Use -ldflags to set git commit version

pkg/version/template.go.tmpl

@@ -1,23 +0,0 @@
-/*
-Copyright 2014 Google Inc. All rights reserved.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package version
-
-// This file is the template for the machine-edited autogenerated.go.
-// Do not modify this file without also modifying hack/version-gen.sh.
-var (
-	commitFromGit = `@@GIT_COMMIT@@`
-)

pkg/version/version.go

@@ -20,6 +20,10 @@ import (
 	"fmt"
 )
 
+// commitFromGit is a constant representing the source version that
+// generated this build. It should be set during build via -ldflags.
+var commitFromGit string
+
 // Info contains versioning information.
 // TODO: Add []string of api versions supported? It's still unclear
 // how we'll want to distribute that information.
@@ -41,5 +45,9 @@ func Get() Info {
 
 // String returns info as a human-friendly version string.
 func (info Info) String() string {
-	return fmt.Sprintf("version %s.%s, build %s", info.Major, info.Minor, info.GitCommit)
+	commit := info.GitCommit
+	if commit == "" {
+		commit = "(unknown)"
+	}
+	return fmt.Sprintf("version %s.%s, build %s", info.Major, info.Minor, commit)
 }