Getting StartedBuild a dAppNode OperationDeveloper Hub

VM Tracing

NOTE The 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 and only allow pre-defined tracers.

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.

Return Value

Type
Description

JSON string

The structured logs created during the execution of KLVM.

Example

Console

> debug.traceBadBlock("0x1d5ba00e313a81ae6d409d459c153327072665d9ea2f47608369722baf0cfbb6")
[{
    result: {
      failed: false,
      gas: 67100,
      returnValue: "",
      structLogs: []
    }
}, {
    result: {
      failed: false,
      gas: 195179,
      returnValue: "",
      structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
    }
}]

HTTP RPC

$ 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

Parameters

Name
Type
Description

blockRlp

string

The RLP-encoded block.

options

object

See tracing options.

Return Value

Type
Description

JSON string

The structured logs created during the execution of KLVM.

Example

Console

> debug.traceBlock("0xblock_rlp")
[{
    result: {
      failed: false,
      gas: 247922,
      returnValue: "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",
      structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
    }
}]

HTTP RPC

$ 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":"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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_traceBlockByHash

Similar to 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.

Return Value

Type
Description

JSON string

The structured logs created during the execution of KLVM.

Example

Console

> debug.traceBlockByHash("0x244acf3f11f0999b93616cb156dc1b43ee87e27c9625a7170cf6de447189d890")
[{
    result: {
      failed: false,
      gas: 247922,
      returnValue: "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",
      structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
    }
}]

HTTP RPC

$ 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, 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.

Return Value

Type
Description

JSON string

The structured logs created during the execution of KLVM.

Example

Console

> debug.traceBlockByNumber(1449)
[{
    result: {
      failed: false,
      gas: 247922,
      returnValue: "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",
      structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
    }
}]

HTTP RPC

$ 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.

Return Value

Type
Description

map(key: block number. value: JSON string)

Value contains the structured logs created during the execution of KLVM.

Example

Console

> debug.traceBlockByNumberRange(21, 30, {})
{
    21: {
        block: "0x15",
            hash: "0x24b0a90822e63295623e6d8f5a8e5d47cead5c8d5854e44db00dc42d28e0850e",
            traces: [{
                result: {...},
                txHash: "0x43ed7e441db8e90f377d74b5d61c6d7d8b85ffd277b965c9f275ce7e93fb1090"
            }, {
                result: {...},
                txHash: "0x1a448049b21d39cd4320ab95f18b8e91d687bfc7136268f50e041e439181fa0d"
            }]
        },
    22: {
        ...
        },
    ...
}

HTTP RPC

$ 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, 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

Parameters

Name
Type
Description

fileName

string

The file name which contains the RLP of the block.

options

object

See 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

> debug.traceBlockFromFile("block.rlp")
[{
    result: {
      failed: false,
      gas: 247922,
      returnValue: "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",
      structLogs: [{...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}, {...}]
    }
}]

HTTP RPC

$ 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.

Return Value

Type
Description

JSON string

The structured logs created during the execution of KLVM.

Example

Console

> 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

$ 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":"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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":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, or block hash.

options

object

See tracing options.

Return Value

Type
Description

JSON string

The structured logs created during the execution of KLVM.

Example Console

> debug.traceCall({from: "0xB2da01761B494F5F257fD3bA626fBAbFaE104313", to: "0xB2da01761B494F5F257fD3bA626fBAbFaE104313", input: "0x6057361d0000000000000000000000000000000000000000000000000000000000000003"}, "latest", {tracer:"revertTracer"})
"this is the revert reason for this tracecall"

HTTP RPC

$ 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.

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.

  • tracer: STRING. Setting this will enable JavaScript-based transaction tracing, described in the next section. 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

> 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

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:

function(log) {
  this.logs.append(log);
}

But this step function will:

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:

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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