# VM Tracing
**NOTE** The [JavaScript-based Tracing](#javascript-based-tracing) of VM Tracing APIs is considered unsafe to be opened to public. If you want to provide VM Tracing APIs to the public, we strongly recommend you to set the `rpc.unsafe-debug.disable` flag which will disable the [Javascript-based Tracing](#javascript-based-tracing) and only allow [pre-defined tracers](#tracing-options).
## debug\_traceBadBlock
The `traceBadBlock` method will return a full stack trace of all invoked opcodes of all transactions that were included in this block.
**NOTE**: the parent of this block must be present or it will fail.
| Client | Method Invocation |
| :-----: | --------------------------------------------------------- |
| Console | `debug.traceBadBlock(hash, [options])` |
| RPC | `{"method": "debug_traceBadBlock", "params": [hash, {}]}` |
**Parameters**
| Name | Type | Description |
| ------- | ------------ | ---------------------------------------- |
| hash | 32-byte DATA | Hash of a block. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ----------- | --------------------------------------------------------- |
| JSON string | The structured logs created during the execution of KLVM. |
**Example**
Console
```javascript
> debug.traceBadBlock("0x1d5ba00e313a81ae6d409d459c153327072665d9ea2f47608369722baf0cfbb6")
[{
result: {
failed: false,
gas: 67100,
returnValue: "",
structLogs: []
}
}, {
result: {
failed: false,
gas: 195179,
returnValue: "",
structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
}
}]
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceBadBlock","params":["0x1d5ba00e313a81ae6d409d459c153327072665d9ea2f47608369722baf0cfbb6"],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":[{"result":{"gas":67100,"failed":false,"returnValue":"","structLogs":[]}},{"result":{"gas":195179,"failed":false,"returnValue":"","structLogs":[{"pc":0,"op":"PUSH1","gas":9975680,"gasCost":3,"depth":1,"stack":[],"memory":[],"storage":{}},{"pc":2,"op":"PUSH1","gas":9975677,"gasCost":3,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080"],"memory":[],"storage":{}},{"pc":4,"op":"MSTORE","gas":9975674,"gasCost":12,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080","0000000000000000000000000000000000000000000000000000000000000040"],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000"],"storage":{}},{"pc":5,"op":"PUSH1","gas":9975662,"gasCost":3,"depth":1,"stack":[],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000080"],"storage":{}},{"pc":7,"op":"CALLDATASIZE","gas":9975659,"gasCost":2,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000004"],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000080"],"storage":{}},
...
,{"pc":853,"op":"STOP","gas":9804821,"gasCost":0,"depth":1,"stack":["000000000000000000000000000000000000000000000000000000007818097c"],"memory":["0000000000000000000000000000000000000000000000000000000000000002","0000000000000000000000000000000000000000000000000000000000000005","00000000000000000000000000000000000000000000000000000000000001c0","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000006","000000000000000000000000500a2e58ae232c5e91bcdcf82c5d6d2165572599","00000000000000000000000000000000000000000000021e19e0c9bab2400000","0000000000000000000000000000000000000000000000000000000000000000","00000000000000000000000081d390a4e469b45642341d6ad111062c24984b37","0000000000000000000000000000000000000000000000000000000000000160","0000000000000000000000000000000000000000000000000000000000000001","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000001","00000000000000000000000081d390a4e469b45642341d6ad111062c24984b37","0000000000000000000000000000000000000000000000000000000000000006","000000000000000000000000500a2e58ae232c5e91bcdcf82c5d6d2165572599","00000000000000000000000000000000000000000000021e19e0c9bab2400000","0000000000000000000000000000000000000000000000000000000000000000","00000000000000000000000000000000000000000000000000000000000000a0","0000000000000000000000000000000000000000000000000000000000000001","00000000000000000000000081d390a4e469b45642341d6ad111062c24984b37"],"storage":{"0000000000000000000000000000000000000000000000000000000000000004":"0000000000000000000000000000000000000000000000000000000000000003","5997abbe896cd022932fc8703dbed777f0bf0d6ed28b2444cb4b79da2805e9a5":"00000000000000000000000081d390a4e469b45642341d6ad111062c24984b37","89832631fb3c3307a103ba2c84ab569c64d6182a18893dcd163f0f1c2090733a":"0000000000000000000000000000000000000000000000000000000000000006","89832631fb3c3307a103ba2c84ab569c64d6182a18893dcd163f0f1c2090733b":"000000000000000000000000500a2e58ae232c5e91bcdcf82c5d6d2165572599","89832631fb3c3307a103ba2c84ab569c64d6182a18893dcd163f0f1c2090733c":"00000000000000000000000000000000000000000000021e19e0c9bab2400000","89832631fb3c3307a103ba2c84ab569c64d6182a18893dcd163f0f1c2090733d":"0000000000000000000000000000000000000000000000000000000000000000","89832631fb3c3307a103ba2c84ab569c64d6182a18893dcd163f0f1c2090733e":"00000000000000000000000081d390a4e469b45642341d6ad111062c24984b37","89832631fb3c3307a103ba2c84ab569c64d6182a18893dcd163f0f1c2090733f":"0000000000000000000000000000000000000000000000000000000000000001","89832631fb3c3307a103ba2c84ab569c64d6182a18893dcd163f0f1c20907340":"0000000000000000000000000000000000000000000000000000000000000001"}}]}}]}
```
## debug\_traceBlock
The `traceBlock` method will return a full stack trace of all invoked opcodes of all transactions that were included in this block.
**NOTE**: the parent of this block must be present or it will fail.
| Client | Method Invocation |
| :-----: | ---------------------------------------------------------- |
| Console | `debug.traceBlock(blockRlp, [options])` |
| RPC | `{"method": "debug_traceBlock", "params": [blockRlp, {}]}` |
References: [RLP](https://github.com/ethereum/wiki/wiki/RLP)
**Parameters**
| Name | Type | Description |
| -------- | ------ | ---------------------------------------- |
| blockRlp | string | The RLP-encoded block. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ----------- | --------------------------------------------------------- |
| JSON string | The structured logs created during the execution of KLVM. |
**Example**
Console
```javascript
> debug.traceBlock("0xblock_rlp")
[{
result: {
failed: false,
gas: 247922,
returnValue: "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",
structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
}
}]
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceBlock","params":["0xblock_rlp"],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":[{"result":{"gas":247922,"failed":false,"returnValue":"60806040526004361061004c576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff16806341c0e1b514610051578063cfae321714610068575b600080fd5b34801561005d57600080fd5b506100666100f8565b005b34801561007457600080fd5b5061007d610168565b6040518080602001828103825283818151815260200191508051906020019080838360005b838110156100bd5780820151818401526020810190506100a2565b50505050905090810190601f1680156100ea5780820380516001836020036101000a031916815260200191505b509250505060405180910390f35b6000809054906101000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffffffffffffffffff161415610166573373ffffffffffffffffffffffffffffffffffffffff16ff5b565b606060018054600181600116156101000203166002900480601f0160208091040260200160405190810160405280929190818152602001828054600181600116156101000203166002900480156102005780601f106101d557610100808354040283529160200191610200565b820191906000526020600020905b8154815290600101906020018083116101e357829003601f168201915b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6c4e54ad49014e2faa152e49e7f9d927c932c72870029","structLogs":[{"pc":0,"op":"PUSH1","gas":891344,"gasCost":3,"depth":1,"stack":[],"memory":[],"storage":{}},{"pc":2,"op":"PUSH1","gas":891341,"gasCost":3,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080"],"memory":[],"storage":{}},{"pc":4,"op":"MSTORE","gas":891338,"gasCost":12,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080","0000000000000000000000000000000000000000000000000000000000000040"],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000"],"storage":{}},{"pc":5,"op":"CALLVALUE","gas":891326,"gasCost":2,"depth":1,"stack":[],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000080"],"storage":{}},
...
,{"pc":322,"op":"RETURN","gas":865278,"gasCost":0,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000236","0000000000000000000000000000000000000000000000000000000000000000"],"memory":["60806040526004361061004c576000357c010000000000000000000000000000","0000000000000000000000000000900463ffffffff16806341c0e1b514610051","578063cfae321714610068575b600080fd5b34801561005d57600080fd5b5061","00666100f8565b005b34801561007457600080fd5b5061007d610168565b6040","5180806020018281038252838181518152602001915080519060200190808383","60005b838110156100bd5780820151818401526020810190506100a2565b5050","5050905090810190601f1680156100ea5780820380516001836020036101000a","031916815260200191505b509250505060405180910390f35b60008090549061","01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffff","ffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffff","ffffffffffffff161415610166573373ffffffffffffffffffffffffffffffff","ffffffff16ff5b565b6060600180546001816001161561010002031660029004","80601f0160208091040260200160405190810160405280929190818152602001","828054600181600116156101000203166002900480156102005780601f106101","d557610100808354040283529160200191610200565b82019190600052602060","0020905b8154815290600101906020018083116101e357829003601f16820191","5b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6","c4e54ad49014e2faa152e49e7f9d927c932c7287002900000000000000000000"],"storage":{"0000000000000000000000000000000000000000000000000000000000000000":"000000000000000000000000b0945862f63b832849a5f20b19e9f8188eb2230a","0000000000000000000000000000000000000000000000000000000000000001":"0000000000000000000000000000000000000000000000000000000000000000"}}]}}]}
```
## debug\_traceBlockByHash
Similar to [debug\_traceBlock](#debug_traceblock), `traceBlockByHash` accepts a block hash and will replay the block that is already present in the database.
| Client | Method Invocation |
| :-----: | ------------------------------------------------------------ |
| Console | `debug.traceBlockByHash(hash, [options])` |
| RPC | `{"method": "debug_traceBlockByHash", "params": [hash, {}]}` |
**Parameters**
| Name | Type | Description |
| ------- | ------------ | ---------------------------------------- |
| hash | 32-byte DATA | Hash of a block. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ----------- | --------------------------------------------------------- |
| JSON string | The structured logs created during the execution of KLVM. |
**Example**
Console
```javascript
> debug.traceBlockByHash("0x244acf3f11f0999b93616cb156dc1b43ee87e27c9625a7170cf6de447189d890")
[{
result: {
failed: false,
gas: 247922,
returnValue: "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",
structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
}
}]
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceBlockByHash","params":["0x244acf3f11f0999b93616cb156dc1b43ee87e27c9625a7170cf6de447189d890", {}],"id":1}' https://public-en-baobab.klaytn.net {"jsonrpc":"2.0","id":1,"result":[{"result":{"gas":247922,"failed":false,"returnValue":"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","structLogs":[{"pc":0,"op":"PUSH1","gas":891344,"gasCost":3,"depth":1,"stack":[],"memory":[],"storage":{}},{"pc":2,"op":"PUSH1","gas":891341,"gasCost":3,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080"],"memory":[],"storage":{}},{"pc":4,"op":"MSTORE","gas":891338,"gasCost":12,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080","0000000000000000000000000000000000000000000000000000000000000040"],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000"],"storage":{}},{"pc":5,"op":"CALLVALUE","gas":891326,"gasCost":2,"depth":1,"stack":[],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000080"],"storage":{}},
...
,{"pc":322,"op":"RETURN","gas":865278,"gasCost":0,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000236","0000000000000000000000000000000000000000000000000000000000000000"],"memory":["60806040526004361061004c576000357c010000000000000000000000000000","0000000000000000000000000000900463ffffffff16806341c0e1b514610051","578063cfae321714610068575b600080fd5b34801561005d57600080fd5b5061","00666100f8565b005b34801561007457600080fd5b5061007d610168565b6040","5180806020018281038252838181518152602001915080519060200190808383","60005b838110156100bd5780820151818401526020810190506100a2565b5050","5050905090810190601f1680156100ea5780820380516001836020036101000a","031916815260200191505b509250505060405180910390f35b60008090549061","01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffff","ffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffff","ffffffffffffff161415610166573373ffffffffffffffffffffffffffffffff","ffffffff16ff5b565b6060600180546001816001161561010002031660029004","80601f0160208091040260200160405190810160405280929190818152602001","828054600181600116156101000203166002900480156102005780601f106101","d557610100808354040283529160200191610200565b82019190600052602060","0020905b8154815290600101906020018083116101e357829003601f16820191","5b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6","c4e54ad49014e2faa152e49e7f9d927c932c7287002900000000000000000000"],"storage":{"0000000000000000000000000000000000000000000000000000000000000000":"000000000000000000000000b0945862f63b832849a5f20b19e9f8188eb2230a","0000000000000000000000000000000000000000000000000000000000000001":"0000000000000000000000000000000000000000000000000000000000000000"}}]}}]}
```
## debug\_traceBlockByNumber
Similar to [debug\_traceBlock](#debug_traceblock), `traceBlockByNumber` accepts a block number and will replay the block that is already present in the database.
| Client | Method Invocation |
| :-----: | ---------------------------------------------------------------- |
| Console | `debug.traceBlockByNumber(number, [options])` |
| RPC | `{"method": "debug_traceBlockByNumber", "params": [number, {}]}` |
**Parameters**
| Name | Type | Description |
| ------- | ------ | ---------------------------------------- |
| number | int | The block number. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ----------- | --------------------------------------------------------- |
| JSON string | The structured logs created during the execution of KLVM. |
**Example**
Console
```javascript
> debug.traceBlockByNumber(1449)
[{
result: {
failed: false,
gas: 247922,
returnValue: "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",
structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
}
}]
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceBlockByNumber","params":["0x5a9", {}],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":[{"result":{"gas":247922,"failed":false,"returnValue":"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","structLogs":[{"pc":0,"op":"PUSH1","gas":891344,"gasCost":3,"depth":1,"stack":[],"memory":[],"storage":{}},{"pc":2,"op":"PUSH1","gas":891341,"gasCost":3,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080"],"memory":[],"storage":{}},{"pc":4,"op":"MSTORE","gas":891338,"gasCost":12,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080","0000000000000000000000000000000000000000000000000000000000000040"],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000"],"storage":{}},{"pc":5,"op":"CALLVALUE","gas":891326,"gasCost":2,"depth":1,"stack":[],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000080"],"storage":{}},
...
,{"pc":322,"op":"RETURN","gas":865278,"gasCost":0,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000236","0000000000000000000000000000000000000000000000000000000000000000"],"memory":["60806040526004361061004c576000357c010000000000000000000000000000","0000000000000000000000000000900463ffffffff16806341c0e1b514610051","578063cfae321714610068575b600080fd5b34801561005d57600080fd5b5061","00666100f8565b005b34801561007457600080fd5b5061007d610168565b6040","5180806020018281038252838181518152602001915080519060200190808383","60005b838110156100bd5780820151818401526020810190506100a2565b5050","5050905090810190601f1680156100ea5780820380516001836020036101000a","031916815260200191505b509250505060405180910390f35b60008090549061","01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffff","ffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffff","ffffffffffffff161415610166573373ffffffffffffffffffffffffffffffff","ffffffff16ff5b565b6060600180546001816001161561010002031660029004","80601f0160208091040260200160405190810160405280929190818152602001","828054600181600116156101000203166002900480156102005780601f106101","d557610100808354040283529160200191610200565b82019190600052602060","0020905b8154815290600101906020018083116101e357829003601f16820191","5b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6","c4e54ad49014e2faa152e49e7f9d927c932c7287002900000000000000000000"],"storage":{"0000000000000000000000000000000000000000000000000000000000000000":"000000000000000000000000b0945862f63b832849a5f20b19e9f8188eb2230a","0000000000000000000000000000000000000000000000000000000000000001":"0000000000000000000000000000000000000000000000000000000000000000"}}]}}]}
```
## debug\_traceBlockByNumberRange
Returns the structured logs created during the execution of EVM between two blocks (including start) as a JSON object. That is, the result of tracing for a total of end-start+1 blocks is returned.
| Client | Method Invocation |
| :-----: | ----------------------------------------------------------------------------- |
| Console | `debug.traceBlockByNumberRange(number, number, [options])` |
| RPC | `{"method": "debug_traceBlockByNumberRange", "params": [number, number, {}]}` |
**NOTE**: Don't trace too many blocks at the same time as it can overuse machine resources.
**Parameters**
| Name | Type | Description |
| ------- | ------ | ---------------------------------------- |
| number | int | Tracing start block number. |
| number | int | Tracing end block number. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ------------------------------------------ | ------------------------------------------------------------------------ |
| map(key: block number. value: JSON string) | Value contains the structured logs created during the execution of KLVM. |
**Example**
Console
```javascript
> debug.traceBlockByNumberRange(21, 30, {})
{
21: {
block: "0x15",
hash: "0x24b0a90822e63295623e6d8f5a8e5d47cead5c8d5854e44db00dc42d28e0850e",
traces: [{
result: {...},
txHash: "0x43ed7e441db8e90f377d74b5d61c6d7d8b85ffd277b965c9f275ce7e93fb1090"
}, {
result: {...},
txHash: "0x1a448049b21d39cd4320ab95f18b8e91d687bfc7136268f50e041e439181fa0d"
}]
},
22: {
...
},
...
}
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceBlockByNumberRange","params":[21, 30, {}],"id":1}' http://localhost:8551
{"jsonrpc":"2.0","id":1,"result":{"21":{"block":"0x15","hash":"0x24b0a90822e63295623e6d8f5a8e5d47cead5c8d5854e44db00dc42d28e0850e","traces":[{"txHash":"0x43ed7e441db8e90f377d74b5d61c6d7d8b85ffd277b965c9f275ce7e93fb1090","result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}},{"txHash":"0x1a448049b21d39cd4320ab95f18b8e91d687bfc7136268f50e041e439181fa0d","result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}}]},
...
"result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}}]}}}
```
## debug\_traceBlockFromFile
Similar to [debug\_traceBlock](#debug_traceblock), `traceBlockFromFile` accepts a file containing the RLP of the block.
**NOTE**: the file must include the associated hexadecimal string without `0x`.
| Client | Method Invocation |
| :-----: | ------------------------------------------------------------------ |
| Console | `debug.traceBlockFromFile(fileName, [options])` |
| RPC | `{"method": "debug_traceBlockFromFile", "params": [fileName, {}]}` |
References: [RLP](https://github.com/ethereum/wiki/wiki/RLP)
**Parameters**
| Name | Type | Description |
| -------- | ------ | -------------------------------------------------- |
| fileName | string | The file name which contains the RLP of the block. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ----------- | --------------------------------------------------------- |
| JSON string | The structured logs created during the execution of KLVM. |
**Example**
The contents of the `block.rlp` file was printed on the running node as follows.
```
$ cat block.rlp
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
```
Console
```javascript
> debug.traceBlockFromFile("block.rlp")
[{
result: {
failed: false,
gas: 247922,
returnValue: "60806040526004361061004c576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff16806341c0e1b514610051578063cfae321714610068575b600080fd5b34801561005d57600080fd5b506100666100f8565b005b34801561007457600080fd5b5061007d610168565b6040518080602001828103825283818151815260200191508051906020019080838360005b838110156100bd5780820151818401526020810190506100a2565b50505050905090810190601f1680156100ea5780820380516001836020036101000a031916815260200191505b509250505060405180910390f35b6000809054906101000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffffffffffffffffff161415610166573373ffffffffffffffffffffffffffffffffffffffff16ff5b565b606060018054600181600116156101000203166002900480601f0160208091040260200160405190810160405280929190818152602001828054600181600116156101000203166002900480156102005780601f106101d557610100808354040283529160200191610200565b820191906000526020600020905b8154815290600101906020018083116101e357829003601f168201915b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6c4e54ad49014e2faa152e49e7f9d927c932c72870029",
structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
}
}]
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceBlockFromFile","params":["block.rlp", {}],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":[{"result":{"gas":247922,"failed":false,"returnValue":"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","structLogs":[{"pc":0,"op":"PUSH1","gas":891344,"gasCost":3,"depth":1,"stack":[],"memory":[],"storage":{}},{"pc":2,"op":"PUSH1","gas":891341,"gasCost":3,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080"],"memory":[],"storage":{}},{"pc":4,"op":"MSTORE","gas":891338,"gasCost":12,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080","0000000000000000000000000000000000000000000000000000000000000040"],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000"],"storage":{}},{"pc":5,"op":"CALLVALUE","gas":891326,"gasCost":2,"depth":1,"stack":[],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000080"],"storage":{}},
...
,{"pc":322,"op":"RETURN","gas":865278,"gasCost":0,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000236","0000000000000000000000000000000000000000000000000000000000000000"],"memory":["60806040526004361061004c576000357c010000000000000000000000000000","0000000000000000000000000000900463ffffffff16806341c0e1b514610051","578063cfae321714610068575b600080fd5b34801561005d57600080fd5b5061","00666100f8565b005b34801561007457600080fd5b5061007d610168565b6040","5180806020018281038252838181518152602001915080519060200190808383","60005b838110156100bd5780820151818401526020810190506100a2565b5050","5050905090810190601f1680156100ea5780820380516001836020036101000a","031916815260200191505b509250505060405180910390f35b60008090549061","01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffff","ffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffff","ffffffffffffff161415610166573373ffffffffffffffffffffffffffffffff","ffffffff16ff5b565b6060600180546001816001161561010002031660029004","80601f0160208091040260200160405190810160405280929190818152602001","828054600181600116156101000203166002900480156102005780601f106101","d557610100808354040283529160200191610200565b82019190600052602060","0020905b8154815290600101906020018083116101e357829003601f16820191","5b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6","c4e54ad49014e2faa152e49e7f9d927c932c7287002900000000000000000000"],"storage":{"0000000000000000000000000000000000000000000000000000000000000000":"000000000000000000000000b0945862f63b832849a5f20b19e9f8188eb2230a","0000000000000000000000000000000000000000000000000000000000000001":"0000000000000000000000000000000000000000000000000000000000000000"}}]}}]}
```
## 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.
| Client | Method Invocation |
| :-----: | -------------------------------------------------------------- |
| Console | `debug.traceTransaction(txHash, [options])` |
| RPC | `{"method": "debug_traceTransaction", "params": [txHash, {}]}` |
**Parameters**
| Name | Type | Description |
| ------- | ------ | ---------------------------------------- |
| txHash | string | The hash of the transaction. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ----------- | --------------------------------------------------------- |
| JSON string | The structured logs created during the execution of KLVM. |
**Example**
Console
```javascript
> debug.traceTransaction("0x07f6057bc93aca52e53cdbfac9b9830f6a9cae2b3f48f0b47e4cb54959143d09")
{
failed: false,
gas: 247922,
returnValue: "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",
structLogs: [{
depth: 1,
gas: 891344,
gasCost: 3,
memory: [],
op: "PUSH1",
pc: 0,
stack: [],
storage: {}
}, {
depth: 1,
gas: 891341,
gasCost: 3,
memory: [],
op: "PUSH1",
pc: 2,
stack: ["0000000000000000000000000000000000000000000000000000000000000080"],
storage: {}
}, {
depth: 1,
gas: 891338,
gasCost: 12,
memory: ["0000000000000000000000000000000000000000000000000000000000000000", "0000000000000000000000000000000000000000000000000000000000000000", "0000000000000000000000000000000000000000000000000000000000000000"],
op: "MSTORE",
pc: 4,
stack: ["0000000000000000000000000000000000000000000000000000000000000080", "0000000000000000000000000000000000000000000000000000000000000040"],
storage: {}
}, {
depth: 1,
gas: 891326,
gasCost: 2,
memory: ["0000000000000000000000000000000000000000000000000000000000000000", "0000000000000000000000000000000000000000000000000000000000000000", "0000000000000000000000000000000000000000000000000000000000000080"],
op: "CALLVALUE",
pc: 5,
stack: [],
storage: {}
}, {
...
}, {
depth: 1,
gas: 865281,
gasCost: 3,
memory: ["60806040526004361061004c576000357c010000000000000000000000000000", "0000000000000000000000000000900463ffffffff16806341c0e1b514610051", "578063cfae321714610068575b600080fd5b34801561005d57600080fd5b5061", "00666100f8565b005b34801561007457600080fd5b5061007d610168565b6040", "5180806020018281038252838181518152602001915080519060200190808383", "60005b838110156100bd5780820151818401526020810190506100a2565b5050", "5050905090810190601f1680156100ea5780820380516001836020036101000a", "031916815260200191505b509250505060405180910390f35b60008090549061", "01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffff", "ffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffff", "ffffffffffffff161415610166573373ffffffffffffffffffffffffffffffff", "ffffffff16ff5b565b6060600180546001816001161561010002031660029004", "80601f0160208091040260200160405190810160405280929190818152602001", "828054600181600116156101000203166002900480156102005780601f106101", "d557610100808354040283529160200191610200565b82019190600052602060", "0020905b8154815290600101906020018083116101e357829003601f16820191", "5b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6", "c4e54ad49014e2faa152e49e7f9d927c932c7287002900000000000000000000"],
op: "PUSH1",
pc: 320,
stack: ["0000000000000000000000000000000000000000000000000000000000000236"],
storage: {
0000000000000000000000000000000000000000000000000000000000000000: "000000000000000000000000b0945862f63b832849a5f20b19e9f8188eb2230a",
0000000000000000000000000000000000000000000000000000000000000001: "0000000000000000000000000000000000000000000000000000000000000000"
}
}, {
depth: 1,
gas: 865278,
gasCost: 0,
memory: ["60806040526004361061004c576000357c010000000000000000000000000000", "0000000000000000000000000000900463ffffffff16806341c0e1b514610051", "578063cfae321714610068575b600080fd5b34801561005d57600080fd5b5061", "00666100f8565b005b34801561007457600080fd5b5061007d610168565b6040", "5180806020018281038252838181518152602001915080519060200190808383", "60005b838110156100bd5780820151818401526020810190506100a2565b5050", "5050905090810190601f1680156100ea5780820380516001836020036101000a", "031916815260200191505b509250505060405180910390f35b60008090549061", "01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffff", "ffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffff", "ffffffffffffff161415610166573373ffffffffffffffffffffffffffffffff", "ffffffff16ff5b565b6060600180546001816001161561010002031660029004", "80601f0160208091040260200160405190810160405280929190818152602001", "828054600181600116156101000203166002900480156102005780601f106101", "d557610100808354040283529160200191610200565b82019190600052602060", "0020905b8154815290600101906020018083116101e357829003601f16820191", "5b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6", "c4e54ad49014e2faa152e49e7f9d927c932c7287002900000000000000000000"],
op: "RETURN",
pc: 322,
stack: ["0000000000000000000000000000000000000000000000000000000000000236", "0000000000000000000000000000000000000000000000000000000000000000"],
storage: {
0000000000000000000000000000000000000000000000000000000000000000: "000000000000000000000000b0945862f63b832849a5f20b19e9f8188eb2230a",
0000000000000000000000000000000000000000000000000000000000000001: "0000000000000000000000000000000000000000000000000000000000000000"
}
}]
}
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceTransaction","params":["0x07f6057bc93aca52e53cdbfac9b9830f6a9cae2b3f48f0b47e4cb54959143d09"],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":{"gas":247922,"failed":false,"returnValue":"60806040526004361061004c576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff16806341c0e1b514610051578063cfae321714610068575b600080fd5b34801561005d57600080fd5b506100666100f8565b005b34801561007457600080fd5b5061007d610168565b6040518080602001828103825283818151815260200191508051906020019080838360005b838110156100bd5780820151818401526020810190506100a2565b50505050905090810190601f1680156100ea5780820380516001836020036101000a031916815260200191505b509250505060405180910390f35b6000809054906101000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffffffffffffffffff161415610166573373ffffffffffffffffffffffffffffffffffffffff16ff5b565b606060018054600181600116156101000203166002900480601f0160208091040260200160405190810160405280929190818152602001828054600181600116156101000203166002900480156102005780601f106101d557610100808354040283529160200191610200565b820191906000526020600020905b8154815290600101906020018083116101e357829003601f168201915b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6c4e54ad49014e2faa152e49e7f9d927c932c72870029","structLogs":[{"pc":0,"op":"PUSH1","gas":891344,"gasCost":3,"depth":1,"stack":[],"memory":[],"storage":{}},{"pc":2,"op":"PUSH1","gas":891341,"gasCost":3,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080"],"memory":[],"storage":{}},{"pc":4,"op":"MSTORE","gas":891338,"gasCost":12,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000080","0000000000000000000000000000000000000000000000000000000000000040"],"memory":["0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000","0000000000000000000000000000000000000000000000000000000000000000"],"storage":{}},
...
,{"pc":322,"op":"RETURN","gas":865278,"gasCost":0,"depth":1,"stack":["0000000000000000000000000000000000000000000000000000000000000236","0000000000000000000000000000000000000000000000000000000000000000"],"memory":["60806040526004361061004c576000357c010000000000000000000000000000","0000000000000000000000000000900463ffffffff16806341c0e1b514610051","578063cfae321714610068575b600080fd5b34801561005d57600080fd5b5061","00666100f8565b005b34801561007457600080fd5b5061007d610168565b6040","5180806020018281038252838181518152602001915080519060200190808383","60005b838110156100bd5780820151818401526020810190506100a2565b5050","5050905090810190601f1680156100ea5780820380516001836020036101000a","031916815260200191505b509250505060405180910390f35b60008090549061","01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffff","ffffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffff","ffffffffffffff161415610166573373ffffffffffffffffffffffffffffffff","ffffffff16ff5b565b6060600180546001816001161561010002031660029004","80601f0160208091040260200160405190810160405280929190818152602001","828054600181600116156101000203166002900480156102005780601f106101","d557610100808354040283529160200191610200565b82019190600052602060","0020905b8154815290600101906020018083116101e357829003601f16820191","5b50505050509050905600a165627a7a72305820f4e74ca2266a24aabd6a8ee6","c4e54ad49014e2faa152e49e7f9d927c932c7287002900000000000000000000"],"storage":{"0000000000000000000000000000000000000000000000000000000000000000":"000000000000000000000000b0945862f63b832849a5f20b19e9f8188eb2230a","0000000000000000000000000000000000000000000000000000000000000001":"0000000000000000000000000000000000000000000000000000000000000000"}}]}}
```
## debug\_traceCall
The `traceCall` returns the tracing result by executing a klay call within the context of the given block execution.
**Parameters**
| Name | Type | Description |
| ----------------- | ----------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| callObject | Object | The transaction call object. See the next table for the object's properties. |
| blockNumberOrHash | QUANTITY \| TAG \| HASH | Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](https://github.com/klaytn/klaytn-docs/blob/main/docs/dapp/json-rpc/api-references/debug/block.md#the-default-block-parameter), or block hash. |
| options | object | See [tracing options](#tracing-options). |
**Return Value**
| Type | Description |
| ----------- | --------------------------------------------------------- |
| JSON string | The structured logs created during the execution of KLVM. |
**Example** Console
```javascript
> debug.traceCall({from: "0xB2da01761B494F5F257fD3bA626fBAbFaE104313", to: "0xB2da01761B494F5F257fD3bA626fBAbFaE104313", input: "0x6057361d0000000000000000000000000000000000000000000000000000000000000003"}, "latest", {tracer:"revertTracer"})
"this is the revert reason for this tracecall"
```
HTTP RPC
```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceCall","params":[{"from": "0xB2da01761B494F5F257fD3bA626fBAbFaE104313", "to": "0xB2da01761B494F5F257fD3bA626fBAbFaE104313", "input": "0x6057361d0000000000000000000000000000000000000000000000000000000000000003"}, "latest", {"tracer":"revertTracer"}],"id":1}' http://localhost:8551
"this is the revert reason for this tracecall"
```
## debug\_traceChain
Returns the structured logs created during the execution of EVM between two blocks (excluding start) as a JSON object. This endpoint must be invoked via debug\_subscribe as follows:
**NOTE**: Don't trace too many blocks at the same time as it can overuse machine resources.
**Parameters**
| Name | Type | Description |
| ------- | ------ | ---------------------------------------- |
| number | int | Tracing start block number. |
| number | int | Tracing end block number. |
| options | object | See [tracing options](#tracing-options). |
**Example**
```
wscat -c ws://localhost:8552
> {"id": 1, "method": "debug_subscribe", "params": ["traceChain", 21, 30, {}]}
< {"jsonrpc":"2.0","id":1,"result":"0xcef1ebe5819ce55a11e97c28cee5d36b"}
< {"jsonrpc":"2.0","method":"debug_subscription","params":{"subscription":"0xcef1ebe5819ce55a11e97c28cee5d36b","result":{"block":"0x16","hash":"0xb620aa234c0a9279d3eb467d5be96d93a31edc580385cae632c6f7c231c3ac72","traces":[{"txHash":"0xeb6b4ddb206952f8600dd64d04618d518b51bfe722226d6717ce5c96aa243070","result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}},{"txHash":"0xf389f44a0e61b6497517c2b4569343adeab59e2b099d6a43ae1c6c10a71823b2","result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}}]}}}
< {"jsonrpc":"2.0","method":"debug_subscription","params":{"subscription":"0xcef1ebe5819ce55a11e97c28cee5d36b","result":{"block":"0x17","hash":"0x634c41b5687fe733dacb9d4a4062fd29f744132771f8529838c1956d18efadd4","traces":[{"txHash":"0xa0bdd0e9c69f45295e7cb8fe2e6fb6c35f0d99b69d31d496fd57e40e4da6f85e","result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}},{"txHash":"0x5762193b76c0c61cbe272e3bc54d0d7e123677efb12cc62e2e08a4743992f1ff","result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}}]}}}
...
>
```
## Tracing Options
You may give trace API function a secondary optional argument, which specifies the options for this specific call. The possible options are:
* `disableStorage`: `BOOL`. Setting this to true will disable storage capture (default = false).
* `disableMemory`: `BOOL`. Setting this to true will disable memory capture (default = false).
* `disableStack`: `BOOL`. Setting this to true will disable stack capture (default = false).
* `timeout`: `STRING`. Overrides the default timeout of 5 seconds for JavaScript-based tracing calls. Valid values are described [here](https://golang.org/pkg/time/#ParseDuration).
* `tracer`: `STRING`. Setting this will enable JavaScript-based transaction tracing, described in the [next section](#javascript-based-tracing). If set, the previous four arguments will be ignored. The predefined tracers can also be used as the following table.
| Tracer Name | Description |
| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 4byteTracer | 4byteTracer searches for 4byte-identifiers, and collects them for post-processing. It collects the methods identifiers along with the size of the supplied data, so a reversed signature can be matched against the size of the data. |
| callTracer | callTracer is a full-blown transaction tracer that extracts and reports all the internal calls made by a transaction, along with any useful information. |
| fastCallTracer | fastCallTracer is a Go-native version of callTracer. Since it is not executed on JavaScript VM, it shows more than 10x speedup compared to callTracer. Please use fastCallTracer instead of callTracer if the performance is the matter of the first importance. |
| evmdisTracer | evmdisTracer returns sufficient information from a trace to perform evmdis-style disassembly. |
| noopTracer | noopTracer is just the barebone boilerplate code required from a JavaScript object to be usable as a transaction tracer. |
| opcountTracer | opcountTracer is a sample tracer that just counts the number of instructions executed by the KLVM before the transaction terminated. |
| prestateTracer | prestateTracer outputs sufficient information to create a local execution of the transaction from a custom assembled genesis block. |
| revertTracer | revertTracer outputs the error string of REVERT. If the execution is not reverted, it outputs an empty string. |
| unigramTracer | unigramTracer returns the number of occurrences of each opcode. |
| bigramTracer | bigramTracer returns the number of occurrences of two consecutive opcodes. |
| trigramTracer | trigramTracer returns the number of occurrences of three consecutive opcodes. |
**Example**
Console
```javascript
> debug.traceTransaction("0x07f6057bc93aca52e53cdbfac9b9830f6a9cae2b3f48f0b47e4cb54959143d09", {tracer: "callTracer"})
{
from: "0xb0945862f63b832849a5f20b19e9f8188eb2230a",
gas: "0xd99d0",
gasUsed: "0x22002",
input: "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",
output: "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",
time: "2.507969ms",
to: "0x98cf8b777dab0137b47a7fdaad1378ec93a7b80b",
type: "CREATE",
value: "0x0"
}
> debug.traceTransaction("0xbae8bd56daa6a3f1bba16854d14e37f265e76976c960ac57c4c7b56a78729e53", {tracer:'revertTracer'})
"reverted due to XXX"
```
HTTP RPC
```shell
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceTransaction","params":["0x07f6057bc93aca52e53cdbfac9b9830f6a9cae2b3f48f0b47e4cb54959143d09", {"tracer": "callTracer"}],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":{"type":"CREATE","from":"0xb0945862f63b832849a5f20b19e9f8188eb2230a","to":"0x98cf8b777dab0137b47a7fdaad1378ec93a7b80b","value":"0x0","gas":"0xd99d0","gasUsed":"0x22002","input":"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","output":"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","time":"2.510754ms"}}
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_traceTransaction","params":["0xbae8bd56daa6a3f1bba16854d14e37f265e76976c960ac57c4c7b56a78729e53", {"tracer": "revertTracer"}],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":"reverted due to XXX"}
```
## JavaScript-based Tracing
**NOTE** The JavaScript-based Tracing allows the user to run arbitrary JS code, which is **unsafe**. If you want to provide debug namespace APIs to the public, we strongly recommend to set the `rpc.unsafe-debug.disable` flag when running the EN, so the JavaScript-based Tracing can be disabled.
Specifying the `tracer` option in the second argument enables JavaScript-based tracing. In this mode, `tracer` is interpreted as a JavaScript expression that is expected to evaluate to an object with (at least) two methods, named `step` and `result`.
`step` is a function that takes two arguments, `log` and `db`, and is called for each step of the KLVM, or when an error occurs, as the specified transaction is traced.
`log` has the following fields:
| Field Name | Type | Description |
| ---------- | --------------- | ----------------------------------------------------------- |
| `pc` | Number | The current program counter. |
| `op` | Object | An OpCode object representing the current opcode. |
| `gas` | Number | The amount of gas remaining. |
| `gasPrice` | Number | The cost in peb of each unit of gas. |
| `memory` | Object | A structure representing the contract's memory space. |
| `stack` | array\[big.Int] | The KLVM execution stack. |
| `depth` | Number | The execution depth. |
| `account` | String | The address of the account executing the current operation. |
| `err` | String | If an error occurred, information about the error. |
If `err` is non-null, all other fields should be ignored.
For efficiency, the same `log` object is reused on each execution step, updated with current values; make sure to copy values you want to preserve beyond the current call. For instance, this step function will not work:
```javascript
function(log) {
this.logs.append(log);
}
```
But this step function will:
```javascript
function(log) {
this.logs.append({gas: log.gas, pc: log.pc, ...});
}
```
`log.op` has the following methods:
| Method Name | Description |
| ------------ | ------------------------------------------------ |
| `isPush()` | Returns true if the opcode is a `PUSHn`. |
| `toString()` | Returns the string representation of the opcode. |
| `toNumber()` | Returns the opcode's number. |
`log.memory` has the following methods:
| Method Name | Description |
| -------------------- | -------------------------------------------------------- |
| `slice(start, stop)` | Returns the specified segment of memory as a byte slice. |
| `length()` | Returns the length of the memory. |
`log.stack` has the following methods:
| Method Name | Description |
| ----------- | ----------------------------------------------------------------------------------------------- |
| `peek(idx)` | Returns the idx-th element from the top of the stack (0 is the topmost element) as a `big.Int`. |
| `length()` | Returns the number of elements in the stack. |
`db` has the following methods:
| Method Name | Description |
| ------------------------- | ------------------------------------------------------------------------- |
| `getBalance(address)` | Returns a `big.Int` with the specified account's balance. |
| `getNonce(address)` | Returns a Number with the specified account's nonce. |
| `getCode(address)` | Returns a byte slice with the code for the specified account. |
| `getState(address, hash)` | Returns the state value for the specified account and the specified hash. |
| `exists(address)` | Returns true if the specified address exists. |
The second function, `result`, takes no arguments, and is expected to return a JSON-serializable value to return to the RPC caller.
If the `step` function throws an exception or executes an illegal operation at any point, it will not be called on any further VM steps, and the error will be returned to the caller.
Note that several values are Golang `big.Int` objects, not JavaScript numbers or JS bigints. As such, they have the same interface as described in the godocs. Their default serialization to JSON is as a Javascript number; to serialize large numbers accurately call `.String()` on them. For convenience, `big.NewInt(x)` is provided, and will convert a uint to a Golang `big.Int`.
As an usage example below, it returns the top element of the stack at each CALL opcode only:
```javascript
debug.traceTransaction(txhash, {tracer: '{data: [], step: function(log) { if(log.op.toString() == "CALL") this.data.push(log.stack.peek(0)); }, result: function() { return this.data; }}'});
```
---
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Perform an HTTP GET request on the current page URL with the `ask` query parameter:
```
GET https://archive-docs.klaytn.foundation/content/dapp/json-rpc/api-references/debug/tracing.md?ask=
```
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The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
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