diff --git a/.deepsource.toml b/.deepsource.toml
new file mode 100644
index 0000000..94df216
--- /dev/null
+++ b/.deepsource.toml
@@ -0,0 +1,7 @@
+version = 1
+
+[[analyzers]]
+name = "go"
+
+  [analyzers.meta]
+  import_root = "github.com/ikawaha/kagome"
\ No newline at end of file
diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 9f8028d..f016752 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -23,13 +23,13 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Set up Go 1.x
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version-file: 'go.mod'
           cache: true
 
       - name: Set up Graphviz
-        uses: ts-graphviz/setup-graphviz@v1
+        uses: ts-graphviz/setup-graphviz@v2
 
       - name: Build
         run: go build -v ./...
@@ -46,7 +46,7 @@ jobs:
       - name: Check out code into the Go module directory
         uses: actions/checkout@v4
       - name: Set up Go 1.x
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version-file: 'go.mod'
           cache: true
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 390f550..a2948c8 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -18,7 +18,7 @@ jobs:
 
       # Setup Go
       - name: Set up Go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version-file: 'go.mod'
           cache: true
@@ -38,6 +38,14 @@ jobs:
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
 
+      # Login to GitHub Container Registry before push.
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GO_RELEASER_TOKEN }}
+
       # Build and release
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v5
diff --git a/.goreleaser.yml b/.goreleaser.yml
index 516049b..31c6c68 100644
--- a/.goreleaser.yml
+++ b/.goreleaser.yml
@@ -70,6 +70,7 @@ brews:
 dockers:
   - image_templates:
       - "ikawaha/kagome:{{ .Version }}-amd64"
+      - "ghcr.io/ikawaha/kagome:{{ .Version }}-amd64"
     use: buildx
     goarch: amd64
     dockerfile: Dockerfile
@@ -78,6 +79,7 @@ dockers:
 
   - image_templates:
       - "ikawaha/kagome:{{ .Version }}-arm64"
+      - "ghcr.io/ikawaha/kagome:{{ .Version }}-arm64"
     use: buildx
     goarch: arm64
     dockerfile: Dockerfile
@@ -86,6 +88,7 @@ dockers:
 
   - image_templates:
       - "ikawaha/kagome:{{ .Version }}-arm32v5"
+      - "ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v5"
     use: buildx
     goarch: arm
     goarm: 5
@@ -95,6 +98,7 @@ dockers:
 
   - image_templates:
       - "ikawaha/kagome:{{ .Version }}-arm32v6"
+      - "ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v6"
     use: buildx
     goarch: arm
     goarm: 6
@@ -104,6 +108,7 @@ dockers:
 
   - image_templates:
       - "ikawaha/kagome:{{ .Version }}-arm32v7"
+      - "ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v7"
     use: buildx
     goarch: arm
     goarm: 7
@@ -114,6 +119,7 @@ dockers:
 # Create multiarch manifest file of Docker image. This will bind all the images
 # above into a single manifest file for "latest" and each version tag.
 docker_manifests:
+  # Manifest for Docker Hub
   - name_template: ikawaha/kagome:{{ .Version }}
     image_templates:
       - ikawaha/kagome:{{ .Version }}-amd64
@@ -127,4 +133,20 @@ docker_manifests:
       - ikawaha/kagome:{{ .Version }}-arm64
       - ikawaha/kagome:{{ .Version }}-arm32v5
       - ikawaha/kagome:{{ .Version }}-arm32v6
-      - ikawaha/kagome:{{ .Version }}-arm32v7
\ No newline at end of file
+      - ikawaha/kagome:{{ .Version }}-arm32v7
+
+  # Manifest for GitHub Container Registry
+  - name_template: ghcr.io/ikawaha/kagome:{{ .Version }}
+    image_templates:
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-amd64
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm64
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v5
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v6
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v7
+  - name_template: ghcr.io/ikawaha/kagome:latest
+    image_templates:
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-amd64
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm64
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v5
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v6
+      - ghcr.io/ikawaha/kagome:{{ .Version }}-arm32v7
diff --git a/README.md b/README.md
index 24b7916..32b0771 100644
--- a/README.md
+++ b/README.md
@@ -248,6 +248,8 @@ Start a server and try to access the "/tokenize" endpoint.
 
 ![webapp](https://raw.githubusercontent.com/wiki/ikawaha/kagome/images/demoapp.gif)
 
+GitHub Page: https://ikawaha.github.io/kagome/
+
 Start a server and access `http://localhost:6060`.
 (To draw a lattice, demo application uses graphviz . You need graphviz installed.)
 
@@ -274,16 +276,25 @@ A debug tool of tokenize process outputs a lattice in graphviz dot format.
 ```sh
 # Compatible architectures: AMD64, Arm64, Arm32 (Arm v5, v6 and v7)
 docker pull ikawaha/kagome:latest
+
+# Alternatively, you can pull from GitHub Container Registry
+docker pull ghcr.io/ikawaha/kagome:latest
 ```
 
 ```sh
 # Interactive/REPL mode
 docker run --rm -it ikawaha/kagome:latest
+
+# If pulling from GitHub Container Registry
+docker run --rm -it ghcr.io/ikawaha/kagome:latest
 ```
 
 ```sh
 # Server mode (http://localhost:6060)
 docker run --rm -p 6060:6060 ikawaha/kagome:latest server
+
+# If pulling from GitHub Container Registry
+docker run --rm -p 6060:6060 ghcr.io/ikawaha/kagome:latest server
 ```
 
 # Building to WebAssembly
diff --git a/cmd/lattice/cmd.go b/cmd/lattice/cmd.go
index d4d1ddf..dee8c70 100644
--- a/cmd/lattice/cmd.go
+++ b/cmd/lattice/cmd.go
@@ -59,7 +59,7 @@ func (o *option) parse(args []string) error {
 	}
 	// validations
 	if o.flagSet.NArg() == 0 {
-		return fmt.Errorf("input is empty")
+		return errors.New("no option is specified")
 	}
 	if o.dict != "" && o.dict != "ipa" && o.dict != "uni" {
 		return fmt.Errorf("invalid argument: -dict %v", o.dict)
@@ -121,7 +121,7 @@ func command(_ context.Context, opt *option) error {
 	}
 	out := Stdout
 	if opt.output != "" {
-		f, err := os.OpenFile(opt.output, os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0o666)
+		f, err := os.OpenFile(opt.output, os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0o600)
 		if err != nil {
 			return err
 		}
@@ -153,7 +153,7 @@ func Run(ctx context.Context, args []string) error {
 	if err := opt.parse(args); err != nil {
 		Usage()
 		PrintDefaults(flag.ContinueOnError)
-		return errors.New("")
+		return err
 	}
 	return command(ctx, opt)
 }
diff --git a/cmd/server/cmd.go b/cmd/server/cmd.go
index da7a16d..cb7b7a9 100644
--- a/cmd/server/cmd.go
+++ b/cmd/server/cmd.go
@@ -2,7 +2,6 @@ package server
 
 import (
 	"context"
-	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -11,6 +10,7 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 
 	"github.com/ikawaha/kagome-dict/dict"
 	"github.com/ikawaha/kagome-dict/ipa"
@@ -106,8 +106,9 @@ func command(ctx context.Context, opt *option) error {
 	mux.Handle("/", &TokenizeDemoHandler{tokenizer: t})
 	mux.Handle("/tokenize", &TokenizeHandler{tokenizer: t})
 	srv := http.Server{
-		Addr:    opt.http,
-		Handler: mux,
+		Addr:              opt.http,
+		Handler:           mux,
+		ReadHeaderTimeout: 20 * time.Second,
 	}
 	ch := make(chan error)
 	go func() {
@@ -132,17 +133,15 @@ func Run(ctx context.Context, args []string) error {
 	if err := opt.parse(args); err != nil {
 		Usage()
 		PrintDefaults(flag.ContinueOnError)
-		return errors.New("")
+		return fmt.Errorf("option parse error: %w", err)
 	}
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 	go func() {
 		c := make(chan os.Signal, 1)
 		signal.Notify(c, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
-		select {
-		case <-c:
-			cancel()
-		}
+		<-c
+		cancel()
 	}()
 	return command(ctx, opt)
 }
diff --git a/kagome_test.go b/kagome_test.go
index 12045f2..0872db0 100644
--- a/kagome_test.go
+++ b/kagome_test.go
@@ -38,7 +38,7 @@ func TestKagomeTokenizerGolden(t *testing.T) {
 	}
 	defer golden.Close()
 
-	dump, err := os.OpenFile(dumpText, os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0o666)
+	dump, err := os.OpenFile(dumpText, os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0o600)
 	if err != nil {
 		t.Fatalf("unexpected error, %v", err)
 	}
diff --git a/sample/_example/db_search/main.go b/sample/_example/db_search/main.go
index bc2ca32..a811a27 100644
--- a/sample/_example/db_search/main.go
+++ b/sample/_example/db_search/main.go
@@ -24,11 +24,12 @@ Acknowledgements:
 
 This example is taken in part from the following book for reference.
 
-- p.372, 9.2 "データーベース登録プログラム", "Go言語プログラミングエッセンス エンジニア選書"
+- p.204, 9.2 "データーベース登録プログラム", "Go言語プログラミングエッセンス エンジニア選書"
   - Written by: Mattn
   - Published: 2023/3/9 (技術評論社)
   - ISBN: 4297134195 / 978-4297134198
   - ASIN: B0BVZCJQ4F / https://amazon.co.jp/dp/4297134195
+  - Original sample code: https://github.com/mattn/aozora-search
 */
 package main
 
@@ -37,6 +38,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"os"
 	"strings"
 
 	"github.com/ikawaha/kagome-dict/ipa"
@@ -45,6 +47,13 @@ import (
 )
 
 func main() {
+	if err := run(); err != nil {
+		log.Println(err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
 	// Contents to be inserted into the database. Each element represents a line
 	// of text and will be inserted into a row of the database.
 	lines := []string{
@@ -58,26 +67,30 @@ func main() {
 
 	// Create a database. In-memory database is used for simplicity.
 	db, err := sql.Open("sqlite3", ":memory:")
-	PanicOnError(err)
-
+	if err != nil {
+		return err
+	}
 	defer db.Close()
 
 	// Create tables.
 	// The first table "contents_fts" is for storing the original content, and
 	// the second table "fts" is for storing the tokenized content.
-	_, err = db.Exec(`
+	if _, err = db.Exec(`
 		CREATE TABLE IF NOT EXISTS contents_fts(docid INTEGER PRIMARY KEY AUTOINCREMENT, content TEXT);
 		CREATE VIRTUAL TABLE IF NOT EXISTS fts USING fts4(words);
-	`)
-	PanicOnError(err)
+	`); err != nil {
+		return err
+	}
 
 	// Insert contents
 	for _, line := range lines {
 		rowID, err := insertContent(db, line)
-		PanicOnError(err)
-
-		err = insertSearchToken(db, rowID, line)
-		PanicOnError(err)
+		if err != nil {
+			return err
+		}
+		if err := insertSearchToken(db, rowID, line); err != nil {
+			return err
+		}
 	}
 
 	// Search by word.
@@ -98,7 +111,9 @@ func main() {
 		fmt.Println("Searching for:", searchWord)
 
 		rowIDsFound, err := searchFTS4(db, searchWord)
-		PanicOnError(err)
+		if err != nil {
+			return err
+		}
 
 		if len(rowIDsFound) == 0 {
 			fmt.Println("  No results found")
@@ -108,8 +123,9 @@ func main() {
 		// Print search results
 		for _, rowID := range rowIDsFound {
 			cont, err := retrieveContent(db, rowID)
-			PanicOnError(err)
-
+			if err != nil {
+				return err
+			}
 			fmt.Printf("  Found content: %s at line: %v\n", cont, rowID)
 		}
 	}
@@ -124,6 +140,8 @@ func main() {
 	//   Found content: 北方の海の色は、青うございました。 at line: 3
 	// Searching for: 北
 	//   Found content: 北の海にも棲んでいたのであります。 at line: 2
+
+	return nil
 }
 
 func insertContent(db *sql.DB, content string) (int64, error) {
@@ -142,7 +160,9 @@ func insertSearchToken(db *sql.DB, rowID int64, content string) error {
 	// This example uses the IPA dictionary, but it may be more efficient to use
 	// the 'Uni' dictionary if memory is available.
 	tknzr, err := tokenizer.New(ipa.Dict(), tokenizer.OmitBosEos())
-	PanicOnError(err)
+	if err != nil {
+		return err
+	}
 
 	seg := tknzr.Wakati(content)
 	tokenizedContent := strings.Join(seg, " ")
@@ -156,13 +176,6 @@ func insertSearchToken(db *sql.DB, rowID int64, content string) error {
 	return err
 }
 
-// PanicOnError exits the program with panic if the given error is not nil.
-func PanicOnError(err error) {
-	if err != nil {
-		log.Panic(err)
-	}
-}
-
 func retrieveContent(db *sql.DB, rowID int) (string, error) {
 	rows, err := db.Query(
 		`SELECT rowid, content FROM contents_fts WHERE rowid=?`,