pkg/generator: add cmd/main.go generator

pkg/generator/gen_main.go

@@ -0,0 +1,67 @@
+package generator
+
+import (
+	"io"
+	"path/filepath"
+	"text/template"
+)
+
+const (
+	// sdkImport is the operator-sdk import path.
+	sdkImport = "github.com/coreos/operator-sdk/pkg/sdk"
+	main      = "main"
+)
+
+// Main contains all the customized data needed to generate cmd/<projectName>/main.go for a new operator
+// when pairing with mainTmpl template.
+type Main struct {
+	// imports
+	OperatorSDKImport string
+	APIImport         string
+	StubImport        string
+
+	// Service defintion in pkg/apis/..
+	ServicePlural string
+	Service       string
+}
+
+// renderMain generates the cmd/<projectName>/main.go file given a repo path ("github.com/coreos/play"), apiVersion ("v1alpha1"),
+// projectName ("play"), service ("PlayService"), and servicePlural ("PlayServicePlural").
+//
+// for example:
+// renderMain(w, "github.com/coreos/play", "v1alpha1", "play", "PlayService", "PlayServicePlural" )
+// output:
+//
+// package main
+//
+// import (
+// 	"context"
+//
+// 	sdk "github.com/coreos/operator-sdk/pkg/sdk"
+// 	api "github.com/coreos/play/pkg/apis/play/v1alpha1"
+// 	stub "github.com/coreos/play/pkg/stub"
+// )
+//
+// func main() {
+// 	namespace := "default"
+// 	sdk.Watch(api.PlayServicePlural, namespace, api.PlayService)
+//  	sdk.Handle(&stub.Handler{})
+//  	sdk.Run(context.TODO())
+// }
+//
+func renderMain(w io.Writer, repo, version, projectName, service, servicePlural string) error {
+	t := template.New("cmd/<projectName>/main.go")
+	t, err := t.Parse(mainTmpl)
+	if err != nil {
+		return err
+	}
+
+	m := Main{
+		OperatorSDKImport: sdkImport,
+		APIImport:         filepath.Join(repo, apisDir, projectName, version),
+		StubImport:        filepath.Join(repo, stubDir),
+		ServicePlural:     servicePlural,
+		Service:           service,
+	}
+	return t.Execute(w, m)
+}

pkg/generator/main_tmpl.go

@@ -0,0 +1,20 @@
+package generator
+
+// mainTmpl is the template for cmd/main.go.
+const mainTmpl = `package main
+
+import (
+	"context"
+
+	sdk "{{.OperatorSDKImport}}"
+	api "{{.APIImport}}"
+	stub "{{.StubImport}}"
+)
+
+func main() {
+	namespace := "default"
+	sdk.Watch(api.{{.ServicePlural}}, namespace, api.{{.Service}})
+ 	sdk.Handle(&stub.Handler{})
+ 	sdk.Run(context.TODO())
+}
+`