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105 lines
3.2 KiB
105 lines
3.2 KiB
// Copyright 2017 clair authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package pgsql
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import (
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"errors"
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"time"
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log "github.com/sirupsen/logrus"
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"github.com/coreos/clair/pkg/commonerr"
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)
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const (
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soiLock = `INSERT INTO lock(name, owner, until) VALUES ($1, $2, $3)`
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searchLock = `SELECT until FROM Lock WHERE name = $1`
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updateLock = `UPDATE Lock SET until = $3 WHERE name = $1 AND owner = $2`
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removeLock = `DELETE FROM Lock WHERE name = $1 AND owner = $2`
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removeLockExpired = `DELETE FROM LOCK WHERE until < CURRENT_TIMESTAMP`
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)
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var (
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errLockNotFound = errors.New("lock is not in database")
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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 (tx *pgSession) Lock(name string, owner string, duration time.Duration, renew bool) (bool, time.Time, error) {
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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{}, commonerr.NewBadRequestError("Invalid Lock Parameters")
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}
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until := time.Now().Add(duration)
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if renew {
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defer observeQueryTime("Lock", "update", time.Now())
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// Renew lock.
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r, err := tx.Exec(updateLock, name, owner, until)
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if err != nil {
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return false, until, handleError("updateLock", err)
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}
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if n, err := r.RowsAffected(); err == nil {
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return n > 0, until, nil
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}
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return false, until, handleError("updateLock", err)
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} else if err := tx.pruneLocks(); err != nil {
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return false, until, err
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}
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// Lock.
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defer observeQueryTime("Lock", "soiLock", time.Now())
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_, err := tx.Exec(soiLock, name, owner, until)
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if err != nil {
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if isErrUniqueViolation(err) {
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// Return the existing locks expiration.
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err := tx.QueryRow(searchLock, name).Scan(&until)
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return false, until, handleError("searchLock", err)
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}
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return false, until, handleError("insertLock", err)
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}
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return true, until, nil
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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 (tx *pgSession) Unlock(name, owner string) error {
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if name == "" || owner == "" {
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return commonerr.NewBadRequestError("Invalid Lock Parameters")
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}
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defer observeQueryTime("Unlock", "all", time.Now())
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_, err := tx.Exec(removeLock, name, owner)
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return err
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}
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// pruneLocks removes every expired locks from the database
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func (tx *pgSession) pruneLocks() error {
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defer observeQueryTime("pruneLocks", "all", time.Now())
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if r, err := tx.Exec(removeLockExpired); err != nil {
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return handleError("removeLockExpired", err)
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} else if affected, err := r.RowsAffected(); err != nil {
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return handleError("removeLockExpired", err)
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} else {
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log.Debugf("Pruned %d Locks", affected)
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}
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return nil
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}
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