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

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## Rationale
[Nimbus: an Ethereum 2.0 Sharding Client](https://github.com/status-im/nimbus/blob/master/doc/Nimbus%20-%20An%20Ethereum%202.0%20Sharding%20Client_xt.md)

## Building & Testing

### Prerequisites

* A recent version of Nim
  * We use the version in the [Status fork](https://github.com/status-im/Nim)
  * Normally, this is the latest released version of Nim but it may also include custom patches
  * Follow the Nim installation instructions or use [choosenim](https://github.com/dom96/choosenim) to manage your Nim versions
* A recent version of Facebook's [RocksDB](https://github.com/facebook/rocksdb/)
  * Compile [from source](https://github.com/facebook/rocksdb/blob/master/INSTALL.md) or use the package manager of your OS

### Obtaining the prerequisites through the Nix package manager

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

``` bash
nix-shell nimbus.nix
```

### Build

We use [Nimble](https://github.com/nim-lang/nimble) to manage dependencies and run tests.

To build and run test suite:
```bash
nimble test
```

Based on our config, Nimble will write binaries to `build/` - you can do this manually also, as in the following examples:

Run example:
```bash
mkdir -p build
nim c -o:build/decompile_smart_contract -r examples/decompile_smart_contract.nim
```

Run Ethereum [JSON-based VM tests](https://github.com/ethereum/tests/):
```
mkdir -p build
nim c -o:build/test_vm_json -r --experimental:forLoopMacros tests/test_vm_json.nim
```

#### Troubleshooting

Sometimes, the build will fail even though the latest CI is green - here are a few tips to handle this:

* Wrong Nim version
  * We depend on many bleeding-edge features - Nim regressions often happen
  * Use the [Status fork](https://github.com/status-im/Nim) of Nim
* Wrong versions of dependencies
  * nimble dependency tracking often breaks due to its global registry
  * wipe the nimble folder and try again
* C compile or link fails
  * Nim compile cache is pretty buggy and sometimes will fail to recompile
  * wipe your nimcache folder

## License

Licensed under one of the following:

 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license: [LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT