How to differentiate between different logs in ethclient

Question

I have events like this in my .sol file

event userActivated(address owner, address contractAddr);
event userDeactivated(address owner, address contractAddr);

And I am using ethclient Go module to parse events. here is the code

func listEvents() string{
    var tempEvents Event
    client, err := ethclient.Dial(RpcPath)
    if err!=nil{
        glog.Fatal("Client error",err)
    }
    query := ethereum.FilterQuery{
        FromBlock: nil,
        ToBlock:   nil,
        Addresses: []common.Address{},
   }
   logs, err := client.FilterLogs(context.Background(), query)
   if err != nil {
      glog.Fatal(err)
   }
   //get ABI for parsing data
   contractAbi, err := 
   abi.JSON(strings.NewReader(string(contracts.NewUserABI)))
   if err != nil {
      glog.Fatal("ABI error",err)
   }
   for _, vLog := range logs {
       //fmt.Println(string(vLog))
       err := contractAbi.Unpack(&tempEvents, "userActivated", vLog.Data)
      if err != nil {
            glog.Fatal(err)
      } 
      fmt.Println(tempEvents.ContractAddr.Hex(),tempEvents.Owner.Hex())
   }
  if err!=nil{
      glog.Fatal(err.Error())
  }
return ""

}

My event structure is here

type Event struct {
    Owner common.Address
    ContractAddr common.Address
}

But it lists both events, userActivated and userDeactivated even if I gave unPack parameter as "userActivated"

Is there any way to check event name in log data?

Answer 1

The log structure includes a topics array. The first topic is the signature of the event.

var topics [4]string
for i := range vLog.Topics {
  topics[i] = vLog.Topics[i].Hex()
}

fmt.Println(topics[0]) // 0xe79e73da417710ae99aa2088575580a60415d359acfad9cdd3382d59c80281d4

To calculate the topic for an event

eventSignature := []byte("ItemSet(bytes32,bytes32)")
hash := crypto.Keccak256Hash(eventSignature)
fmt.Println(hash.Hex()) // 0xe79e73da417710ae99aa2088575580a60415d359acfad9cdd3382d59c80281d4