Add basic templating support for manifests

manifests/coredns.yaml

@@ -162,7 +162,7 @@ metadata:
 spec:
   selector:
     k8s-app: kube-dns
-  clusterIP: 10.43.0.10
+  clusterIP: %{CLUSTER_DNS}%
   ports:
   - name: dns
     port: 53

pkg/deploy/stage.go

 package deploy
 
 import (
+	"bytes"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	"io/ioutil"
 	"os"
 	"path/filepath"
-
-	"github.com/pkg/errors"
-	"github.com/sirupsen/logrus"
 )
 
-func Stage(dataDir string) error {
+func Stage(dataDir string, templateVars map[string]string) error {
 	os.MkdirAll(dataDir, 0700)
 
 	for _, name := range AssetNames() {
@@ -17,7 +17,9 @@ func Stage(dataDir string) error {
 		if err != nil {
 			return err
 		}
-
+		for k, v := range templateVars {
+			content = bytes.Replace(content, []byte(k), []byte(v), -1)
+		}
 		p := filepath.Join(dataDir, name)
 		logrus.Info("Writing manifest: ", p)
 		if err := ioutil.WriteFile(p, content, 0600); err != nil {

pkg/server/server.go

@@ -120,7 +120,8 @@ func startNorman(ctx context.Context, config *Config) (string, error) {
 			},
 			func(ctx context.Context) error {
 				dataDir := filepath.Join(controlConfig.DataDir, "manifests")
-				if err := deploy.Stage(dataDir); err != nil {
+				templateVars := map[string]string{"%{CLUSTER_DNS}%": controlConfig.ClusterDNS.String()}
+				if err := deploy.Stage(dataDir, templateVars); err != nil {
 					return err
 				}
 				if err := deploy.WatchFiles(ctx, controlConfig.Skips, dataDir); err != nil {