pezkuwi-subxt/substrate

= Polkadot
:Author: Polkadot developers
:Revision: 0.2.0
:toc:
:sectnums:

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


== To play

If you'd like to play with Polkadot, you'll need to install a client like this
one. First, get Rust (1.26.1 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
----

Then, install Polkadot PoC-2:

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

You'll now have a `polkadot` binary installed to your `PATH`. You can drop the
`--branch v0.2` or run `cargo install --git https://github.com/paritytech/polkadot.git polkadot`
to get the very latest version of Polkadot, but these instructions might not work in that case.

If you want a specific version of polkadot, say `0.2.2`, you may run `cargo install --git https://github.com/paritytech/polkadot.git --tag v0.2.2 polkadot`.

=== Krumme Lanke Testnet

You will connect to the global Krumme Lanke testnet by default. To do this, just use:

[source, shell]
polkadot

If you want to do anything on it (not that there's much to do), then you'll need
to get some 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.


== 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.


== 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


== Using Docker

=== The easiest way

The easiest/faster option is to use the latest image.


.First run
Let´s first check the version we have. The first time you run this command, the polkadot docker image will be downloaded. This takes a bit of time and bandwidth, be patient:

[source, shell]
docker run --rm -it chevdor/polkadot:latest polkadot --version


.Polkadot arguments
You can also pass any argument/flag that polkadot supports:

[source, shell]
docker run --rm -it chevdor/polkadot:latest polkadot --name "PolkaDocker"


.Run as deamon
Once you are done experimenting and picking the best node name :) you can start polkadot as daemon, exposes the polkadot ports and mount a volume that will keep your blockchain data locally:

[source, shell]
docker run -d -p 30333:30333 -p 9933:9933 -p 9944:9944 -v /my/local/folder:/data chevdor/polkadot:latest polkadot

.Docker image update
If you have an image such as `latest` locally, docker will *not* bother downloading the very latest that may be available.
To update:

- stop and delete your containers (`docker stop ...` `docker rm ...`)
- delete your previous image (`docker rmi chevdor/polkadot:latest`)
- run as daemon again, the very latest image will be downloaded again

=== Build your own image

To get up and running with the smallest footprint on your system, you may use the Polkadot Docker image.
You can either build it yourself (it takes a while...):

[source, shell]
----
./docker/build.sh
----

=== Reporting issues

If you run into issues with polkadot when using docker, please run the following command
(replace the tag with the appropriate one if you do not use latest):

[source, shell]
docker run --rm -it chevdor/polkadot:latest polkadot --version

This will show you the polkadot version as well as the git commit ref that was used to build your container.
Just paste that in the issue you create.


== Shell completion

The Polkadot cli command supports shell auto-completion. For this to work, you will need to run the completion script matching you build and system.

Assuming you built a release version using `cargo build --release` and use `bash` run the following:

[source, shell]
source target/release/completion-scripts/polkadot.bash

You can find completion scripts for:
- bash
- fish
- zsh
- elvish
- powershell

To make this change persistent, you can proceed as follow:

=== First install

[source, shell]
----
COMPL_DIR=$HOME/.completion
mkdir -p $COMPL_DIR
cp -f target/release/completion-scripts/polkadot.bash $COMPL_DIR/
echo "source $COMPL_DIR/polkadot.bash" >> $HOME/.bash_profile
source $HOME/.bash_profile
----

=== Update

When you build a new version of Polkadot, the following will ensure you auto-completion script matches the current binary:

[source, shell]
----
COMPL_DIR=$HOME/.completion
mkdir -p $COMPL_DIR
cp -f target/release/completion-scripts/polkadot.bash $COMPL_DIR/
source $HOME/.bash_profile
----

include::doc/packages.adoc[]