| // Copyright 2017 The etcd Authors |
| // |
| // 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 leasing |
| |
| import ( |
| "context" |
| "strings" |
| |
| v3 "github.com/coreos/etcd/clientv3" |
| v3pb "github.com/coreos/etcd/etcdserver/etcdserverpb" |
| ) |
| |
| type txnLeasing struct { |
| v3.Txn |
| lkv *leasingKV |
| ctx context.Context |
| cs []v3.Cmp |
| opst []v3.Op |
| opse []v3.Op |
| } |
| |
| func (txn *txnLeasing) If(cs ...v3.Cmp) v3.Txn { |
| txn.cs = append(txn.cs, cs...) |
| txn.Txn = txn.Txn.If(cs...) |
| return txn |
| } |
| |
| func (txn *txnLeasing) Then(ops ...v3.Op) v3.Txn { |
| txn.opst = append(txn.opst, ops...) |
| txn.Txn = txn.Txn.Then(ops...) |
| return txn |
| } |
| |
| func (txn *txnLeasing) Else(ops ...v3.Op) v3.Txn { |
| txn.opse = append(txn.opse, ops...) |
| txn.Txn = txn.Txn.Else(ops...) |
| return txn |
| } |
| |
| func (txn *txnLeasing) Commit() (*v3.TxnResponse, error) { |
| if resp, err := txn.eval(); resp != nil || err != nil { |
| return resp, err |
| } |
| return txn.serverTxn() |
| } |
| |
| func (txn *txnLeasing) eval() (*v3.TxnResponse, error) { |
| // TODO: wait on keys in comparisons |
| thenOps, elseOps := gatherOps(txn.opst), gatherOps(txn.opse) |
| ops := make([]v3.Op, 0, len(thenOps)+len(elseOps)) |
| ops = append(ops, thenOps...) |
| ops = append(ops, elseOps...) |
| |
| for _, ch := range txn.lkv.leases.NotifyOps(ops) { |
| select { |
| case <-ch: |
| case <-txn.ctx.Done(): |
| return nil, txn.ctx.Err() |
| } |
| } |
| |
| txn.lkv.leases.mu.RLock() |
| defer txn.lkv.leases.mu.RUnlock() |
| succeeded, ok := txn.lkv.leases.evalCmp(txn.cs) |
| if !ok || txn.lkv.leases.header == nil { |
| return nil, nil |
| } |
| if ops = txn.opst; !succeeded { |
| ops = txn.opse |
| } |
| |
| resps, ok := txn.lkv.leases.evalOps(ops) |
| if !ok { |
| return nil, nil |
| } |
| return &v3.TxnResponse{copyHeader(txn.lkv.leases.header), succeeded, resps}, nil |
| } |
| |
| // fallback computes the ops to fetch all possible conflicting |
| // leasing keys for a list of ops. |
| func (txn *txnLeasing) fallback(ops []v3.Op) (fbOps []v3.Op) { |
| for _, op := range ops { |
| if op.IsGet() { |
| continue |
| } |
| lkey, lend := txn.lkv.pfx+string(op.KeyBytes()), "" |
| if len(op.RangeBytes()) > 0 { |
| lend = txn.lkv.pfx + string(op.RangeBytes()) |
| } |
| fbOps = append(fbOps, v3.OpGet(lkey, v3.WithRange(lend))) |
| } |
| return fbOps |
| } |
| |
| func (txn *txnLeasing) guardKeys(ops []v3.Op) (cmps []v3.Cmp) { |
| seen := make(map[string]bool) |
| for _, op := range ops { |
| key := string(op.KeyBytes()) |
| if op.IsGet() || len(op.RangeBytes()) != 0 || seen[key] { |
| continue |
| } |
| rev := txn.lkv.leases.Rev(key) |
| cmps = append(cmps, v3.Compare(v3.CreateRevision(txn.lkv.pfx+key), "<", rev+1)) |
| seen[key] = true |
| } |
| return cmps |
| } |
| |
| func (txn *txnLeasing) guardRanges(ops []v3.Op) (cmps []v3.Cmp, err error) { |
| for _, op := range ops { |
| if op.IsGet() || len(op.RangeBytes()) == 0 { |
| continue |
| } |
| |
| key, end := string(op.KeyBytes()), string(op.RangeBytes()) |
| maxRevLK, err := txn.lkv.revokeRange(txn.ctx, key, end) |
| if err != nil { |
| return nil, err |
| } |
| |
| opts := append(v3.WithLastRev(), v3.WithRange(end)) |
| getResp, err := txn.lkv.kv.Get(txn.ctx, key, opts...) |
| if err != nil { |
| return nil, err |
| } |
| maxModRev := int64(0) |
| if len(getResp.Kvs) > 0 { |
| maxModRev = getResp.Kvs[0].ModRevision |
| } |
| |
| noKeyUpdate := v3.Compare(v3.ModRevision(key).WithRange(end), "<", maxModRev+1) |
| noLeaseUpdate := v3.Compare( |
| v3.CreateRevision(txn.lkv.pfx+key).WithRange(txn.lkv.pfx+end), |
| "<", |
| maxRevLK+1) |
| cmps = append(cmps, noKeyUpdate, noLeaseUpdate) |
| } |
| return cmps, nil |
| } |
| |
| func (txn *txnLeasing) guard(ops []v3.Op) ([]v3.Cmp, error) { |
| cmps := txn.guardKeys(ops) |
| rangeCmps, err := txn.guardRanges(ops) |
| return append(cmps, rangeCmps...), err |
| } |
| |
| func (txn *txnLeasing) commitToCache(txnResp *v3pb.TxnResponse, userTxn v3.Op) { |
| ops := gatherResponseOps(txnResp.Responses, []v3.Op{userTxn}) |
| txn.lkv.leases.mu.Lock() |
| for _, op := range ops { |
| key := string(op.KeyBytes()) |
| if op.IsDelete() && len(op.RangeBytes()) > 0 { |
| end := string(op.RangeBytes()) |
| for k := range txn.lkv.leases.entries { |
| if inRange(k, key, end) { |
| txn.lkv.leases.delete(k, txnResp.Header) |
| } |
| } |
| } else if op.IsDelete() { |
| txn.lkv.leases.delete(key, txnResp.Header) |
| } |
| if op.IsPut() { |
| txn.lkv.leases.Update(op.KeyBytes(), op.ValueBytes(), txnResp.Header) |
| } |
| } |
| txn.lkv.leases.mu.Unlock() |
| } |
| |
| func (txn *txnLeasing) revokeFallback(fbResps []*v3pb.ResponseOp) error { |
| for _, resp := range fbResps { |
| _, err := txn.lkv.revokeLeaseKvs(txn.ctx, resp.GetResponseRange().Kvs) |
| if err != nil { |
| return err |
| } |
| } |
| return nil |
| } |
| |
| func (txn *txnLeasing) serverTxn() (*v3.TxnResponse, error) { |
| if err := txn.lkv.waitSession(txn.ctx); err != nil { |
| return nil, err |
| } |
| |
| userOps := gatherOps(append(txn.opst, txn.opse...)) |
| userTxn := v3.OpTxn(txn.cs, txn.opst, txn.opse) |
| fbOps := txn.fallback(userOps) |
| |
| defer closeAll(txn.lkv.leases.LockWriteOps(userOps)) |
| for { |
| cmps, err := txn.guard(userOps) |
| if err != nil { |
| return nil, err |
| } |
| resp, err := txn.lkv.kv.Txn(txn.ctx).If(cmps...).Then(userTxn).Else(fbOps...).Commit() |
| if err != nil { |
| for _, cmp := range cmps { |
| txn.lkv.leases.Evict(strings.TrimPrefix(string(cmp.Key), txn.lkv.pfx)) |
| } |
| return nil, err |
| } |
| if resp.Succeeded { |
| txn.commitToCache((*v3pb.TxnResponse)(resp), userTxn) |
| userResp := resp.Responses[0].GetResponseTxn() |
| userResp.Header = resp.Header |
| return (*v3.TxnResponse)(userResp), nil |
| } |
| if err := txn.revokeFallback(resp.Responses); err != nil { |
| return nil, err |
| } |
| } |
| } |