Carlos Florêncio
105 lines
2.9 KiB
Go
105 lines
2.9 KiB
Go
package db
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import (
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"database/sql"
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"fmt"
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"os"
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"path/filepath"
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"time"
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_ "github.com/mattn/go-sqlite3"
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)
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const (
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defaultBusyTimeout = 5 * time.Second
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// defaultSQLiteReaderConns is the number of concurrent read connections.
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// SQLite WAL mode allows many readers alongside a single writer; 4 is a
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// reasonable default for a desktop/server workload.
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defaultSQLiteReaderConns = 4
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)
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// OpenSQLite opens a SQLite database configured for writes (single connection).
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func OpenSQLite(dbPath string) (*sql.DB, error) {
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normalizedPath := normalizeSQLitePath(dbPath)
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if err := ensureSQLiteDir(normalizedPath); err != nil {
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return nil, fmt.Errorf("failed to prepare database path: %w", err)
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}
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if err := ensureSQLiteFile(normalizedPath); err != nil {
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return nil, fmt.Errorf("failed to create database file: %w", err)
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}
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// Writer DSN settings:
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// - foreign_keys=on: enforce FK constraints consistently.
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// - busy_timeout: wait briefly on locks to reduce transient "database is locked".
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// - journal_mode=WAL: better read concurrency with a single writer.
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// - synchronous=NORMAL: reasonable durability/perf tradeoff for app workloads.
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// - cache=shared: allow multiple connections to share a page cache.
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dsn := fmt.Sprintf(
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"file:%s?_foreign_keys=on&_mode=rwc&_busy_timeout=%d&_journal_mode=WAL&_synchronous=NORMAL&_cache=shared",
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normalizedPath,
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int(defaultBusyTimeout/time.Millisecond),
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)
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db, err := sql.Open("sqlite3", dsn)
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if err != nil {
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return nil, fmt.Errorf("failed to open database: %w", err)
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}
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// Single writer connection: serializes writes and avoids SQLITE_BUSY.
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db.SetMaxOpenConns(1)
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db.SetMaxIdleConns(1)
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return db, nil
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}
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// OpenSQLiteReader opens a read-only SQLite connection pool with multiple
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// concurrent connections. Combined with WAL mode, this allows readers to
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// proceed without blocking on (or being blocked by) writes.
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func OpenSQLiteReader(dbPath string) (*sql.DB, error) {
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normalizedPath := normalizeSQLitePath(dbPath)
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// Reader DSN: read-only mode, FK enforcement, shared cache.
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// journal_mode and synchronous are database-level (set by the writer).
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dsn := fmt.Sprintf(
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"file:%s?_foreign_keys=on&_mode=ro&_busy_timeout=%d&_cache=shared",
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normalizedPath,
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int(defaultBusyTimeout/time.Millisecond),
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)
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db, err := sql.Open("sqlite3", dsn)
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if err != nil {
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return nil, fmt.Errorf("failed to open read-only database: %w", err)
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}
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db.SetMaxOpenConns(defaultSQLiteReaderConns)
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db.SetMaxIdleConns(defaultSQLiteReaderConns)
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return db, nil
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}
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func ensureSQLiteDir(dbPath string) error {
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dir := filepath.Dir(dbPath)
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if dir == "." || dir == "" {
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return nil
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}
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return os.MkdirAll(dir, 0o755)
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}
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func ensureSQLiteFile(dbPath string) error {
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file, err := os.OpenFile(dbPath, os.O_RDWR|os.O_CREATE, 0o644)
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if err != nil {
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return err
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}
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return file.Close()
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}
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func normalizeSQLitePath(dbPath string) string {
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if dbPath == "" {
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return dbPath
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}
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abs, err := filepath.Abs(dbPath)
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if err != nil {
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return dbPath
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}
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return abs
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}
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