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## Motivation
Round timing in the Hare was based on timers and tickers integrated in the flow. This has two main downsides:
1. Round timing depends on the time it takes to run the code before the timer is set (this is mitigated by running most code in goroutines, reducing the time and variability of time before setting timers, but in environments with tight resources this could still be an issue).
2. It's practically impossible to mock/patch the timing mechanism for accelerated or tightly controlled tests.

## Changes
This PR introduces a Hare-round clock that calculates when a round ends based on the time the layer starts and then sets precise timers internally based on those calculations. Each "consensus process" (Hare for a particular layer) has its own clock instance which is generated by a clock factory that can be easily mocked and patched in test code to achieve desired behaviors.

## Test Plan
- New unit tests for the new clock.
- Hare unit tests now take advantage of the ability to patch the clock.
- Existing Hare and general system tests.

- [ ] Test changes and document test plan

## DevOps Notes
<!-- Please uncheck these items as applicable to make DevOps aware of changes that may affect releases -->
- [x] This PR does not require configuration changes (e.g., environment variables, GitHub secrets, VM resources)
- [x] This PR does not affect public APIs
- [x] This PR does not rely on a new version of external services (PoET, elasticsearch, etc.)
- [x] This PR does not make changes to log messages (which monitoring infrastructure may rely on)

Co-authored-by: Alexey Sudachen <>

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A Programmable Cryptocurrency

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💾⏰💪 Thanks for your interest in this open source project. This repo is the go implementation of the Spacemesh p2p full node software.

Spacemesh is a decentralized blockchain computer using a new race-free consensus protocol that doesn't involve energy-wasteful proof of work.

We aim to create a secure and scalable decentralized computer formed by a large number of desktop PCs at home.

We are designing and coding a modern blockchain platform from the ground up for scale, security and speed based on the learnings of the achievements and mistakes of previous projects in this space.

To learn more about Spacemesh head over to

To learn more about the Spacemesh protocol watch this video.


Spacemesh is designed to create a decentralized blockchain smart contracts computer and a cryptocurrency that is formed by connecting the home PCs of people from around the world into one virtual computer without incurring massive energy waste and mining pools issues that are inherent in other blockchain computers, and provide a provably-secure and incentive-compatible smart contracts execution environment.

Spacemesh is designed to be ASIC-resistant and in a way that doesn’t give an unfair advantage to rich parties who can afford setting up dedicated computers on the network. We achieve this by using a novel consensus protocol and optimize the software to be most effectively be used on home PCs that are also used for interactive apps.

What is this good for?

Provide dapp and app developers with a robust way to add value exchange and other value related features to their apps at scale. Our goal is to create a truly decentralized cryptocurrency that fulfills the original vision behind bitcoin to become a secure trustless store of value as well as a transactional currency with extremely low transaction fees.

Target Users

go-spacemesh is designed to be installed and operated on users' home PCs to form one decentralized computer. It is going to be distributed in the Spacemesh App but people can also build and run it from source code.

Project Status

We are working hard towards our first major milestone - a public permissionless testnet running the Spacemesh consensus protocol.


Thank you for considering to contribute to the go-spacemesh open source project!

We welcome contributions large and small and we actively accept contributions.

Diggin' Deeper

Please read the Spacemesh full FAQ.

go-spacemesh Architecture

High Level Design

Client Software Architecture


git clone

-- or --

Fork the project from

Since the project uses Go Modules it is best to place the code outside your $GOPATH. Read this for alternatives.

Setting Up Local Dev Environment

Building is supported on OS X, Linux, FreeBSD, and Windows.

Install Go 1.15 or later for your platform, if you haven't already.

On Windows you need to install make via msys2, MingGW-w64 or [mingw] (

Ensure that $GOPATH is set correctly and that the $GOPATH/bin directory appears in $PATH.

Before building we need to set up the golang environment. Do this by running:

make install


To build go-spacemesh for your current system architecture, from the project root directory, use:

make build

(On FreeBSD, you should instead use gmake build. You can install gmake with pkg install gmake if it isn't already installed.)

This will build the go-spacemesh binary, saving it in the build/ directory.

To build a binary for a specific architecture directory use:

make darwin | linux | freebsd | windows

Platform-specific binaries are saved to the /build directory.

Using go build and go test without make

To build code without using make the CGO_LDFLAGS environment variable must be set appropriately. The required value can be obtained by running make print-ldflags or make print-test-ldflags.

This can be done in 3 ways:

  1. Setting the variable in the shell environment (e.g., in bash run CGO_LDFLAGS=$(make print-ldflags)).
  2. Prefixing the key and value to the go command (e.g., CGO_LDFLAGS=$(make print-ldflags) go build).
  3. Using go env -w CGO_LDFLAGS=$(make print-ldflags), which persistently adds this value to Go's environment for any future runs.

There's a handy shortcut for the 3rd method: make go-env or make go-env-test.


go-spacemesh is p2p software which is designed to form a decentralized network by connecting to other instances of go-spacemesh running on remote computers.

To run go-spacemesh you need to specify the parameters shared between all instances on a specific network.

You specify these parameters by providing go-spacemesh with a json config file. Other CLI flags control local node behavior and override default values.

Joining a Testnet (without mining)

  1. Build go-spacemesh from source code.
  2. Download the testnet's json config file. Make sure your local config file suffix is .json.
  3. Start go-spacemesh with the following arguments:
./go-spacemesh --tcp-port [a_port] --config [configFileLocation] -d [nodeDataFilesPath]

Assuming tn1.json is a testnet config file saved in the same directory as go-spacemesh, use the following command to join the testnet. The data folder will be created in the same directory as go-spacemesh. The node will use TCP port 7513 and UDP port 7513 for p2p connections:

./go-spacemesh --tcp-port 7513 --config ./tn1.json -d ./sm_data
  1. Build the CLI Wallet from source code and run it:

  2. Use the CLI Wallet commands to setup accounts, start smeshing and execute transactions.


Joining a Testnet (with mining)

  1. Run go-spacemesh to join a testnet without mining (see above).
  2. Run the CLI Wallet to create a coinbase account. Save your coinbase account public address - you'll need it later.
  3. Stop go-spacemesh and start it with the following params:
./go-spacemesh --tcp-port [a_port] --config [configFileLocation] -d [nodeDataFilesPath] --coinbase [coinbase_account] --start-mining --post-datadir [dir_for_post_data]
./go-spacemesh --tcp-port 7513 --config ./tn1.json -d ./sm_data --coinbase 0x36168c60e06abbb4f5df6d1dd6a1b15655d71e75 --start-mining --post-datadir ./post_data
  1. Use the CLI wallet to check your coinbase account balance and to transact

Joining Spacemesh (TweedleDee) Testnet

Find the latest Testnet release in the releases and download the precompiled binary for your platform of choice (or you can compile go-spacemesh yourself, from source, using the release tag). The release notes contain a link to a config.json file that you'll need to join the testnet.

Note that you must download (or build) precisely this version (latest Testnet release) of go-spacemesh, and the compatible config file, in order to join the current testnet. Older versions of the code may be incompatible with this testnet, and a different config file will not work.


NOTE: if tests are hanging try running ulimit -n 400. some tests require that to work.

make test


make cover

Continuous Integration

We've enabled continuous integration on this repository in GitHub. You can read more about our CI workflows.


A Dockerfile is included in the project allowing anyone to build and run a docker image:

docker build -t spacemesh .
docker run -d --name=spacemesh spacemesh


On Windows you will need the following prerequisites:

  • Powershell - included by in Windows by default since Windows 7 and Windows Server 2008 R2
  • Git for Windows - after installation remove C:\Program Files\Git\bin from System PATH (if present) and add C:\Program Files\Git\cmd to System PATH (if not already present)
  • Make - after installation add C:\Program Files (x86)\GnuWin32\bin to System PATH
  • Golang
  • GCC. There are several ways to install gcc on Windows, including Cygwin. Instead, we recommend tdm-gcc which we've tested.

Close and reopen powershell to load the new PATH. You can then run the command make install followed by make build as on UNIX-based systems.

Running a Local Testnet

  • You can run a local Spacemesh Testnet with 6 full nodes, 6 user accounts, and 1 POET support service on your computer using docker.
  • The local testnet full nodes are built from this repo.
  • This is a great way to get a feel for the protocol and the platform and to start hacking on Spacemesh.
  • Follow the steps in our Local Testnet Guide

Next Steps...

Got Questions?