zebra/README.md

![Zebra logotype](https://zfnd.org/wp-content/uploads/2022/03/zebra-logotype.png)

---

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## Contents

- [About](#about)
- [Getting Started](#getting-started)
  - [Docker](#docker)
  - [Building Zebra](#building-zebra)
    - [Optional Features](#optional-features)
- [Known Issues](#known-issues)
- [Future Work](#future-work)
- [Documentation](#documentation)
- [User support](#user-support)
- [Security](#security)
- [License](#license)

## About

[Zebra](https://zebra.zfnd.org/) is the Zcash Foundation's independent,
consensus-compatible implementation of a Zcash node.

Zebra's network stack is interoperable with `zcashd`, and Zebra implements all
the features required to reach Zcash network consensus, including the validation
of all the consensus rules for the NU5 network upgrade.
[Here](https://doc.zebra.zfnd.org/zebrad/index.html#zebra-advantages) are some
benefits of Zebra.

Zebra validates blocks and transactions, but needs extra software to generate
them:

- To generate transactions, [run Zebra with
  `lightwalletd`](https://zebra.zfnd.org/user/lightwalletd.html).
- To generate blocks, [enable mining
  support](https://zebra.zfnd.org/user/mining.html), and use a mining pool or
  miner with Zebra's mining JSON-RPCs. Mining support is currently incomplete,
  experimental, and off by default.

Please [join us on Discord](https://discord.gg/na6QZNd) if you'd like to find
out more or get involved!

## Getting Started

You can run Zebra using our Docker image or you can build it manually. Please
see the [System Requirements](https://zebra.zfnd.org/user/requirements.html)
section in the Zebra book for system requirements.

### Docker

This command will run our latest release, and sync it to the tip:

```sh
docker run zfnd/zebra:latest
```

For more information, read our [Docker documentation](https://zebra.zfnd.org/user/docker.html).

### Building Zebra

Building Zebra requires [Rust](https://www.rust-lang.org/tools/install),
[libclang](https://clang.llvm.org/doxygen/group__CINDEX.html),
[pkg-config](http://pkgconf.org/), and a C++ compiler.

Zebra is tested with the latest `stable` Rust version. Earlier versions are not
supported or tested. Any Zebra release can start depending on new features in the
latest stable Rust.

Every few weeks, we release a [new Zebra version](https://github.com/ZcashFoundation/zebra/releases).

Below are quick summaries for installing the dependencies on your machine.

<details>

<summary><h4>General instructions for installing dependencies</h4></summary>

1. Install [`cargo` and `rustc`](https://www.rust-lang.org/tools/install).

2. Install Zebra's build dependencies:

   - **libclang** is a library that might have different names depending on your
     package manager. Typical names are `libclang`, `libclang-dev`, `llvm`, or
     `llvm-dev`.
   - **clang** or another C++ compiler: `g++` (all platforms) or `Xcode` (macOS).
   - **pkg-config**

</details>

<details>

<summary><h4>Dependencies on Arch</h4></summary>

```sh
sudo pacman -S rust clang pkgconf
```

Note that the package `clang` includes `libclang` as well as the C++ compiler.

</details>

Once the dependencies are in place, you can build and install Zebra:

```sh
cargo install --locked zebrad
```

You can start Zebra by

```sh
zebrad start
```

See the [Installing Zebra](https://zebra.zfnd.org/user/install.html) and [Running Zebra](https://zebra.zfnd.org/user/run.html)
sections in the book for more details.

#### Optional Features

You can also build Zebra with additional [Cargo features](https://doc.rust-lang.org/cargo/reference/features.html#command-line-feature-options):

- `getblocktemplate-rpcs` for [mining support](https://zebra.zfnd.org/user/mining.html)
- `prometheus` for [Prometheus metrics](https://zebra.zfnd.org/user/metrics.html)
- `progress-bar` [experimental progress bars](https://zfnd.org/experimental-zebra-progress-bars/)
- `sentry` for [Sentry monitoring](https://zebra.zfnd.org/user/tracing.html#sentry-production-monitoring)
- `elasticsearch` for [experimental Elasticsearch support](https://zebra.zfnd.org/user/elasticsearch.html)

You can combine multiple features by listing them as parameters of the `--features` flag:

```sh
cargo install --features="<feature1> <feature2> ..." ...
```

Our full list of experimental and developer features is in [the API
documentation](https://doc.zebra.zfnd.org/zebrad/index.html#zebra-feature-flags).

Some debugging and monitoring features are disabled in release builds to increase
performance.

## Known Issues

There are a few bugs in Zebra that we're still working on fixing:

- Zebra currently gossips and connects to [private IP addresses](https://en.wikipedia.org/wiki/IP_address#Private_addresses), we want to [disable private IPs but provide a config (#3117)](https://github.com/ZcashFoundation/zebra/issues/3117) in an upcoming release

- If Zebra fails downloading the Zcash parameters, use [the Zcash parameters download script](https://github.com/zcash/zcash/blob/master/zcutil/fetch-params.sh) instead.

- Block download and verification sometimes times out during Zebra's initial sync [#5709](https://github.com/ZcashFoundation/zebra/issues/5709). The full sync still finishes reasonably quickly.

- Rust 1.70 [causes crashes during shutdown on macOS x86_64 (#6812)](https://github.com/ZcashFoundation/zebra/issues/6812). The state cache should stay valid despite the crash.

- No Windows support [#3801](https://github.com/ZcashFoundation/zebra/issues/3801). We used to test with Windows Server 2019, but not any more; see the issue for details.

- Experimental Tor support is disabled until [Zebra upgrades to the latest `arti-client`](https://github.com/ZcashFoundation/zebra/issues/5492). This happened due to a Rust dependency conflict, which could only be resolved by `arti` upgrading to a version of `x25519-dalek` with the dependency fix.

## Future Work

We will continue to add new features as part of future network upgrades, and in response to community feedback.

## Documentation

The [Zebra website](https://zebra.zfnd.org/) contains user documentation, such
as how to run or configure Zebra, set up metrics integrations, etc., as well as
developer documentation, such as design documents. We also render [API
documentation](https://doc.zebra.zfnd.org) for the external API of our crates,
as well as [internal documentation](https://doc-internal.zebra.zfnd.org) for
private APIs.

## User support

For bug reports please [open a bug report ticket in the Zebra repository](https://github.com/ZcashFoundation/zebra/issues/new?assignees=&labels=C-bug%2C+S-needs-triage&projects=&template=bug_report.yml&title=%5BUser+reported+bug%5D%3A+).

Alternatively by chat, [Join the Zcash Foundation Discord Server](https://discord.com/invite/aRgNRVwsM8) and find the #zebra-support channel.

## Security

Zebra has a [responsible disclosure policy](https://github.com/ZcashFoundation/zebra/blob/main/SECURITY.md), which we encourage security researchers to follow.

## License

Zebra is distributed under the terms of both the MIT license
and the Apache License (Version 2.0).

See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT).

Some Zebra crates are distributed under the [MIT license only](LICENSE-MIT),
because some of their code was originally from MIT-licensed projects.
See each crate's directory for details.