sslobodr | d046be8 | 2019-01-16 10:02:22 -0500 | [diff] [blame] | 1 | // Copyright 2017 The etcd Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package leasing |
| 16 | |
| 17 | import ( |
| 18 | "context" |
| 19 | "strings" |
| 20 | |
| 21 | v3 "github.com/coreos/etcd/clientv3" |
| 22 | v3pb "github.com/coreos/etcd/etcdserver/etcdserverpb" |
| 23 | ) |
| 24 | |
| 25 | type txnLeasing struct { |
| 26 | v3.Txn |
| 27 | lkv *leasingKV |
| 28 | ctx context.Context |
| 29 | cs []v3.Cmp |
| 30 | opst []v3.Op |
| 31 | opse []v3.Op |
| 32 | } |
| 33 | |
| 34 | func (txn *txnLeasing) If(cs ...v3.Cmp) v3.Txn { |
| 35 | txn.cs = append(txn.cs, cs...) |
| 36 | txn.Txn = txn.Txn.If(cs...) |
| 37 | return txn |
| 38 | } |
| 39 | |
| 40 | func (txn *txnLeasing) Then(ops ...v3.Op) v3.Txn { |
| 41 | txn.opst = append(txn.opst, ops...) |
| 42 | txn.Txn = txn.Txn.Then(ops...) |
| 43 | return txn |
| 44 | } |
| 45 | |
| 46 | func (txn *txnLeasing) Else(ops ...v3.Op) v3.Txn { |
| 47 | txn.opse = append(txn.opse, ops...) |
| 48 | txn.Txn = txn.Txn.Else(ops...) |
| 49 | return txn |
| 50 | } |
| 51 | |
| 52 | func (txn *txnLeasing) Commit() (*v3.TxnResponse, error) { |
| 53 | if resp, err := txn.eval(); resp != nil || err != nil { |
| 54 | return resp, err |
| 55 | } |
| 56 | return txn.serverTxn() |
| 57 | } |
| 58 | |
| 59 | func (txn *txnLeasing) eval() (*v3.TxnResponse, error) { |
| 60 | // TODO: wait on keys in comparisons |
| 61 | thenOps, elseOps := gatherOps(txn.opst), gatherOps(txn.opse) |
| 62 | ops := make([]v3.Op, 0, len(thenOps)+len(elseOps)) |
| 63 | ops = append(ops, thenOps...) |
| 64 | ops = append(ops, elseOps...) |
| 65 | |
| 66 | for _, ch := range txn.lkv.leases.NotifyOps(ops) { |
| 67 | select { |
| 68 | case <-ch: |
| 69 | case <-txn.ctx.Done(): |
| 70 | return nil, txn.ctx.Err() |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | txn.lkv.leases.mu.RLock() |
| 75 | defer txn.lkv.leases.mu.RUnlock() |
| 76 | succeeded, ok := txn.lkv.leases.evalCmp(txn.cs) |
| 77 | if !ok || txn.lkv.leases.header == nil { |
| 78 | return nil, nil |
| 79 | } |
| 80 | if ops = txn.opst; !succeeded { |
| 81 | ops = txn.opse |
| 82 | } |
| 83 | |
| 84 | resps, ok := txn.lkv.leases.evalOps(ops) |
| 85 | if !ok { |
| 86 | return nil, nil |
| 87 | } |
| 88 | return &v3.TxnResponse{copyHeader(txn.lkv.leases.header), succeeded, resps}, nil |
| 89 | } |
| 90 | |
| 91 | // fallback computes the ops to fetch all possible conflicting |
| 92 | // leasing keys for a list of ops. |
| 93 | func (txn *txnLeasing) fallback(ops []v3.Op) (fbOps []v3.Op) { |
| 94 | for _, op := range ops { |
| 95 | if op.IsGet() { |
| 96 | continue |
| 97 | } |
| 98 | lkey, lend := txn.lkv.pfx+string(op.KeyBytes()), "" |
| 99 | if len(op.RangeBytes()) > 0 { |
| 100 | lend = txn.lkv.pfx + string(op.RangeBytes()) |
| 101 | } |
| 102 | fbOps = append(fbOps, v3.OpGet(lkey, v3.WithRange(lend))) |
| 103 | } |
| 104 | return fbOps |
| 105 | } |
| 106 | |
| 107 | func (txn *txnLeasing) guardKeys(ops []v3.Op) (cmps []v3.Cmp) { |
| 108 | seen := make(map[string]bool) |
| 109 | for _, op := range ops { |
| 110 | key := string(op.KeyBytes()) |
| 111 | if op.IsGet() || len(op.RangeBytes()) != 0 || seen[key] { |
| 112 | continue |
| 113 | } |
| 114 | rev := txn.lkv.leases.Rev(key) |
| 115 | cmps = append(cmps, v3.Compare(v3.CreateRevision(txn.lkv.pfx+key), "<", rev+1)) |
| 116 | seen[key] = true |
| 117 | } |
| 118 | return cmps |
| 119 | } |
| 120 | |
| 121 | func (txn *txnLeasing) guardRanges(ops []v3.Op) (cmps []v3.Cmp, err error) { |
| 122 | for _, op := range ops { |
| 123 | if op.IsGet() || len(op.RangeBytes()) == 0 { |
| 124 | continue |
| 125 | } |
| 126 | |
| 127 | key, end := string(op.KeyBytes()), string(op.RangeBytes()) |
| 128 | maxRevLK, err := txn.lkv.revokeRange(txn.ctx, key, end) |
| 129 | if err != nil { |
| 130 | return nil, err |
| 131 | } |
| 132 | |
| 133 | opts := append(v3.WithLastRev(), v3.WithRange(end)) |
| 134 | getResp, err := txn.lkv.kv.Get(txn.ctx, key, opts...) |
| 135 | if err != nil { |
| 136 | return nil, err |
| 137 | } |
| 138 | maxModRev := int64(0) |
| 139 | if len(getResp.Kvs) > 0 { |
| 140 | maxModRev = getResp.Kvs[0].ModRevision |
| 141 | } |
| 142 | |
| 143 | noKeyUpdate := v3.Compare(v3.ModRevision(key).WithRange(end), "<", maxModRev+1) |
| 144 | noLeaseUpdate := v3.Compare( |
| 145 | v3.CreateRevision(txn.lkv.pfx+key).WithRange(txn.lkv.pfx+end), |
| 146 | "<", |
| 147 | maxRevLK+1) |
| 148 | cmps = append(cmps, noKeyUpdate, noLeaseUpdate) |
| 149 | } |
| 150 | return cmps, nil |
| 151 | } |
| 152 | |
| 153 | func (txn *txnLeasing) guard(ops []v3.Op) ([]v3.Cmp, error) { |
| 154 | cmps := txn.guardKeys(ops) |
| 155 | rangeCmps, err := txn.guardRanges(ops) |
| 156 | return append(cmps, rangeCmps...), err |
| 157 | } |
| 158 | |
| 159 | func (txn *txnLeasing) commitToCache(txnResp *v3pb.TxnResponse, userTxn v3.Op) { |
| 160 | ops := gatherResponseOps(txnResp.Responses, []v3.Op{userTxn}) |
| 161 | txn.lkv.leases.mu.Lock() |
| 162 | for _, op := range ops { |
| 163 | key := string(op.KeyBytes()) |
| 164 | if op.IsDelete() && len(op.RangeBytes()) > 0 { |
| 165 | end := string(op.RangeBytes()) |
| 166 | for k := range txn.lkv.leases.entries { |
| 167 | if inRange(k, key, end) { |
| 168 | txn.lkv.leases.delete(k, txnResp.Header) |
| 169 | } |
| 170 | } |
| 171 | } else if op.IsDelete() { |
| 172 | txn.lkv.leases.delete(key, txnResp.Header) |
| 173 | } |
| 174 | if op.IsPut() { |
| 175 | txn.lkv.leases.Update(op.KeyBytes(), op.ValueBytes(), txnResp.Header) |
| 176 | } |
| 177 | } |
| 178 | txn.lkv.leases.mu.Unlock() |
| 179 | } |
| 180 | |
| 181 | func (txn *txnLeasing) revokeFallback(fbResps []*v3pb.ResponseOp) error { |
| 182 | for _, resp := range fbResps { |
| 183 | _, err := txn.lkv.revokeLeaseKvs(txn.ctx, resp.GetResponseRange().Kvs) |
| 184 | if err != nil { |
| 185 | return err |
| 186 | } |
| 187 | } |
| 188 | return nil |
| 189 | } |
| 190 | |
| 191 | func (txn *txnLeasing) serverTxn() (*v3.TxnResponse, error) { |
| 192 | if err := txn.lkv.waitSession(txn.ctx); err != nil { |
| 193 | return nil, err |
| 194 | } |
| 195 | |
| 196 | userOps := gatherOps(append(txn.opst, txn.opse...)) |
| 197 | userTxn := v3.OpTxn(txn.cs, txn.opst, txn.opse) |
| 198 | fbOps := txn.fallback(userOps) |
| 199 | |
| 200 | defer closeAll(txn.lkv.leases.LockWriteOps(userOps)) |
| 201 | for { |
| 202 | cmps, err := txn.guard(userOps) |
| 203 | if err != nil { |
| 204 | return nil, err |
| 205 | } |
| 206 | resp, err := txn.lkv.kv.Txn(txn.ctx).If(cmps...).Then(userTxn).Else(fbOps...).Commit() |
| 207 | if err != nil { |
| 208 | for _, cmp := range cmps { |
| 209 | txn.lkv.leases.Evict(strings.TrimPrefix(string(cmp.Key), txn.lkv.pfx)) |
| 210 | } |
| 211 | return nil, err |
| 212 | } |
| 213 | if resp.Succeeded { |
| 214 | txn.commitToCache((*v3pb.TxnResponse)(resp), userTxn) |
| 215 | userResp := resp.Responses[0].GetResponseTxn() |
| 216 | userResp.Header = resp.Header |
| 217 | return (*v3.TxnResponse)(userResp), nil |
| 218 | } |
| 219 | if err := txn.revokeFallback(resp.Responses); err != nil { |
| 220 | return nil, err |
| 221 | } |
| 222 | } |
| 223 | } |