[Trace] debug_traceTransaction

The traceTransaction debugging method will attempt to run the transaction in the exact same manner as it was executed on the network. It will replay any transaction that may have been executed prior to this one before it will finally attempt to execute the transaction that corresponds to the given hash.

JSONRPC: debug_traceTransaction

Request

application/json

Body

params

undefined[]

Array [

TxHash TxHash (string)

The hash of the transaction.

TracingOptions

object

disableStorage boolean

Setting this to true will disable storage capture in the null (structLog) tracer (default: false).

disableMemory boolean

Setting this to true will disable memory capture in the null (structLog) tracer (default: false).

disableStack boolean

Setting this to true will disable stack capture in the null (structLog) tracer (default: false).

timeout string

Overrides the default timeout of 5 seconds for trace-enabled EVM execution. A duration string can be anything that is accepted by Go time.ParseDuration function such as "10s" or "300ms".

tracer string

Possible values: [null, 4byteTracer, callTracer, fastCallTracer, evmdisTracer, noopTracer, opcountTracer, prestateTracer, revertTracer, unigramTracer, bigramTracer, trigramTracer, custom javascript tracer code]

If this field is empty or null, then the structLog tracer is used where the execution of every opcode is shown in detail. This null tracer is extremely heavy and usually too verbose for any debugging purpose, so it is advised to use other predefined tracers. This field can be the name of one of the predefined tracers shown below.

Tracer Name	Description
4byteTracer	traces 4-byte solidity function signatures.
callTracer	a slow version of fastCallTracer. It is deprecated in favor of fastCallTracer.
fastCallTracer	traces internal contract calls, gas usage, and call results.
evmdisTracer	returns information needed to perform evmdis-style disassembly.
noopTracer	is a template tracer that does nothing.
opcountTracer	is a sample tracer that counts the executed opcode.
prestateTracer	returns information needed to construct a custom local genesis state that this transaction can run on.
revertTracer	returns the revert reason, or an empty string if the transaction has not reverted.
unigramTracer	counts the occurrence of each opcode.
bigramTracer	counts the occurrence of two consecutive opcodes.
trigramTracer	counts the occurrence of three consecutive opcodes.

Otherwise this field is interpreted as a piece of javascript code. You can find more about custom JS tracer here and here. Below is an example custom tracer that prints the gasUsed after each opcode "{gasUsed: [], step: function(log) { this.gasUsed.push(log.getGas()); }, result: function() { return this.gasUsed; }, fault: function() {}}". Note that some nodes with --rpc.unsafe-debug.disable option will prohibit custom tracer.

]

Responses

200

The structured logs created during the execution of KLVM.

application/json

Schema

Schema

error

object

code int64required

A Number that indicates the error type that occurred. This MUST be an integer.

code	message	description
-32700	Parse error	invalid JSON was received by the server. An error occurred on the server while parsing the JSON text.
-32602	Invalid params	Invalid method parameter(s).

message string

A String providing a short description of the error. The message SHOULD be limited to a concise single sentence.

data string

A Primitive or Structured value that contains additional information about the error. This may be omitted. The value of this member is defined by the Server (e.g. detailed error information, nested errors etc.).

result

object

The structured logs created during the execution of KLVM.

failed booleanrequired

gas integerrequired

returnValue stringrequired

structLogs

object[]

required

Array [

computation number

computationCost number

depth number

gas number

gasCost number

memory string[]

op string

pc number

stack string[]

The status of the response

storage object

The status of the response

]

Example (from schema)

{
  "jsonrpc": "2.0",
  "id": 0,
  "error": {
    "code": -32700,
    "message": "Parse error",
    "data": "string"
  },
  "result": {
    "failed": false,
    "gas": 28110,
    "returnValue": "",
    "structLogs": [
      {
        "computation": 149999880,
        "computationCost": 120,
        "depth": 1,
        "gas": 6710,
        "gasCost": 3,
        "memory": [],
        "op": "PUSH1",
        "pc": 0,
        "stack": [],
        "storage": {}
      },
      {
        "computation": 149999760,
        "computationCost": 120,
        "depth": 1,
        "gas": 6707,
        "gasCost": 3,
        "memory": [],
        "op": "PUSH1",
        "pc": 2,
        "stack": [
          "0000000000000000000000000000000000000000000000000000000000000080"
        ],
        "storage": {}
      },
      {
        "...": null
      },
      {
        "computation": 149965613,
        "computationCost": 0,
        "depth": 1,
        "gas": 0,
        "gasCost": 0,
        "memory": [
          "0000000000000000000000000000000000000000000000000000000000000000",
          "0000000000000000000000000000000000000000000000000000000000000000",
          "0000000000000000000000000000000000000000000000000000000000000080",
          "0000000000000000000000000000000000000000000000000000000000000000",
          "0000000000000000000000000000000000000000000000000000000000000002"
        ],
        "op": "STOP",
        "pc": 176,
        "stack": [
          "00000000000000000000000000000000000000000000000000000000d09de08a"
        ],
        "storage": {
          "0": "0000000000000000000000000000000000000000000000000000000000000002"
        }
      }
    ]
  }
}

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