Official Go implementation of the Ethereum protocol
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go-ethereum/eth/tracers/api.go

798 lines
27 KiB

// Copyright 2021 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package tracers
import (
"bufio"
"bytes"
"context"
"errors"
"fmt"
"io/ioutil"
"os"
"runtime"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/consensus"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/rpc"
)
const (
// defaultTraceTimeout is the amount of time a single transaction can execute
// by default before being forcefully aborted.
defaultTraceTimeout = 5 * time.Second
// defaultTraceReexec is the number of blocks the tracer is willing to go back
// and reexecute to produce missing historical state necessary to run a specific
// trace.
defaultTraceReexec = uint64(128)
)
// Backend interface provides the common API services (that are provided by
// both full and light clients) with access to necessary functions.
type Backend interface {
HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error)
BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
BlockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error)
GetTransaction(ctx context.Context, txHash common.Hash) (*types.Transaction, common.Hash, uint64, uint64, error)
RPCGasCap() uint64
ChainConfig() *params.ChainConfig
Engine() consensus.Engine
ChainDb() ethdb.Database
StateAtBlock(ctx context.Context, block *types.Block, reexec uint64) (*state.StateDB, func(), error)
StateAtTransaction(ctx context.Context, block *types.Block, txIndex int, reexec uint64) (core.Message, vm.BlockContext, *state.StateDB, func(), error)
StatesInRange(ctx context.Context, fromBlock *types.Block, toBlock *types.Block, reexec uint64) ([]*state.StateDB, func(), error)
}
// API is the collection of tracing APIs exposed over the private debugging endpoint.
type API struct {
backend Backend
}
// NewAPI creates a new API definition for the tracing methods of the Ethereum service.
func NewAPI(backend Backend) *API {
return &API{backend: backend}
}
type chainContext struct {
api *API
ctx context.Context
}
func (context *chainContext) Engine() consensus.Engine {
return context.api.backend.Engine()
}
func (context *chainContext) GetHeader(hash common.Hash, number uint64) *types.Header {
header, err := context.api.backend.HeaderByNumber(context.ctx, rpc.BlockNumber(number))
if err != nil {
return nil
}
if header.Hash() == hash {
return header
}
header, err = context.api.backend.HeaderByHash(context.ctx, hash)
if err != nil {
return nil
}
return header
}
// chainContext construts the context reader which is used by the evm for reading
// the necessary chain context.
func (api *API) chainContext(ctx context.Context) core.ChainContext {
return &chainContext{api: api, ctx: ctx}
}
// blockByNumber is the wrapper of the chain access function offered by the backend.
// It will return an error if the block is not found.
func (api *API) blockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error) {
block, err := api.backend.BlockByNumber(ctx, number)
if err != nil {
return nil, err
}
if block == nil {
return nil, fmt.Errorf("block #%d not found", number)
}
return block, nil
}
// blockByHash is the wrapper of the chain access function offered by the backend.
// It will return an error if the block is not found.
func (api *API) blockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
block, err := api.backend.BlockByHash(ctx, hash)
if err != nil {
return nil, err
}
if block == nil {
return nil, fmt.Errorf("block %s not found", hash.Hex())
}
return block, nil
}
// blockByNumberAndHash is the wrapper of the chain access function offered by
// the backend. It will return an error if the block is not found.
//
// Note this function is friendly for the light client which can only retrieve the
// historical(before the CHT) header/block by number.
func (api *API) blockByNumberAndHash(ctx context.Context, number rpc.BlockNumber, hash common.Hash) (*types.Block, error) {
block, err := api.blockByNumber(ctx, number)
if err != nil {
return nil, err
}
if block.Hash() == hash {
return block, nil
}
return api.blockByHash(ctx, hash)
}
// TraceConfig holds extra parameters to trace functions.
type TraceConfig struct {
*vm.LogConfig
Tracer *string
Timeout *string
Reexec *uint64
}
// StdTraceConfig holds extra parameters to standard-json trace functions.
type StdTraceConfig struct {
vm.LogConfig
Reexec *uint64
TxHash common.Hash
}
// txTraceResult is the result of a single transaction trace.
type txTraceResult struct {
Result interface{} `json:"result,omitempty"` // Trace results produced by the tracer
Error string `json:"error,omitempty"` // Trace failure produced by the tracer
}
// blockTraceTask represents a single block trace task when an entire chain is
// being traced.
type blockTraceTask struct {
statedb *state.StateDB // Intermediate state prepped for tracing
block *types.Block // Block to trace the transactions from
results []*txTraceResult // Trace results procudes by the task
}
// blockTraceResult represets the results of tracing a single block when an entire
// chain is being traced.
type blockTraceResult struct {
Block hexutil.Uint64 `json:"block"` // Block number corresponding to this trace
Hash common.Hash `json:"hash"` // Block hash corresponding to this trace
Traces []*txTraceResult `json:"traces"` // Trace results produced by the task
}
// txTraceTask represents a single transaction trace task when an entire block
// is being traced.
type txTraceTask struct {
statedb *state.StateDB // Intermediate state prepped for tracing
index int // Transaction offset in the block
}
// TraceChain returns the structured logs created during the execution of EVM
// between two blocks (excluding start) and returns them as a JSON object.
func (api *API) TraceChain(ctx context.Context, start, end rpc.BlockNumber, config *TraceConfig) (*rpc.Subscription, error) { // Fetch the block interval that we want to trace
from, err := api.blockByNumber(ctx, start)
if err != nil {
return nil, err
}
to, err := api.blockByNumber(ctx, end)
if err != nil {
return nil, err
}
if from.Number().Cmp(to.Number()) >= 0 {
return nil, fmt.Errorf("end block (#%d) needs to come after start block (#%d)", end, start)
}
return api.traceChain(ctx, from, to, config)
}
// traceChain configures a new tracer according to the provided configuration, and
// executes all the transactions contained within. The return value will be one item
// per transaction, dependent on the requested tracer.
func (api *API) traceChain(ctx context.Context, start, end *types.Block, config *TraceConfig) (*rpc.Subscription, error) {
// Tracing a chain is a **long** operation, only do with subscriptions
notifier, supported := rpc.NotifierFromContext(ctx)
if !supported {
return &rpc.Subscription{}, rpc.ErrNotificationsUnsupported
}
sub := notifier.CreateSubscription()
// Shift the border to a block ahead in order to get the states
// before these blocks.
endBlock, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(end.NumberU64()-1), end.ParentHash())
if err != nil {
return nil, err
}
// Prepare all the states for tracing. Note this procedure can take very
// long time. Timeout mechanism is necessary.
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
states, release, err := api.backend.StatesInRange(ctx, start, endBlock, reexec)
if err != nil {
return nil, err
}
defer release() // Release all the resources in the last step.
blocks := int(end.NumberU64() - start.NumberU64())
threads := runtime.NumCPU()
if threads > blocks {
threads = blocks
}
var (
pend = new(sync.WaitGroup)
tasks = make(chan *blockTraceTask, threads)
results = make(chan *blockTraceTask, threads)
)
for th := 0; th < threads; th++ {
pend.Add(1)
go func() {
defer pend.Done()
// Fetch and execute the next block trace tasks
for task := range tasks {
signer := types.MakeSigner(api.backend.ChainConfig(), task.block.Number())
blockCtx := core.NewEVMBlockContext(task.block.Header(), api.chainContext(ctx), nil)
// Trace all the transactions contained within
for i, tx := range task.block.Transactions() {
msg, _ := tx.AsMessage(signer)
res, err := api.traceTx(ctx, msg, blockCtx, task.statedb, config)
if err != nil {
task.results[i] = &txTraceResult{Error: err.Error()}
log.Warn("Tracing failed", "hash", tx.Hash(), "block", task.block.NumberU64(), "err", err)
break
}
// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
task.statedb.Finalise(api.backend.ChainConfig().IsEIP158(task.block.Number()))
task.results[i] = &txTraceResult{Result: res}
}
// Stream the result back to the user or abort on teardown
select {
case results <- task:
case <-notifier.Closed():
return
}
}
}()
}
// Start a goroutine to feed all the blocks into the tracers
begin := time.Now()
go func() {
var (
logged time.Time
number uint64
traced uint64
failed error
)
// Ensure everything is properly cleaned up on any exit path
defer func() {
close(tasks)
pend.Wait()
switch {
case failed != nil:
log.Warn("Chain tracing failed", "start", start.NumberU64(), "end", end.NumberU64(), "transactions", traced, "elapsed", time.Since(begin), "err", failed)
case number < end.NumberU64():
log.Warn("Chain tracing aborted", "start", start.NumberU64(), "end", end.NumberU64(), "abort", number, "transactions", traced, "elapsed", time.Since(begin))
default:
log.Info("Chain tracing finished", "start", start.NumberU64(), "end", end.NumberU64(), "transactions", traced, "elapsed", time.Since(begin))
}
close(results)
}()
// Feed all the blocks both into the tracer, as well as fast process concurrently
for number = start.NumberU64() + 1; number <= end.NumberU64(); number++ {
// Stop tracing if interruption was requested
select {
case <-notifier.Closed():
return
default:
}
// Print progress logs if long enough time elapsed
if time.Since(logged) > 8*time.Second {
logged = time.Now()
log.Info("Tracing chain segment", "start", start.NumberU64(), "end", end.NumberU64(), "current", number, "transactions", traced, "elapsed", time.Since(begin))
}
// Retrieve the next block to trace
block, err := api.blockByNumber(ctx, rpc.BlockNumber(number))
if err != nil {
failed = err
break
}
// Send the block over to the concurrent tracers (if not in the fast-forward phase)
txs := block.Transactions()
select {
case tasks <- &blockTraceTask{statedb: states[int(number-start.NumberU64()-1)], block: block, results: make([]*txTraceResult, len(txs))}:
case <-notifier.Closed():
return
}
traced += uint64(len(txs))
}
}()
// Keep reading the trace results and stream the to the user
go func() {
var (
done = make(map[uint64]*blockTraceResult)
next = start.NumberU64() + 1
)
for res := range results {
// Queue up next received result
result := &blockTraceResult{
Block: hexutil.Uint64(res.block.NumberU64()),
Hash: res.block.Hash(),
Traces: res.results,
}
done[uint64(result.Block)] = result
// Stream completed traces to the user, aborting on the first error
for result, ok := done[next]; ok; result, ok = done[next] {
if len(result.Traces) > 0 || next == end.NumberU64() {
notifier.Notify(sub.ID, result)
}
delete(done, next)
next++
}
}
}()
return sub, nil
}
// TraceBlockByNumber returns the structured logs created during the execution of
// EVM and returns them as a JSON object.
func (api *API) TraceBlockByNumber(ctx context.Context, number rpc.BlockNumber, config *TraceConfig) ([]*txTraceResult, error) {
block, err := api.blockByNumber(ctx, number)
if err != nil {
return nil, err
}
return api.traceBlock(ctx, block, config)
}
// TraceBlockByHash returns the structured logs created during the execution of
// EVM and returns them as a JSON object.
func (api *API) TraceBlockByHash(ctx context.Context, hash common.Hash, config *TraceConfig) ([]*txTraceResult, error) {
block, err := api.blockByHash(ctx, hash)
if err != nil {
return nil, err
}
return api.traceBlock(ctx, block, config)
}
// TraceBlock returns the structured logs created during the execution of EVM
// and returns them as a JSON object.
func (api *API) TraceBlock(ctx context.Context, blob []byte, config *TraceConfig) ([]*txTraceResult, error) {
block := new(types.Block)
if err := rlp.Decode(bytes.NewReader(blob), block); err != nil {
return nil, fmt.Errorf("could not decode block: %v", err)
}
return api.traceBlock(ctx, block, config)
}
// TraceBlockFromFile returns the structured logs created during the execution of
// EVM and returns them as a JSON object.
func (api *API) TraceBlockFromFile(ctx context.Context, file string, config *TraceConfig) ([]*txTraceResult, error) {
blob, err := ioutil.ReadFile(file)
if err != nil {
return nil, fmt.Errorf("could not read file: %v", err)
}
return api.TraceBlock(ctx, blob, config)
}
// TraceBadBlock returns the structured logs created during the execution of
// EVM against a block pulled from the pool of bad ones and returns them as a JSON
// object.
func (api *API) TraceBadBlock(ctx context.Context, hash common.Hash, config *TraceConfig) ([]*txTraceResult, error) {
for _, block := range rawdb.ReadAllBadBlocks(api.backend.ChainDb()) {
if block.Hash() == hash {
return api.traceBlock(ctx, block, config)
}
}
return nil, fmt.Errorf("bad block %#x not found", hash)
}
// StandardTraceBlockToFile dumps the structured logs created during the
// execution of EVM to the local file system and returns a list of files
// to the caller.
func (api *API) StandardTraceBlockToFile(ctx context.Context, hash common.Hash, config *StdTraceConfig) ([]string, error) {
block, err := api.blockByHash(ctx, hash)
if err != nil {
return nil, err
}
return api.standardTraceBlockToFile(ctx, block, config)
}
// StandardTraceBadBlockToFile dumps the structured logs created during the
// execution of EVM against a block pulled from the pool of bad ones to the
// local file system and returns a list of files to the caller.
func (api *API) StandardTraceBadBlockToFile(ctx context.Context, hash common.Hash, config *StdTraceConfig) ([]string, error) {
for _, block := range rawdb.ReadAllBadBlocks(api.backend.ChainDb()) {
if block.Hash() == hash {
return api.standardTraceBlockToFile(ctx, block, config)
}
}
return nil, fmt.Errorf("bad block %#x not found", hash)
}
// traceBlock configures a new tracer according to the provided configuration, and
// executes all the transactions contained within. The return value will be one item
// per transaction, dependent on the requestd tracer.
func (api *API) traceBlock(ctx context.Context, block *types.Block, config *TraceConfig) ([]*txTraceResult, error) {
if block.NumberU64() == 0 {
return nil, errors.New("genesis is not traceable")
}
parent, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(block.NumberU64()-1), block.ParentHash())
if err != nil {
return nil, err
}
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
statedb, release, err := api.backend.StateAtBlock(ctx, parent, reexec)
if err != nil {
return nil, err
}
defer release()
// Execute all the transaction contained within the block concurrently
var (
signer = types.MakeSigner(api.backend.ChainConfig(), block.Number())
txs = block.Transactions()
results = make([]*txTraceResult, len(txs))
pend = new(sync.WaitGroup)
jobs = make(chan *txTraceTask, len(txs))
)
threads := runtime.NumCPU()
if threads > len(txs) {
threads = len(txs)
}
blockCtx := core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
for th := 0; th < threads; th++ {
pend.Add(1)
go func() {
defer pend.Done()
// Fetch and execute the next transaction trace tasks
for task := range jobs {
msg, _ := txs[task.index].AsMessage(signer)
res, err := api.traceTx(ctx, msg, blockCtx, task.statedb, config)
if err != nil {
results[task.index] = &txTraceResult{Error: err.Error()}
continue
}
results[task.index] = &txTraceResult{Result: res}
}
}()
}
// Feed the transactions into the tracers and return
var failed error
for i, tx := range txs {
// Send the trace task over for execution
jobs <- &txTraceTask{statedb: statedb.Copy(), index: i}
// Generate the next state snapshot fast without tracing
msg, _ := tx.AsMessage(signer)
txContext := core.NewEVMTxContext(msg)
vmenv := vm.NewEVM(blockCtx, txContext, statedb, api.backend.ChainConfig(), vm.Config{})
if _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(msg.Gas())); err != nil {
failed = err
break
}
// Finalize the state so any modifications are written to the trie
// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
statedb.Finalise(vmenv.ChainConfig().IsEIP158(block.Number()))
}
close(jobs)
pend.Wait()
// If execution failed in between, abort
if failed != nil {
return nil, failed
}
return results, nil
}
// standardTraceBlockToFile configures a new tracer which uses standard JSON output,
// and traces either a full block or an individual transaction. The return value will
// be one filename per transaction traced.
func (api *API) standardTraceBlockToFile(ctx context.Context, block *types.Block, config *StdTraceConfig) ([]string, error) {
// If we're tracing a single transaction, make sure it's present
if config != nil && config.TxHash != (common.Hash{}) {
if !containsTx(block, config.TxHash) {
return nil, fmt.Errorf("transaction %#x not found in block", config.TxHash)
}
}
if block.NumberU64() == 0 {
return nil, errors.New("genesis is not traceable")
}
parent, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(block.NumberU64()-1), block.ParentHash())
if err != nil {
return nil, err
}
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
statedb, release, err := api.backend.StateAtBlock(ctx, parent, reexec)
if err != nil {
return nil, err
}
defer release()
// Retrieve the tracing configurations, or use default values
var (
logConfig vm.LogConfig
txHash common.Hash
)
if config != nil {
logConfig = config.LogConfig
txHash = config.TxHash
}
logConfig.Debug = true
// Execute transaction, either tracing all or just the requested one
var (
dumps []string
signer = types.MakeSigner(api.backend.ChainConfig(), block.Number())
chainConfig = api.backend.ChainConfig()
vmctx = core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
canon = true
)
// Check if there are any overrides: the caller may wish to enable a future
// fork when executing this block. Note, such overrides are only applicable to the
// actual specified block, not any preceding blocks that we have to go through
// in order to obtain the state.
// Therefore, it's perfectly valid to specify `"futureForkBlock": 0`, to enable `futureFork`
if config != nil && config.Overrides != nil {
// Copy the config, to not screw up the main config
// Note: the Clique-part is _not_ deep copied
chainConfigCopy := new(params.ChainConfig)
*chainConfigCopy = *chainConfig
chainConfig = chainConfigCopy
if berlin := config.LogConfig.Overrides.BerlinBlock; berlin != nil {
chainConfig.BerlinBlock = berlin
canon = false
}
}
for i, tx := range block.Transactions() {
// Prepare the trasaction for un-traced execution
var (
msg, _ = tx.AsMessage(signer)
txContext = core.NewEVMTxContext(msg)
vmConf vm.Config
dump *os.File
writer *bufio.Writer
err error
)
// If the transaction needs tracing, swap out the configs
if tx.Hash() == txHash || txHash == (common.Hash{}) {
// Generate a unique temporary file to dump it into
prefix := fmt.Sprintf("block_%#x-%d-%#x-", block.Hash().Bytes()[:4], i, tx.Hash().Bytes()[:4])
if !canon {
prefix = fmt.Sprintf("%valt-", prefix)
}
dump, err = ioutil.TempFile(os.TempDir(), prefix)
if err != nil {
return nil, err
}
dumps = append(dumps, dump.Name())
// Swap out the noop logger to the standard tracer
writer = bufio.NewWriter(dump)
vmConf = vm.Config{
Debug: true,
Tracer: vm.NewJSONLogger(&logConfig, writer),
EnablePreimageRecording: true,
}
}
// Execute the transaction and flush any traces to disk
vmenv := vm.NewEVM(vmctx, txContext, statedb, chainConfig, vmConf)
_, err = core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(msg.Gas()))
if writer != nil {
writer.Flush()
}
if dump != nil {
dump.Close()
log.Info("Wrote standard trace", "file", dump.Name())
}
if err != nil {
return dumps, err
}
// Finalize the state so any modifications are written to the trie
// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
statedb.Finalise(vmenv.ChainConfig().IsEIP158(block.Number()))
// If we've traced the transaction we were looking for, abort
if tx.Hash() == txHash {
break
}
}
return dumps, nil
}
// containsTx reports whether the transaction with a certain hash
// is contained within the specified block.
func containsTx(block *types.Block, hash common.Hash) bool {
for _, tx := range block.Transactions() {
if tx.Hash() == hash {
return true
}
}
return false
}
// TraceTransaction returns the structured logs created during the execution of EVM
// and returns them as a JSON object.
func (api *API) TraceTransaction(ctx context.Context, hash common.Hash, config *TraceConfig) (interface{}, error) {
_, blockHash, blockNumber, index, err := api.backend.GetTransaction(ctx, hash)
if err != nil {
return nil, err
}
// It shouldn't happen in practice.
if blockNumber == 0 {
return nil, errors.New("genesis is not traceable")
}
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
block, err := api.blockByNumberAndHash(ctx, rpc.BlockNumber(blockNumber), blockHash)
if err != nil {
return nil, err
}
msg, vmctx, statedb, release, err := api.backend.StateAtTransaction(ctx, block, int(index), reexec)
if err != nil {
return nil, err
}
defer release()
return api.traceTx(ctx, msg, vmctx, statedb, config)
}
// TraceCall lets you trace a given eth_call. It collects the structured logs
// created during the execution of EVM if the given transaction was added on
// top of the provided block and returns them as a JSON object.
// You can provide -2 as a block number to trace on top of the pending block.
func (api *API) TraceCall(ctx context.Context, args ethapi.CallArgs, blockNrOrHash rpc.BlockNumberOrHash, config *TraceConfig) (interface{}, error) {
// Try to retrieve the specified block
var (
err error
block *types.Block
)
if hash, ok := blockNrOrHash.Hash(); ok {
block, err = api.blockByHash(ctx, hash)
} else if number, ok := blockNrOrHash.Number(); ok {
block, err = api.blockByNumber(ctx, number)
}
if err != nil {
return nil, err
}
// try to recompute the state
reexec := defaultTraceReexec
if config != nil && config.Reexec != nil {
reexec = *config.Reexec
}
statedb, release, err := api.backend.StateAtBlock(ctx, block, reexec)
if err != nil {
return nil, err
}
defer release()
// Execute the trace
msg := args.ToMessage(api.backend.RPCGasCap())
vmctx := core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
return api.traceTx(ctx, msg, vmctx, statedb, config)
}
// traceTx configures a new tracer according to the provided configuration, and
// executes the given message in the provided environment. The return value will
// be tracer dependent.
func (api *API) traceTx(ctx context.Context, message core.Message, vmctx vm.BlockContext, statedb *state.StateDB, config *TraceConfig) (interface{}, error) {
// Assemble the structured logger or the JavaScript tracer
var (
tracer vm.Tracer
err error
txContext = core.NewEVMTxContext(message)
)
switch {
case config != nil && config.Tracer != nil:
// Define a meaningful timeout of a single transaction trace
timeout := defaultTraceTimeout
if config.Timeout != nil {
if timeout, err = time.ParseDuration(*config.Timeout); err != nil {
return nil, err
}
}
// Constuct the JavaScript tracer to execute with
if tracer, err = New(*config.Tracer, txContext); err != nil {
return nil, err
}
// Handle timeouts and RPC cancellations
deadlineCtx, cancel := context.WithTimeout(ctx, timeout)
go func() {
<-deadlineCtx.Done()
tracer.(*Tracer).Stop(errors.New("execution timeout"))
}()
defer cancel()
case config == nil:
tracer = vm.NewStructLogger(nil)
default:
tracer = vm.NewStructLogger(config.LogConfig)
}
// Run the transaction with tracing enabled.
vmenv := vm.NewEVM(vmctx, txContext, statedb, api.backend.ChainConfig(), vm.Config{Debug: true, Tracer: tracer})
result, err := core.ApplyMessage(vmenv, message, new(core.GasPool).AddGas(message.Gas()))
if err != nil {
return nil, fmt.Errorf("tracing failed: %v", err)
}
// Depending on the tracer type, format and return the output.
switch tracer := tracer.(type) {
case *vm.StructLogger:
// If the result contains a revert reason, return it.
returnVal := fmt.Sprintf("%x", result.Return())
if len(result.Revert()) > 0 {
returnVal = fmt.Sprintf("%x", result.Revert())
}
return &ethapi.ExecutionResult{
Gas: result.UsedGas,
Failed: result.Failed(),
ReturnValue: returnVal,
StructLogs: ethapi.FormatLogs(tracer.StructLogs()),
}, nil
case *Tracer:
return tracer.GetResult()
default:
panic(fmt.Sprintf("bad tracer type %T", tracer))
}
}
// APIs return the collection of RPC services the tracer package offers.
func APIs(backend Backend) []rpc.API {
// Append all the local APIs and return
return []rpc.API{
{
Namespace: "debug",
Version: "1.0",
Service: NewAPI(backend),
Public: false,
},
}
}