= Polkadot
:Author: Polkadot developers
:Revision: 0.3.0
:toc:
:sectnums:

Implementation of a https://polkadot.network node in Rust.

== NOTE

In 2017 we split our implementation of "Polkadot" from its platform-level component "Substrate". When we split them, we split the Polkadot code off into another repo (this repo), leaving the link:https://github.com/paritytech/substrate[**Substrate** repo] to be what used to be Polkadot, along with its branches and releases.

We are actively building both Substrate and Polkadot, but things will be a little odd for a while.

To play on the ("Alexander") testnet, you'll want the PoC-3 code which is in this **Polkadot** repo.

* **Polkadot PoC-3 "Alexander"** is in this link:https://github.com/paritytech/polkadot/tree/v0.3[**Polkadot**]repo branch `v0.3`

* **Polkadot PoC-2 "Krumme Lanke"** is in the link:https://github.com/paritytech/substrate/tree/v0.2[**Substrate**] repo branch `v0.2`

If you see "substrate" and are wondering why you need it for Polkadot, now you know.

Note that **Polkadot PoC-4** is yet to be released and *will be* in branch `v0.4` in this **Polkadot** repo.


== To play

=== Install Rust
If you'd like to play with Polkadot, you'll need to install a client like this
one. First, get Rust (1.32.0 or later) and the support software if you don't already have it:

[source, shell]
----
curl https://sh.rustup.rs -sSf | sh
sudo apt install make clang pkg-config libssl-dev
----

If you already have Rust installed, make sure you're using the latest version by running:


[source, shell]
----
rustup update
----

=== Install PoC-3 "Alexander" Testnet

Install Polkadot PoC-3 and have a `polkadot` binary installed to your `PATH` with:

[source, shell]
cargo install --git https://github.com/paritytech/polkadot.git --branch v0.3 polkadot

Connect to the global "Alexander" testnet by default by running:

[source, shell]
polkadot

=== Install PoC-2 "Krumme Lanke" Testnet

Install Polkadot PoC-2 and have a `polkadot` binary installed to your `PATH` with:

[source, shell]
cargo install --git https://github.com/paritytech/substrate.git --branch v0.2 polkadot

Connect to the global "Krumme Lanke" testnet by default by running:

[source, shell]
polkadot

=== Install a custom Testnet version

You can run the following to get the very latest version of Polkadot, but these instructions will not work in that case.

[source, shell]
cargo install --git https://github.com/paritytech/polkadot.git polkadot

If you want a specific version of Polkadot, say `0.2.5`, you may run

[source, shell]
cargo install --git https://github.com/paritytech/substrate.git --tag v0.2.5 polkadot

=== Obtaining DOTs

If you want to do anything on it (not that there's much to do), then you'll need to get an account and some Alexander or Krumme Lanke DOTs. Ask in the Polkadot watercooler.

=== Development

You can run a simple single-node development "network" on your machine by
running in a terminal:

[source, shell]
polkadot --dev

You can muck around by cloning and building the http://github.com/paritytech/polka-ui and http://github.com/paritytech/polkadot-ui or just heading to https://polkadot.js.org/apps and choose "Alexander (hosted by Parity)" from the Settings menu.


== Building

=== Hacking on Polkadot

If you'd actually like hack on Polkadot, you can just grab the source code and build it. Ensure you have Rust and the support software installed:

[source, shell]
----
curl https://sh.rustup.rs -sSf | sh
rustup update nightly
rustup target add wasm32-unknown-unknown --toolchain nightly
rustup update stable
cargo install --git https://github.com/alexcrichton/wasm-gc
sudo apt install cmake pkg-config libssl-dev git
----

Then, grab the Polkadot source code:

[source, shell]
----
git clone https://github.com/paritytech/polkadot.git
cd polkadot
----

Then build the code:

[source, shell]
----
./scripts/build.sh  # Builds the WebAssembly binaries
cargo build # Builds all native code
----

You can run the tests if you like:

[source, shell]
cargo test --all

You can start a development chain with:

[source, shell]
cargo run -- --dev

Detailed logs may be shown by running the node with the following environment variables set:

[source, shell]
RUST_LOG=debug RUST_BACKTRACE=1 cargo run —- --dev

=== Local Two-node Testnet

If you want to see the multi-node consensus algorithm in action locally, then you can create a local testnet. You'll need two terminals open. In one, run:

[source, shell]
polkadot --chain=local --validator --key Alice -d /tmp/alice

And in the other, run:

[source, shell]
polkadot --chain=local --validator --key Bob -d /tmp/bob --port 30334 --bootnodes '/ip4/127.0.0.1/tcp/30333/p2p/ALICE_BOOTNODE_ID_HERE'

Ensure you replace `ALICE_BOOTNODE_ID_HERE` with the node ID from the output of the first terminal.

=== Using Docker
link:doc/docker.adoc[Using Docker]

=== Shell Completion
link:doc/shell-completion.adoc[Shell Completion]

=== Polkadot Networks
link:doc/networks/networks.adoc[Polkadot Networks]

== Contributing

=== Contributing Guidelines

link:CONTRIBUTING.adoc[Contribution Guidelines]

=== Contributor Code of Conduct

link:CODE_OF_CONDUCT.adoc[Code of Conduct]

== License

https://github.com/paritytech/polkadot/blob/master/LICENSE[LICENSE]

== Important Notice

https://polkadot.network/testnetdisclaimer
