open-vault/helper/locksutil/locks.go
Jeff Mitchell 9ef0680e7f
Fix leader info repopulation (#6167)
* Two things:

* Change how we populate and clear leader UUID. This fixes a case where
if a standby disconnects from an active node and reconnects, without the
active node restarting, the UUID doesn't change so triggers on a new
active node don't get run.

* Add a bunch of test helpers and minor updates to things.
2019-02-05 21:01:18 -05:00

60 lines
1.3 KiB
Go

package locksutil
import (
"sync"
"github.com/hashicorp/vault/helper/cryptoutil"
)
const (
LockCount = 256
)
type LockEntry struct {
sync.RWMutex
}
// CreateLocks returns an array so that the locks can be iterated over in
// order.
//
// This is only threadsafe if a process is using a single lock, or iterating
// over the entire lock slice in order. Using a consistent order avoids
// deadlocks because you can never have the following:
//
// Lock A, Lock B
// Lock B, Lock A
//
// Where process 1 is now deadlocked trying to lock B, and process 2 deadlocked trying to lock A
//
func CreateLocks() []*LockEntry {
ret := make([]*LockEntry, LockCount)
for i := range ret {
ret[i] = new(LockEntry)
}
return ret
}
func LockIndexForKey(key string) uint8 {
return uint8(cryptoutil.Blake2b256Hash(key)[0])
}
func LockForKey(locks []*LockEntry, key string) *LockEntry {
return locks[LockIndexForKey(key)]
}
func LocksForKeys(locks []*LockEntry, keys []string) []*LockEntry {
lockIndexes := make(map[uint8]struct{}, len(keys))
for _, k := range keys {
lockIndexes[LockIndexForKey(k)] = struct{}{}
}
locksToReturn := make([]*LockEntry, 0, len(keys))
for i, l := range locks {
if _, ok := lockIndexes[uint8(i)]; ok {
locksToReturn = append(locksToReturn, l)
}
}
return locksToReturn
}