PLT-2899 adding clustering of app servers (#3682)

* PLT-2899 adding clustering of app servers

* PLT-2899 base framework

* PLT-2899 HA backend

* PLT-2899 Fixing config file

* PLT-2899 adding config syncing

* PLT-2899 set System console to readonly when clustering enabled.

* PLT-2899 Fixing publish API

* PLT-2899 fixing strings

model/cluster_info.go

@@ -0,0 +1,66 @@
+// Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"encoding/json"
+	"io"
+)
+
+type ClusterInfo struct {
+	Id                 string `json:"id"`
+	Version            string `json:"version"`
+	ConfigHash         string `json:"config_hash"`
+	InterNodeUrl       string `json:"internode_url"`
+	Hostname           string `json:"hostname"`
+	LastSuccessfulPing int64  `json:"last_ping"`
+	IsAlive            bool   `json:"is_alive"`
+}
+
+func (me *ClusterInfo) ToJson() string {
+	b, err := json.Marshal(me)
+	if err != nil {
+		return ""
+	} else {
+		return string(b)
+	}
+}
+
+func ClusterInfoFromJson(data io.Reader) *ClusterInfo {
+	decoder := json.NewDecoder(data)
+	var me ClusterInfo
+	err := decoder.Decode(&me)
+	if err == nil {
+		return &me
+	} else {
+		return nil
+	}
+}
+
+func (me *ClusterInfo) HaveEstablishedInitialContact() bool {
+	if me.Id != "" {
+		return true
+	}
+
+	return false
+}
+
+func ClusterInfosToJson(objmap []*ClusterInfo) string {
+	if b, err := json.Marshal(objmap); err != nil {
+		return ""
+	} else {
+		return string(b)
+	}
+}
+
+func ClusterInfosFromJson(data io.Reader) []*ClusterInfo {
+	decoder := json.NewDecoder(data)
+
+	var objmap []*ClusterInfo
+	if err := decoder.Decode(&objmap); err != nil {
+		return make([]*ClusterInfo, 0)
+	} else {
+		return objmap
+	}
+}