Blockchain: optional consensus (#2002)

* blockchain: add optional consensus param

* blockchain: add algorithm property to consensus

* blockchain: rework consensus setup

* fix examples

* fix blockchain test runner

* add more tests

* add blockchain checks to clique

* skip merge check on custom consensus

* Fix consensus check and add more tests

* lint fix

packages/blockchain/src/blockchain.ts

@@ -118,18 +118,22 @@ export class Blockchain implements BlockchainInterface {
     this.db = opts.db ? opts.db : new MemoryLevel()
     this.dbManager = new DBManager(this.db, this._common)
 
-    switch (this._common.consensusAlgorithm()) {
-      case ConsensusAlgorithm.Casper:
-        this.consensus = new CasperConsensus({ blockchain: this })
-        break
-      case ConsensusAlgorithm.Clique:
-        this.consensus = new CliqueConsensus({ blockchain: this })
-        break
-      case ConsensusAlgorithm.Ethash:
-        this.consensus = new EthashConsensus({ blockchain: this })
-        break
-      default:
-        throw new Error(`consensus algorithm ${this._common.consensusAlgorithm()} not supported`)
+    if (opts.consensus) {
+      this.consensus = opts.consensus
+    } else {
+      switch (this._common.consensusAlgorithm()) {
+        case ConsensusAlgorithm.Casper:
+          this.consensus = new CasperConsensus()
+          break
+        case ConsensusAlgorithm.Clique:
+          this.consensus = new CliqueConsensus()
+          break
+        case ConsensusAlgorithm.Ethash:
+          this.consensus = new EthashConsensus()
+          break
+        default:
+          throw new Error(`consensus algorithm ${this._common.consensusAlgorithm()} not supported`)
+      }
     }
 
     if (this._validateConsensus) {
@@ -184,6 +188,8 @@ export class Blockchain implements BlockchainInterface {
    * @hidden
    */
   private async _init(genesisBlock?: Block): Promise<void> {
+    await this.consensus.setup({ blockchain: this })
+
     if (this._isInitialized) return
     let dbGenesisBlock
     try {
@@ -230,8 +236,6 @@ export class Blockchain implements BlockchainInterface {
       await this.consensus.genesisInit(genesisBlock)
     }
 
-    await this.consensus.setup()
-
     // At this point, we can safely set the genesis:
     // it is either the one we put in the DB, or it is equal to the one
     // which we read from the DB.
@@ -1170,20 +1174,24 @@ export class Blockchain implements BlockchainInterface {
   protected checkAndTransitionHardForkByNumber(number: bigint, td?: BigIntLike): void {
     this._common.setHardforkByBlockNumber(number, td)
 
+    // If custom consensus algorithm is used, skip merge hardfork consensus checks
+    if (!Object.values(ConsensusAlgorithm).includes(this.consensus.algorithm as ConsensusAlgorithm))
+      return
+
     switch (this._common.consensusAlgorithm()) {
       case ConsensusAlgorithm.Casper:
         if (!(this.consensus instanceof CasperConsensus)) {
-          this.consensus = new CasperConsensus({ blockchain: this })
+          this.consensus = new CasperConsensus()
         }
         break
       case ConsensusAlgorithm.Clique:
         if (!(this.consensus instanceof CliqueConsensus)) {
-          this.consensus = new CliqueConsensus({ blockchain: this })
+          this.consensus = new CliqueConsensus()
         }
         break
       case ConsensusAlgorithm.Ethash:
         if (!(this.consensus instanceof EthashConsensus)) {
-          this.consensus = new EthashConsensus({ blockchain: this })
+          this.consensus = new EthashConsensus()
         }
         break
       default:

packages/blockchain/src/consensus/casper.ts

@@ -1,15 +1,15 @@
 import { BlockHeader } from '@ethereumjs/block'
-import Blockchain from '..'
-import { Consensus, ConsensusOptions } from './interface'
+import { ConsensusAlgorithm } from '@ethereumjs/common'
+import { Consensus } from './interface'
 
 /**
  * This class encapsulates Casper-related consensus functionality when used with the Blockchain class.
  */
 export class CasperConsensus implements Consensus {
-  blockchain: Blockchain
+  algorithm: ConsensusAlgorithm
 
-  constructor({ blockchain }: ConsensusOptions) {
-    this.blockchain = blockchain
+  constructor() {
+    this.algorithm = ConsensusAlgorithm.Casper
   }
 
   public async genesisInit(): Promise<void> {}

packages/blockchain/src/consensus/clique.ts

@@ -4,7 +4,7 @@ import { Address, bigIntToBuffer, bufferToBigInt, arrToBufArr, bufArrToArr } fro
 import RLP from 'rlp'
 import Blockchain from '..'
 import { Consensus, ConsensusOptions } from './interface'
-import { CliqueConfig } from '@ethereumjs/common'
+import { CliqueConfig, ConsensusAlgorithm } from '@ethereumjs/common'
 
 const debug = createDebugLogger('blockchain:clique')
 
@@ -46,7 +46,8 @@ type CliqueLatestBlockSigners = CliqueBlockSigner[]
  * This class encapsulates Clique-related consensus functionality when used with the Blockchain class.
  */
 export class CliqueConsensus implements Consensus {
-  blockchain: Blockchain
+  blockchain: Blockchain | undefined
+  algorithm: ConsensusAlgorithm
 
   /**
    * Keep signer history data (signer states and votes)
@@ -95,11 +96,18 @@ export class CliqueConsensus implements Consensus {
    */
   public _cliqueLatestBlockSigners: CliqueLatestBlockSigners = []
 
-  constructor({ blockchain }: ConsensusOptions) {
-    this.blockchain = blockchain
+  constructor() {
+    this.algorithm = ConsensusAlgorithm.Clique
   }
 
-  async setup(): Promise<void> {
+  /**
+   *
+   * @param param dictionary containin a {@link Blockchain} object
+   *
+   * Note: this method must be called before consensus checks are used or type errors will occur
+   */
+  async setup({ blockchain }: ConsensusOptions): Promise<void> {
+    this.blockchain = blockchain
     this._cliqueLatestSignerStates = await this.getCliqueLatestSignerStates()
     this._cliqueLatestVotes = await this.getCliqueLatestVotes()
     this._cliqueLatestBlockSigners = await this.getCliqueLatestBlockSigners()
@@ -110,6 +118,10 @@ export class CliqueConsensus implements Consensus {
   }
 
   async validateConsensus(block: Block): Promise<void> {
+    if (!this.blockchain) {
+      throw new Error('blockchain not provided')
+    }
+
     const { header } = block
     const valid = header.cliqueVerifySignature(this.cliqueActiveSigners())
     if (!valid) {
@@ -137,6 +149,10 @@ export class CliqueConsensus implements Consensus {
   }
 
   async validateDifficulty(header: BlockHeader): Promise<void> {
+    if (!this.blockchain) {
+      throw new Error('blockchain not provided')
+    }
+
     if (header.difficulty !== CLIQUE_DIFF_INTURN && header.difficulty !== CLIQUE_DIFF_NOTURN) {
       const msg = `difficulty for clique block must be INTURN (2) or NOTURN (1), received: ${header.difficulty}`
       throw new Error(`${msg} ${header.errorStr()}`)
@@ -168,7 +184,7 @@ export class CliqueConsensus implements Consensus {
     if (commonAncestorNumber !== undefined) {
       await this._cliqueDeleteSnapshots(commonAncestorNumber + BigInt(1))
       for (let number = commonAncestorNumber + BigInt(1); number <= header.number; number++) {
-        const canonicalHeader = await this.blockchain.getCanonicalHeader(number)
+        const canonicalHeader = await this.blockchain!.getCanonicalHeader(number)
         await this._cliqueBuildSnapshots(canonicalHeader)
       }
     }
@@ -219,7 +235,7 @@ export class CliqueConsensus implements Consensus {
       bigIntToBuffer(state[0]),
       state[1].map((a) => a.toBuffer()),
     ])
-    await this.blockchain.db.put(
+    await this.blockchain!.db.put(
       CLIQUE_SIGNERS_KEY,
       Buffer.from(RLP.encode(bufArrToArr(formatted))),
       DB_OPTS
@@ -252,7 +268,7 @@ export class CliqueConsensus implements Consensus {
         const lastEpochBlockNumber =
           header.number -
           (header.number %
-            BigInt((this.blockchain._common.consensusConfig() as CliqueConfig).epoch))
+            BigInt((this.blockchain!._common.consensusConfig() as CliqueConfig).epoch))
         const limit = this.cliqueSignerLimit()
         let activeSigners = this.cliqueActiveSigners()
         let consensus = false
@@ -363,7 +379,7 @@ export class CliqueConsensus implements Consensus {
       const lastEpochBlockNumber =
         lastBlockNumber -
         (lastBlockNumber %
-          BigInt((this.blockchain._common.consensusConfig() as CliqueConfig).epoch))
+          BigInt((this.blockchain!._common.consensusConfig() as CliqueConfig).epoch))
       const blockLimit = lastEpochBlockNumber - BigInt(limit)
       this._cliqueLatestVotes = this._cliqueLatestVotes.filter((state) => state[0] >= blockLimit)
     }
@@ -373,7 +389,7 @@ export class CliqueConsensus implements Consensus {
       bigIntToBuffer(v[0]),
       [v[1][0].toBuffer(), v[1][1].toBuffer(), v[1][2]],
     ])
-    await this.blockchain.db.put(
+    await this.blockchain!.db.put(
       CLIQUE_VOTES_KEY,
       Buffer.from(RLP.encode(bufArrToArr(formatted))),
       DB_OPTS
@@ -481,7 +497,7 @@ export class CliqueConsensus implements Consensus {
       bigIntToBuffer(b[0]),
       b[1].toBuffer(),
     ])
-    await this.blockchain.db.put(
+    await this.blockchain!.db.put(
       CLIQUE_BLOCK_SIGNERS_SNAPSHOT_KEY,
       Buffer.from(RLP.encode(bufArrToArr(formatted))),
       DB_OPTS
@@ -494,7 +510,10 @@ export class CliqueConsensus implements Consensus {
    */
   private async getCliqueLatestSignerStates(): Promise<CliqueLatestSignerStates> {
     try {
-      const signerStates = await this.blockchain.db.get<string, Buffer>(CLIQUE_SIGNERS_KEY, DB_OPTS)
+      const signerStates = await this.blockchain!.db.get<string, Buffer>(
+        CLIQUE_SIGNERS_KEY,
+        DB_OPTS
+      )
       const states = arrToBufArr(RLP.decode(Uint8Array.from(signerStates))) as [Buffer, Buffer[]]
       return states.map((state) => {
         const blockNum = bufferToBigInt(state[0] as Buffer)
@@ -515,7 +534,7 @@ export class CliqueConsensus implements Consensus {
    */
   private async getCliqueLatestVotes(): Promise<CliqueLatestVotes> {
     try {
-      const signerVotes = await this.blockchain.db.get<string, Buffer>(CLIQUE_VOTES_KEY, DB_OPTS)
+      const signerVotes = await this.blockchain!.db.get<string, Buffer>(CLIQUE_VOTES_KEY, DB_OPTS)
       const votes = arrToBufArr(RLP.decode(Uint8Array.from(signerVotes))) as [
         Buffer,
         [Buffer, Buffer, Buffer]
@@ -541,7 +560,7 @@ export class CliqueConsensus implements Consensus {
    */
   private async getCliqueLatestBlockSigners(): Promise<CliqueLatestBlockSigners> {
     try {
-      const blockSigners = await this.blockchain.db.get<string, Buffer>(
+      const blockSigners = await this.blockchain!.db.get<string, Buffer>(
         CLIQUE_BLOCK_SIGNERS_SNAPSHOT_KEY,
         DB_OPTS
       )
@@ -581,7 +600,7 @@ export class CliqueConsensus implements Consensus {
     if (signerIndex === -1) {
       throw new Error('Signer not found')
     }
-    const { number } = await this.blockchain.getCanonicalHeadHeader()
+    const { number } = await this.blockchain!.getCanonicalHeadHeader()
     //eslint-disable-next-line
     return (number + BigInt(1)) % BigInt(signers.length) === BigInt(signerIndex)
   }

packages/blockchain/src/consensus/ethash.ts

@@ -1,4 +1,5 @@
 import { Block, BlockHeader } from '@ethereumjs/block'
+import { ConsensusAlgorithm } from '@ethereumjs/common'
 import Ethash, { EthashCacheDB } from '@ethereumjs/ethash'
 import Blockchain from '..'
 import { Consensus, ConsensusOptions } from './interface'
@@ -7,15 +8,18 @@ import { Consensus, ConsensusOptions } from './interface'
  * This class encapsulates Ethash-related consensus functionality when used with the Blockchain class.
  */
 export class EthashConsensus implements Consensus {
-  blockchain: Blockchain
-  _ethash: Ethash
+  blockchain: Blockchain | undefined
+  algorithm: ConsensusAlgorithm
+  _ethash: Ethash | undefined
 
-  constructor({ blockchain }: ConsensusOptions) {
-    this.blockchain = blockchain
-    this._ethash = new Ethash(this.blockchain.db as unknown as EthashCacheDB)
+  constructor() {
+    this.algorithm = ConsensusAlgorithm.Ethash
   }
 
   async validateConsensus(block: Block): Promise<void> {
+    if (!this._ethash) {
+      throw new Error('blockchain not provided')
+    }
     const valid = await this._ethash.verifyPOW(block)
     if (!valid) {
       throw new Error('invalid POW')
@@ -27,13 +31,19 @@ export class EthashConsensus implements Consensus {
    * @param header - header of block to be checked
    */
   async validateDifficulty(header: BlockHeader) {
+    if (!this.blockchain) {
+      throw new Error('blockchain not provided')
+    }
     const parentHeader = (await this.blockchain.getBlock(header.parentHash)).header
     if (header.ethashCanonicalDifficulty(parentHeader) !== header.difficulty) {
       throw new Error(`invalid difficulty ${header.errorStr()}`)
     }
   }
 
   public async genesisInit(): Promise<void> {}
-  public async setup(): Promise<void> {}
+  public async setup({ blockchain }: ConsensusOptions): Promise<void> {
+    this.blockchain = blockchain
+    this._ethash = new Ethash(this.blockchain.db as unknown as EthashCacheDB)
+  }
   public async newBlock(): Promise<void> {}
 }

packages/blockchain/src/consensus/interface.ts

@@ -1,10 +1,12 @@
 import { Block, BlockHeader } from '@ethereumjs/block'
+import { ConsensusAlgorithm } from '@ethereumjs/common'
 import Blockchain from '..'
 
 /**
  * Interface that a consensus class needs to implement.
  */
 export interface Consensus {
+  algorithm: ConsensusAlgorithm | string
   /**
    * Initialize genesis for consensus mechanism
    * @param genesisBlock genesis block
@@ -14,7 +16,7 @@ export interface Consensus {
   /**
    * Set up consensus mechanism
    */
-  setup(): Promise<void>
+  setup({ blockchain }: ConsensusOptions): Promise<void>
 
   /**
    * Validate block consensus parameters

packages/blockchain/src/types.ts

@@ -1,6 +1,7 @@
 import { Block } from '@ethereumjs/block'
 import Common from '@ethereumjs/common'
 import { AbstractLevel } from 'abstract-level'
+import { Consensus } from '.'
 import { GenesisState } from './genesisStates'
 
 export type OnBlock = (block: Block, reorg: boolean) => Promise<void> | void
@@ -124,4 +125,9 @@ export interface BlockchainOptions {
    * ```
    */
   genesisState?: GenesisState
+
+  /**
+   * Optional custom consensus that implements the {@link Consensus} class
+   */
+  consensus?: Consensus
 }