From ab4bfcbcfbb919e4fae01d2fad6aa75d806d2556 Mon Sep 17 00:00:00 2001
From: Thomas Miceli <27960254+thomiceli@users.noreply.github.com>
Date: Mon, 9 Sep 2024 11:44:22 +0200
Subject: [PATCH] Add atomic pointer for indexer (#321)

---
 internal/cli/main.go    | 29 ++++++++++++---
 internal/index/bleve.go | 79 ++++++++++++++++++++++++++++++++---------
 2 files changed, 88 insertions(+), 20 deletions(-)

diff --git a/internal/cli/main.go b/internal/cli/main.go
index e313c23..c64939f 100644
--- a/internal/cli/main.go
+++ b/internal/cli/main.go
@@ -12,8 +12,10 @@ import (
 	"github.com/thomiceli/opengist/internal/web"
 	"github.com/urfave/cli/v2"
 	"os"
+	"os/signal"
 	"path"
 	"path/filepath"
+	"syscall"
 )
 
 var CmdVersion = cli.Command{
@@ -29,10 +31,17 @@ var CmdStart = cli.Command{
 	Name:  "start",
 	Usage: "Start Opengist server",
 	Action: func(ctx *cli.Context) error {
+		stopCtx, stop := signal.NotifyContext(ctx.Context, syscall.SIGINT, syscall.SIGTERM)
+		defer stop()
+
 		Initialize(ctx)
+
 		go web.NewServer(os.Getenv("OG_DEV") == "1", path.Join(config.GetHomeDir(), "sessions")).Start()
 		go ssh.Start()
-		select {}
+
+		<-stopCtx.Done()
+		shutdown()
+		return nil
 	},
 }
 
@@ -110,12 +119,24 @@ func Initialize(ctx *cli.Context) {
 
 	if config.C.IndexEnabled {
 		log.Info().Msg("Index directory: " + filepath.Join(homePath, config.C.IndexDirname))
-		if err := index.Open(filepath.Join(homePath, config.C.IndexDirname)); err != nil {
-			log.Fatal().Err(err).Msg("Failed to open index")
-		}
+		index.Init(filepath.Join(homePath, config.C.IndexDirname))
 	}
 }
 
+func shutdown() {
+	log.Info().Msg("Shutting down database...")
+	if err := db.Close(); err != nil {
+		log.Error().Err(err).Msg("Failed to close database")
+	}
+
+	if config.C.IndexEnabled {
+		log.Info().Msg("Shutting down index...")
+		index.Close()
+	}
+
+	log.Info().Msg("Shutdown complete")
+}
+
 func createSymlink(homePath string, configPath string) error {
 	if err := os.MkdirAll(filepath.Join(homePath, "symlinks"), 0755); err != nil {
 		return err
diff --git a/internal/index/bleve.go b/internal/index/bleve.go
index 21b2293..6747dd2 100644
--- a/internal/index/bleve.go
+++ b/internal/index/bleve.go
@@ -9,25 +9,44 @@ import (
 	"github.com/blevesearch/bleve/v2/analysis/token/unicodenorm"
 	"github.com/blevesearch/bleve/v2/analysis/tokenizer/unicode"
 	"github.com/blevesearch/bleve/v2/search/query"
+	"github.com/rs/zerolog/log"
 	"github.com/thomiceli/opengist/internal/config"
 	"strconv"
+	"sync/atomic"
 )
 
-var bleveIndex bleve.Index
+var atomicIndexer atomic.Pointer[Indexer]
+
+type Indexer struct {
+	Index bleve.Index
+}
 
 func Enabled() bool {
 	return config.C.IndexEnabled
 }
 
-func Open(indexFilename string) error {
-	var err error
-	bleveIndex, err = bleve.Open(indexFilename)
+func Init(indexFilename string) {
+	atomicIndexer.Store(&Indexer{Index: nil})
+
+	go func() {
+		bleveIndex, err := open(indexFilename)
+		if err != nil {
+			log.Error().Err(err).Msg("Failed to open index")
+			(*atomicIndexer.Load()).close()
+		}
+		atomicIndexer.Store(&Indexer{Index: bleveIndex})
+		log.Info().Msg("Indexer initialized")
+	}()
+}
+
+func open(indexFilename string) (bleve.Index, error) {
+	bleveIndex, err := bleve.Open(indexFilename)
 	if err == nil {
-		return nil
+		return bleveIndex, nil
 	}
 
 	if !errors.Is(err, bleve.ErrorIndexPathDoesNotExist) {
-		return err
+		return nil, err
 	}
 
 	docMapping := bleve.NewDocumentMapping()
@@ -40,7 +59,7 @@ func Open(indexFilename string) error {
 		"type": unicodenorm.Name,
 		"form": unicodenorm.NFC,
 	}); err != nil {
-		return err
+		return nil, err
 	}
 
 	if err = mapping.AddCustomAnalyzer("gistAnalyser", map[string]interface{}{
@@ -49,43 +68,71 @@ func Open(indexFilename string) error {
 		"tokenizer":     unicode.Name,
 		"token_filters": []string{"unicodeNormalize", camelcase.Name, lowercase.Name},
 	}); err != nil {
-		return err
+		return nil, err
 	}
 
 	docMapping.DefaultAnalyzer = "gistAnalyser"
 
-	bleveIndex, err = bleve.New(indexFilename, mapping)
-
-	return err
+	return bleve.New(indexFilename, mapping)
 }
 
-func Close() error {
-	return bleveIndex.Close()
+func Close() {
+	(*atomicIndexer.Load()).close()
+}
+
+func (i *Indexer) close() {
+	if i == nil || i.Index == nil {
+		return
+	}
+
+	err := i.Index.Close()
+	if err != nil {
+		log.Error().Err(err).Msg("Failed to close bleve index")
+	}
+	log.Info().Msg("Indexer closed")
+	atomicIndexer.Store(&Indexer{Index: nil})
+}
+
+func checkForIndexer() error {
+	if (*atomicIndexer.Load()).Index == nil {
+		return errors.New("indexer is not initialized")
+	}
+
+	return nil
 }
 
 func AddInIndex(gist *Gist) error {
 	if !Enabled() {
 		return nil
 	}
+	if err := checkForIndexer(); err != nil {
+		return err
+	}
 
 	if gist == nil {
 		return errors.New("failed to add nil gist to index")
 	}
-	return bleveIndex.Index(strconv.Itoa(int(gist.GistID)), gist)
+	return (*atomicIndexer.Load()).Index.Index(strconv.Itoa(int(gist.GistID)), gist)
 }
 
 func RemoveFromIndex(gistID uint) error {
 	if !Enabled() {
 		return nil
 	}
+	if err := checkForIndexer(); err != nil {
+		return err
+	}
 
-	return bleveIndex.Delete(strconv.Itoa(int(gistID)))
+	return (*atomicIndexer.Load()).Index.Delete(strconv.Itoa(int(gistID)))
 }
 
 func SearchGists(queryStr string, queryMetadata SearchGistMetadata, gistsIds []uint, page int) ([]uint, uint64, map[string]int, error) {
 	if !Enabled() {
 		return nil, 0, nil, nil
 	}
+	if err := checkForIndexer(); err != nil {
+		return nil, 0, nil, err
+	}
 
 	var err error
 	var indexerQuery query.Query
@@ -134,7 +181,7 @@ func SearchGists(queryStr string, queryMetadata SearchGistMetadata, gistsIds []u
 	s.Fields = []string{"GistID"}
 	s.IncludeLocations = false
 
-	results, err := bleveIndex.Search(s)
+	results, err := (*atomicIndexer.Load()).Index.Search(s)
 	if err != nil {
 		return nil, 0, nil, err
 	}