# Nimbus: an Ethereum 2.0 Sharding Client for Resource-Restricted Devices

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## Rationale

[Nimbus: an Ethereum 2.0 Sharding Client](https://our.status.im/nimbus-for-newbies/). The code in this repository is currently focusing on Ethereum 1.0 feature parity, while all 2.0 research and development is happening in parallel in [nim-beacon-chain](https://github.com/status-im/nim-beacon-chain).

## Development Updates

To keep up to date with changes and development progress, follow the [Nimbus blog](https://our.status.im/tag/nimbus/).

## Building & Testing

_We currently do not guarantee that Nimbus will work on Windows._

### Prerequisites

#### Rocksdb

A recent version of Facebook's [RocksDB](https://github.com/facebook/rocksdb/) is needed - it can usually be installed using a package manager of your choice:

```bash
# MacOS
brew install rocksdb

# Fedora
dnf install rocksdb-devel

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

# Arch (AUR)
pakku -S rocksdb
```

On Windows, you can [download pre-compiled DLLs](#windows).

You can also build and install it by following [their instructions](https://github.com/facebook/rocksdb/blob/master/INSTALL.md).

### PCRE

If you don't already have it, you will also need PCRE to build Nimbus.

```bash
# MacOS
brew install pcre

# Fedora
dnf install pcre

# Debian and Ubuntu
sudo apt-get install libpcre libpcre-dev

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

On Windows, the aforementioned DLL download will take care of this for you ([download pre-compiled DLLs](#windows)).

#### Developer tools

GNU make, Bash and the usual POSIX utilities

#### Obtaining the prerequisites through the Nix package manager

*Experimental*

Users of the [Nix package manager](https://nixos.org/nix/download.html) can install all prerequisites simply by running:

``` bash
nix-shell default.nix
```

### Build & Develop

#### POSIX-compatible OS

To build Nimbus (in "build/nimbus"), just execute:

```bash
make
```

Running `./build/nimbus --help` will provide you with a list of
the available command-line options. To start syncing with mainnet, just execute `./build/nimbus`
without any parameters.

To execute all tests:
```bash
make test
```

To pull the latest changes in all the Git repositories involved:
```bash
git pull
make update
```

To run a command that might use binaries from the Status Nim fork:
```bash
./env.sh bash
which nim
```

Our Wiki provides additional helpful information for [debugging individual test cases][1]
and for [pairing Nimbus with a locally running copy of Geth][2].

#### Windows

_Experimental support!_

Install Mingw-w64 for your architecture using the "[MinGW-W64 Online
Installer](https://sourceforge.net/projects/mingw-w64/files/)" (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](https://gitforwindows.org/) and use a "Git Bash" shell to clone and build Nimbus.

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

#### Raspberry PI

*Experimental* The code can be compiled on a Raspberry PI:

* Raspberry PI 3b+
* 64gb SD Card (less might work too, but the default recommended 4-8GB will probably be too small)
* [Rasbian Buster Lite](https://www.raspberrypi.org/downloads/raspbian/) - Lite version is enough to get going and will save some disk space!

Assuming you're working with a freshly written image:

```bash

# Start by increasing swap size to 2gb:
sudo vi /etc/dphys-swapfile
# Set CONF_SWAPSIZE=2048
# :wq
sudo reboot

# Install prerequisites
sudo apt-get install git libgflags-dev libsnappy-dev

mkdir status
cd status

# Install rocksdb
git clone https://github.com/facebook/rocksdb.git
cd rocksdb
make shared_lib
sudo make install
cd..

# Raspberry pi doesn't include /usr/local/lib in library search path - need to add
export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

git clone https://github.com/status-im/nimbus.git

cd nimbus

# Follow instructions above!
```

### Development tips

- you can switch the DB backend with a Nim compiler define:
  `-d:nimbus_db_backend=...` where the (case-insensitive) value is one of
  "rocksdb" (the default), "sqlite", "lmdb"

- the Premix debugging tools are [documented separately](premix/readme.md)

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

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

- same for the [Chronicles log level](https://github.com/status-im/nim-chronicles#chronicles_log_level):

```bash
make LOG_LEVEL=DEBUG nimbus # this is the default
make LOG_LEVEL=TRACE nimbus # log everything
```

- pass arbitrary parameters to the Nim compiler:

```bash
make NIMFLAGS="-d:release"
```

- if you want to use SSH keys with GitHub (also handles submodules):

```bash
make github-ssh
```

- force a Nim compiler rebuild:

```bash
rm vendor/Nim/bin/nim
make -j8 build-nim
```

#### Git submodule workflow

Working on a dependency:

```bash
cd vendor/nim-chronicles
git checkout -b mybranch
# make some changes
git status
git commit -a
git push origin mybranch
# create a GitHub PR and wait for it to be approved and merged
git checkout master
git pull
git branch -d mybranch
# realise that the merge was done without "--no-ff"
git branch -D mybranch
# update the submodule's commit in the superproject
cd ../..
git status
git add vendor/nim-chronicles
git commit
```

It's important that you only update the submodule commit after it's available upstream.

You might want to do this on a new branch of the superproject, so you can make
a GitHub PR for it and see the CI test results.

Don't update all Git submodules at once, just because you found the relevant
Git command or `make` target. You risk updating submodules to other people's
latest commits when they are not ready to be used in the superproject.

Adding the submodule "https://github.com/status-im/foo" to "vendor/foo":

```bash
./add_submodule.sh status-im/foo
```

Removing the submodule "vendor/bar":

```bash
git submodule deinit -f -- vendor/bar
git rm -f vendor/bar
```

Checking out older commits, either to bisect something or to reproduce an older build:

```bash
git checkout <commit hash here>
make clean
make -j8 update
```

Running a dependency's test suite using `nim` instead of `nimble` (which cannot be
convinced not to run a dependency check, thus clashing with our jury-rigged
"vendor/.nimble/pkgs"):

```bash
cd vendor/nim-blscurve
../../nimble.sh test
```

### Troubleshooting

Report any errors you encounter, please, if not [already documented](https://github.com/status-im/nimbus/issues)!

* Turn it off and on again:

```bash
make clean
make update
```

## License

Licensed and distributed under either of

* MIT license: [LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT

or

* Apache License, Version 2.0, ([LICENSE-APACHEv2](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.

[1]: https://github.com/status-im/nimbus/wiki/Understanding-and-debugging-Nimbus-EVM-JSON-tests
[2]: https://github.com/status-im/nimbus/wiki/Debugging-state-reconstruction