78 lines
2.2 KiB
Go
78 lines
2.2 KiB
Go
package dbsync
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import (
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"context"
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"database/sql"
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"fmt"
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"time"
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)
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const FlagTable = "_ajz_sync_flag"
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// EnsureFlagTable：SQLite 用表标记「正在应用远端变更」，避免触发器回声。
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func EnsureFlagTable(ctx context.Context, db *sql.DB, driver Driver) error {
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if driver != DriverSQLite {
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return nil
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}
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_, err := db.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS `+FlagTable+` (
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k TEXT PRIMARY KEY,
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v INTEGER NOT NULL DEFAULT 0
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);`)
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if err != nil {
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return err
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}
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_, _ = db.ExecContext(ctx, `INSERT OR IGNORE INTO `+FlagTable+`(k,v) VALUES('applying',0)`)
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return nil
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}
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// WithApplying 在写入目标库时置位，使触发器不写 outbox（防 A↔B 回声导致「多」）。
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func WithApplying(ctx context.Context, db *sql.DB, driver Driver, fn func() error) error {
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switch driver {
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case DriverSQLite:
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if err := EnsureFlagTable(ctx, db, driver); err != nil {
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return err
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}
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if _, err := db.ExecContext(ctx, `UPDATE `+FlagTable+` SET v=1 WHERE k='applying'`); err != nil {
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return err
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}
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defer func() {
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_, _ = db.ExecContext(context.Background(), `UPDATE `+FlagTable+` SET v=0 WHERE k='applying'`)
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}()
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return fn()
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case DriverMySQL:
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if _, err := db.ExecContext(ctx, `SET @ajz_applying = 1`); err != nil {
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return err
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}
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defer func() { _, _ = db.ExecContext(context.Background(), `SET @ajz_applying = 0`) }()
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return fn()
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case DriverPostgres:
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if _, err := db.ExecContext(ctx, `SELECT set_config('ajz.applying', '1', false)`); err != nil {
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return err
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}
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defer func() {
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_, _ = db.ExecContext(context.Background(), `SELECT set_config('ajz.applying', '0', false)`)
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}()
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return fn()
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default:
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return fn()
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}
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}
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func EnqueueOutbox(ctx context.Context, db *sql.DB, driver Driver, table, pk, op, payload string, version int64) error {
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if version <= 0 {
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version = time.Now().UnixMilli()
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}
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switch driver {
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case DriverPostgres:
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_, err := db.ExecContext(ctx, fmt.Sprintf(`
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INSERT INTO %s(table_name,row_pk,op,payload,version) VALUES($1,$2,$3,$4,$5)`, OutboxTable),
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table, pk, op, payload, version)
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return err
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default:
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_, err := db.ExecContext(ctx, fmt.Sprintf(`
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INSERT INTO %s(table_name,row_pk,op,payload,version) VALUES(?,?,?,?,?)`, OutboxTable),
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table, pk, op, payload, version)
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return err
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}
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}
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