MM-11243: Make Elasticsearch work after enabling without restart. (#9146)

* MM-11243: Make Elasticsearch work after enabling without restart.

* Also cope with config vars changing whilst enabled.

4 files changed, 61 insertions, 5 deletions

diff --git a/app/app.go b/app/app.go
index fb1fc725b..6da16c28c 100644
--- a/app/app.go
+++ b/app/app.go
@@ -680,3 +680,54 @@ func (a *App) DoEmojisPermissionsMigration() {
 		mlog.Critical(fmt.Sprint(result.Err))
 	}
 }
+
+func (a *App) StartElasticsearch() {
+	a.Go(func() {
+		if err := a.Elasticsearch.Start(); err != nil {
+			mlog.Error(err.Error())
+		}
+	})
+
+	a.AddConfigListener(func(oldConfig *model.Config, newConfig *model.Config) {
+		if *oldConfig.ElasticsearchSettings.EnableIndexing == false && *newConfig.ElasticsearchSettings.EnableIndexing == true {
+			a.Go(func() {
+				if err := a.Elasticsearch.Start(); err != nil {
+					mlog.Error(err.Error())
+				}
+			})
+		} else if *oldConfig.ElasticsearchSettings.EnableIndexing == true && *newConfig.ElasticsearchSettings.EnableIndexing == false {
+			a.Go(func() {
+				if err := a.Elasticsearch.Stop(); err != nil {
+					mlog.Error(err.Error())
+				}
+			})
+		} else if *oldConfig.ElasticsearchSettings.Password != *newConfig.ElasticsearchSettings.Password || *oldConfig.ElasticsearchSettings.Username != *newConfig.ElasticsearchSettings.Username || *oldConfig.ElasticsearchSettings.ConnectionUrl != *newConfig.ElasticsearchSettings.ConnectionUrl || *oldConfig.ElasticsearchSettings.Sniff != *newConfig.ElasticsearchSettings.Sniff {
+			a.Go(func() {
+				if *oldConfig.ElasticsearchSettings.EnableIndexing == true {
+					if err := a.Elasticsearch.Stop(); err != nil {
+						mlog.Error(err.Error())
+					}
+					if err := a.Elasticsearch.Start(); err != nil {
+						mlog.Error(err.Error())
+					}
+				}
+			})
+		}
+	})
+
+	a.AddLicenseListener(func() {
+		if a.License() != nil {
+			a.Go(func() {
+				if err := a.Elasticsearch.Start(); err != nil {
+					mlog.Error(err.Error())
+				}
+			})
+		} else {
+			a.Go(func() {
+				if err := a.Elasticsearch.Stop(); err != nil {
+					mlog.Error(err.Error())
+				}
+			})
+		}
+	})
+}
diff --git a/cmd/mattermost/commands/server.go b/cmd/mattermost/commands/server.go
index 1fab5c83a..1c33505f5 100644
--- a/cmd/mattermost/commands/server.go
+++ b/cmd/mattermost/commands/server.go
@@ -176,11 +176,7 @@ func runServer(configFileLocation string, disableConfigWatch bool, usedPlatform
 	}
 
 	if a.Elasticsearch != nil {
-		a.Go(func() {
-			if err := a.Elasticsearch.Start(); err != nil {
-				mlog.Error(err.Error())
-			}
-		})
+		a.StartElasticsearch()
 	}
 
 	if *a.Config().JobSettings.RunJobs {
diff --git a/einterfaces/elasticsearch.go b/einterfaces/elasticsearch.go
index 1b7444b2b..bf24dc577 100644
--- a/einterfaces/elasticsearch.go
+++ b/einterfaces/elasticsearch.go
@@ -11,6 +11,7 @@ import (
 
 type ElasticsearchInterface interface {
 	Start() *model.AppError
+	Stop() *model.AppError
 	IndexPost(post *model.Post, teamId string) *model.AppError
 	SearchPosts(channels *model.ChannelList, searchParams []*model.SearchParams) ([]string, model.PostSearchMatches, *model.AppError)
 	DeletePost(post *model.Post) *model.AppError
diff --git a/i18n/en.json b/i18n/en.json
index 986dfc81b..9ed77b07d 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -168,6 +168,14 @@
     "translation": "Channel is already deleted"
   },
   {
+    "id": "ent.elasticsearch.start.already_started.app_error",
+    "translation": "Elasticsearch is already started"
+  },
+  {
+    "id": "ent.elasticsearch.stop.already_stopped.app_error",
+    "translation": "Elasticsearch is already stopped"
+  },
+  {
     "id": "api.channel.join_channel.permissions.app_error",
     "translation": "You do not have the appropriate permissions"
   },