89 lines
2.1 KiB
Go
89 lines
2.1 KiB
Go
package pgsql
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import (
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"database/sql"
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"time"
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cerrors "github.com/coreos/clair/utils/errors"
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)
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// Lock tries to set a temporary lock in the database.
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//
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// Lock does not block, instead, it returns true and its expiration time
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// is the lock has been successfully acquired or false otherwise
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func (pgSQL *pgSQL) Lock(name string, owner string, duration time.Duration, renew bool) (bool, time.Time) {
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if name == "" || owner == "" || duration == 0 {
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log.Warning("could not create an invalid lock")
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return false, time.Time{}
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}
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// Prune locks.
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pgSQL.pruneLocks()
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// Compute expiration.
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until := time.Now().Add(duration)
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if renew {
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// Renew lock.
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r, err := pgSQL.Exec(getQuery("u_lock"), name, owner, until)
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if err != nil {
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handleError("u_lock", err)
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return false, until
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}
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if n, _ := r.RowsAffected(); n > 0 {
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// Updated successfully.
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return true, until
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}
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}
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// Lock.
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_, err := pgSQL.Exec(getQuery("i_lock"), name, owner, until)
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if err != nil {
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if !isErrUniqueViolation(err) {
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handleError("i_lock", err)
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}
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return false, until
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}
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return true, until
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}
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// Unlock unlocks a lock specified by its name if I own it
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func (pgSQL *pgSQL) Unlock(name, owner string) {
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if name == "" || owner == "" {
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log.Warning("could not delete an invalid lock")
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return
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}
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pgSQL.Exec(getQuery("r_lock"), name, owner)
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}
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// FindLock returns the owner of a lock specified by its name and its
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// expiration time.
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func (pgSQL *pgSQL) FindLock(name string) (string, time.Time, error) {
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if name == "" {
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log.Warning("could not find an invalid lock")
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return "", time.Time{}, cerrors.NewBadRequestError("could not find an invalid lock")
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}
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var owner string
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var until time.Time
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err := pgSQL.QueryRow(getQuery("f_lock"), name).Scan(&owner, &until)
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if err == sql.ErrNoRows {
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return owner, until, cerrors.ErrNotFound
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}
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if err != nil {
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return owner, until, handleError("f_lock", err)
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}
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return owner, until, nil
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}
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// pruneLocks removes every expired locks from the database
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func (pgSQL *pgSQL) pruneLocks() {
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if _, err := pgSQL.Exec(getQuery("r_lock_expired")); err != nil {
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handleError("r_lock_expired", err)
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}
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}
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