Add missing build_info.go file.

Change-Id: Ie6fe120a8eee3273a65f2a68da8d8e59e9470080

build_info.go

@@ -0,0 +1,44 @@
+// Copyright 2013 Prometheus Team
+// 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 main
+
+import (
+	"text/template"
+)
+
+// Build information. Populated by Makefile.
+var (
+	buildVersion string
+	buildBranch  string
+	buildUser    string
+	buildDate    string
+	goVersion    string
+)
+
+// BuildInfo encapsulates compile-time metadata about Prometheus made available
+// via go tool ld such that this can be reported on-demand.
+var BuildInfo = map[string]string{
+	"version":    buildVersion,
+	"branch":     buildBranch,
+	"user":       buildUser,
+	"date":       buildDate,
+	"go_version": goVersion,
+}
+
+var versionInfoTmpl = template.Must(template.New("version").Parse(
+	`alertmanager, version {{.version}} ({{.branch}})
+  build user:       {{.user}}
+  build date:       {{.date}}
+  go version:       {{.go_version}}
+`))