hyperledger-besu-ethers

v0.2.1

Published

3 years ago

JavaScript library that extends Ethers.js with Pantheon APIs including private transactions, administration, Clique, IBFT and Txpool

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sambacha

Hyperledger Besu PegaSys Ethereum Enterprise Ethereum Alliance EEA private privacy privacy group Clique IBFT JavaScript library

Ethers.js for Hyperledger Besu

An extension of Richard Moore's excellent Ethers.js Ethereum JavaScript library that adds support for Hyperledger Besu's private transactions and Hyperledger Besu's extended APIs like Admin, Clique, IBFT 2.0, Permissioning and Txpool JSON-RPC APIs.

Disclaimer

This library uses Ethers.js version 5 which is still in experimental status. It is not yet ready for production use. See Ethers.js for more details.

Besu's new privacy features are not ready for production use. See Privacy Group Limitations for more details.

Install

Until hyperledger-besu-ethers is published on npm using the PegaSysEng account, installs will have to be done from this git repository.

npm install PegaSysEng/hyperledger-besu-ethers

Usage - Private Transaction

Besu's private transactions are based off Enterprise Ethereum Alliance's Ethereum Client Specification for private transactions. At a high level, it adds the privateFor, privateFrom and restriction transaction properties to the JSON-RPC API calls. The spec is not yet finalised so hopefully it can be brought into line with the features Besu currently has and has planned in its roadmap.

Private transactions are supported by PegaSys's Hyperledger Besu Ethereum client and J.P.Morgan's Quorum distributed ledger. Unfortunately, Quorum's and Hyperledger Besu's JSON-RPC interfaces for private transactions are different and both don't match the EEA specification, so this library only works with Hyperledger Besu and not Quorum.

New Private Classes

See Ethers.js version 5 documentation for details on how the Ethers.js library works. This section will just document the differences for private transactions.

New PrivateJsonRpcProvider provider that extends JsonRpcProvider and implements the PrivateProvider interface

export interface PrivateProvider extends Provider {
    sendPrivateTransaction(signedTransaction: string | Promise<string>): Promise<PrivateTransactionResponse>;
    getPrivateTransactionCount(
        addressOrName: string | Promise<string>,
        privacyGroupOptions: PrivacyGroupOptions,
    ): Promise<number>;
    getPrivateTransactionReceipt(publicTransactionHash: string): Promise<PrivateTransactionReceipt>;
    getPrivateTransaction(transactionHash: string): Promise<PrivateTransactionResponse>;

    // Privacy Group functions
    createPrivacyGroup(
        addresses: string[] | Promise<string[]>,
        name?: string | Promise<string>,
        description?: string | Promise<string>,
    ): Promise<string>;
    deletePrivacyGroup(privacyGroupId: string | Promise<string>): Promise<string>;
    findPrivacyGroup(members: string[] | Promise<string[]>): Promise<FindPrivacyGroup[]>;
    getPrivacyPrecompileAddress(): Promise<string>;
}

New PrivateWallet that extends Wallet and implements the PrivateSigner interace

export interface PrivateSigner extends Signer {
    readonly provider: PrivateProvider;
    privateCall(transaction: PrivateTransactionRequest): Promise<string>;
    signPrivateTransaction(transaction: PrivateTransactionRequest): Promise<string>;
    sendPrivateTransaction(transaction: PrivateTransactionRequest): Promise<PrivateTransactionResponse>;
}

The PrivateUnsignedTransaction, PrivateTransaction, PrivateTransactionRequest interfaces have the following privacy fields added to them.

    privateFrom?: string;
    privateFor?: string | string[];
    restriction?: 'restricted' | 'unrestricted';

See privateTransactions.js for a full example of how a private contract can be deployed and its functions called from different nodes. Here's a short summary using the Simple Storage contract.

const BesuEthers = require('hyperledger-besu-ethers');

// Create providers pointing to node 1 in the Privacy Enabled Quickstart Tutorial
const providerNode1 = new BesuEthers.providers.PrivateJsonRpcProvider('http://localhost:20000');

// Create a privacy group for nodes 1 and 2. Node 3 will not see the private contract
const privacyGroupId = await providerNode1.createPrivacyGroup(
    ['A1aVtMxLCUHmBVHXoZzzBgPbW/wj5axDpW9X8l91SGo=', 'Ko2bVqD+nNlNYL5EE7y3IdOnviftjiizpjRt+HTuFBs='],
    'Name of top secret group',
    'Description of super secret group',
);

// Create a wallet which will have address 0x2B5AD5c4795c026514f8317c7a215E218DcCD6cF
const walletNode1 = new BesuEthers.PrivateWallet(
    '0x0000000000000000000000000000000000000000000000000000000000000002',
    providerNode1,
);

// Simple Storage contract application programming interface (ABI) and Ethereum virtual machine (EVM) byte code
const abi = [
    {
        constant: false,
        inputs: [{ name: 'x', type: 'uint256' }],
        name: 'set',
        outputs: [],
        payable: false,
        stateMutability: 'nonpayable',
        type: 'function',
    },
    {
        constant: true,
        inputs: [],
        name: 'get',
        outputs: [{ name: '', type: 'uint256' }],
        payable: false,
        stateMutability: 'view',
        type: 'function',
    },
];
const bytecode =
    '6080604052348015600f57600080fd5b5060ab8061001e6000396000f3fe6080604052348015600f57600080fd5b506004361060325760003560e01c806360fe47b11460375780636d4ce63c146053575b600080fd5b605160048036036020811015604b57600080fd5b5035606b565b005b60596070565b60408051918252519081900360200190f35b600055565b6000549056fea265627a7a72305820b53c3a12a533365b0624ed636be47997f66ab3082086dde2044ab5b5e529c2fd64736f6c634300050a0032';

// PrivateContractFactory is like Ethers ContractFactory
const factory = new BesuEthers.PrivateContractFactory(abi, bytecode, walletNode1);

// Deploy a private contract using an existing privacy group
const contractNode1 = await factory.privateDeploy({ privateFor: privacyGroupId });

// wait until the contract has been deployed
const deployReceipt = await contractNode1.deployPrivateTransaction.wait();

// Send a transaction to call the set function on the SimpleStorage contract
let tx = await contractNode1.set(666);

// Wait for the transaction to be mined. This returns a transaction receipt
await tx.wait();

// Read the stored value back
const value = await contractNode1.get();

More examples are in the src/ts/__tests__/contract.test.ts unit tests.

Privacy Group Management

Create, find and delete a privacy group.

Full code examples using promises examples/privacyGroupManagementPromises.js or async/await example/privacyGroupManagementAsync.js work against the Privacy Enabled Quickstart Tutorial.

The PrivateJsonRpcProvider used in the below examples can be instantiated with

const providers = require('hyperledger-besu-ethers').providers;
const provider = new providers.PrivateJsonRpcProvider('http://localhost:20000');

Create a new privacy group - priv_createPrivacyGroup

const privacyGroupId = await provider.createPrivacyGroup(
    ['A1aVtMxLCUHmBVHXoZzzBgPbW/wj5axDpW9X8l91SGo=', 'Ko2bVqD+nNlNYL5EE7y3IdOnviftjiizpjRt+HTuFBs='],
    'Name of group',
    'Description of top secret group',
);
console.log(privacyGroupId); // GcFhoLY7EMQg7jxJDC6Aei1GZTN/ZaRepptX48VcUBk=

Find privacy groups - priv_findPrivacyGroup

const results = await provider.findPrivacyGroup([
    'A1aVtMxLCUHmBVHXoZzzBgPbW/wj5axDpW9X8l91SGo=',
    'Ko2bVqD+nNlNYL5EE7y3IdOnviftjiizpjRt+HTuFBs=',
]);
console.log(results);
/*
  [ { privacyGroupId: 'GcFhoLY7EMQg7jxJDC6Aei1GZTN/ZaRepptX48VcUBk=', 
      name: 'Name of group',
      description: 'Description of top secret group',
      type: 'PANTHEON',
      members:
       [ 'A1aVtMxLCUHmBVHXoZzzBgPbW/wj5axDpW9X8l91SGo=',
         'Ko2bVqD+nNlNYL5EE7y3IdOnviftjiizpjRt+HTuFBs=' ] } ]
   */

Delete privacy group - priv_deletePrivacyGroup

const deletedId = await provider.deletePrivacyGroup(privacyGroupId);
console.log(deletedId); // GcFhoLY7EMQg7jxJDC6Aei1GZTN/ZaRepptX48VcUBk=

Privacy Group Limitations

There are a number of limitations in the Besu 1.2 release that is being addressed in future releases:

There is no way to check if a private transaction succeeded or failed as there is no status or gasUsed fields on the private transaction receipt.
Calling read-only functions are done via sending a signed transaction as there is no equivalent of eth_call for private transactions.
Private transactions default to 10 million gas limit as there is no equivalent of eth_estimateGas to estimate the gas of a private transaction. This gas limit can be overridden via Ethers.js' optional override object.
The client must wait until a contract has been mined before calling a contract method. Ethers.js supports calling function methods before a deployed contract has been mined by polling eth_getCode. There is no equivalent method for private transactions.
You can't get events from private transactions as there is no equivalent of getLogs for private transactions.
You can not add/remove nodes to/from a privacy group.

Usage - Besu APIs

A new BesuProvider provider that extends the new PrivateJsonRpcProvider class adds the Besu specifics APIs that are not to do with private transactions. eg Admin, Clique, IBFT, Txpool.

The BesuProvider used in the below examples can be instantiated with

const providers = require('hyperledger-besu-ethers').providers;
const provider = new providers.BesuProvider('http://localhost:20000');

Administration

Calls Hyperledger Besu's administration JSON-RPC APIs. See examples/admin.js for the full example code using async/await.

The admin methods require the ADMIN API methods to be enabled by Hyperledger Besu's --rpc-http-api command line option.

Get module versions - rpc_modules

const moduleVersions = await provider.getModuleVersions();
console.log(moduleVersions); // {eea: '1.0', web3: '1.0', eth: '1.0', admin: '1.0', priv: '1.0', net: '1.0'}

Change log level - admin_changeLogLevel

See logging for the allowed log levels.

await provider.changeLogLevel('TRACE');

Get node information - admin_nodeInfo

const nodeInfo = await provider.getNodeInfo();
console.log(nodeInfo);
/*
{ enode:
   'enode://192f022ba160677f05283443a6e548551b95faebbce659823cacd87489401f914bf34cd61f4905c0e6c19ea4ccd0cb91aa45041536f1e7f759e8caa323a148cc@127.0.0.1:30303',
  listenAddr: '127.0.0.1:30303',
  ip: '127.0.0.1',
  name: 'besu/v1.3.0/linux-x86_64/oracle_openjdk-java-11',
  id:
   '192f022ba160677f05283443a6e548551b95faebbce659823cacd87489401f914bf34cd61f4905c0e6c19ea4ccd0cb91aa45041536f1e7f759e8caa323a148cc',
  ports: { discovery: 30303, listener: 30303 },
  protocols:
   { eth:
      { config: [Object],
        difficulty: 65536,
        genesis:
         '0xa08d1edb37ba1c62db764ef7c2566cbe368b850f5b3762c6c24114a3fd97b87f',
        head:
         '0xa08d1edb37ba1c62db764ef7c2566cbe368b850f5b3762c6c24114a3fd97b87f',
        network: 2018 } } }
*/

Get peers - admin_peers

const peers = await provider.getPeers();
console.log(peers);
/*
[ { version: '0x5',
    name: 'besu/v1.3.0/linux-x86_64/oracle_openjdk-java-11',
    caps: [ 'eth/62', 'eth/63' ],
    network:
     { localAddress: '172.21.0.9:30303',
       remoteAddress: '172.21.0.5:50758' },
    port: '0x765f',
    id:
     '0x048781b21b8df1d29fc93b7f47a1e6483be25dc2442f2f0f42514d13b43853a1d37a8b6a8ef4178bf02a2d65b60292e47f0df224c6c92764e664c7275f43aad3' },
  { version: '0x5',
    name: 'besu/v1.3.0/linux-x86_64/oracle_openjdk-java-11',
    caps: [ 'eth/62', 'eth/63' ],
    network:
     { localAddress: '172.21.0.9:54614',
       remoteAddress: '172.21.0.10:30303' },
    port: '0x765f',
    id:
     '0xcdaaefe4e76f5ca77b5a365baab2f81e585ddad4ff8b21052420b653b3f736af8a300a8497cac63d3ad6cdefcec01463e9119ace11cec52ccb9d4b3325990870' } ]
*/

Remove peer - admin_removePeer

const success = await provider.removePeer(
    'enode://af80b90d25145da28c583359beb47b21796b2fe1a23c1511e443e7a64dfdb27d7434c380f0aa4c500e220aa1a9d068514b1ff4d5019e624e7ba1efe82b340a59@127.0.0.1:30304',
);
console.log(success); // true

Add peer - admin_addPeer

const success = await provider.addPeer(
    'enode://af80b90d25145da28c583359beb47b21796b2fe1a23c1511e443e7a64dfdb27d7434c380f0aa4c500e220aa1a9d068514b1ff4d5019e624e7ba1efe82b340a59@127.0.0.1:30304',
);
console.log(success); // true

Clique

Calls Hyperledger Besu's Clique JSON-RPC APIs. See examples/clique.js for the full example code using async/await.

The Clique methods require the CLIQUE API methods to be enabled by Hyperledger Besu's --rpc-http-api command line option.

Get Signers - clique_getSigners

const signers = await provider.cliqueGetSigners('latest');
console.log(signers);
// [ "0x42eb768f2244c8811c63729a21a3569731535f06", "0x7ffc57839b00206d1ad20c69a1981b489f772031", "0xb279182d99e65703f0076e4812653aab85fca0f0" ]

Get Signers at hash - clique_getSignersAtHash

const signers = await provider.cliqueGetSignersAtHash(
    '0x98b2ddb5106b03649d2d337d42154702796438b3c74fd25a5782940e84237a48',
);
console.log(signers);
// [ "0x42eb768f2244c8811c63729a21a3569731535f06", "0x7ffc57839b00206d1ad20c69a1981b489f772031", "0xb279182d99e65703f0076e4812653aab85fca0f0" ]

Propose Signer - clique_propose

const success = await provider.cliquePropose('0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73', true);
console.log(success); // true

Discard Proposal - clique_discard

const success = await provider.cliqueDiscard('0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73');
console.log(success); // true

Get Proposals - clique_proposals

const proposals = await provider.cliqueGetProposals();
console.log(proposals);
/*
{
    "0x42eb768f2244c8811c63729a21a3569731535f07": false,
    "0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73": true
}
*/

IBFT 2.0

Calls Hyperledger Besu's IBFT 2.0 JSON-RPC APIs. See examples/IBFT.js for the full example code using async/await.

The IBFT methods require the IBFT API methods to be enabled by Hyperledger Besu's --rpc-http-api command line option.

Get Validators by block parameter - ibft_getValidatorsByBlockNumber

See Block Number for allowed parameter values.

const validators = await provider.ibftGetValidatorsByBlockNumber('latest');
console.log(validators);
// [ "0x42d4287eac8078828cf5f3486cfe601a275a49a5", "0xb1b2bc9582d2901afdc579f528a35ca41403fa85", "0xef1bfb6a12794615c9b0b5a21e6741f01e570185" ]

Get Validators at hash - ibft_getValidatorsByBlockHash

const validators = await provider.ibftGetValidatorsByBlockHash(
    '0xbae7d3feafd743343b9a4c578cab5e5d65eb735f6855fb845c00cab356331256',
);
console.log(validators);
// [ "0x42d4287eac8078828cf5f3486cfe601a275a49a5", "0xb1b2bc9582d2901afdc579f528a35ca41403fa85", "0xef1bfb6a12794615c9b0b5a21e6741f01e570185" ]

Propose Validator Vote - ibft_proposeValidatorVote

const success = await provider.ibftProposeValidatorVote('0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73', true);
console.log(success); // true

Discard Validator Vote - ibft_discardValidatorVote

const success = await provider.ibftDiscardValidatorVote('0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73');
console.log(success); // true

Get Validator Votes - ibft_getPendingVotes

const validatorVotes = await provider.ibftGetPendingVotes();
console.log(validatorVotes);
/*
  {
    "0x42eb768f2244c8811c63729a21a3569731535f07": false,
    "0xFE3B557E8Fb62b89F4916B721be55cEb828dBd73": true
  }
*/

Permissioning

Calls Hyperledger Besu's permissioning JSON-RPC APIs. See examples/permissioning.js for the full example code using async/await.

The local permissioning methods require the PERM API methods to be enabled by Hyperledger Besu's --rpc-http-api command line option.

Hyperledger Besu's account and node whitelists also need to be configured for the below API calls to work. See Hyperledger Besu Local Permissioning documentation for how to do this.

Add Accounts To Whitelist - perm_addAccountsToWhitelist

const result = await provider.addAccountsToWhitelist([
    '0xb9b81ee349c3807e46bc71aa2632203c5b462032',
    '0xb9b81ee349c3807e46bc71aa2632203c5b462034',
]);
console.log(result); // Success

Get Accounts on Whitelist - perm_getAccountsWhitelist

const accounts = await provider.getAccountsWhitelist();
console.log(accounts); // ["0xb9b81ee349c3807e46bc71aa2632203c5b462032", "0xb9b81ee349c3807e46bc71aa2632203c5b462034"]

Remove Accounts To Whitelist - perm_removeAccountsFromWhitelist

const result = await provider.removeAccountsFromWhitelist([
    '0xb9b81ee349c3807e46bc71aa2632203c5b462032',
    '0xb9b81ee349c3807e46bc71aa2632203c5b462034',
]);
console.log(result); // Success

Add Nodes To Whitelist - perm_addNodesToWhitelist

const result = await provider.addNodesToWhitelist([
    'enode://7e4ef30e9ec683f26ad76ffca5b5148fa7a6575f4cfad4eb0f52f9c3d8335f4a9b6f9e66fcc73ef95ed7a2a52784d4f372e7750ac8ae0b544309a5b391a23dd7@127.0.0.1:30303',
    'enode://2feb33b3c6c4a8f77d84a5ce44954e83e5f163e7a65f7f7a7fec499ceb0ddd76a46ef635408c513d64c076470eac86b7f2c8ae4fcd112cb28ce82c0d64ec2c94@127.0.0.1:30304',
]);
console.log(result); // Success

Get Nodes on Whitelist - perm_getNodesWhitelist

const nodes = await provider.getNodesWhitelist();
console.log(nodes);
/* [
  "enode://7b61d5ee4b44335873e6912cb5dd3e3877c860ba21417c9b9ef1f7e500a82213737d4b269046d0669fb2299a234ca03443f25fe5f706b693b3669e5c92478ade@127.0.0.1:30305",
  "enode://2feb33b3c6c4a8f77d84a5ce44954e83e5f163e7a65f7f7a7fec499ceb0ddd76a46ef635408c513d64c076470eac86b7f2c8ae4fcd112cb28ce82c0d64ec2c94@127.0.0.1:30304"
] */

Remove Nodes To Whitelist - perm_removeNodesFromWhitelist

const result = await provider.removeNodesFromWhitelist([
    'enode://7e4ef30e9ec683f26ad76ffca5b5148fa7a6575f4cfad4eb0f52f9c3d8335f4a9b6f9e66fcc73ef95ed7a2a52784d4f372e7750ac8ae0b544309a5b391a23dd7@127.0.0.1:30303',
    'enode://2feb33b3c6c4a8f77d84a5ce44954e83e5f163e7a65f7f7a7fec499ceb0ddd76a46ef635408c513d64c076470eac86b7f2c8ae4fcd112cb28ce82c0d64ec2c94@127.0.0.1:30304',
]);
console.log(result); // Success

Reload Permissions From File - perm_reloadPermissionsFromFile

const result = await provider.reloadPermissionsFromFile();
console.log(result); // Success

Txpool

The txpool methods require the TXPOOL API methods to be enabled by Hyperledger Besu's --rpc-http-api command line option.

Besu Statistics - txpool_besuStatistics

const stats = await provider.getBesuStatistics();
console.log(stats); // {"maxSize": 4096, "localCount": 1, "remoteCount": 0}

Besu Transactions - txpool_besuTransactions

const results = await provider.getBesuTransactions();
console.log(results);
/* [
    {
        "hash": "0x8a66830098be4006a3f63a03b6e9b67aa721e04bd6b46d420b8f1937689fb4f1",
        "isReceivedFromLocalSource": true,
        "addedToPoolAt": "2019-03-21T01:35:50.911Z"
    },
    {
        "hash": "0x41ee803c3987ceb5bcea0fad7a76a8106a2a6dd654409007d9931032ea54579b",
        "isReceivedFromLocalSource": true,
        "addedToPoolAt": "2019-03-21T01:36:00.374Z"
    }]
*/

Hyperledger Besu

Hyperledger Besu is an open-source Ethereum client written in Java. It runs on the Ethereum public network, private networks, and test networks such as Rinkeby, Ropsten, and Görli. Hyperledger Besu implements Proof of Work (Ethash) and Proof of Authority (IBFT 2.0 and Clique) consensus mechanisms.

This library will only work against Hyperledger Besu 1.3.0 and above. It will not work against the 1.2.xPa releases. The library uses Hyperledger Besu's JSON-RPC APIs over HTTP.

See Privacy Overview for more details on how Hyperledger Besu supports private transactions.

Private Network with Privacy Enabled Quickstart Tutorial steps through setting up a three node private network managed by Docker Compose. The TL;DR version is

git clone https://github.com/PegaSysEng/besu-quickstart.git
cd besu-quickstart/privacy
./run.sh

You can see the logs from the nodes running on docker-compose with

./list.sh   # lists the status of the docker servers. ie are they up or down
./logs.sh   # tail the logs of each of the docker services
./stop.sh   # shuts down all of the docker services
./remove.sh # stops and then removes the server volumes so the chain will start back at block 0

A blockchain explorer will be at http://localhost:32768

To tail the logs of a specific docker service. eg node 1

docker-compose logs -f node1 orion1

To list the cpu and memory used by each container

docker ps -q | xargs  docker stats --no-stream

To bash into the to the Hyperledger Besu image used by the quickstart

docker run -it --entrypoint=sh quickstart/besu:develop-privacy

To bash into a running docker-compose service. eg node1

docker-compose exec node1 sh

To pull the latest Hyperledger Besu and Orion docker images from the develop branch and build a quickstart/besu:develop-privacy image

cd privacy
docker image pull hyperledger/besu:develop
docker-compose build bootnode
docker-compose build --pull orion1

The Hyperledger Besu tags for the Docker images can be found at https://hub.docker.com/r/hyperledger/besu/tags

There are three pre-funded accounts if you run Hyperledger Besu in dev mode. See the alloc section in https://github.com/hyperledger/besu/blob/master/config/src/main/resources/dev.json

Web3.js

Hyperledger Besu has an EEA JavaScript library that is an extension of the Web3.js JavaScript library. The EEA JavaScript library is an alternative to this Ethers.js extended library. It can also be used as a reference to how Hyperledger Besu privacy transactions are encoded. The EEA Web3js library does not include the Hyperledger Besu extended APIs like admin, clique, ibft, txpool, perm and priv.

Ethers.js

Ethers.js version 5 is used as its modular packages makes it easier to extend the classes to add private transaction support. See Richard's blog on Beta Release: ethers.js v5 for more details.

For regression testing purposes, ethers version 4 is also installed in the devDependencies. This uses an npm alias which is available from npm version 6.9.0. See (this)[https://stackoverflow.com/a/56495895/3144809] Stack Overflow answer for more information.

npm i ethers-4@npm:[email protected]

Ethers.js links

Development

The following is only required if you are contributing to the develop of this library.

Build

This library has been developed with TypeScript so it needs to be compiled to JavaScript with

npm run build

This uses the tsconfig.json TypeScript config file and outputs the JavaScript and type definition files to the dist folder.

Solidity

The Solidity contracts used in the examples and tests can be compiled with the following.

npm run buildSol

This uses the scripts/buildSol.sh script which uses a locally installed Solidity compiler solc. The ABI and evm files from compilation are output to the dist/abis folder.

See the Solidity documentation on how to install the Solidity binary packages on your operating system.

Test

Jest is used to run the unit tests with the configuration in jest.config.js

jest --detectOpenHandles --forceExit --runInBand

Publish

Before publishing a new package to npm, bump the package version in package.json and src/ts/_version.ts.

The following will build, test and publish

npm run build
npm run test
npm publish

One way to test a new package before publishing it is to run npm pack and then update the examples to point to the created package file. eg hyperledger-besu-ethers-0.0.4.tgz. In examples/package.json, change the hyperledger-besu-ethers dependency to point to the created package file. eg "hyperledger-besu-ethers": "../hyperledger-besu-ethers-0.0.4.tgz". You can then run an example.

npm pack
cd examples
node privateTransactions.js