Refactor issue indexer (#5363)

22 files changed, 1045 insertions, 116 deletions

diff --git a/Gopkg.lock b/Gopkg.lock
index fa2a58a1a3..3ef6f552ed 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -617,6 +617,14 @@
   revision = "e3534c89ef969912856dfa39e56b09e58c5f5daf"
 
 [[projects]]
+  branch = "master"
+  digest = "1:3ea59a5ada4bbac04da58e6177ca63da8c377a3143b48fca584408bf415fdafb"
+  name = "github.com/lunny/levelqueue"
+  packages = ["."]
+  pruneopts = "NUT"
+  revision = "02b525a4418e684a7786215296984e364746806f"
+
+[[projects]]
   digest = "1:1e6a29ed1f189354030e3371f63ec58aacbc2bf232fd104c6e0d41174ac5af48"
   name = "github.com/lunny/log"
   packages = ["."]
@@ -1270,6 +1278,7 @@
     "github.com/lafriks/xormstore",
     "github.com/lib/pq",
     "github.com/lunny/dingtalk_webhook",
+    "github.com/lunny/levelqueue",
     "github.com/markbates/goth",
     "github.com/markbates/goth/gothic",
     "github.com/markbates/goth/providers/bitbucket",
diff --git a/models/issue.go b/models/issue.go
index 8ce8658fee..835c6cf9fc 100644
--- a/models/issue.go
+++ b/models/issue.go
@@ -183,12 +183,21 @@ func (issue *Issue) LoadPullRequest() error {
 }
 
 func (issue *Issue) loadComments(e Engine) (err error) {
+	return issue.loadCommentsByType(e, CommentTypeUnknown)
+}
+
+// LoadDiscussComments loads discuss comments
+func (issue *Issue) LoadDiscussComments() error {
+	return issue.loadCommentsByType(x, CommentTypeComment)
+}
+
+func (issue *Issue) loadCommentsByType(e Engine, tp CommentType) (err error) {
 	if issue.Comments != nil {
 		return nil
 	}
 	issue.Comments, err = findComments(e, FindCommentsOptions{
 		IssueID: issue.ID,
-		Type:    CommentTypeUnknown,
+		Type:    tp,
 	})
 	return err
 }
@@ -681,7 +690,6 @@ func updateIssueCols(e Engine, issue *Issue, cols ...string) error {
 	if _, err := e.ID(issue.ID).Cols(cols...).Update(issue); err != nil {
 		return err
 	}
-	UpdateIssueIndexerCols(issue.ID, cols...)
 	return nil
 }
 
@@ -1217,6 +1225,12 @@ func getIssuesByIDs(e Engine, issueIDs []int64) ([]*Issue, error) {
 	return issues, e.In("id", issueIDs).Find(&issues)
 }
 
+func getIssueIDsByRepoID(e Engine, repoID int64) ([]int64, error) {
+	var ids = make([]int64, 0, 10)
+	err := e.Table("issue").Where("repo_id = ?", repoID).Find(&ids)
+	return ids, err
+}
+
 // GetIssuesByIDs return issues with the given IDs.
 func GetIssuesByIDs(issueIDs []int64) ([]*Issue, error) {
 	return getIssuesByIDs(x, issueIDs)
diff --git a/models/issue_comment.go b/models/issue_comment.go
index 1b02918cb7..c3654460ff 100644
--- a/models/issue_comment.go
+++ b/models/issue_comment.go
@@ -1035,6 +1035,7 @@ func UpdateComment(doer *User, c *Comment, oldContent string) error {
 	if err := c.LoadIssue(); err != nil {
 		return err
 	}
+
 	if err := c.Issue.LoadAttributes(); err != nil {
 		return err
 	}
@@ -1093,6 +1094,7 @@ func DeleteComment(doer *User, comment *Comment) error {
 	if err := comment.LoadIssue(); err != nil {
 		return err
 	}
+
 	if err := comment.Issue.LoadAttributes(); err != nil {
 		return err
 	}
diff --git a/models/issue_indexer.go b/models/issue_indexer.go
index 48c0b9f246..d02b7164da 100644
--- a/models/issue_indexer.go
+++ b/models/issue_indexer.go
@@ -7,25 +7,60 @@ package models
 import (
 	"fmt"
 
-	"code.gitea.io/gitea/modules/indexer"
+	"code.gitea.io/gitea/modules/indexer/issues"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
 )
 
-// issueIndexerUpdateQueue queue of issue ids to be updated
-var issueIndexerUpdateQueue chan int64
+var (
+	// issueIndexerUpdateQueue queue of issue ids to be updated
+	issueIndexerUpdateQueue issues.Queue
+	issueIndexer            issues.Indexer
+)
 
 // InitIssueIndexer initialize issue indexer
-func InitIssueIndexer() {
-	indexer.InitIssueIndexer(populateIssueIndexer)
-	issueIndexerUpdateQueue = make(chan int64, setting.Indexer.UpdateQueueLength)
-	go processIssueIndexerUpdateQueue()
+func InitIssueIndexer() error {
+	var populate bool
+	switch setting.Indexer.IssueType {
+	case "bleve":
+		issueIndexer = issues.NewBleveIndexer(setting.Indexer.IssuePath)
+		exist, err := issueIndexer.Init()
+		if err != nil {
+			return err
+		}
+		populate = !exist
+	default:
+		return fmt.Errorf("unknow issue indexer type: %s", setting.Indexer.IssueType)
+	}
+
+	var err error
+	switch setting.Indexer.IssueIndexerQueueType {
+	case setting.LevelQueueType:
+		issueIndexerUpdateQueue, err = issues.NewLevelQueue(
+			issueIndexer,
+			setting.Indexer.IssueIndexerQueueDir,
+			setting.Indexer.IssueIndexerQueueBatchNumber)
+		if err != nil {
+			return err
+		}
+	case setting.ChannelQueueType:
+		issueIndexerUpdateQueue = issues.NewChannelQueue(issueIndexer, setting.Indexer.IssueIndexerQueueBatchNumber)
+	default:
+		return fmt.Errorf("Unsupported indexer queue type: %v", setting.Indexer.IssueIndexerQueueType)
+	}
+
+	go issueIndexerUpdateQueue.Run()
+
+	if populate {
+		go populateIssueIndexer()
+	}
+
+	return nil
 }
 
 // populateIssueIndexer populate the issue indexer with issue data
-func populateIssueIndexer() error {
-	batch := indexer.IssueIndexerBatch()
+func populateIssueIndexer() {
 	for page := 1; ; page++ {
 		repos, _, err := SearchRepositoryByName(&SearchRepoOptions{
 			Page:        page,
@@ -35,98 +70,79 @@ func populateIssueIndexer() error {
 			Collaborate: util.OptionalBoolFalse,
 		})
 		if err != nil {
-			return fmt.Errorf("Repositories: %v", err)
+			log.Error(4, "SearchRepositoryByName: %v", err)
+			continue
 		}
 		if len(repos) == 0 {
-			return batch.Flush()
+			return
 		}
+
 		for _, repo := range repos {
-			issues, err := Issues(&IssuesOptions{
+			is, err := Issues(&IssuesOptions{
 				RepoIDs:  []int64{repo.ID},
 				IsClosed: util.OptionalBoolNone,
 				IsPull:   util.OptionalBoolNone,
 			})
 			if err != nil {
-				return err
+				log.Error(4, "Issues: %v", err)
+				continue
 			}
-			if err = IssueList(issues).LoadComments(); err != nil {
-				return err
+			if err = IssueList(is).LoadDiscussComments(); err != nil {
+				log.Error(4, "LoadComments: %v", err)
+				continue
 			}
-			for _, issue := range issues {
-				if err := issue.update().AddToFlushingBatch(batch); err != nil {
-					return err
-				}
+			for _, issue := range is {
+				UpdateIssueIndexer(issue)
 			}
 		}
 	}
 }
 
-func processIssueIndexerUpdateQueue() {
-	batch := indexer.IssueIndexerBatch()
-	for {
-		var issueID int64
-		select {
-		case issueID = <-issueIndexerUpdateQueue:
-		default:
-			// flush whatever updates we currently have, since we
-			// might have to wait a while
-			if err := batch.Flush(); err != nil {
-				log.Error(4, "IssueIndexer: %v", err)
-			}
-			issueID = <-issueIndexerUpdateQueue
-		}
-		issue, err := GetIssueByID(issueID)
-		if err != nil {
-			log.Error(4, "GetIssueByID: %v", err)
-		} else if err = issue.update().AddToFlushingBatch(batch); err != nil {
-			log.Error(4, "IssueIndexer: %v", err)
-		}
-	}
-}
-
-func (issue *Issue) update() indexer.IssueIndexerUpdate {
-	comments := make([]string, 0, 5)
+// UpdateIssueIndexer add/update an issue to the issue indexer
+func UpdateIssueIndexer(issue *Issue) {
+	var comments []string
 	for _, comment := range issue.Comments {
 		if comment.Type == CommentTypeComment {
 			comments = append(comments, comment.Content)
 		}
 	}
-	return indexer.IssueIndexerUpdate{
-		IssueID: issue.ID,
-		Data: &indexer.IssueIndexerData{
-			RepoID:   issue.RepoID,
-			Title:    issue.Title,
-			Content:  issue.Content,
-			Comments: comments,
-		},
-	}
+	issueIndexerUpdateQueue.Push(&issues.IndexerData{
+		ID:       issue.ID,
+		RepoID:   issue.RepoID,
+		Title:    issue.Title,
+		Content:  issue.Content,
+		Comments: comments,
+	})
 }
 
-// updateNeededCols whether a change to the specified columns requires updating
-// the issue indexer
-func updateNeededCols(cols []string) bool {
-	for _, col := range cols {
-		switch col {
-		case "name", "content":
-			return true
-		}
+// DeleteRepoIssueIndexer deletes repo's all issues indexes
+func DeleteRepoIssueIndexer(repo *Repository) {
+	var ids []int64
+	ids, err := getIssueIDsByRepoID(x, repo.ID)
+	if err != nil {
+		log.Error(4, "getIssueIDsByRepoID failed: %v", err)
+		return
+	}
+
+	if len(ids) <= 0 {
+		return
 	}
-	return false
-}
 
-// UpdateIssueIndexerCols update an issue in the issue indexer, given changes
-// to the specified columns
-func UpdateIssueIndexerCols(issueID int64, cols ...string) {
-	updateNeededCols(cols)
+	issueIndexerUpdateQueue.Push(&issues.IndexerData{
+		IDs:      ids,
+		IsDelete: true,
+	})
 }
 
-// UpdateIssueIndexer add/update an issue to the issue indexer
-func UpdateIssueIndexer(issueID int64) {
-	select {
-	case issueIndexerUpdateQueue <- issueID:
-	default:
-		go func() {
-			issueIndexerUpdateQueue <- issueID
-		}()
+// SearchIssuesByKeyword search issue ids by keywords and repo id
+func SearchIssuesByKeyword(repoID int64, keyword string) ([]int64, error) {
+	var issueIDs []int64
+	res, err := issueIndexer.Search(keyword, repoID, 1000, 0)
+	if err != nil {
+		return nil, err
+	}
+	for _, r := range res.Hits {
+		issueIDs = append(issueIDs, r.ID)
 	}
+	return issueIDs, nil
 }
diff --git a/models/issue_list.go b/models/issue_list.go
index 7e4c264643..a1aab488fc 100644
--- a/models/issue_list.go
+++ b/models/issue_list.go
@@ -4,7 +4,11 @@
 
 package models
 
-import "fmt"
+import (
+	"fmt"
+
+	"github.com/go-xorm/builder"
+)
 
 // IssueList defines a list of issues
 type IssueList []*Issue
@@ -338,7 +342,7 @@ func (issues IssueList) loadAttachments(e Engine) (err error) {
 	return nil
 }
 
-func (issues IssueList) loadComments(e Engine) (err error) {
+func (issues IssueList) loadComments(e Engine, cond builder.Cond) (err error) {
 	if len(issues) == 0 {
 		return nil
 	}
@@ -354,6 +358,7 @@ func (issues IssueList) loadComments(e Engine) (err error) {
 		rows, err := e.Table("comment").
 			Join("INNER", "issue", "issue.id = comment.issue_id").
 			In("issue.id", issuesIDs[:limit]).
+			Where(cond).
 			Rows(new(Comment))
 		if err != nil {
 			return err
@@ -479,5 +484,10 @@ func (issues IssueList) LoadAttachments() error {
 
 // LoadComments loads comments
 func (issues IssueList) LoadComments() error {
-	return issues.loadComments(x)
+	return issues.loadComments(x, builder.NewCond())
+}
+
+// LoadDiscussComments loads discuss comments
+func (issues IssueList) LoadDiscussComments() error {
+	return issues.loadComments(x, builder.Eq{"comment.type": CommentTypeComment})
 }
diff --git a/models/models.go b/models/models.go
index daef7c07e8..b8fe588b5a 100644
--- a/models/models.go
+++ b/models/models.go
@@ -12,7 +12,6 @@ import (
 	"net/url"
 	"os"
 	"path"
-	"path/filepath"
 	"strings"
 
 	"code.gitea.io/gitea/modules/log"
@@ -158,19 +157,6 @@ func LoadConfigs() {
 	DbCfg.SSLMode = sec.Key("SSL_MODE").MustString("disable")
 	DbCfg.Path = sec.Key("PATH").MustString("data/gitea.db")
 	DbCfg.Timeout = sec.Key("SQLITE_TIMEOUT").MustInt(500)
-
-	sec = setting.Cfg.Section("indexer")
-	setting.Indexer.IssuePath = sec.Key("ISSUE_INDEXER_PATH").MustString(path.Join(setting.AppDataPath, "indexers/issues.bleve"))
-	if !filepath.IsAbs(setting.Indexer.IssuePath) {
-		setting.Indexer.IssuePath = path.Join(setting.AppWorkPath, setting.Indexer.IssuePath)
-	}
-	setting.Indexer.RepoIndexerEnabled = sec.Key("REPO_INDEXER_ENABLED").MustBool(false)
-	setting.Indexer.RepoPath = sec.Key("REPO_INDEXER_PATH").MustString(path.Join(setting.AppDataPath, "indexers/repos.bleve"))
-	if !filepath.IsAbs(setting.Indexer.RepoPath) {
-		setting.Indexer.RepoPath = path.Join(setting.AppWorkPath, setting.Indexer.RepoPath)
-	}
-	setting.Indexer.UpdateQueueLength = sec.Key("UPDATE_BUFFER_LEN").MustInt(20)
-	setting.Indexer.MaxIndexerFileSize = sec.Key("MAX_FILE_SIZE").MustInt64(1024 * 1024)
 }
 
 // parsePostgreSQLHostPort parses given input in various forms defined in
diff --git a/models/unit_tests.go b/models/unit_tests.go
index 28cd91215e..f87dd7ee96 100644
--- a/models/unit_tests.go
+++ b/models/unit_tests.go
@@ -44,6 +44,10 @@ func MainTest(m *testing.M, pathToGiteaRoot string) {
 		fatalTestError("Error creating test engine: %v\n", err)
 	}
 
+	if err = InitIssueIndexer(); err != nil {
+		fatalTestError("Error InitIssueIndexer: %v\n", err)
+	}
+
 	setting.AppURL = "https://try.gitea.io/"
 	setting.RunUser = "runuser"
 	setting.SSH.Port = 3000
diff --git a/modules/indexer/issues/bleve.go b/modules/indexer/issues/bleve.go
new file mode 100644
index 0000000000..36279198b8
--- /dev/null
+++ b/modules/indexer/issues/bleve.go
@@ -0,0 +1,250 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issues
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+
+	"github.com/blevesearch/bleve"
+	"github.com/blevesearch/bleve/analysis/analyzer/custom"
+	"github.com/blevesearch/bleve/analysis/token/lowercase"
+	"github.com/blevesearch/bleve/analysis/token/unicodenorm"
+	"github.com/blevesearch/bleve/analysis/tokenizer/unicode"
+	"github.com/blevesearch/bleve/index/upsidedown"
+	"github.com/blevesearch/bleve/mapping"
+	"github.com/blevesearch/bleve/search/query"
+	"github.com/ethantkoenig/rupture"
+)
+
+const (
+	issueIndexerAnalyzer      = "issueIndexer"
+	issueIndexerDocType       = "issueIndexerDocType"
+	issueIndexerLatestVersion = 1
+)
+
+// indexerID a bleve-compatible unique identifier for an integer id
+func indexerID(id int64) string {
+	return strconv.FormatInt(id, 36)
+}
+
+// idOfIndexerID the integer id associated with an indexer id
+func idOfIndexerID(indexerID string) (int64, error) {
+	id, err := strconv.ParseInt(indexerID, 36, 64)
+	if err != nil {
+		return 0, fmt.Errorf("Unexpected indexer ID %s: %v", indexerID, err)
+	}
+	return id, nil
+}
+
+// numericEqualityQuery a numeric equality query for the given value and field
+func numericEqualityQuery(value int64, field string) *query.NumericRangeQuery {
+	f := float64(value)
+	tru := true
+	q := bleve.NewNumericRangeInclusiveQuery(&f, &f, &tru, &tru)
+	q.SetField(field)
+	return q
+}
+
+func newMatchPhraseQuery(matchPhrase, field, analyzer string) *query.MatchPhraseQuery {
+	q := bleve.NewMatchPhraseQuery(matchPhrase)
+	q.FieldVal = field
+	q.Analyzer = analyzer
+	return q
+}
+
+const unicodeNormalizeName = "unicodeNormalize"
+
+func addUnicodeNormalizeTokenFilter(m *mapping.IndexMappingImpl) error {
+	return m.AddCustomTokenFilter(unicodeNormalizeName, map[string]interface{}{
+		"type": unicodenorm.Name,
+		"form": unicodenorm.NFC,
+	})
+}
+
+const maxBatchSize = 16
+
+// openIndexer open the index at the specified path, checking for metadata
+// updates and bleve version updates.  If index needs to be created (or
+// re-created), returns (nil, nil)
+func openIndexer(path string, latestVersion int) (bleve.Index, error) {
+	_, err := os.Stat(path)
+	if err != nil && os.IsNotExist(err) {
+		return nil, nil
+	} else if err != nil {
+		return nil, err
+	}
+
+	metadata, err := rupture.ReadIndexMetadata(path)
+	if err != nil {
+		return nil, err
+	}
+	if metadata.Version < latestVersion {
+		// the indexer is using a previous version, so we should delete it and
+		// re-populate
+		return nil, os.RemoveAll(path)
+	}
+
+	index, err := bleve.Open(path)
+	if err != nil && err == upsidedown.IncompatibleVersion {
+		// the indexer was built with a previous version of bleve, so we should
+		// delete it and re-populate
+		return nil, os.RemoveAll(path)
+	} else if err != nil {
+		return nil, err
+	}
+
+	return index, nil
+}
+
+// BleveIndexerData an update to the issue indexer
+type BleveIndexerData IndexerData
+
+// Type returns the document type, for bleve's mapping.Classifier interface.
+func (i *BleveIndexerData) Type() string {
+	return issueIndexerDocType
+}
+
+// createIssueIndexer create an issue indexer if one does not already exist
+func createIssueIndexer(path string, latestVersion int) (bleve.Index, error) {
+	mapping := bleve.NewIndexMapping()
+	docMapping := bleve.NewDocumentMapping()
+
+	numericFieldMapping := bleve.NewNumericFieldMapping()
+	numericFieldMapping.IncludeInAll = false
+	docMapping.AddFieldMappingsAt("RepoID", numericFieldMapping)
+
+	textFieldMapping := bleve.NewTextFieldMapping()
+	textFieldMapping.Store = false
+	textFieldMapping.IncludeInAll = false
+	docMapping.AddFieldMappingsAt("Title", textFieldMapping)
+	docMapping.AddFieldMappingsAt("Content", textFieldMapping)
+	docMapping.AddFieldMappingsAt("Comments", textFieldMapping)
+
+	if err := addUnicodeNormalizeTokenFilter(mapping); err != nil {
+		return nil, err
+	} else if err = mapping.AddCustomAnalyzer(issueIndexerAnalyzer, map[string]interface{}{
+		"type":          custom.Name,
+		"char_filters":  []string{},
+		"tokenizer":     unicode.Name,
+		"token_filters": []string{unicodeNormalizeName, lowercase.Name},
+	}); err != nil {
+		return nil, err
+	}
+
+	mapping.DefaultAnalyzer = issueIndexerAnalyzer
+	mapping.AddDocumentMapping(issueIndexerDocType, docMapping)
+	mapping.AddDocumentMapping("_all", bleve.NewDocumentDisabledMapping())
+
+	index, err := bleve.New(path, mapping)
+	if err != nil {
+		return nil, err
+	}
+
+	if err = rupture.WriteIndexMetadata(path, &rupture.IndexMetadata{
+		Version: latestVersion,
+	}); err != nil {
+		return nil, err
+	}
+	return index, nil
+}
+
+var (
+	_ Indexer = &BleveIndexer{}
+)
+
+// BleveIndexer implements Indexer interface
+type BleveIndexer struct {
+	indexDir string
+	indexer  bleve.Index
+}
+
+// NewBleveIndexer creates a new bleve local indexer
+func NewBleveIndexer(indexDir string) *BleveIndexer {
+	return &BleveIndexer{
+		indexDir: indexDir,
+	}
+}
+
+// Init will initial the indexer
+func (b *BleveIndexer) Init() (bool, error) {
+	var err error
+	b.indexer, err = openIndexer(b.indexDir, issueIndexerLatestVersion)
+	if err != nil {
+		return false, err
+	}
+	if b.indexer != nil {
+		return true, nil
+	}
+
+	b.indexer, err = createIssueIndexer(b.indexDir, issueIndexerLatestVersion)
+	return false, err
+}
+
+// Index will save the index data
+func (b *BleveIndexer) Index(issues []*IndexerData) error {
+	batch := rupture.NewFlushingBatch(b.indexer, maxBatchSize)
+	for _, issue := range issues {
+		if err := batch.Index(indexerID(issue.ID), struct {
+			RepoID   int64
+			Title    string
+			Content  string
+			Comments []string
+		}{
+			RepoID:   issue.RepoID,
+			Title:    issue.Title,
+			Content:  issue.Content,
+			Comments: issue.Comments,
+		}); err != nil {
+			return err
+		}
+	}
+	return batch.Flush()
+}
+
+// Delete deletes indexes by ids
+func (b *BleveIndexer) Delete(ids ...int64) error {
+	batch := rupture.NewFlushingBatch(b.indexer, maxBatchSize)
+	for _, id := range ids {
+		if err := batch.Delete(indexerID(id)); err != nil {
+			return err
+		}
+	}
+	return batch.Flush()
+}
+
+// Search searches for issues by given conditions.
+// Returns the matching issue IDs
+func (b *BleveIndexer) Search(keyword string, repoID int64, limit, start int) (*SearchResult, error) {
+	indexerQuery := bleve.NewConjunctionQuery(
+		numericEqualityQuery(repoID, "RepoID"),
+		bleve.NewDisjunctionQuery(
+			newMatchPhraseQuery(keyword, "Title", issueIndexerAnalyzer),
+			newMatchPhraseQuery(keyword, "Content", issueIndexerAnalyzer),
+			newMatchPhraseQuery(keyword, "Comments", issueIndexerAnalyzer),
+		))
+	search := bleve.NewSearchRequestOptions(indexerQuery, limit, start, false)
+
+	result, err := b.indexer.Search(search)
+	if err != nil {
+		return nil, err
+	}
+
+	var ret = SearchResult{
+		Hits: make([]Match, 0, len(result.Hits)),
+	}
+	for _, hit := range result.Hits {
+		id, err := idOfIndexerID(hit.ID)
+		if err != nil {
+			return nil, err
+		}
+		ret.Hits = append(ret.Hits, Match{
+			ID:     id,
+			RepoID: repoID,
+		})
+	}
+	return &ret, nil
+}
diff --git a/modules/indexer/issues/bleve_test.go b/modules/indexer/issues/bleve_test.go
new file mode 100644
index 0000000000..720266e3b5
--- /dev/null
+++ b/modules/indexer/issues/bleve_test.go
@@ -0,0 +1,88 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issues
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIndexAndSearch(t *testing.T) {
+	dir := "./bleve.index"
+	indexer := NewBleveIndexer(dir)
+	defer os.RemoveAll(dir)
+
+	_, err := indexer.Init()
+	assert.NoError(t, err)
+
+	err = indexer.Index([]*IndexerData{
+		{
+			ID:      1,
+			RepoID:  2,
+			Title:   "Issue search should support Chinese",
+			Content: "As title",
+			Comments: []string{
+				"test1",
+				"test2",
+			},
+		},
+		{
+			ID:      2,
+			RepoID:  2,
+			Title:   "CJK support could be optional",
+			Content: "Chinese Korean and Japanese should be supported but I would like it's not enabled by default",
+			Comments: []string{
+				"LGTM",
+				"Good idea",
+			},
+		},
+	})
+	assert.NoError(t, err)
+
+	var (
+		keywords = []struct {
+			Keyword string
+			IDs     []int64
+		}{
+			{
+				Keyword: "search",
+				IDs:     []int64{1},
+			},
+			{
+				Keyword: "test1",
+				IDs:     []int64{1},
+			},
+			{
+				Keyword: "test2",
+				IDs:     []int64{1},
+			},
+			{
+				Keyword: "support",
+				IDs:     []int64{1, 2},
+			},
+			{
+				Keyword: "chinese",
+				IDs:     []int64{1, 2},
+			},
+			{
+				Keyword: "help",
+				IDs:     []int64{},
+			},
+		}
+	)
+
+	for _, kw := range keywords {
+		res, err := indexer.Search(kw.Keyword, 2, 10, 0)
+		assert.NoError(t, err)
+
+		var ids = make([]int64, 0, len(res.Hits))
+		for _, hit := range res.Hits {
+			ids = append(ids, hit.ID)
+		}
+		assert.EqualValues(t, kw.IDs, ids)
+	}
+}
diff --git a/modules/indexer/issues/indexer.go b/modules/indexer/issues/indexer.go
new file mode 100644
index 0000000000..c31006d0dd
--- /dev/null
+++ b/modules/indexer/issues/indexer.go
@@ -0,0 +1,36 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issues
+
+// IndexerData data stored in the issue indexer
+type IndexerData struct {
+	ID       int64
+	RepoID   int64
+	Title    string
+	Content  string
+	Comments []string
+	IsDelete bool
+	IDs      []int64
+}
+
+// Match represents on search result
+type Match struct {
+	ID     int64   `json:"id"`
+	RepoID int64   `json:"repo_id"`
+	Score  float64 `json:"score"`
+}
+
+// SearchResult represents search results
+type SearchResult struct {
+	Hits []Match
+}
+
+// Indexer defines an inteface to indexer issues contents
+type Indexer interface {
+	Init() (bool, error)
+	Index(issue []*IndexerData) error
+	Delete(ids ...int64) error
+	Search(kw string, repoID int64, limit, start int) (*SearchResult, error)
+}
diff --git a/modules/indexer/issues/queue.go b/modules/indexer/issues/queue.go
new file mode 100644
index 0000000000..6f4ee4c13a
--- /dev/null
+++ b/modules/indexer/issues/queue.go
@@ -0,0 +1,11 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issues
+
+// Queue defines an interface to save an issue indexer queue
+type Queue interface {
+	Run() error
+	Push(*IndexerData)
+}
diff --git a/modules/indexer/issues/queue_channel.go b/modules/indexer/issues/queue_channel.go
new file mode 100644
index 0000000000..99a90ad499
--- /dev/null
+++ b/modules/indexer/issues/queue_channel.go
@@ -0,0 +1,56 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issues
+
+import (
+	"time"
+
+	"code.gitea.io/gitea/modules/setting"
+)
+
+// ChannelQueue implements
+type ChannelQueue struct {
+	queue       chan *IndexerData
+	indexer     Indexer
+	batchNumber int
+}
+
+// NewChannelQueue create a memory channel queue
+func NewChannelQueue(indexer Indexer, batchNumber int) *ChannelQueue {
+	return &ChannelQueue{
+		queue:       make(chan *IndexerData, setting.Indexer.UpdateQueueLength),
+		indexer:     indexer,
+		batchNumber: batchNumber,
+	}
+}
+
+// Run starts to run the queue
+func (c *ChannelQueue) Run() error {
+	var i int
+	var datas = make([]*IndexerData, 0, c.batchNumber)
+	for {
+		select {
+		case data := <-c.queue:
+			datas = append(datas, data)
+			if len(datas) >= c.batchNumber {
+				c.indexer.Index(datas)
+				// TODO: save the point
+				datas = make([]*IndexerData, 0, c.batchNumber)
+			}
+		case <-time.After(time.Millisecond * 100):
+			i++
+			if i >= 3 && len(datas) > 0 {
+				c.indexer.Index(datas)
+				// TODO: save the point
+				datas = make([]*IndexerData, 0, c.batchNumber)
+			}
+		}
+	}
+}
+
+// Push will push the indexer data to queue
+func (c *ChannelQueue) Push(data *IndexerData) {
+	c.queue <- data
+}
diff --git a/modules/indexer/issues/queue_disk.go b/modules/indexer/issues/queue_disk.go
new file mode 100644
index 0000000000..97e9a3d965
--- /dev/null
+++ b/modules/indexer/issues/queue_disk.go
@@ -0,0 +1,104 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issues
+
+import (
+	"encoding/json"
+	"time"
+
+	"code.gitea.io/gitea/modules/log"
+	"github.com/lunny/levelqueue"
+)
+
+var (
+	_ Queue = &LevelQueue{}
+)
+
+// LevelQueue implements a disk library queue
+type LevelQueue struct {
+	indexer     Indexer
+	queue       *levelqueue.Queue
+	batchNumber int
+}
+
+// NewLevelQueue creates a ledis local queue
+func NewLevelQueue(indexer Indexer, dataDir string, batchNumber int) (*LevelQueue, error) {
+	queue, err := levelqueue.Open(dataDir)
+	if err != nil {
+		return nil, err
+	}
+
+	return &LevelQueue{
+		indexer:     indexer,
+		queue:       queue,
+		batchNumber: batchNumber,
+	}, nil
+}
+
+// Run starts to run the queue
+func (l *LevelQueue) Run() error {
+	var i int
+	var datas = make([]*IndexerData, 0, l.batchNumber)
+	for {
+		bs, err := l.queue.RPop()
+		if err != nil {
+			log.Error(4, "RPop: %v", err)
+			time.Sleep(time.Millisecond * 100)
+			continue
+		}
+
+		i++
+		if len(datas) > l.batchNumber || (len(datas) > 0 && i > 3) {
+			l.indexer.Index(datas)
+			datas = make([]*IndexerData, 0, l.batchNumber)
+			i = 0
+		}
+
+		if len(bs) <= 0 {
+			time.Sleep(time.Millisecond * 100)
+			continue
+		}
+
+		var data IndexerData
+		err = json.Unmarshal(bs, &data)
+		if err != nil {
+			log.Error(4, "Unmarshal: %v", err)
+			time.Sleep(time.Millisecond * 100)
+			continue
+		}
+
+		log.Trace("LedisLocalQueue: task found: %#v", data)
+
+		if data.IsDelete {
+			if data.ID > 0 {
+				if err = l.indexer.Delete(data.ID); err != nil {
+					log.Error(4, "indexer.Delete: %v", err)
+				}
+			} else if len(data.IDs) > 0 {
+				if err = l.indexer.Delete(data.IDs...); err != nil {
+					log.Error(4, "indexer.Delete: %v", err)
+				}
+			}
+			time.Sleep(time.Millisecond * 10)
+			continue
+		}
+
+		datas = append(datas, &data)
+		time.Sleep(time.Millisecond * 10)
+	}
+}
+
+// Push will push the indexer data to queue
+func (l *LevelQueue) Push(data *IndexerData) {
+	bs, err := json.Marshal(data)
+	if err != nil {
+		log.Error(4, "Marshal: %v", err)
+		return
+	}
+	err = l.queue.LPush(bs)
+	if err != nil {
+		log.Error(4, "LPush: %v", err)
+	}
+}
diff --git a/modules/notification/indexer/indexer.go b/modules/notification/indexer/indexer.go
index 3fd3352188..66d483c017 100644
--- a/modules/notification/indexer/indexer.go
+++ b/modules/notification/indexer/indexer.go
@@ -6,6 +6,7 @@ package indexer
 
 import (
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/notification/base"
 )
 
@@ -25,38 +26,83 @@ func NewNotifier() base.Notifier {
 func (r *indexerNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
 	issue *models.Issue, comment *models.Comment) {
 	if comment.Type == models.CommentTypeComment {
-		models.UpdateIssueIndexer(issue.ID)
+		if issue.Comments == nil {
+			if err := issue.LoadDiscussComments(); err != nil {
+				log.Error(4, "LoadComments failed: %v", err)
+				return
+			}
+		} else {
+			issue.Comments = append(issue.Comments, comment)
+		}
+
+		models.UpdateIssueIndexer(issue)
 	}
 }
 
 func (r *indexerNotifier) NotifyNewIssue(issue *models.Issue) {
-	models.UpdateIssueIndexer(issue.ID)
+	models.UpdateIssueIndexer(issue)
 }
 
 func (r *indexerNotifier) NotifyNewPullRequest(pr *models.PullRequest) {
-	models.UpdateIssueIndexer(pr.Issue.ID)
+	models.UpdateIssueIndexer(pr.Issue)
 }
 
 func (r *indexerNotifier) NotifyUpdateComment(doer *models.User, c *models.Comment, oldContent string) {
 	if c.Type == models.CommentTypeComment {
-		models.UpdateIssueIndexer(c.IssueID)
+		var found bool
+		if c.Issue.Comments != nil {
+			for i := 0; i < len(c.Issue.Comments); i++ {
+				if c.Issue.Comments[i].ID == c.ID {
+					c.Issue.Comments[i] = c
+					found = true
+					break
+				}
+			}
+		}
+
+		if !found {
+			if err := c.Issue.LoadDiscussComments(); err != nil {
+				log.Error(4, "LoadComments failed: %v", err)
+				return
+			}
+		}
+
+		models.UpdateIssueIndexer(c.Issue)
 	}
 }
 
 func (r *indexerNotifier) NotifyDeleteComment(doer *models.User, comment *models.Comment) {
 	if comment.Type == models.CommentTypeComment {
-		models.UpdateIssueIndexer(comment.IssueID)
+		var found bool
+		if comment.Issue.Comments != nil {
+			for i := 0; i < len(comment.Issue.Comments); i++ {
+				if comment.Issue.Comments[i].ID == comment.ID {
+					comment.Issue.Comments = append(comment.Issue.Comments[:i], comment.Issue.Comments[i+1:]...)
+					found = true
+					break
+				}
+			}
+		}
+
+		if !found {
+			if err := comment.Issue.LoadDiscussComments(); err != nil {
+				log.Error(4, "LoadComments failed: %v", err)
+				return
+			}
+		}
+		// reload comments to delete the old comment
+		models.UpdateIssueIndexer(comment.Issue)
 	}
 }
 
 func (r *indexerNotifier) NotifyDeleteRepository(doer *models.User, repo *models.Repository) {
-	models.DeleteRepoFromIndexer(repo)
+	models.DeleteRepoIssueIndexer(repo)
 }
 
 func (r *indexerNotifier) NotifyIssueChangeContent(doer *models.User, issue *models.Issue, oldContent string) {
-	models.UpdateIssueIndexer(issue.ID)
+	models.UpdateIssueIndexer(issue)
 }
 
 func (r *indexerNotifier) NotifyIssueChangeTitle(doer *models.User, issue *models.Issue, oldTitle string) {
-	models.UpdateIssueIndexer(issue.ID)
+	models.UpdateIssueIndexer(issue)
 }
diff --git a/modules/setting/indexer.go b/modules/setting/indexer.go
new file mode 100644
index 0000000000..245ebb0496
--- /dev/null
+++ b/modules/setting/indexer.go
@@ -0,0 +1,55 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package setting
+
+import (
+	"path"
+	"path/filepath"
+)
+
+// enumerates all the indexer queue types
+const (
+	LevelQueueType   = "levelqueue"
+	ChannelQueueType = "channel"
+)
+
+var (
+	// Indexer settings
+	Indexer = struct {
+		IssueType                    string
+		IssuePath                    string
+		RepoIndexerEnabled           bool
+		RepoPath                     string
+		UpdateQueueLength            int
+		MaxIndexerFileSize           int64
+		IssueIndexerQueueType        string
+		IssueIndexerQueueDir         string
+		IssueIndexerQueueBatchNumber int
+	}{
+		IssueType:                    "bleve",
+		IssuePath:                    "indexers/issues.bleve",
+		IssueIndexerQueueType:        LevelQueueType,
+		IssueIndexerQueueDir:         "indexers/issues.queue",
+		IssueIndexerQueueBatchNumber: 20,
+	}
+)
+
+func newIndexerService() {
+	sec := Cfg.Section("indexer")
+	Indexer.IssuePath = sec.Key("ISSUE_INDEXER_PATH").MustString(path.Join(AppDataPath, "indexers/issues.bleve"))
+	if !filepath.IsAbs(Indexer.IssuePath) {
+		Indexer.IssuePath = path.Join(AppWorkPath, Indexer.IssuePath)
+	}
+	Indexer.RepoIndexerEnabled = sec.Key("REPO_INDEXER_ENABLED").MustBool(false)
+	Indexer.RepoPath = sec.Key("REPO_INDEXER_PATH").MustString(path.Join(AppDataPath, "indexers/repos.bleve"))
+	if !filepath.IsAbs(Indexer.RepoPath) {
+		Indexer.RepoPath = path.Join(AppWorkPath, Indexer.RepoPath)
+	}
+	Indexer.UpdateQueueLength = sec.Key("UPDATE_BUFFER_LEN").MustInt(20)
+	Indexer.MaxIndexerFileSize = sec.Key("MAX_FILE_SIZE").MustInt64(1024 * 1024)
+	Indexer.IssueIndexerQueueType = sec.Key("ISSUE_INDEXER_QUEUE_TYPE").MustString(LevelQueueType)
+	Indexer.IssueIndexerQueueDir = sec.Key("ISSUE_INDEXER_QUEUE_DIR").MustString(path.Join(AppDataPath, "indexers/issues.queue"))
+	Indexer.IssueIndexerQueueBatchNumber = sec.Key("ISSUE_INDEXER_QUEUE_BATCH_NUMBER").MustInt(20)
+}
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 5f65570540..4c016f3489 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -179,15 +179,6 @@ var (
 	DBConnectRetries int
 	DBConnectBackoff time.Duration
 
-	// Indexer settings
-	Indexer struct {
-		IssuePath          string
-		RepoIndexerEnabled bool
-		RepoPath           string
-		UpdateQueueLength  int
-		MaxIndexerFileSize int64
-	}
-
 	// Repository settings
 	Repository = struct {
 		AnsiCharset                             string
@@ -1214,6 +1205,7 @@ func NewContext() {
 			IsInputFile:    sec.Key("IS_INPUT_FILE").MustBool(false),
 		})
 	}
+
 	sec = Cfg.Section("U2F")
 	U2F.TrustedFacets, _ = shellquote.Split(sec.Key("TRUSTED_FACETS").MustString(strings.TrimRight(AppURL, "/")))
 	U2F.AppID = sec.Key("APP_ID").MustString(strings.TrimRight(AppURL, "/"))
@@ -1240,4 +1232,5 @@ func NewServices() {
 	newRegisterMailService()
 	newNotifyMailService()
 	newWebhookService()
+	newIndexerService()
 }
diff --git a/routers/api/v1/repo/issue.go b/routers/api/v1/repo/issue.go
index d339d8f0b7..b13af33548 100644
--- a/routers/api/v1/repo/issue.go
+++ b/routers/api/v1/repo/issue.go
@@ -13,7 +13,6 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/context"
-	"code.gitea.io/gitea/modules/indexer"
 	"code.gitea.io/gitea/modules/notification"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
@@ -78,7 +77,7 @@ func ListIssues(ctx *context.APIContext) {
 	var labelIDs []int64
 	var err error
 	if len(keyword) > 0 {
-		issueIDs, err = indexer.SearchIssuesByKeyword(ctx.Repo.Repository.ID, keyword)
+		issueIDs, err = models.SearchIssuesByKeyword(ctx.Repo.Repository.ID, keyword)
 	}
 
 	if splitted := strings.Split(ctx.Query("labels"), ","); len(splitted) > 0 {
diff --git a/routers/init.go b/routers/init.go
index 4da786cc00..1da21a351b 100644
--- a/routers/init.go
+++ b/routers/init.go
@@ -90,7 +90,9 @@ func GlobalInit() {
 
 		// Booting long running goroutines.
 		cron.NewContext()
-		models.InitIssueIndexer()
+		if err := models.InitIssueIndexer(); err != nil {
+			log.Fatal(4, "Failed to initialize issue indexer: %v", err)
+		}
 		models.InitRepoIndexer()
 		models.InitSyncMirrors()
 		models.InitDeliverHooks()
diff --git a/routers/repo/issue.go b/routers/repo/issue.go
index 6783d279b5..1843e00144 100644
--- a/routers/repo/issue.go
+++ b/routers/repo/issue.go
@@ -23,7 +23,6 @@ import (
 	"code.gitea.io/gitea/modules/auth"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/context"
-	"code.gitea.io/gitea/modules/indexer"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup/markdown"
 	"code.gitea.io/gitea/modules/notification"
@@ -147,7 +146,11 @@ func issues(ctx *context.Context, milestoneID int64, isPullOption util.OptionalB
 
 	var issueIDs []int64
 	if len(keyword) > 0 {
-		issueIDs, err = indexer.SearchIssuesByKeyword(repo.ID, keyword)
+		issueIDs, err = models.SearchIssuesByKeyword(repo.ID, keyword)
+		if err != nil {
+			ctx.ServerError("issueIndexer.Search", err)
+			return
+		}
 		if len(issueIDs) == 0 {
 			forceEmpty = true
 		}
diff --git a/vendor/github.com/lunny/levelqueue/LICENSE b/vendor/github.com/lunny/levelqueue/LICENSE
new file mode 100644
index 0000000000..4a5a4ea0ff
--- /dev/null
+++ b/vendor/github.com/lunny/levelqueue/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2019 Lunny Xiao
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/vendor/github.com/lunny/levelqueue/error.go b/vendor/github.com/lunny/levelqueue/error.go
new file mode 100644
index 0000000000..d639c5d496
--- /dev/null
+++ b/vendor/github.com/lunny/levelqueue/error.go
@@ -0,0 +1,12 @@
+// Copyright 2019 Lunny Xiao. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package levelqueue
+
+import "errors"
+
+var (
+	// ErrNotFound means no element in queue
+	ErrNotFound = errors.New("no key found")
+)
diff --git a/vendor/github.com/lunny/levelqueue/queue.go b/vendor/github.com/lunny/levelqueue/queue.go
new file mode 100644
index 0000000000..0b2bef6c84
--- /dev/null
+++ b/vendor/github.com/lunny/levelqueue/queue.go
@@ -0,0 +1,214 @@
+// Copyright 2019 Lunny Xiao. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package levelqueue
+
+import (
+	"bytes"
+	"encoding/binary"
+	"sync"
+
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+// Queue defines a queue struct
+type Queue struct {
+	db       *leveldb.DB
+	highLock sync.Mutex
+	lowLock  sync.Mutex
+	low      int64
+	high     int64
+}
+
+// Open opens a queue object or create it if not exist
+func Open(dataDir string) (*Queue, error) {
+	db, err := leveldb.OpenFile(dataDir, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	var queue = &Queue{
+		db: db,
+	}
+	queue.low, err = queue.readID(lowKey)
+	if err == leveldb.ErrNotFound {
+		queue.low = 1
+		err = db.Put(lowKey, id2bytes(1), nil)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	queue.high, err = queue.readID(highKey)
+	if err == leveldb.ErrNotFound {
+		err = db.Put(highKey, id2bytes(0), nil)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return queue, nil
+}
+
+func (queue *Queue) readID(key []byte) (int64, error) {
+	bs, err := queue.db.Get(key, nil)
+	if err != nil {
+		return 0, err
+	}
+	return bytes2id(bs)
+}
+
+var (
+	lowKey  = []byte("low")
+	highKey = []byte("high")
+)
+
+func (queue *Queue) highincrement() (int64, error) {
+	id := queue.high + 1
+	queue.high = id
+	err := queue.db.Put(highKey, id2bytes(queue.high), nil)
+	if err != nil {
+		queue.high = queue.high - 1
+		return 0, err
+	}
+	return id, nil
+}
+
+func (queue *Queue) highdecrement() (int64, error) {
+	queue.high = queue.high - 1
+	err := queue.db.Put(highKey, id2bytes(queue.high), nil)
+	if err != nil {
+		queue.high = queue.high + 1
+		return 0, err
+	}
+	return queue.high, nil
+}
+
+func (queue *Queue) lowincrement() (int64, error) {
+	queue.low = queue.low + 1
+	err := queue.db.Put(lowKey, id2bytes(queue.low), nil)
+	if err != nil {
+		queue.low = queue.low - 1
+		return 0, err
+	}
+	return queue.low, nil
+}
+
+func (queue *Queue) lowdecrement() (int64, error) {
+	queue.low = queue.low - 1
+	err := queue.db.Put(lowKey, id2bytes(queue.low), nil)
+	if err != nil {
+		queue.low = queue.low + 1
+		return 0, err
+	}
+	return queue.low, nil
+}
+
+// Len returns the length of the queue
+func (queue *Queue) Len() int64 {
+	queue.lowLock.Lock()
+	queue.highLock.Lock()
+	l := queue.high - queue.low + 1
+	queue.highLock.Unlock()
+	queue.lowLock.Unlock()
+	return l
+}
+
+func id2bytes(id int64) []byte {
+	var buf = make([]byte, 8)
+	binary.PutVarint(buf, id)
+	return buf
+}
+
+func bytes2id(b []byte) (int64, error) {
+	return binary.ReadVarint(bytes.NewReader(b))
+}
+
+// RPush pushes a data from right of queue
+func (queue *Queue) RPush(data []byte) error {
+	queue.highLock.Lock()
+	id, err := queue.highincrement()
+	if err != nil {
+		queue.highLock.Unlock()
+		return err
+	}
+	err = queue.db.Put(id2bytes(id), data, nil)
+	queue.highLock.Unlock()
+	return err
+}
+
+// LPush pushes a data from left of queue
+func (queue *Queue) LPush(data []byte) error {
+	queue.highLock.Lock()
+	id, err := queue.lowdecrement()
+	if err != nil {
+		queue.highLock.Unlock()
+		return err
+	}
+	err = queue.db.Put(id2bytes(id), data, nil)
+	queue.highLock.Unlock()
+	return err
+}
+
+// RPop pop a data from right of queue
+func (queue *Queue) RPop() ([]byte, error) {
+	queue.highLock.Lock()
+	currentID := queue.high
+
+	res, err := queue.db.Get(id2bytes(currentID), nil)
+	if err != nil {
+		queue.highLock.Unlock()
+		if err == leveldb.ErrNotFound {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+
+	_, err = queue.highdecrement()
+	if err != nil {
+		queue.highLock.Unlock()
+		return nil, err
+	}
+
+	err = queue.db.Delete(id2bytes(currentID), nil)
+	queue.highLock.Unlock()
+	if err != nil {
+		return nil, err
+	}
+	return res, nil
+}
+
+// LPop pop a data from left of queue
+func (queue *Queue) LPop() ([]byte, error) {
+	queue.lowLock.Lock()
+	currentID := queue.low
+
+	res, err := queue.db.Get(id2bytes(currentID), nil)
+	if err != nil {
+		queue.lowLock.Unlock()
+		if err == leveldb.ErrNotFound {
+			return nil, ErrNotFound
+		}
+		return nil, err
+	}
+
+	_, err = queue.lowincrement()
+	if err != nil {
+		return nil, err
+	}
+
+	err = queue.db.Delete(id2bytes(currentID), nil)
+	queue.lowLock.Unlock()
+	if err != nil {
+		return nil, err
+	}
+	return res, nil
+}
+
+// Close closes the queue
+func (queue *Queue) Close() error {
+	err := queue.db.Close()
+	queue.db = nil
+	return err
+}