Play with the blockchain

Running the harmony blockchain with docker

The easiest way to run our blockchain locally is to use docker.
If you are on OS X, then install docker via brew.

$ brew cask install docker
$ open /Applications/Docker.app

then you can run

$ docker run -it harmonyone/main:stable /bin/bash

You’ll be in this current repository when the shell opens up, now let’s catch up on any missing
commits (all the following commands assume you are in the running docker container)

Bleeding edge master

$ git fetch
$ git reset --hard origin/master

Mainnet release intended branch

$ git fetch
$ git checkout t3
$ git reset --hard origin/t3

And now run the local blockchain

$ test/debug.sh

Using our hmy command line tool

Assuming that you got test/debug.sh running in your docker container, we can interact with
the running blockchain using our hmy command line tool. Its part of our
go-sdk repo, but our docker container already has it as
well and built.

Find your running container’s ID, here’s an example

$ docker container ls
CONTAINER ID        IMAGE                    COMMAND             CREATED             STATUS              PORTS               NAMES
62572a199bac        harmonyone/main:stable   "/bin/bash"         2 minutes ago       Up 2 minutes                            awesome_cohen

now lets get our second shell in the running container:

$ docker exec -it 62572a199bac /bin/bash

The container already comes with a prebuilt hmy that you can invoke anywhere, but lets go ahead
and build the latest version.

$ cd ../go-sdk
$ git fetch
$ git reset --hard origin/master
$ make
$ ./hmy version
Harmony (C) 2020. hmy, version v211-698b282 (@harmony.one 2020-01-17T00:58:51+0000)

Then checkout ./hmy cookbook for example usages. The majority of commands output legal JSON,
here is one example:

[email protected]:~/go/src/github.com/harmony-one/go-sdk# ./hmy blockchain latest-header
  "id": "0",
  "jsonrpc": "2.0",
  "result": {
    "blockHash": "0x34a8b155f90b8fc22342fc8b5d1c969ed836a2f666c506e4017b570dc337e88c",
    "blockNumber": 0,
    "epoch": 0,
    "lastCommitBitmap": "",
    "lastCommitSig": "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
    "leader": "one1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqquzw7vz",
    "shardID": 0,
    "timestamp": "2019-06-28 15:00:00 +0000 UTC",
    "unixtime": 1561734000,
    "viewID": 0

Developing in the container

The docker container is a full harmony development environment and comes with emacs, vim, ag, tig
and other creature comforts. Most importantly, it already has the go environment with our C/C++
based library dependencies (libbls and mcl) setup correctly for you. You can also change go
versions easily, an example:

$ eval $(gimme 1.14.1)

Note that changing the go version might mean that dependencies won’t work out right when trying to
run test/debug.sh again, get the correct environment again easily by exec bash.

Installation Requirements for directly on your MacOS X

GMP and OpenSSL

brew install gmp
brew install openssl

On Linux Box (assuming Amazon Linux 2 or Cent OS)

sudo yum install glibc-static gmp-devel gmp-static openssl-libs openssl-static gcc-c++

Dev Environment Setup

The required go version is: go1.14.1

export GOPATH=$HOME/<path_of_your_choice>

mkdir -p $HOME/<path_of_your_choice>/src/github.com/harmony-one

cd $HOME/<path_of_your_choice>/src/github.com/harmony-one

git clone [email protected]:harmony-one/mcl.git
git clone [email protected]:harmony-one/bls.git
git clone [email protected]:harmony-one/harmony.git

cd harmony


Note: make sure to run scripts/install_build_tools.shto make sure build tools are of correct versions.


If you want to bypass the Makefile:

export CGO_CFLAGS="-I$GOPATH/src/github.com/harmony-one/bls/include -I$GOPATH/src/github.com/harmony-one/mcl/include -I/usr/local/opt/openssl/include"
export CGO_LDFLAGS="-L$GOPATH/src/github.com/harmony-one/bls/lib -L/usr/local/opt/openssl/lib"
export LD_LIBRARY_PATH=$GOPATH/src/github.com/harmony-one/bls/lib:$GOPATH/src/github.com/harmony-one/mcl/lib:/usr/local/opt/openssl/lib
export GO111MODULE=on

Note : Some of our scripts require bash 4.x support, please install bash 4.x on MacOS X.

Build all executables

You can run the script ./scripts/go_executable_build.sh to build all the executables.

Build individual executables

Harmony server / main node:

./scripts/go_executable_build.sh harmony

Harmony docs and guides


API guides


Running locally

The debug.sh script calls test/deploy.sh script to create a local environment of Harmony blockchain devnet based on the configuration file.
The configuration file configures number of nodes and their IP/Port.
The script starts 2 shards and 7 nodes in each shard.


Terminate the local blockchain



Make sure you use the following command and make sure everything passed before submitting your code.



Harmony is licensed under the MIT License. See LICENSE file for
the terms and conditions.

Harmony includes third-party open source code. In general, a source subtree
with a LICENSE or COPYRIGHT file is from a third party, and our
modifications thereto are licensed under the same third-party open source

Also please see our Fiduciary License Agreement if you are
contributing to the project. By your submission of your contribution to us, you
and we mutually agree to the terms and conditions of the agreement.

Contributing To Harmony

See CONTRIBUTING for details.

Development Status

Features Done

  • Fully sharded network with beacon chain and shard chains
  • Sharded P2P network and P2P gossiping
  • FBFT (Fast Byzantine Fault Tolerance) Consensus with BLS multi-signature
  • Consensus view-change protocol
  • Account model and support for Solidity
  • Cross-shard transaction
  • VRF (Verifiable Random Function) and VDF (Verifiable Delay Function)
  • Cross-links
  • EPoS staking mechanism
  • Kademlia routing

Features Planned after Mainnet Open Staking

  • Resharding
  • Integration with WASM
  • Fast state synchronization
  • Auditable privacy asset using ZK proof


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