host templates

cmd/dkl-dir2config/main.go

@@ -96,7 +96,7 @@ func main() {
 			ctx.Host.Versions["modules"] = ctx.Host.Kernel
 		}
 
-		dst.Hosts = append(dst.Hosts, &localconfig.Host{
+		renderedHost := &localconfig.Host{
 			Name: host.Name,
 
 			ClusterName: ctx.Cluster.Name,
@@ -115,7 +115,13 @@ func main() {
 
 			BootstrapConfig: ctx.BootstrapConfig(),
 			Config:          ctx.Config(),
-		})
+		}
+
+		if host.Template {
+			dst.HostTemplates = append(dst.HostTemplates, renderedHost)
+		} else {
+			dst.Hosts = append(dst.Hosts, renderedHost)
+		}
 	}
 
 	// ----------------------------------------------------------------------

cmd/dkl-dir2config/render-context.go

@@ -2,8 +2,6 @@ package main
 
 import (
 	"bytes"
-	"crypto/sha1"
-	"encoding/hex"
 	"fmt"
 	"io"
 	"log"
@@ -180,9 +178,20 @@ func (ctx *renderContext) renderConfigTo(buf io.Writer, configTemplate *clusters
 		return string(ba), err
 	}
 
+	extraFuncs["host_ip"] = func() string {
+		if ctx.Host.Template {
+			return "{{ host_ip }}"
+		}
+		return ctx.Host.IP
+	}
+	extraFuncs["host_name"] = func() string {
+		if ctx.Host.Template {
+			return "{{ host_name }}"
+		}
+		return ctx.Host.Name
+	}
 	extraFuncs["machine_id"] = func() string {
-		ba := sha1.Sum([]byte(ctx.Cluster.Name + "/" + ctx.Host.Name)) // TODO: check semantics of machine-id
-		return hex.EncodeToString(ba[:])
+		return "{{ machine_id }}"
 	}
 
 	extraFuncs["version"] = func() string { return Version }

cmd/dkl-dir2config/render-host.go

@@ -63,7 +63,7 @@ func (ctx *renderContext) renderHostTemplates(setName string,
 
 	log.Print("rendering host templates in ", setName)
 
-	buf := &bytes.Buffer{}
+	buf := bytes.NewBuffer(make([]byte, 0, 16<<10))
 
 	for _, t := range templates {
 		log.Print("- template: ", setName, ": ", t.Name)