Feature: Add configuration to set message compression level in db (0-3) (#447 & #448)

cmd/root.go

@@ -83,6 +83,7 @@ func init() {
 	initConfigFromEnv()
 
 	rootCmd.Flags().StringVarP(&config.Database, "database", "d", config.Database, "Database to store persistent data")
+	rootCmd.Flags().IntVar(&config.Compression, "compression", config.Compression, "Compression level to store raw messages (0-3)")
 	rootCmd.Flags().StringVar(&config.Label, "label", config.Label, "Optional label identify this Mailpit instance")
 	rootCmd.Flags().StringVar(&config.TenantID, "tenant-id", config.TenantID, "Database tenant ID to isolate data")
 	rootCmd.Flags().IntVarP(&config.MaxMessages, "max", "m", config.MaxMessages, "Max number of messages to store")
@@ -181,6 +182,10 @@ func initConfigFromEnv() {
 		config.Database = os.Getenv("MP_DATABASE")
 	}
 
+	if len(os.Getenv("MP_COMPRESSION")) > 0 {
+		config.Compression, _ = strconv.Atoi(os.Getenv("MP_COMPRESSION"))
+	}
+
 	config.TenantID = os.Getenv("MP_TENANT_ID")
 
 	config.Label = os.Getenv("MP_LABEL")

config/config.go

@@ -28,6 +28,10 @@ var (
 	// Database for mail (optional)
 	Database string
 
+	// Compression is the compression level used to store raw messages in the database:
+	// 0 = off, 1 = fastest (default), 2 = standard, 3 = best compression
+	Compression = 1
+
 	// TenantID is an optional prefix to be applied to all database tables,
 	// allowing multiple isolated instances of Mailpit to share a database.
 	TenantID string
@@ -250,6 +254,10 @@ func VerifyConfig() error {
 		Database = filepath.Join(Database, "mailpit.db")
 	}
 
+	if Compression < 0 || Compression > 3 {
+		return errors.New("[db] compression level must be between 0 and 3")
+	}
+
 	Label = tools.Normalize(Label)
 
 	if err := parseMaxAge(); err != nil {

internal/storage/database.go

@@ -32,7 +32,7 @@ var (
 	dbLastAction time.Time
 
 	// zstd compression encoder & decoder
-	dbEncoder, _ = zstd.NewWriter(nil, zstd.WithEncoderLevel(zstd.SpeedFastest))
+	dbEncoder    *zstd.Encoder
 	dbDecoder, _ = zstd.NewReader(nil)
 
 	temporaryFiles = []string{}
@@ -40,11 +40,31 @@ var (
 
 // InitDB will initialise the database
 func InitDB() error {
+	// dbEncoder
 	var (
 		dsn string
 		err error
 	)
 
+	if config.Compression > 0 {
+		var compression zstd.EncoderLevel
+		switch config.Compression {
+		case 1:
+			compression = zstd.SpeedFastest
+		case 2:
+			compression = zstd.SpeedDefault
+		case 3:
+			compression = zstd.SpeedBestCompression
+		}
+		dbEncoder, err = zstd.NewWriter(nil, zstd.WithEncoderLevel(compression))
+		if err != nil {
+			return err
+		}
+		logger.Log().Debugf("[db] storing messages with compression: %s", compression.String())
+	} else {
+		logger.Log().Debug("[db] storing messages with no compression")
+	}
+
 	p := config.Database
 
 	if p == "" {
@@ -101,7 +121,7 @@ func InitDB() error {
 
 	if sqlDriver == "sqlite" {
 		// SQLite performance tuning (https://phiresky.github.io/blog/2020/sqlite-performance-tuning/)
-		_, err = db.Exec("PRAGMA journal_mode = WAL; PRAGMA synchronous = normal;")
+		_, err = db.Exec("PRAGMA journal_mode=WAL; PRAGMA synchronous=NORMAL;")
 		if err != nil {
 			return err
 		}

internal/storage/messages.go

@@ -102,17 +102,25 @@ func Store(body *[]byte) (string, error) {
 		return "", err
 	}
 
-	// insert compressed raw message
-	encoded := dbEncoder.EncodeAll(*body, make([]byte, 0, int(size)))
+	if config.Compression > 0 {
+		// insert compressed raw message
+		compressed := dbEncoder.EncodeAll(*body, make([]byte, 0, int(size)))
 
-	if sqlDriver == "rqlite" {
-		// rqlite does not support binary data in query, so we need to encode the compressed message into hexadecimal
-		// string and then generate the SQL query, which is more memory intensive especially with large messages
-		hexStr := hex.EncodeToString(encoded)
-		_, err = tx.Exec(fmt.Sprintf(`INSERT INTO %s (ID, Email) VALUES(?, x'%s')`, tenant("mailbox_data"), hexStr), id) // #nosec
+		if sqlDriver == "rqlite" {
+			// rqlite does not support binary data in query, so we need to encode the compressed message into hexadecimal
+			// string and then generate the SQL query, which is more memory intensive, especially with large messages
+			hexStr := hex.EncodeToString(compressed)
+			_, err = tx.Exec(fmt.Sprintf(`INSERT INTO %s (ID, Email, Compressed) VALUES(?, x'%s', 1)`, tenant("mailbox_data"), hexStr), id) // #nosec
+		} else {
+			_, err = tx.Exec(fmt.Sprintf(`INSERT INTO %s (ID, Email, Compressed) VALUES(?, ?, 1)`, tenant("mailbox_data")), id, compressed) // #nosec
+		}
+
+		compressed = nil
 	} else {
-		_, err = tx.Exec(fmt.Sprintf(`INSERT INTO %s (ID, Email) VALUES(?, ?)`, tenant("mailbox_data")), id, encoded) // #nosec
+		// insert uncompressed raw message
+		_, err = tx.Exec(fmt.Sprintf(`INSERT INTO %s (ID, Email, Compressed) VALUES(?, ?, 0)`, tenant("mailbox_data")), id, string(*body)) // #nosec
 	}
+
 	if err != nil {
 		return "", err
 	}
@@ -121,8 +129,6 @@ func Store(body *[]byte) (string, error) {
 		return "", err
 	}
 
-	encoded = nil
-
 	// extract tags using pre-set tag filters, empty slice if not set
 	tags := findTagsInRawMessage(body)
 
@@ -367,11 +373,12 @@ func GetMessage(id string) (*Message, error) {
 
 // GetMessageRaw returns an []byte of the full message
 func GetMessageRaw(id string) ([]byte, error) {
-	var i string
-	var msg string
+	var i, msg string
+	var compressed int
 	q := sqlf.From(tenant("mailbox_data")).
 		Select(`ID`).To(&i).
 		Select(`Email`).To(&msg).
+		Select(`Compressed`).To(&compressed).
 		Where(`ID = ?`, id)
 	err := q.QueryRowAndClose(context.Background(), db)
 	if err != nil {
@@ -383,7 +390,7 @@ func GetMessageRaw(id string) ([]byte, error) {
 	}
 
 	var data []byte
-	if sqlDriver == "rqlite" {
+	if sqlDriver == "rqlite" && compressed == 1 {
 		data, err = base64.StdEncoding.DecodeString(msg)
 		if err != nil {
 			return nil, fmt.Errorf("error decoding base64 message: %w", err)
@@ -392,14 +399,18 @@ func GetMessageRaw(id string) ([]byte, error) {
 		data = []byte(msg)
 	}
 
-	raw, err := dbDecoder.DecodeAll(data, nil)
-	if err != nil {
-		return nil, fmt.Errorf("error decompressing message: %s", err.Error())
-	}
-
 	dbLastAction = time.Now()
 
-	return raw, err
+	if compressed == 1 {
+		raw, err := dbDecoder.DecodeAll(data, nil)
+		if err != nil {
+			return nil, fmt.Errorf("error decompressing message: %s", err.Error())
+		}
+
+		return raw, err
+	}
+
+	return data, nil
 }
 
 // GetAttachmentPart returns an *enmime.Part (attachment or inline) from a message

internal/storage/schemas/1.23.0.sql

@@ -0,0 +1,5 @@
+-- CREATE Compressed COLUMN IN mailbox_data
+ALTER TABLE {{ tenant "mailbox_data" }} ADD COLUMN Compressed INTEGER NOT NULL DEFAULT '0';
+
+-- SET Compressed = 1 for all existing data
+UPDATE {{ tenant "mailbox_data" }} SET Compressed = 1;