# Canvas

This is a node implementation for Canvas, a [Substrate](https://github.com/paritytech/substrate)
parachain for smart contracts.

It is based on the
[`substrate-parachain-template`](https://github.com/substrate-developer-hub/substrate-parachain-template/),
which we modified to use Substrate's smart contract module ‒ the [`contracts`](https://github.com/paritytech/substrate/tree/master/frame/contracts)
pallet.

**Note:** This used to be a standalone smart contract node used for the ink! workshop. We
have moved the standalone node to [substrate-contracts-node](https://github.com/paritytech/substrate-contracts-node/).

## Quickstart

### Installation 

You need to have executables of both Polkadot, as well as Canvas.

Binary releases can be found here:
[Polkadot releases](https://github.com/paritytech/polkadot/releases),
[Canvas releases](https://github.com/paritytech/canvas/releases).

Alternatively you can install (or build) the projects yourself:

* `cargo install --git https://github.com/paritytech/polkadot.git --force --locked`
* `cargo install --git https://github.com/paritytech/canvas.git --force --locked`

The `--locked` flag makes the installation (or build) use the same versions as the `Cargo.lock`
in those repositories ‒ ensuring that the last known-to-work version of the dependencies is used.

### Launching

Starting this project is best done using the [`polkadot-launch`](https://github.com/paritytech/polkadot-launch) tool ‒
it starts Polkadot and registers the Canvas parachain on it automatically.

To use `polkadot-launch` you must ensure that you're using Node.js `v14.x` or newer. If
you're on macOS, you must also ensure that your machine's firewall is disabled. You can
do this by going to "System Preferences" > "Security & Privacy" > "Firewall" and ensuring
that it's off.

Now that you have the prerequisites:
1. Install it with `yarn global add polkadot-launch` or `npm i polkadot-launch -g`
1. Check that the paths in `polkadot-launch/config.json` point to the `polkadot` and `canvas` executables
1. Launch the network with `polkadot-launch polkadot-launch/config.json`

At this point you should be able to use [Polkadot JS Apps](https://polkadot.js.org/apps/)
to connect to the Polkadot relay chain nodes as well as the Canvas collator.

## Building from source

Follow the [official installation steps](https://substrate.dev/docs/en/knowledgebase/getting-started/) 
to set up all Substrate prerequisites.

Afterwards you can install this node via

```bash
git clone https://github.com/paritytech/canvas.git 
cd canvas/
cargo build --release --locked 
```

### Substrate Compatibility

The latest confirmed working Substrate commit which will then be used is
[9b15da908a2e797e7960edac7011dd9d8b1106c6](https://github.com/paritytech/substrate/commit/9b15da908a2e797e7960edac7011dd9d8b1106c6).

### Unstable Features

If you're the type of person that likes to drink your soup before it cools, you might
also be wondering about how to activate unstable `pallet-contracts` features. To do this
you can run the previous installation command with the following flag: 
`--features contracts-unstable-interface`.