feat: multi db support

internal/database/database.go

@@ -7,13 +7,68 @@ import (
 	"database/sql"
 	"fmt"
 	"log/slog"
+	"strings"
+	"time"
 )
 
+type DBKind int
+
+const (
+	DBKindPostgres DBKind = iota
+	DBKindCockroach
+	DBKindSqlite
+)
+
+var dbKindProto = map[DBKind]string{
+	DBKindPostgres:  "postgresql",
+	DBKindCockroach: "cockroachdb",
+	DBKindSqlite:    "sqlite",
+}
+
+var dbKindDriver = map[DBKind]string{
+	DBKindPostgres:  "postgres",
+	DBKindCockroach: "postgres",
+	DBKindSqlite:    "sqlite",
+}
+
+func DetectKind(conn string) (DBKind, error) {
+	switch {
+	case strings.HasPrefix(conn, "postgres"),
+		strings.HasPrefix(conn, "postgresql"):
+		return DBKindPostgres, nil
+	case strings.HasPrefix(conn, "cockroach"),
+		strings.HasPrefix(conn, "cockroachdb"):
+		return DBKindCockroach, nil
+	case strings.HasPrefix(conn, "file"),
+		strings.HasPrefix(conn, "sqlite"):
+		return DBKindSqlite, nil
+	default:
+		return 0, fmt.Errorf("unknown db kind in conn string: %q", conn)
+	}
+}
+
+type Migration func(*sql.Tx) error
+
+var dbKindMigrations = map[DBKind][]Migration{
+	DBKindPostgres:  postgresMigrations,
+	DBKindCockroach: cockroachMigrations,
+	DBKindSqlite:    sqliteMigrations,
+}
+
+var dbKindSchemaVersion = map[DBKind]int{
+	DBKindPostgres:  postgresSchemaVersion,
+	DBKindCockroach: cockroachSchemaVersion,
+	DBKindSqlite:    sqliteSchemaVersion,
+}
+
 // Migrate executes database migrations.
-func Migrate(db *sql.DB) error {
+func Migrate(kind DBKind, db *sql.DB) error {
 	var currentVersion int
 	db.QueryRow(`SELECT version FROM schema_version`).Scan(&currentVersion)
 
+	migrations := dbKindMigrations[kind]
+	schemaVersion := dbKindSchemaVersion[kind]
+
 	slog.Info("Running database migrations",
 		slog.Int("current_version", currentVersion),
 		slog.Int("latest_version", schemaVersion),
@@ -32,14 +87,24 @@ func Migrate(db *sql.DB) error {
 			return fmt.Errorf("[Migration v%d] %v", newVersion, err)
 		}
 
-		if _, err := tx.Exec(`TRUNCATE schema_version`); err != nil {
-			tx.Rollback()
-			return fmt.Errorf("[Migration v%d] %v", newVersion, err)
-		}
-
-		if _, err := tx.Exec(`INSERT INTO schema_version (version) VALUES ($1)`, newVersion); err != nil {
-			tx.Rollback()
-			return fmt.Errorf("[Migration v%d] %v", newVersion, err)
+		if kind == DBKindSqlite {
+			if _, err := tx.Exec(`DELETE FROM schema_version`); err != nil {
+				tx.Rollback()
+				return fmt.Errorf("[Migration v%d] %v", newVersion, err)
+			}
+			if _, err := tx.Exec(`INSERT INTO schema_version (version) VALUES (?)`, newVersion); err != nil {
+				tx.Rollback()
+				return fmt.Errorf("[Migration v%d] %v", newVersion, err)
+			}
+		} else {
+			if _, err := tx.Exec(`TRUNCATE schema_version`); err != nil {
+				tx.Rollback()
+				return fmt.Errorf("[Migration v%d] %v", newVersion, err)
+			}
+			if _, err := tx.Exec(`INSERT INTO schema_version (version) VALUES ($1)`, newVersion); err != nil {
+				tx.Rollback()
+				return fmt.Errorf("[Migration v%d] %v", newVersion, err)
+			}
 		}
 
 		if err := tx.Commit(); err != nil {
@@ -51,7 +116,9 @@ func Migrate(db *sql.DB) error {
 }
 
 // IsSchemaUpToDate checks if the database schema is up to date.
-func IsSchemaUpToDate(db *sql.DB) error {
+func IsSchemaUpToDate(kind DBKind, db *sql.DB) error {
+	schemaVersion := dbKindSchemaVersion[kind]
+
 	var currentVersion int
 	db.QueryRow(`SELECT version FROM schema_version`).Scan(&currentVersion)
 	if currentVersion < schemaVersion {
@@ -59,3 +126,25 @@ func IsSchemaUpToDate(db *sql.DB) error {
 	}
 	return nil
 }
+
+func NewConnectionPool(kind DBKind, dsn string, minConnections, maxConnections int, connectionLifetime time.Duration) (*sql.DB, error) {
+	driver := dbKindDriver[kind]
+
+	// replace cockroachdb protocol with postgres
+	// we use cockroachdb protocol to detect cockroachdb but go wants postgres
+	if kind == DBKindCockroach {
+		split := strings.SplitN(dsn, ":", 2)
+		dsn = fmt.Sprintf("postgres:%s", split[1])
+	}
+
+	db, err := sql.Open(driver, dsn)
+	if err != nil {
+		return nil, err
+	}
+
+	db.SetMaxOpenConns(maxConnections)
+	db.SetMaxIdleConns(minConnections)
+	db.SetConnMaxLifetime(connectionLifetime)
+
+	return db, nil
+}