Show fission deployment version with cli (#538)

Add version information to binary through go ldflags

version.go

@@ -0,0 +1,48 @@
+/*
+Copyright 2017 The Fission Authors.
+
+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 fission
+
+import (
+	"encoding/json"
+)
+
+var (
+	GitCommit string // $(git rev-parse HEAD) (1b4716ab84903b2e477135a3dc5afdb07f685cb7)
+	BuildDate string // $(date -u +'%Y-%m-%dT%H:%M:%SZ') (2018-03-08T18:54:38Z)
+	Version   string // fission release version (0.6.0)
+)
+
+type (
+	Info struct {
+		GitCommit string `json:"GitCommit,omitempty"`
+		BuildDate string `json:"BuildDate,omitempty"`
+		Version   string `json:"Version,omitempty"`
+	}
+)
+
+func VersionInfo() Info {
+	return Info{
+		GitCommit: GitCommit,
+		BuildDate: BuildDate,
+		Version:   Version,
+	}
+}
+
+func (info Info) String() string {
+	v, _ := json.Marshal(info)
+	return string(v)
+}