1// Copyright 2015 The go-ethereum Authors 2// This file is part of the go-ethereum library. 3// 4// The go-ethereum library is free software: you can redistribute it and/or modify 5// it under the terms of the GNU Lesser General Public License as published by 6// the Free Software Foundation, either version 3 of the License, or 7// (at your option) any later version. 8// 9// The go-ethereum library is distributed in the hope that it will be useful, 10// but WITHOUT ANY WARRANTY; without even the implied warranty of 11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12// GNU Lesser General Public License for more details. 13// 14// You should have received a copy of the GNU Lesser General Public License 15// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. 16 17package core 18 19import ( 20 "fmt" 21 "math/big" 22 23 "github.com/ethereum/go-ethereum/consensus/ethash" 24 "github.com/ethereum/go-ethereum/core/rawdb" 25 "github.com/ethereum/go-ethereum/core/types" 26 "github.com/ethereum/go-ethereum/core/vm" 27 "github.com/ethereum/go-ethereum/crypto" 28 "github.com/ethereum/go-ethereum/params" 29) 30 31func ExampleGenerateChain() { 32 var ( 33 key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291") 34 key2, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a") 35 key3, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee") 36 addr1 = crypto.PubkeyToAddress(key1.PublicKey) 37 addr2 = crypto.PubkeyToAddress(key2.PublicKey) 38 addr3 = crypto.PubkeyToAddress(key3.PublicKey) 39 db = rawdb.NewMemoryDatabase() 40 ) 41 42 // Ensure that key1 has some funds in the genesis block. 43 gspec := &Genesis{ 44 Config: ¶ms.ChainConfig{HomesteadBlock: new(big.Int)}, 45 Alloc: GenesisAlloc{addr1: {Balance: big.NewInt(1000000)}}, 46 } 47 genesis := gspec.MustCommit(db) 48 49 // This call generates a chain of 5 blocks. The function runs for 50 // each block and adds different features to gen based on the 51 // block index. 52 signer := types.HomesteadSigner{} 53 chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 5, func(i int, gen *BlockGen) { 54 switch i { 55 case 0: 56 // In block 1, addr1 sends addr2 some ether. 57 tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), params.TxGas, nil, nil), signer, key1) 58 gen.AddTx(tx) 59 case 1: 60 // In block 2, addr1 sends some more ether to addr2. 61 // addr2 passes it on to addr3. 62 tx1, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key1) 63 tx2, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key2) 64 gen.AddTx(tx1) 65 gen.AddTx(tx2) 66 case 2: 67 // Block 3 is empty but was mined by addr3. 68 gen.SetCoinbase(addr3) 69 gen.SetExtra([]byte("yeehaw")) 70 case 3: 71 // Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data). 72 b2 := gen.PrevBlock(1).Header() 73 b2.Extra = []byte("foo") 74 gen.AddUncle(b2) 75 b3 := gen.PrevBlock(2).Header() 76 b3.Extra = []byte("foo") 77 gen.AddUncle(b3) 78 } 79 }) 80 81 // Import the chain. This runs all block validation rules. 82 blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil) 83 defer blockchain.Stop() 84 85 if i, err := blockchain.InsertChain(chain); err != nil { 86 fmt.Printf("insert error (block %d): %v\n", chain[i].NumberU64(), err) 87 return 88 } 89 90 state, _ := blockchain.State() 91 fmt.Printf("last block: #%d\n", blockchain.CurrentBlock().Number()) 92 fmt.Println("balance of addr1:", state.GetBalance(addr1)) 93 fmt.Println("balance of addr2:", state.GetBalance(addr2)) 94 fmt.Println("balance of addr3:", state.GetBalance(addr3)) 95 // Output: 96 // last block: #5 97 // balance of addr1: 989000 98 // balance of addr2: 10000 99 // balance of addr3: 19687500000000001000 100} 101