| 105 | } |
| 106 | |
| 107 | func multipleOperationsExample() { |
| 108 | fmt.Println("--- Example 2: Watch Multiple Operations ---") |
| 109 | key := []byte("multi_op_key") |
| 110 | done := make(chan struct{}) |
| 111 | ctx, cancel := context.WithCancel(context.Background()) |
| 112 | mu := sync.Mutex{} |
| 113 | |
| 114 | messageCount := 0 |
| 115 | watcher, err := db.Watch(ctx, bucket, key, func(msg *nutsdb.Message) error { |
| 116 | mu.Lock() |
| 117 | defer mu.Unlock() |
| 118 | |
| 119 | messageCount++ |
| 120 | fmt.Printf("[Watch] Operation #%d: ", messageCount) |
| 121 | |
| 122 | switch msg.Flag { |
| 123 | case nutsdb.DataSetFlag: |
| 124 | fmt.Printf("SET - Value: %s\n", string(msg.Value)) |
| 125 | case nutsdb.DataDeleteFlag: |
| 126 | fmt.Printf("DELETE - Key: %s\n", msg.Key) |
| 127 | } |
| 128 | |
| 129 | if messageCount >= 3 { |
| 130 | cancel() |
| 131 | close(done) |
| 132 | } |
| 133 | return nil |
| 134 | }) |
| 135 | |
| 136 | if err != nil { |
| 137 | log.Fatal(err) |
| 138 | } |
| 139 | |
| 140 | go func() { |
| 141 | if err := watcher.Run(); err != nil { |
| 142 | log.Fatal(err) |
| 143 | } |
| 144 | }() |
| 145 | |
| 146 | if err := watcher.WaitReady(10 * time.Second); err != nil { |
| 147 | log.Fatal(err) |
| 148 | } |
| 149 | |
| 150 | // Perform multiple operations |
| 151 | operations := []struct { |
| 152 | action string |
| 153 | value string |
| 154 | }{ |
| 155 | {"put", "First value"}, |
| 156 | {"put", "Updated value"}, |
| 157 | {"delete", ""}, |
| 158 | } |
| 159 | |
| 160 | for _, op := range operations { |
| 161 | switch op.action { |
| 162 | case "put": |
| 163 | if err := db.Update(func(tx *nutsdb.Tx) error { |
| 164 | return tx.Put(bucket, key, []byte(op.value), nutsdb.Persistent) |