open-consul/consul/state/txn.go
2016-05-12 16:11:26 -07:00

128 lines
3.2 KiB
Go

package state
import (
"fmt"
"github.com/hashicorp/consul/consul/structs"
"github.com/hashicorp/go-memdb"
)
// txnKVS handles all KV-related operations.
func (s *StateStore) txnKVS(tx *memdb.Txn, idx uint64, op *structs.TxnKVOp) (structs.TxnKVResult, error) {
var entry *structs.DirEntry
var err error
switch op.Verb {
case structs.KVSSet:
entry = &op.DirEnt
err = s.kvsSetTxn(tx, idx, entry, false)
case structs.KVSDelete:
err = s.kvsDeleteTxn(tx, idx, op.DirEnt.Key)
case structs.KVSDeleteCAS:
var ok bool
ok, err = s.kvsDeleteCASTxn(tx, idx, op.DirEnt.ModifyIndex, op.DirEnt.Key)
if !ok && err == nil {
err = fmt.Errorf("failed to delete key %q, index is stale", op.DirEnt.Key)
}
case structs.KVSDeleteTree:
err = s.kvsDeleteTreeTxn(tx, idx, op.DirEnt.Key)
case structs.KVSCAS:
var ok bool
entry = &op.DirEnt
ok, err = s.kvsSetCASTxn(tx, idx, entry)
if !ok && err == nil {
err = fmt.Errorf("failed to set key %q, index is stale", op.DirEnt.Key)
}
case structs.KVSLock:
var ok bool
entry = &op.DirEnt
ok, err = s.kvsLockTxn(tx, idx, entry)
if !ok && err == nil {
err = fmt.Errorf("failed to lock key %q, lock is already held", op.DirEnt.Key)
}
case structs.KVSUnlock:
var ok bool
entry = &op.DirEnt
ok, err = s.kvsUnlockTxn(tx, idx, entry)
if !ok && err == nil {
err = fmt.Errorf("failed to unlock key %q, lock isn't held, or is held by another session", op.DirEnt.Key)
}
case structs.KVSGet:
_, entry, err = s.kvsGetTxn(tx, op.DirEnt.Key)
if entry == nil && err == nil {
err = fmt.Errorf("key %q doesn't exist", op.DirEnt.Key)
}
case structs.KVSCheckSession:
entry, err = s.kvsCheckSessionTxn(tx, op.DirEnt.Key, op.DirEnt.Session)
case structs.KVSCheckIndex:
entry, err = s.kvsCheckIndexTxn(tx, op.DirEnt.Key, op.DirEnt.ModifyIndex)
default:
err = fmt.Errorf("unknown KV verb %q", op.Verb)
}
if err != nil {
return nil, err
}
// For a GET we keep the value, otherwise we clone and blank out the
// value (we have to clone so we don't modify the entry being used by
// the state store).
if entry != nil {
if op.Verb == structs.KVSGet {
return entry, nil
}
clone := entry.Clone()
clone.Value = nil
return clone, nil
}
return nil, nil
}
// TxnRun tries to run the given operations all inside a single transaction. If
// any of the operations fail, the entire transaction will be rolled back.
func (s *StateStore) TxnRun(idx uint64, ops structs.TxnOps) (structs.TxnResults, structs.TxnErrors) {
tx := s.db.Txn(true)
defer tx.Abort()
// Dispatch all of the operations inside the transaction.
results := make(structs.TxnResults, 0, len(ops))
errors := make(structs.TxnErrors, 0, len(ops))
for i, op := range ops {
var result structs.TxnResult
var err error
// Dispatch based on the type of operation.
if op.KV != nil {
result.KV, err = s.txnKVS(tx, idx, op.KV)
} else {
err = fmt.Errorf("no operation specified")
}
// Accumulate the results.
results = append(results, &result)
// Capture any error along with the index of the operation that
// failed.
if err != nil {
errors = append(errors, &structs.TxnError{i, err.Error()})
}
}
if len(errors) > 0 {
return nil, errors
}
tx.Commit()
return results, nil
}