burrow

Hyperledger Burrow

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Hyperledger Burrow is a permissioned Ethereum smart-contract blockchain node. It executes Ethereum EVM smart contract code (usually written in Solidity) on a permissioned virtual machine. Burrow provides transaction finality and high transaction throughput on a proof-of-stake Tendermint consensus engine.

What is Burrow

Hyperledger Burrow is a permissioned blockchain node that executes smart contract code following the Ethereum specification. Burrow is built for a multi-chain universe with application specific optimization in mind. Burrow as a node is constructed out of three main components: the consensus engine, the permissioned Ethereum virtual machine and the rpc gateway. More specifically Burrow consists of the following:

• Consensus Engine: Transactions are ordered and finalised with the Byzantine fault-tolerant Tendermint protocol. The Tendermint protocol provides high transaction throughput over a set of known validators and prevents the blockchain from forking.
• Application Blockchain Interface (ABCI): The smart contract application interfaces with the consensus engine over the ABCI. The ABCI allows for the consensus engine to remain agnostic from the smart contract application.
• Smart Contract Application: Transactions are validated and applied to the application state in the order that the consensus engine has finalised them. The application state consists of all accounts, the validator set and the name registry. Accounts in Burrow have permissions and either contain smart contract code or correspond to a public-private key pair. A transaction that calls on the smart contract code in a given account will activate the execution of that account’s code in a permissioned virtual machine.
• Permissioned Ethereum Virtual Machine: This virtual machine is built to observe the Ethereum operation code specification and additionally asserts the correct permissions have been granted. Permissioning is enforced through secure native functions and underlies all smart contract code. An arbitrary but finite amount of gas is handed out for every execution to ensure a finite execution duration - “You don’t need money to play, when you have permission to play”.
• Application Binary Interface (ABI): Transactions need to be formulated in a binary format that can be processed by the blockchain node. Current tooling provides functionality to compile, deploy and link solidity smart contracts and formulate transactions to call smart contracts on the chain.
• API Gateway: Burrow exposes REST and JSON-RPC endpoints to interact with the blockchain network and the application state through broadcasting transactions, or querying the current state of the application. Websockets allow subscribing to events, which is particularly valuable as the consensus engine and smart contract application can give unambiguously finalised results to transactions within one blocktime of about one second.

Project documentation and Roadmap

Project information generally updated on a quarterly basis can be found on the Hyperledger Burrow Wiki.

Installation

• Install go version 1.10 or above and have $GOPATH set

go get github.com/hyperledger/burrow
cd github.com/hyperledger/burrow
make build

This will build the burrow and burrow-client binaries and put them in the bin/ directory. They can be executed from there or put wherever is convenient.

You can also install burrow into $GOPATH/bin with make install_db,

Usage

The end result will be a burrow.toml that will be read in from your current working directory when starting burrow.

Configuration

Configure Burrow

The quick-and-dirty one-liner looks like:

# Read spec on stdin
burrow spec -p1 -f1 | burrow configure -s- > burrow.toml

which translates into:

# This is a place we can store config files and burrow's working directory '.burrow'
mkdir chain_dir && cd chain_dir
burrow spec --participant-accounts=1 --full-accounts=1 > genesis-spec.json
burrow configure --genesis-spec=genesis-spec.json > burrow.toml

Run Burrow

Once the burrow.toml has been created, we run:

# To select our validator address by index in the GenesisDoc
burrow serve --validator-index=0
# Or to select based on address directly (substituting the example address below with your validator's):
burrow serve --validator-address=BE584820DC904A55449D7EB0C97607B40224B96E

and the logs will start streaming through.

If you would like to reset your node, you can just delete its working directory with rm -rf .burrow. In the context of a multi-node chain it will resync with peers, otherwise it will restart from height 0.

Logging

Logging is highly configurable through the burrow.toml [logging] section. Each log line is a list of key-value pairs that flows from the root sink through possible child sinks. Each sink can have an output, a transform, and sinks that it outputs to. Below is a more involved example than the one appearing in the default generated config of what you can configure:

# This is a top level config section within the main Burrow config
[logging]
  # All log lines are sent to the root sink from all sources
  [logging.root_sink]
    # We define two child sinks that each receive all log lines
    [[logging.root_sink.sinks]]
      # We send all output to stderr
      [logging.root_sink.sinks.output]
        output_type = "stderr"

    [[logging.root_sink.sinks]]
      # But for the second sink we define a transform that filters log lines from Tendermint's p2p module
      [logging.root_sink.sinks.transform]
        transform_type = "filter"
        filter_mode = "exclude_when_all_match"

        [[logging.root_sink.sinks.transform.predicates]]
          key_regex = "module"
          value_regex = "p2p"

        [[logging.root_sink.sinks.transform.predicates]]
          key_regex = "captured_logging_source"
          value_regex = "tendermint_log15"

      # The child sinks of this filter transform sink are syslog and file and will omit log lines originating from p2p
      [[logging.root_sink.sinks.sinks]]
        [logging.root_sink.sinks.sinks.output]
          output_type = "syslog"
          url = ""
          tag = "Burrow-network"

      [[logging.root_sink.sinks.sinks]]
        [logging.root_sink.sinks.sinks.output]
          output_type = "file"
          path = "/var/log/burrow-network.log"

Deploy Contracts

Now that the burrow node is running, we can deploy contracts.

For this step, we need two things: one or more solidity contracts, and an deploy.yaml.

Let's take a simple example, found in this directory.

The deploy.yaml should look like:

jobs:

- name: deployStorageK
  deploy:
    contract: storage.sol

- name: setStorageBaseBool
  set:
    val: "true"

- name: setStorageBool
  call:
    destination: $deployStorageK
    function: setBool
    data: [$setStorageBaseBool]

- name: queryStorageBool
  query-contract:
    destination: $deployStorageK
    function: getBool

- name: assertStorageBool
  assert:
    key: $queryStorageBool
    relation: eq
    val: $setStorageBaseBool

# tests string bools: #71
- name: setStorageBool2
  call:
    destination: $deployStorageK
    function: setBool2
    data: [true]

- name: queryStorageBool2
  query-contract:
    destination: $deployStorageK
    function: getBool2

- name: assertStorageBool2
  assert:
    key: $queryStorageBool2
    relation: eq
    val: "true"

- name: setStorageBaseInt
  set:
    val: 50000

- name: setStorageInt
  call:
    destination: $deployStorageK
    function: setInt
    data: [$setStorageBaseInt]

- name: queryStorageInt
  query-contract:
    destination: $deployStorageK
    function: getInt

- name: assertStorageInt
  assert:
    key: $queryStorageInt
    relation: eq
    val: $setStorageBaseInt

- name: setStorageBaseUint
  set:
    val: 9999999

- name: setStorageUint
  call:
    destination: $deployStorageK
    function: setUint
    data: [$setStorageBaseUint]

- name: queryStorageUint
  query-contract:
    destination: $deployStorageK
    function: getUint

- name: assertStorageUint
  assert:
    key: $queryStorageUint
    relation: eq
    val: $setStorageBaseUint

- name: setStorageBaseAddress
  set:
    val: "1040E6521541DAB4E7EE57F21226DD17CE9F0FB7"

- name: setStorageAddress
  call:
    destination: $deployStorageK
    function: setAddress
    data: [$setStorageBaseAddress]

- name: queryStorageAddress
  query-contract:
    destination: $deployStorageK
    function: getAddress

- name: assertStorageAddress
  assert:
    key: $queryStorageAddress
    relation: eq
    val: $setStorageBaseAddress

- name: setStorageBaseBytes
  set:
    val: marmatoshi

- name: setStorageBytes
  call:
    destination: $deployStorageK
    function: setBytes
    data: [$setStorageBaseBytes]

- name: queryStorageBytes
  query-contract:
    destination: $deployStorageK
    function: getBytes

- name: assertStorageBytes
  assert:
    key: $queryStorageBytes
    relation: eq
    val: $setStorageBaseBytes

- name: setStorageBaseString
  set:
    val: nakaburrow

- name: setStorageString
  call:
    destination: $deployStorageK
    function: setString
    data: [$setStorageBaseString]

- name: queryStorageString
  query-contract:
    destination: $deployStorageK
    function: getString

- name: assertStorageString
  assert:
    key: $queryStorageString
    relation: eq
    val: $setStorageBaseString

while our Solidity contract (storage.sol) looks like:

pragma solidity >=0.0.0;

contract SimpleStorage {
  bool storedBool;
  bool storedBool2;
  int storedInt;
  uint storedUint;
  address storedAddress;
  bytes32 storedBytes;
  string storedString;

  function setBool(bool x) {
    storedBool = x;
  }

  function getBool() constant returns (bool retBool) {
    return storedBool;
  }

  function setBool2(bool x) {
    storedBool2 = x;
  }

  function getBool2() constant returns (bool retBool) {
    return storedBool2;
  }

  function setInt(int x) {
    storedInt = x;
  }

  function getInt() constant returns (int retInt) {
    return storedInt;
  }

  function setUint(uint x) {
    storedUint = x;
  }

  function getUint() constant returns (uint retUint) {
    return storedUint;
  }

  function setAddress(address x) {
    storedAddress = x;
  }

  function getAddress() constant returns (address retAddress) {
    return storedAddress;
  }

  function setBytes(bytes32 x) {
    storedBytes = x;
  }

  function getBytes() constant returns (bytes32 retBytes) {
    return storedBytes;
  }

  function setString(string x) {
    storedString = x;
  }

  function getString() constant returns (string retString) {
    return storedString;
  }
}

Both files (deploy.yaml & storage.sol) should be in the same directory with no other yaml or sol files.

From inside that directory, we are ready to deploy.

burrow deploy --address=F71831847564B7008AD30DD56336D9C42787CF63

where you should replace the --address field with the ValidatorAddress at the top of your burrow.toml.

That's it! You've succesfully deployed (and tested) a Soldity contract to a Burrow node.

Note - that to redeploy the burrow chain later, you will need the same genesis-spec.json and burrow.toml files - so keep hold of them!

Contribute

We welcome any and all contributions. Read the contributing file for more information on making your first Pull Request to Burrow!

You can find us on:

• Hyperledger Chat
• Hyperledger Mailing List
• here on Github

Future work

For some (slightly outdated) ideas on future work, see the proposals document.

License

Apache 2.0