PLT-6472: Basic Elastic Search implementation. (#6382)

* PLT-6472: Basic Elastic Search implementation.

This currently supports indexing of posts at create/update/delete time.
It does not support batch indexing or reindexing, and does not support
any entities other than posts yet. The purpose is to more-or-less
replicate the existing full-text search feature but with some of the
immediate benefits of using elastic search.

* Alter settings for AWS compatability.

* Remove unneeded i18n strings.

10 files changed, 343 insertions, 37 deletions

diff --git a/app/post.go b/app/post.go
index bf61bafb2..341287cf4 100644
--- a/app/post.go
+++ b/app/post.go
@@ -125,6 +125,11 @@ func CreatePost(post *model.Post, teamId string, triggerWebhooks bool) (*model.P
 		rpost = result.Data.(*model.Post)
 	}
 
+	esInterface := einterfaces.GetElasticSearchInterface()
+	if (esInterface != nil && *utils.Cfg.ElasticSearchSettings.EnableIndexing) {
+		go esInterface.IndexPost(rpost, teamId)
+	}
+
 	if einterfaces.GetMetricsInterface() != nil {
 		einterfaces.GetMetricsInterface().IncrementPostCreate()
 	}
@@ -308,6 +313,17 @@ func UpdatePost(post *model.Post, safeUpdate bool) (*model.Post, *model.AppError
 	} else {
 		rpost := result.Data.(*model.Post)
 
+		esInterface := einterfaces.GetElasticSearchInterface()
+		if (esInterface != nil && *utils.Cfg.ElasticSearchSettings.EnableIndexing) {
+			go func() {
+				if rchannel := <-Srv.Store.Channel().GetForPost(rpost.Id); rchannel.Err != nil {
+					l4g.Error("Couldn't get channel %v for post %v for ElasticSearch indexing.", rpost.ChannelId, rpost.Id)
+				} else {
+					esInterface.IndexPost(rpost, rchannel.Data.(*model.Channel).TeamId)
+				}
+			}()
+		}
+
 		sendUpdatedPostEvent(rpost)
 
 		InvalidateCacheForChannelPosts(rpost.ChannelId)
@@ -484,6 +500,11 @@ func DeletePost(postId string) (*model.Post, *model.AppError) {
 		go DeletePostFiles(post)
 		go DeleteFlaggedPosts(post.Id)
 
+		esInterface := einterfaces.GetElasticSearchInterface()
+		if (esInterface != nil && *utils.Cfg.ElasticSearchSettings.EnableIndexing) {
+			go esInterface.DeletePost(post.Id)
+		}
+
 		InvalidateCacheForChannelPosts(post.ChannelId)
 
 		return post, nil
@@ -509,27 +530,84 @@ func DeletePostFiles(post *model.Post) {
 
 func SearchPostsInTeam(terms string, userId string, teamId string, isOrSearch bool) (*model.PostList, *model.AppError) {
 	paramsList := model.ParseSearchParams(terms)
-	channels := []store.StoreChannel{}
 
-	for _, params := range paramsList {
-		params.OrTerms = isOrSearch
-		// don't allow users to search for everything
-		if params.Terms != "*" {
-			channels = append(channels, Srv.Store.Post().Search(teamId, userId, params))
+	esInterface := einterfaces.GetElasticSearchInterface()
+	if (esInterface != nil && *utils.Cfg.ElasticSearchSettings.EnableSearching && utils.IsLicensed && *utils.License.Features.ElasticSearch) {
+		finalParamsList := []*model.SearchParams{}
+
+		for _, params := range paramsList {
+			params.OrTerms = isOrSearch
+			// Don't allow users to search for "*"
+			if params.Terms != "*" {
+				// Convert channel names to channel IDs
+				for idx, channelName := range params.InChannels {
+					if channel, err := GetChannelByName(channelName, teamId); err != nil {
+						l4g.Error(err)
+					} else {
+						params.InChannels[idx] = channel.Id
+					}
+				}
+
+				// Convert usernames to user IDs
+				for idx, username := range params.FromUsers {
+					if user, err := GetUserByUsername(username); err != nil {
+						l4g.Error(err)
+					} else {
+						params.FromUsers[idx] = user.Id
+					}
+				}
+
+				finalParamsList = append(finalParamsList, params)
+			}
 		}
-	}
 
-	posts := model.NewPostList()
-	for _, channel := range channels {
-		if result := <-channel; result.Err != nil {
-			return nil, result.Err
+		// We only allow the user to search in channels they are a member of.
+		userChannels, err := GetChannelsForUser(teamId, userId)
+		if err != nil {
+			l4g.Error(err)
+			return nil, err
+		}
+
+		postIds, err := einterfaces.GetElasticSearchInterface().SearchPosts(userChannels, finalParamsList)
+		if err != nil {
+			return nil, err
+		}
+
+		// Get the posts
+		postList := model.NewPostList()
+		if presult := <-Srv.Store.Post().GetPostsByIds(postIds); presult.Err != nil {
+			return nil, presult.Err
 		} else {
-			data := result.Data.(*model.PostList)
-			posts.Extend(data)
+			for _, p := range presult.Data.([]*model.Post) {
+				postList.AddPost(p)
+				postList.AddOrder(p.Id)
+			}
 		}
-	}
 
-	return posts, nil
+		return postList, nil
+	} else {
+		channels := []store.StoreChannel{}
+
+		for _, params := range paramsList {
+			params.OrTerms = isOrSearch
+			// don't allow users to search for everything
+			if params.Terms != "*" {
+				channels = append(channels, Srv.Store.Post().Search(teamId, userId, params))
+			}
+		}
+
+		posts := model.NewPostList()
+		for _, channel := range channels {
+			if result := <-channel; result.Err != nil {
+				return nil, result.Err
+			} else {
+				data := result.Data.(*model.PostList)
+				posts.Extend(data)
+			}
+		}
+
+		return posts, nil
+	}
 }
 
 func GetFileInfosForPost(postId string, readFromMaster bool) ([]*model.FileInfo, *model.AppError) {
diff --git a/cmd/platform/server.go b/cmd/platform/server.go
index 01c8b646a..cb1530951 100644
--- a/cmd/platform/server.go
+++ b/cmd/platform/server.go
@@ -114,6 +114,12 @@ func runServer(configFileLocation string) {
 		einterfaces.GetMetricsInterface().StartServer()
 	}
 
+	if einterfaces.GetElasticSearchInterface() != nil {
+		if err := einterfaces.GetElasticSearchInterface().Start(); err != nil {
+			l4g.Error(err.Error())
+		}
+	}
+
 	// wait for kill signal before attempting to gracefully shutdown
 	// the running service
 	c := make(chan os.Signal)
diff --git a/config/config.json b/config/config.json
index 081616da8..8112331b8 100644
--- a/config/config.json
+++ b/config/config.json
@@ -46,6 +46,14 @@
         "EnableUserStatuses": true,
         "ClusterLogTimeoutMilliseconds": 2000
     },
+    "ElasticSearchSettings": {
+        "ConnectionUrl": "http://dockerhost:9200",
+        "Username": "elastic",
+        "Password": "changeme",
+        "EnableIndexing": false,
+        "EnableSearching": false,
+        "Sniff": true
+    },
     "TeamSettings": {
         "SiteName": "Mattermost",
         "MaxUsersPerTeam": 50,
diff --git a/einterfaces/elasticsearch.go b/einterfaces/elasticsearch.go
new file mode 100644
index 000000000..61e1d532f
--- /dev/null
+++ b/einterfaces/elasticsearch.go
@@ -0,0 +1,23 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package einterfaces
+
+import "github.com/mattermost/platform/model"
+
+type ElasticSearchInterface interface {
+	Start() *model.AppError
+	IndexPost(post *model.Post, teamId string)
+	SearchPosts(channels *model.ChannelList, searchParams []*model.SearchParams) ([]string, *model.AppError)
+	DeletePost(postId string)
+}
+
+var theElasticSearchInterface ElasticSearchInterface
+
+func RegisterElasticSearchInterface(newInterface ElasticSearchInterface) {
+	theElasticSearchInterface = newInterface
+}
+
+func GetElasticSearchInterface() ElasticSearchInterface {
+	return theElasticSearchInterface
+}
diff --git a/i18n/en.json b/i18n/en.json
index 3974243f1..214e91837 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -3308,6 +3308,38 @@
     "translation": "Compliance export started for job '{{.JobName}}' at '{{.FilePath}}'"
   },
   {
+    "id": "ent.elasticsearch.start.connect_failed",
+    "translation": "Setting up ElasticSearch Client Failed"
+  },
+  {
+    "id": "ent.elasticsearch.start.index_exists_failed",
+    "translation": "Failed to establish whether ElasticSearch index exists"
+  },
+  {
+    "id": "ent.elasticsearch.start.index_create_failed",
+    "translation": "Failed to create ElasticSearch index"
+  },
+  {
+    "id": "ent.elasticsearch.start.index_settings_failed",
+    "translation": "Failed to set ElasticSearch index settings"
+  },
+  {
+    "id": "ent.elasticsearch.start.index_mapping_failed",
+    "translation": "Failed to setup ElasticSearch index mapping"
+  },
+  {
+    "id": "ent.elasticsearch.search_posts.disabled",
+    "translation": "ElasticSearch searching is disabled on this server"
+  },
+  {
+    "id": "ent.elasticsearch.search_posts.search_failed",
+    "translation": "Search failed to complete"
+  },
+  {
+    "id": "ent.elasticsearch.search_posts.unmarshall_post_failed",
+    "translation": "Failed to decode search results"
+  },
+  {
     "id": "ent.emoji.licence_disable.app_error",
     "translation": "Custom emoji restrictions disabled by current license. Please contact your system administrator about upgrading your enterprise license."
   },
@@ -3860,6 +3892,22 @@
     "translation": "To must be greater than From"
   },
   {
+    "id": "model.config.is_valid.elastic_search.connection_url.app_error",
+    "translation": "Elastic Search ConnectionUrl setting must be provided when Elastic Search indexing is enabled."
+  },
+  {
+    "id": "model.config.is_valid.elastic_search.username.app_error",
+    "translation": "Elastic Search Username setting must be provided when Elastic Search indexing is enabled."
+  },
+  {
+    "id": "model.config.is_valid.elastic_search.password.app_error",
+    "translation": "Elastic Search Password setting must be provided when Elastic Search indexing is enabled."
+  },
+  {
+    "id": "model.config.is_valid.elastic_search.enable_searching.app_error",
+    "translation": "Elastic Search IndexingEnabled setting must be set to true when Elastic Search SearchEnabled is set to true."
+  },
+  {
     "id": "model.config.is_valid.cluster_email_batching.app_error",
     "translation": "Unable to enable email batching when clustering is enabled."
   },
@@ -5180,6 +5228,10 @@
     "translation": "We couldn't get the post"
   },
   {
+    "id": "store.sql_post.get_posts_by_ids.app_error",
+    "translation": "We couldn't get the posts"
+  },
+  {
     "id": "store.sql_post.get_parents_posts.app_error",
     "translation": "We couldn't get the parent post for the channel"
   },
diff --git a/model/config.go b/model/config.go
index 907620124..14f092373 100644
--- a/model/config.go
+++ b/model/config.go
@@ -401,29 +401,39 @@ type WebrtcSettings struct {
 	TurnSharedKey       *string
 }
 
+type ElasticSearchSettings struct {
+	ConnectionUrl   *string
+	Username        *string
+	Password        *string
+	EnableIndexing  *bool
+	EnableSearching *bool
+	Sniff           *bool
+}
+
 type Config struct {
-	ServiceSettings      ServiceSettings
-	TeamSettings         TeamSettings
-	SqlSettings          SqlSettings
-	LogSettings          LogSettings
-	PasswordSettings     PasswordSettings
-	FileSettings         FileSettings
-	EmailSettings        EmailSettings
-	RateLimitSettings    RateLimitSettings
-	PrivacySettings      PrivacySettings
-	SupportSettings      SupportSettings
-	GitLabSettings       SSOSettings
-	GoogleSettings       SSOSettings
-	Office365Settings    SSOSettings
-	LdapSettings         LdapSettings
-	ComplianceSettings   ComplianceSettings
-	LocalizationSettings LocalizationSettings
-	SamlSettings         SamlSettings
-	NativeAppSettings    NativeAppSettings
-	ClusterSettings      ClusterSettings
-	MetricsSettings      MetricsSettings
-	AnalyticsSettings    AnalyticsSettings
-	WebrtcSettings       WebrtcSettings
+	ServiceSettings       ServiceSettings
+	TeamSettings          TeamSettings
+	SqlSettings           SqlSettings
+	LogSettings           LogSettings
+	PasswordSettings      PasswordSettings
+	FileSettings          FileSettings
+	EmailSettings         EmailSettings
+	RateLimitSettings     RateLimitSettings
+	PrivacySettings       PrivacySettings
+	SupportSettings       SupportSettings
+	GitLabSettings        SSOSettings
+	GoogleSettings        SSOSettings
+	Office365Settings     SSOSettings
+	LdapSettings          LdapSettings
+	ComplianceSettings    ComplianceSettings
+	LocalizationSettings  LocalizationSettings
+	SamlSettings          SamlSettings
+	NativeAppSettings     NativeAppSettings
+	ClusterSettings       ClusterSettings
+	MetricsSettings       MetricsSettings
+	AnalyticsSettings     AnalyticsSettings
+	WebrtcSettings        WebrtcSettings
+	ElasticSearchSettings ElasticSearchSettings
 }
 
 func (o *Config) ToJson() string {
@@ -1217,6 +1227,36 @@ func (o *Config) SetDefaults() {
 		*o.ServiceSettings.ClusterLogTimeoutMilliseconds = 2000
 	}
 
+	if o.ElasticSearchSettings.ConnectionUrl == nil {
+		o.ElasticSearchSettings.ConnectionUrl = new(string)
+		*o.ElasticSearchSettings.ConnectionUrl = ""
+	}
+
+	if o.ElasticSearchSettings.Username == nil {
+		o.ElasticSearchSettings.Username = new(string)
+		*o.ElasticSearchSettings.Username = ""
+	}
+
+	if o.ElasticSearchSettings.Password == nil {
+		o.ElasticSearchSettings.Password = new(string)
+		*o.ElasticSearchSettings.Password = ""
+	}
+
+	if o.ElasticSearchSettings.EnableIndexing == nil {
+		o.ElasticSearchSettings.EnableIndexing = new(bool)
+		*o.ElasticSearchSettings.EnableIndexing = false
+	}
+
+	if o.ElasticSearchSettings.EnableSearching == nil {
+		o.ElasticSearchSettings.EnableSearching = new(bool)
+		*o.ElasticSearchSettings.EnableSearching = false
+	}
+
+	if o.ElasticSearchSettings.Sniff == nil {
+		o.ElasticSearchSettings.Sniff = new(bool)
+		*o.ElasticSearchSettings.Sniff = true
+	}
+
 	o.defaultWebrtcSettings()
 }
 
@@ -1448,6 +1488,16 @@ func (o *Config) IsValid() *AppError {
 		return NewLocAppError("Config.IsValid", "model.config.is_valid.time_between_user_typing.app_error", nil, "")
 	}
 
+	if *o.ElasticSearchSettings.EnableIndexing {
+		if len(*o.ElasticSearchSettings.ConnectionUrl) == 0 {
+			return NewLocAppError("Config.IsValid", "model.config.is_valid.elastic_search.connection_url.app_error", nil, "")
+		}
+	}
+
+	if *o.ElasticSearchSettings.EnableSearching && !*o.ElasticSearchSettings.EnableIndexing {
+		return NewLocAppError("Config.IsValid", "model.config.is_valid.elastic_search.enable_searching.app_error", nil, "")
+	}
+
 	return nil
 }
 
@@ -1488,6 +1538,10 @@ func (o *Config) Sanitize() {
 	for i := range o.SqlSettings.DataSourceSearchReplicas {
 		o.SqlSettings.DataSourceSearchReplicas[i] = FAKE_SETTING
 	}
+
+	*o.ElasticSearchSettings.ConnectionUrl = FAKE_SETTING
+	*o.ElasticSearchSettings.Username = FAKE_SETTING
+	*o.ElasticSearchSettings.Password = FAKE_SETTING
 }
 
 func (o *Config) defaultWebrtcSettings() {
diff --git a/store/sql_post_store.go b/store/sql_post_store.go
index b2211a180..834e488a8 100644
--- a/store/sql_post_store.go
+++ b/store/sql_post_store.go
@@ -1287,3 +1287,30 @@ func (s SqlPostStore) GetPostsCreatedAt(channelId string, time int64) StoreChann
 
 	return storeChannel
 }
+
+func (s SqlPostStore) GetPostsByIds(postIds []string) StoreChannel {
+	storeChannel := make(StoreChannel, 1)
+
+	go func() {
+		result := StoreResult{}
+
+		inClause := `'` + strings.Join(postIds, `', '`) + `'`
+
+		query := `SELECT * FROM Posts WHERE Id in (` + inClause + `) and DeleteAt = 0 ORDER BY CreateAt DESC`
+
+		var posts []*model.Post
+		_, err := s.GetReplica().Select(&posts, query, map[string]interface{}{})
+
+		if err != nil {
+			l4g.Error(err)
+			result.Err = model.NewAppError("SqlPostStore.GetPostsCreatedAt", "store.sql_post.get_posts_by_ids.app_error", nil, "", http.StatusInternalServerError)
+		} else {
+			result.Data = posts
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}
diff --git a/store/sql_post_store_test.go b/store/sql_post_store_test.go
index b69f0f636..f8fd653af 100644
--- a/store/sql_post_store_test.go
+++ b/store/sql_post_store_test.go
@@ -1550,3 +1550,45 @@ func TestPostStoreOverwrite(t *testing.T) {
 		t.Fatal("Failed to set FileIds")
 	}
 }
+
+func TestPostStoreGetPostsByIds(t *testing.T) {
+	Setup()
+
+	o1 := &model.Post{}
+	o1.ChannelId = model.NewId()
+	o1.UserId = model.NewId()
+	o1.Message = "a" + model.NewId() + "AAAAAAAAAAA"
+	o1 = (<-store.Post().Save(o1)).Data.(*model.Post)
+
+	o2 := &model.Post{}
+	o2.ChannelId = o1.ChannelId
+	o2.UserId = model.NewId()
+	o2.Message = "a" + model.NewId() + "CCCCCCCCC"
+	o2 = (<-store.Post().Save(o2)).Data.(*model.Post)
+
+	o3 := &model.Post{}
+	o3.ChannelId = o1.ChannelId
+	o3.UserId = model.NewId()
+	o3.Message = "a" + model.NewId() + "QQQQQQQQQQ"
+	o3 = (<-store.Post().Save(o3)).Data.(*model.Post)
+
+	ro1 := (<-store.Post().Get(o1.Id)).Data.(*model.PostList).Posts[o1.Id]
+	ro2 := (<-store.Post().Get(o2.Id)).Data.(*model.PostList).Posts[o2.Id]
+	ro3 := (<-store.Post().Get(o3.Id)).Data.(*model.PostList).Posts[o3.Id]
+
+	postIds := []string{
+		ro1.Id,
+		ro2.Id,
+		ro3.Id,
+	}
+
+	if ro4 := Must(store.Post().GetPostsByIds(postIds)).([]*model.Post); len(ro4) != 3 {
+		t.Fatalf("Expected 3 posts in results. Got %v", len(ro4))
+	}
+
+	Must(store.Post().Delete(ro1.Id, model.GetMillis()))
+
+	if ro5 := Must(store.Post().GetPostsByIds(postIds)).([]*model.Post); len(ro5) != 2 {
+		t.Fatalf("Expected 2 posts in results. Got %v", len(ro5))
+	}
+}
diff --git a/store/store.go b/store/store.go
index 9916bfcd7..acbeafdd6 100644
--- a/store/store.go
+++ b/store/store.go
@@ -165,6 +165,7 @@ type PostStore interface {
 	InvalidateLastPostTimeCache(channelId string)
 	GetPostsCreatedAt(channelId string, time int64) StoreChannel
 	Overwrite(post *model.Post) StoreChannel
+	GetPostsByIds(postIds []string) StoreChannel
 }
 
 type UserStore interface {
diff --git a/utils/config.go b/utils/config.go
index 58bc339e1..234acae11 100644
--- a/utils/config.go
+++ b/utils/config.go
@@ -492,6 +492,11 @@ func getClientConfig(c *model.Config) map[string]string {
 			props["PasswordRequireNumber"] = strconv.FormatBool(*c.PasswordSettings.Number)
 			props["PasswordRequireSymbol"] = strconv.FormatBool(*c.PasswordSettings.Symbol)
 		}
+
+		if *License.Features.ElasticSearch {
+			props["ElasticSearchEnableIndexing"] = strconv.FormatBool(*c.ElasticSearchSettings.EnableIndexing)
+			props["ElasticSearchEnableSearching"] = strconv.FormatBool(*c.ElasticSearchSettings.EnableSearching)
+		}
 	}
 
 	return props
@@ -560,6 +565,16 @@ func Desanitize(cfg *model.Config) {
 		cfg.SqlSettings.AtRestEncryptKey = Cfg.SqlSettings.AtRestEncryptKey
 	}
 
+	if *cfg.ElasticSearchSettings.ConnectionUrl == model.FAKE_SETTING {
+		*cfg.ElasticSearchSettings.ConnectionUrl = *Cfg.ElasticSearchSettings.ConnectionUrl
+	}
+	if *cfg.ElasticSearchSettings.Username == model.FAKE_SETTING {
+		*cfg.ElasticSearchSettings.Username = *Cfg.ElasticSearchSettings.Username
+	}
+	if *cfg.ElasticSearchSettings.Password == model.FAKE_SETTING {
+		*cfg.ElasticSearchSettings.Password = *Cfg.ElasticSearchSettings.Password
+	}
+
 	for i := range cfg.SqlSettings.DataSourceReplicas {
 		cfg.SqlSettings.DataSourceReplicas[i] = Cfg.SqlSettings.DataSourceReplicas[i]
 	}