = append(svc.Method, &descriptorpb.MethodDescriptorProto{
+		method := &descriptorpb.MethodDescriptorProto{
 			Name:       new(m.name),
 			InputType:  new("." + pt.id + "." + m.request),
 			OutputType: new("." + pt.id + "." + m.response),
-		})
+		}
+		if m.kind == methodClientStreaming {
+			method.ClientStreaming = new(true)
+		}
+		if m.kind == methodServerStreaming {
+			method.ServerStreaming = new(true)
+		}
+		svc.Method = append(svc.Method, method)
 	}
 	fd.Service = []*descriptorpb.ServiceDescriptorProto{svc}
 	return fd, nil

cmd/mobyextgen/generation_test.go

@@ -39,9 +39,11 @@ func TestGeneratedFilesInheritContractNotices(t *testing.T) {
 			assert.NilError(t, os.WriteFile(filepath.Join(dir, "go.mod"), []byte("module example.com/contract\n"), 0o644))
 			const contract = `package contract
 
+import "context"
+
 // SPDX-FileCopyrightText: ignore comments after the package clause
 // SPDX-License-Identifier: ignore comments after the package clause
-type Runtime interface{ Do(ctx interface{}, req *Req) (*Resp, error) }
+type Runtime interface{ Do(ctx context.Context, req *Req) (*Resp, error) }
 type Req struct{}
 type Resp struct{}
 `
@@ -88,8 +90,9 @@ func TestSingleMessageField(t *testing.T) {
 
 func TestInitialismFieldBridgesNames(t *testing.T) {
 	const src = `package p
+import "context"
 import "github.com/moby/extensions"
-type S interface{ Do(ctx interface{}, req *Req) (*Resp, error) }
+type S interface{ Do(ctx context.Context, req *Req) (*Resp, error) }
 type Req struct{ ContainerID string ` + "`pb:\"1\"`" + ` }
 type Resp struct{ Ok bool ` + "`pb:\"1\"`" + ` }
 var Point = extensions.DefinePoint[S]("test.gen.v1")
@@ -114,10 +117,11 @@ var Point = extensions.DefinePoint[S]("test.gen.v1")
 
 func TestServiceContractWithoutAPoint(t *testing.T) {
 	const contract = `package p
+import "context"
 type Req struct{ Name string ` + "`pb:\"1\"`" + ` }
 type Resp struct{ Ok bool ` + "`pb:\"1\"`" + ` }
 
-type Runtime interface{ Do(ctx interface{}, req *Req) (*Resp, error) }
+type Runtime interface{ Do(ctx context.Context, req *Req) (*Resp, error) }
 `
 	pt, err := parseServiceSource(t, contract, "my.proto.pkg.v1.Runtime")
 	assert.NilError(t, err)
@@ -140,13 +144,14 @@ type Runtime interface{ Do(ctx interface{}, req *Req) (*Resp, error) }
 
 func TestOrdinaryPointGeneratesPublicationAndClientAPIs(t *testing.T) {
 	const contract = `package p
+import "context"
 import "github.com/moby/extensions"
 type Req struct{ Name string ` + "`pb:\"1\"`" + ` }
 type Resp struct{ Ok bool ` + "`pb:\"1\"`" + ` }
 
 type Runtime interface {
-	Do(ctx interface{}, req *Req) (*Resp, error)
-	Delete(ctx interface{}, req *Req) error
+	Do(ctx context.Context, req *Req) (*Resp, error)
+	Delete(ctx context.Context, req *Req) error
 }
 var Point = extensions.DefinePoint[Runtime]("my.proto.pkg.v1")
 `
@@ -173,8 +178,9 @@ var Point = extensions.DefinePoint[Runtime]("my.proto.pkg.v1")
 
 func TestReservedFieldNumbers(t *testing.T) {
 	const header = `package p
+import "context"
 import "github.com/moby/extensions"
-type S interface{ Do(ctx interface{}, req *Req) (*Resp, error) }
+type S interface{ Do(ctx context.Context, req *Req) (*Resp, error) }
 type Resp struct{ Ok bool ` + "`pb:\"1\"`" + ` }
 
 var Point = extensions.DefinePoint[S]("test.gen.v1")
@@ -224,8 +230,9 @@ var Point = extensions.DefinePoint[S]("test.gen.v1")
 
 func TestSinglePointCardinality(t *testing.T) {
 	const contract = `package p
+import "context"
 import "github.com/moby/extensions"
-type S interface{ Do(ctx interface{}, req *Req) (*Resp, error) }
+type S interface{ Do(ctx context.Context, req *Req) (*Resp, error) }
 type Req struct{ Name string ` + "`pb:\"1\"`" + ` }
 type Resp struct{ Ok bool ` + "`pb:\"1\"`" + ` }
 `

cmd/mobyextgen/model.go

@@ -14,6 +14,7 @@ type point struct {
 	iface         string // Go service interface name
 	isPoint       bool   // whether the contract declares an extensions.Point
 	isSingle      bool   // whether the point was declared with DefineSinglePoint
+	doc           string // documentation on the provider interface
 	methods       []method
 	messages      []message
 }
@@ -24,12 +25,22 @@ func (p point) grpcService() string { return p.id + "." + p.service }
 func (p point) protogenImport() string { return p.importPath + "/protogen" }
 
 type method struct {
+	kind      methodKind
 	name      string // method/rpc name
 	request   string // request message name
 	response  string // response message name
-	bareError bool   // true for `M(ctx, *Req) error`; response is a generated empty message
+	bareError bool   // true only for legacy unary `M(ctx, *Req) error`
+	doc       string // method documentation
 }
 
+type methodKind int
+
+const (
+	methodUnary methodKind = iota
+	methodServerStreaming
+	methodClientStreaming
+)
+
 type message struct {
 	name     string
 	fields   []field