fleet/server/datastore/mysql/locks.go

85 lines
2.9 KiB
Go

package mysql
import (
"context"
"database/sql"
"time"
"github.com/fleetdm/fleet/v4/server/contexts/ctxerr"
"github.com/fleetdm/fleet/v4/server/fleet"
)
func (ds *Datastore) Lock(ctx context.Context, name string, owner string, expiration time.Duration) (bool, error) {
lockObtainers := []func(context.Context, string, string, time.Duration) (sql.Result, error){
ds.extendLockIfAlreadyAcquired,
ds.overwriteLockIfExpired,
ds.createLock,
}
for _, lockFunc := range lockObtainers {
res, err := lockFunc(ctx, name, owner, expiration)
if err != nil {
return false, ctxerr.Wrap(ctx, err, "lock")
}
rowsAffected, err := res.RowsAffected()
if err != nil {
return false, ctxerr.Wrap(ctx, err, "rows affected")
}
if rowsAffected > 0 {
return true, nil
}
}
return false, nil
}
func (ds *Datastore) createLock(ctx context.Context, name string, owner string, expiration time.Duration) (sql.Result, error) {
return ds.writer.ExecContext(ctx,
`INSERT IGNORE INTO locks (name, owner, expires_at) VALUES (?, ?, ?)`,
name, owner, time.Now().Add(expiration),
)
}
func (ds *Datastore) extendLockIfAlreadyAcquired(ctx context.Context, name string, owner string, expiration time.Duration) (sql.Result, error) {
return ds.writer.ExecContext(ctx,
`UPDATE locks SET name = ?, owner = ?, expires_at = ? WHERE name = ? and owner = ?`,
name, owner, time.Now().Add(expiration), name, owner,
)
}
func (ds *Datastore) overwriteLockIfExpired(ctx context.Context, name string, owner string, expiration time.Duration) (sql.Result, error) {
return ds.writer.ExecContext(ctx,
`UPDATE locks SET name = ?, owner = ?, expires_at = ? WHERE expires_at < CURRENT_TIMESTAMP and name = ?`,
name, owner, time.Now().Add(expiration), name,
)
}
func (ds *Datastore) Unlock(ctx context.Context, name string, owner string) error {
_, err := ds.writer.ExecContext(ctx, `UPDATE locks SET expires_at = CURRENT_TIMESTAMP WHERE name = ? AND owner = ?`, name, owner)
return err
}
func (ds *Datastore) DBLocks(ctx context.Context) ([]*fleet.DBLock, error) {
stmt := `
SELECT
r.trx_id waiting_trx_id,
r.trx_mysql_thread_id waiting_thread,
r.trx_query waiting_query,
b.trx_id blocking_trx_id,
b.trx_mysql_thread_id blocking_thread,
b.trx_query blocking_query
FROM information_schema.innodb_lock_waits w
INNER JOIN information_schema.innodb_trx b
ON b.trx_id = w.blocking_trx_id
INNER JOIN information_schema.innodb_trx r
ON r.trx_id = w.requesting_trx_id`
var locks []*fleet.DBLock
// Even though this is a Read, use the writer as we want the db locks from
// the primary database (the read replica should have little to no trx locks).
if err := ds.writer.SelectContext(ctx, &locks, stmt); err != nil {
return nil, ctxerr.Wrap(ctx, err, "select locking information")
}
return locks, nil
}