How to encode transaction hash argument in go ethclient CallContext

Question

I am trying to call debug_traceTransaction in go by doing:

cl, err := ethclient.Dial("http://localhost:8545")
    
if err != nil {
    panic("Failed starting")
}

txnHash := common.HexToHash("0x60eb378a5ceeb61a72e06363e6f69f03a04b5dd0a76be51872f3f2563d5124e2")

encodedTxHash := hexutil.Encode(txnHash.Bytes())

var result interface{}

err = cl.CallContext(context.Background(), &result, "debug_traceTransaction", encodedTxHash, nil)

if err != nil {
    panic(err)
}

I am getting this error:

panic: invalid argument 0: json: cannot unmarshal non-string into Go value of type common.Hash
    
goroutine 1 [running]:
main.main()
        /root/atlas-erigon/atlas/main.go:432 +0x26c
exit status 2

How should I encode the transaction hash?

Answer 1

You can refer to this answer, that says:

Transaction tracing is not exposed via ethclient. You must connect over the regular rpc and invoke it as a regular call.

The reasoning for that is given here.

So, the revised code using the rpc would be:

package main

import (
    "context"
    "log"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/rpc"
)

func main() {
    rpcURL := "http://localhost:8545"

    txnHashHex := "0x60eb378a5ceeb61a72e06363e6f69f03a04b5dd0a76be51872f3f2563d5124e2"

    // Dial the Ethereum RPC endpoint
    cl, err := rpc.Dial(rpcURL)
    if err != nil {
        log.Fatalf("Failed to dial: %v", err)
    }

    // Convert the transaction hash from hex to bytes
    txnHash := common.HexToHash(txnHashHex)

    // Prepare the trace configuration
    traceConfig := map[string]interface{}{
        "tracer": "callTracer",
        "tracerConfig": map[string]interface{}{
            "withLog": true,
        },
    }

    // Call the debug_traceTransaction method
    result := new(interface{})
    err = cl.CallContext(context.Background(), result, "debug_traceTransaction", txnHash.Hex(), traceConfig)
    if err != nil {
        log.Fatalf("Failed to trace transaction: %v", err)
    }

    // Process the result as needed
    log.Printf("Trace result: %v", *result)
}