sslobodr | d046be8 | 2019-01-16 10:02:22 -0500 | [diff] [blame] | 1 | // Copyright 2016 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 clientv3 |
| 16 | |
| 17 | import ( |
| 18 | "context" |
| 19 | "sync" |
| 20 | |
| 21 | pb "github.com/coreos/etcd/etcdserver/etcdserverpb" |
| 22 | |
| 23 | "google.golang.org/grpc" |
| 24 | ) |
| 25 | |
| 26 | // Txn is the interface that wraps mini-transactions. |
| 27 | // |
| 28 | // Txn(context.TODO()).If( |
| 29 | // Compare(Value(k1), ">", v1), |
| 30 | // Compare(Version(k1), "=", 2) |
| 31 | // ).Then( |
| 32 | // OpPut(k2,v2), OpPut(k3,v3) |
| 33 | // ).Else( |
| 34 | // OpPut(k4,v4), OpPut(k5,v5) |
| 35 | // ).Commit() |
| 36 | // |
| 37 | type Txn interface { |
| 38 | // If takes a list of comparison. If all comparisons passed in succeed, |
| 39 | // the operations passed into Then() will be executed. Or the operations |
| 40 | // passed into Else() will be executed. |
| 41 | If(cs ...Cmp) Txn |
| 42 | |
| 43 | // Then takes a list of operations. The Ops list will be executed, if the |
| 44 | // comparisons passed in If() succeed. |
| 45 | Then(ops ...Op) Txn |
| 46 | |
| 47 | // Else takes a list of operations. The Ops list will be executed, if the |
| 48 | // comparisons passed in If() fail. |
| 49 | Else(ops ...Op) Txn |
| 50 | |
| 51 | // Commit tries to commit the transaction. |
| 52 | Commit() (*TxnResponse, error) |
| 53 | } |
| 54 | |
| 55 | type txn struct { |
| 56 | kv *kv |
| 57 | ctx context.Context |
| 58 | |
| 59 | mu sync.Mutex |
| 60 | cif bool |
| 61 | cthen bool |
| 62 | celse bool |
| 63 | |
| 64 | isWrite bool |
| 65 | |
| 66 | cmps []*pb.Compare |
| 67 | |
| 68 | sus []*pb.RequestOp |
| 69 | fas []*pb.RequestOp |
| 70 | |
| 71 | callOpts []grpc.CallOption |
| 72 | } |
| 73 | |
| 74 | func (txn *txn) If(cs ...Cmp) Txn { |
| 75 | txn.mu.Lock() |
| 76 | defer txn.mu.Unlock() |
| 77 | |
| 78 | if txn.cif { |
| 79 | panic("cannot call If twice!") |
| 80 | } |
| 81 | |
| 82 | if txn.cthen { |
| 83 | panic("cannot call If after Then!") |
| 84 | } |
| 85 | |
| 86 | if txn.celse { |
| 87 | panic("cannot call If after Else!") |
| 88 | } |
| 89 | |
| 90 | txn.cif = true |
| 91 | |
| 92 | for i := range cs { |
| 93 | txn.cmps = append(txn.cmps, (*pb.Compare)(&cs[i])) |
| 94 | } |
| 95 | |
| 96 | return txn |
| 97 | } |
| 98 | |
| 99 | func (txn *txn) Then(ops ...Op) Txn { |
| 100 | txn.mu.Lock() |
| 101 | defer txn.mu.Unlock() |
| 102 | |
| 103 | if txn.cthen { |
| 104 | panic("cannot call Then twice!") |
| 105 | } |
| 106 | if txn.celse { |
| 107 | panic("cannot call Then after Else!") |
| 108 | } |
| 109 | |
| 110 | txn.cthen = true |
| 111 | |
| 112 | for _, op := range ops { |
| 113 | txn.isWrite = txn.isWrite || op.isWrite() |
| 114 | txn.sus = append(txn.sus, op.toRequestOp()) |
| 115 | } |
| 116 | |
| 117 | return txn |
| 118 | } |
| 119 | |
| 120 | func (txn *txn) Else(ops ...Op) Txn { |
| 121 | txn.mu.Lock() |
| 122 | defer txn.mu.Unlock() |
| 123 | |
| 124 | if txn.celse { |
| 125 | panic("cannot call Else twice!") |
| 126 | } |
| 127 | |
| 128 | txn.celse = true |
| 129 | |
| 130 | for _, op := range ops { |
| 131 | txn.isWrite = txn.isWrite || op.isWrite() |
| 132 | txn.fas = append(txn.fas, op.toRequestOp()) |
| 133 | } |
| 134 | |
| 135 | return txn |
| 136 | } |
| 137 | |
| 138 | func (txn *txn) Commit() (*TxnResponse, error) { |
| 139 | txn.mu.Lock() |
| 140 | defer txn.mu.Unlock() |
| 141 | |
| 142 | r := &pb.TxnRequest{Compare: txn.cmps, Success: txn.sus, Failure: txn.fas} |
| 143 | |
| 144 | var resp *pb.TxnResponse |
| 145 | var err error |
| 146 | resp, err = txn.kv.remote.Txn(txn.ctx, r, txn.callOpts...) |
| 147 | if err != nil { |
| 148 | return nil, toErr(txn.ctx, err) |
| 149 | } |
| 150 | return (*TxnResponse)(resp), nil |
| 151 | } |