106 lines
2.8 KiB
Go
106 lines
2.8 KiB
Go
// 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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"time"
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"github.com/coreos/clair/pkg/commonerr"
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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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defer observeQueryTime("Lock", "all", time.Now())
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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(updateLock, name, owner, until)
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if err != nil {
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handleError("updateLock", 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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} else {
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// Prune locks.
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pgSQL.pruneLocks()
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}
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// Lock.
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_, err := pgSQL.Exec(insertLock, name, owner, until)
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if err != nil {
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if !isErrUniqueViolation(err) {
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handleError("insertLock", 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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defer observeQueryTime("Unlock", "all", time.Now())
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pgSQL.Exec(removeLock, 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{}, commonerr.NewBadRequestError("could not find an invalid lock")
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}
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defer observeQueryTime("FindLock", "all", time.Now())
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var owner string
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var until time.Time
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err := pgSQL.QueryRow(searchLock, name).Scan(&owner, &until)
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if err != nil {
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return owner, until, handleError("searchLock", 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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defer observeQueryTime("pruneLocks", "all", time.Now())
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if _, err := pgSQL.Exec(removeLockExpired); err != nil {
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handleError("removeLockExpired", err)
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}
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}
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