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

5 files changed, 135 insertions, 0 deletions

diff --git a/model/client.go b/model/client.go
index b9a5d8830..3aff3c931 100644
--- a/model/client.go
+++ b/model/client.go
@@ -20,6 +20,7 @@ import (
 const (
 	HEADER_REQUEST_ID         = "X-Request-ID"
 	HEADER_VERSION_ID         = "X-Version-ID"
+	HEADER_CLUSTER_ID         = "X-Cluster-ID"
 	HEADER_ETAG_SERVER        = "ETag"
 	HEADER_ETAG_CLIENT        = "If-None-Match"
 	HEADER_FORWARDED          = "X-Forwarded-For"
@@ -808,6 +809,15 @@ func (c *Client) GetLogs() (*Result, *AppError) {
 	}
 }
 
+func (c *Client) GetClusterStatus() ([]*ClusterInfo, *AppError) {
+	if r, err := c.DoApiGet("/admin/cluster_status", "", ""); err != nil {
+		return nil, err
+	} else {
+		defer closeBody(r)
+		return ClusterInfosFromJson(r.Body), nil
+	}
+}
+
 func (c *Client) GetAllAudits() (*Result, *AppError) {
 	if r, err := c.DoApiGet("/admin/audits", "", ""); err != nil {
 		return nil, err
diff --git a/model/cluster_info.go b/model/cluster_info.go
new file mode 100644
index 000000000..7c3384ae2
--- /dev/null
+++ b/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
+	}
+}
diff --git a/model/cluster_info_test.go b/model/cluster_info_test.go
new file mode 100644
index 000000000..d6348f5d1
--- /dev/null
+++ b/model/cluster_info_test.go
@@ -0,0 +1,32 @@
+// Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestClusterInfoJson(t *testing.T) {
+	cluster := ClusterInfo{Id: NewId(), InterNodeUrl: NewId(), Hostname: NewId()}
+	json := cluster.ToJson()
+	result := ClusterInfoFromJson(strings.NewReader(json))
+
+	if cluster.Id != result.Id {
+		t.Fatal("Ids do not match")
+	}
+}
+
+func TestClusterInfosJson(t *testing.T) {
+	cluster := ClusterInfo{Id: NewId(), InterNodeUrl: NewId(), Hostname: NewId()}
+	clusterInfos := make([]*ClusterInfo, 1)
+	clusterInfos[0] = &cluster
+	json := ClusterInfosToJson(clusterInfos)
+	result := ClusterInfosFromJson(strings.NewReader(json))
+
+	if clusterInfos[0].Id != result[0].Id {
+		t.Fatal("Ids do not match")
+	}
+
+}
diff --git a/model/config.go b/model/config.go
index b239c83ca..7fe575e58 100644
--- a/model/config.go
+++ b/model/config.go
@@ -80,6 +80,12 @@ type ServiceSettings struct {
 	RestrictCustomEmojiCreation       *string
 }
 
+type ClusterSettings struct {
+	Enable                 *bool
+	InterNodeListenAddress *string
+	InterNodeUrls          []string
+}
+
 type SSOSettings struct {
 	Enable          bool
 	Secret          string
@@ -297,6 +303,7 @@ type Config struct {
 	LocalizationSettings LocalizationSettings
 	SamlSettings         SamlSettings
 	NativeAppSettings    NativeAppSettings
+	ClusterSettings      ClusterSettings
 }
 
 func (o *Config) ToJson() string {
@@ -707,6 +714,20 @@ func (o *Config) SetDefaults() {
 		*o.ServiceSettings.RestrictCustomEmojiCreation = RESTRICT_EMOJI_CREATION_ALL
 	}
 
+	if o.ClusterSettings.InterNodeListenAddress == nil {
+		o.ClusterSettings.InterNodeListenAddress = new(string)
+		*o.ClusterSettings.InterNodeListenAddress = ":8075"
+	}
+
+	if o.ClusterSettings.Enable == nil {
+		o.ClusterSettings.Enable = new(bool)
+		*o.ClusterSettings.Enable = false
+	}
+
+	if o.ClusterSettings.InterNodeUrls == nil {
+		o.ClusterSettings.InterNodeUrls = []string{}
+	}
+
 	if o.ComplianceSettings.Enable == nil {
 		o.ComplianceSettings.Enable = new(bool)
 		*o.ComplianceSettings.Enable = false
diff --git a/model/license.go b/model/license.go
index a60695890..a27b36263 100644
--- a/model/license.go
+++ b/model/license.go
@@ -38,6 +38,7 @@ type Features struct {
 	GoogleSSO            *bool `json:"google_sso"`
 	Office365SSO         *bool `json:"office365_sso"`
 	Compliance           *bool `json:"compliance"`
+	Cluster              *bool `json:"cluster"`
 	CustomBrand          *bool `json:"custom_brand"`
 	MHPNS                *bool `json:"mhpns"`
 	SAML                 *bool `json:"saml"`
@@ -81,6 +82,11 @@ func (f *Features) SetDefaults() {
 		*f.Compliance = *f.FutureFeatures
 	}
 
+	if f.Cluster == nil {
+		f.Cluster = new(bool)
+		*f.Cluster = *f.FutureFeatures
+	}
+
 	if f.CustomBrand == nil {
 		f.CustomBrand = new(bool)
 		*f.CustomBrand = *f.FutureFeatures