minio/cmd/lock-rest-server-common.go
Harshavardhana 4e63e0e372 Return appropriate errors API versions changes across REST APIs (#8480)
This PR adds code to appropriately handle versioning issues
that come up quite constantly across our API changes. Currently
we were also routing our requests wrong which sort of made it
harder to write a consistent error handling code to appropriately
reject or honor requests.

This PR potentially fixes issues

 - old mc is used against new minio release which is incompatible
   returns an appropriate for client action.
 - any older servers talking to each other, report appropriate error
 - incompatible peer servers should report error and reject the calls
   with appropriate error
2019-11-04 09:30:59 -08:00

110 lines
3.7 KiB
Go

/*
* MinIO Cloud Storage, (C) 2019 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"errors"
"time"
)
const (
lockRESTVersion = "v2"
lockRESTVersionPrefix = SlashSeparator + "v2"
lockRESTPrefix = minioReservedBucketPath + "/lock"
lockRESTPath = lockRESTPrefix + lockRESTVersionPrefix
)
const (
lockRESTMethodLock = "/lock"
lockRESTMethodRLock = "/rlock"
lockRESTMethodUnlock = "/unlock"
lockRESTMethodRUnlock = "/runlock"
lockRESTMethodForceUnlock = "/forceunlock"
lockRESTMethodExpired = "/expired"
// Unique ID of lock/unlock request.
lockRESTUID = "uid"
// Source contains the line number, function and file name of the code
// on the client node that requested the lock.
lockRESTSource = "source"
// Resource contains a entity to be locked/unlocked.
lockRESTResource = "resource"
// ServerAddr contains the address of the server who requested lock/unlock of the above resource.
lockRESTServerAddr = "serverAddr"
// ServiceEndpoint contains the network path of above server to do lock/unlock.
lockRESTServerEndpoint = "serverEndpoint"
)
// nameLockRequesterInfoPair is a helper type for lock maintenance
type nameLockRequesterInfoPair struct {
name string
lri lockRequesterInfo
}
var errLockConflict = errors.New("lock conflict")
var errLockNotExpired = errors.New("lock not expired")
// Similar to removeEntry but only removes an entry only if the lock entry exists in map.
func (l *localLocker) removeEntryIfExists(nlrip nameLockRequesterInfoPair) {
// Check if entry is still in map (could have been removed altogether by 'concurrent' (R)Unlock of last entry)
if lri, ok := l.lockMap[nlrip.name]; ok {
// Even if the entry exists, it may not be the same entry which was
// considered as expired, so we simply an attempt to remove it if its
// not possible there is nothing we need to do.
l.removeEntry(nlrip.name, nlrip.lri.UID, &lri)
}
}
// removeEntry based on the uid of the lock message, removes a single entry from the
// lockRequesterInfo array or the whole array from the map (in case of a write lock
// or last read lock)
func (l *localLocker) removeEntry(name, uid string, lri *[]lockRequesterInfo) bool {
// Find correct entry to remove based on uid.
for index, entry := range *lri {
if entry.UID == uid {
if len(*lri) == 1 {
// Remove the write lock.
delete(l.lockMap, name)
} else {
// Remove the appropriate read lock.
*lri = append((*lri)[:index], (*lri)[index+1:]...)
l.lockMap[name] = *lri
}
return true
}
}
// None found return false, perhaps entry removed in previous run.
return false
}
// getLongLivedLocks returns locks that are older than a certain time and
// have not been 'checked' for validity too soon enough
func getLongLivedLocks(m map[string][]lockRequesterInfo, interval time.Duration) []nameLockRequesterInfoPair {
rslt := []nameLockRequesterInfoPair{}
for name, lriArray := range m {
for idx := range lriArray {
// Check whether enough time has gone by since last check
if time.Since(lriArray[idx].TimeLastCheck) >= interval {
rslt = append(rslt, nameLockRequesterInfoPair{name: name, lri: lriArray[idx]})
lriArray[idx].TimeLastCheck = UTCNow()
}
}
}
return rslt
}