Ethereum Beacon Chain

Nimbus beacon chain is a research implementation of the beacon chain component of the upcoming Ethereum Serenity upgrade, aka eth2. See the main Nimbus project for the bigger picture.

Interop (for other Eth2 clients)

Nimbus is currently going through interoperability testing with several other beacon chain implementations - several tools are available to make this testing easier:

• multinet - a set of scripts to build and run several Eth2 clients locally
• ncli - command line tools for working with SSZ files and state transitions

⚠️ Important: To save bandwith export GIT_LFS_SKIP_SMUDGE=1 before cloning the repo. This prevents LFS during unusual clones (i.e. when you add --recurse-submodules without being instructed to do so).

Related

• status-im/nimbus: main Nimbus repository - start here to learn more about the Nimbus eco-system
• ethereum/eth2.0-specs: Serenity specification that this project implements
• ethereum/beacon_chain: reference implementation from the Ethereum foundation

You can check where the beacon chain fits in the Ethereum research ecosystem in the Status Athenaeum.

Building and Testing

Prerequisites

• RocksDB
• PCRE
• Go 1.12 (for compiling libp2p daemon - being phased out)
• GNU Make, Bash and the usual POSIX utilities. Git 2.9.4 or newer.

On Windows, a precompiled DLL collection download is available through the fetch-dlls Makefile target: (Windows instructions).

# MacOS with Homebrew
brew install rocksdb pcre

# Fedora
dnf install rocksdb-devel pcre

# Debian and Ubuntu
sudo apt-get install librocksdb-dev libpcre3-dev

# Arch (AUR)
pakku -S rocksdb pcre-static

rocksdb can also be installed by following their instructions.

Build & Develop

POSIX-compatible OS

make # The first `make` invocation will update all Git submodules and prompt you to run `make` again.
     # It's only required once per Git clone. You'll run `make update` after each `git pull`, in the future,
     # to keep those submodules up to date.

# Run tests
make test

# Update to latest version
git pull
make update

To run a command that might use binaries from the Status Nim fork:

./env.sh bash # start a new interactive shell with the right env vars set
which nim
nim --version

# or without starting a new interactive shell:
./env.sh which nim
./env.sh nim --version

Windows

(Experimental support!)

Install Mingw-w64 for your architecture using the "MinGW-W64 Online Installer" (first link under the directory listing). Run it and select your architecture in the setup menu ("i686" on 32-bit, "x86_64" on 64-bit), set the threads to "win32" and the exceptions to "dwarf" on 32-bit and "seh" on 64-bit. Change the installation directory to "C:\mingw-w64" and add it to your system PATH in "My Computer"/"This PC" -> Properties -> Advanced system settings -> Environment Variables -> Path -> Edit -> New -> C:\mingw-w64\mingw64\bin (it's "C:\mingw-w64\mingw32\bin" on 32-bit)

Install Git for Windows and use a "Git Bash" shell to clone and build nim-beacon-chain.

If you don't want to compile RocksDB and SQLite separately, you can fetch pre-compiled DLLs with:

mingw32-make # this first invocation will update the Git submodules
mingw32-make fetch-dlls # this will place the right DLLs for your architecture in the "build/" directory

You can now follow those instructions in the previous section by replacing make with mingw32-make (regardless of your 32-bit or 64-bit architecture):

mingw32-make test # run the test suite

Raspberry PI

Raspberry PI support is experimental - see Nimbus instructions for how to prepare the Raspberry for building nim-beacon-chain.

Beacon node simulation

The beacon node simulation will create a full peer-to-peer network of beacon nodes and validators, and run the beacon chain in real time. To change network parameters such as shard and validator counts, see start.sh.

# Clear data files from your last run and start the simulation with a new genesis block:
make VALIDATORS=192 NODES=6 MISSING_NODES=1 eth2_network_simulation

# In another terminal, get a shell with the right environment variables set:
./env.sh bash

# In the above example, the network is prepared for 7 beacon nodes but one of
# them is not started by default (`MISSING_NODES`) - you can start it separately
# by running:
./tests/simulation/run_node.sh 6 # (or the 0-based node number of the missing node)

# Running a separate node allows you to test sync as well as see what the action
# looks like from a single nodes' perspective.

You can also separate the output from each beacon node in its own panel, using multitail:

make USE_MULTITAIL="yes" eth2_network_simulation

You can find out more about it in the development update.

Alternatively, fire up our experimental Vagrant instance with Nim pre-installed and give us yout feedback about the process!

Visualising simulation metrics

Those generic instructions from the Nimbus repo apply here as well.

Specific steps:

# This will generate the Prometheus config and the Grafana dashboard on the fly,
# based on the number of nodes (which you can control by passing something like NODES=6 to `make`).
make VALIDATORS=192 NODES=6 MISSING_NODES=0 eth2_network_simulation

# In another terminal tab, after the sim started:
cd tests/simulation/prometheus
prometheus

The dashboard you need to import in Grafana is "tests/simulation/beacon-chain-sim-all-nodes-Grafana-dashboard.json".

Obligatory screenshot.

Makefile tips and tricks for developers

• build all those tools known to the Makefile:

# (assuming you have 4 CPU cores and want to take advantage of them):
make -j4

• build a specific tool:

make state_sim

• you can control the Makefile's verbosity with the V variable (defaults to 0):

make V=1 # verbose
make V=2 test # even more verbose

• same for the Chronicles log level:

make LOG_LEVEL=DEBUG bench_bls_sig_agggregation # this is the default
make LOG_LEVEL=TRACE beacon_node # log everything

• pass arbitrary parameters to the Nim compiler:

make NIMFLAGS="-d:release"

• you can freely combine those variables on the make command line:

make -j8 NIMFLAGS="-d:release" USE_MULTITAIL=yes eth2_network_simulation

State transition simulation

The state transition simulator can quickly run the Beacon chain state transition function in isolation and output JSON snapshots of the state. The simulation runs without networking and blocks are processed without slot time delays.

# build and run the state simulator, then display its help ("-d:release" speeds it
# up substantially, allowing the simulation of longer runs in reasonable time)
make NIMFLAGS="-d:release" state_sim
build/state_sim --help

Testnet

The beacon chain now has a public testnet available. Connect to it with:

make testnet0
scripts/testnet0.sh # this launches the testnet0-specific node you just built

For more information about the testnet and to find out how to launch your own, see this announcement and the official docs on launching the testnets.

Convention

Ethereum Foundation uses:

• snake_case for fields and procedure names
• MACRO_CASE for constants
• PascalCase for types

Nim NEP-1 recommends:

• camelCase for fields and procedure names
• PascalCase for constants
• PascalCase for types

To facilitate collaboration and comparison, nim-beacon-chain uses the Ethereum Foundation convention.

License

Licensed and distributed under either of

• MIT license: LICENSE-MIT or http://opensource.org/licenses/MIT

or

• Apache License, Version 2.0, (LICENSE-APACHEv2 or http://www.apache.org/licenses/LICENSE-2.0)

at your option. These files may not be copied, modified, or distributed except according to those terms.