cargo build
./target/debug/node-template --dev --tmp
./target/debug/node-template build-spec
Install nix and optionally direnv and lorri for a fully plug
and play experience for setting up the development environment. To get all the correct dependencies activate direnv direnv allow
and lorri lorri shell
.
First, complete the basic Rust setup instructions.
Use Rust's native cargo
command to build and launch the template node:
cargo run --release -- --dev --tmp
The cargo run
command will perform an initial build. Use the following command to build the node
without launching it:
cargo build --release
NOTE: You must use the release builds for parachains! The optimizations here are required as in debug mode, it is expected that nodes are not able to run fast enough to produce blocks.
NOTE: In the following two sections, we document how to manually start a few relay chain nodes, start a parachain node (collator), and register the parachain with the relay chain.
We also have the
polkadot-launch
CLI tool that automate the following steps and help you easily launch relay chains and parachains. However it is still good to go through the following procedures once to understand the mechanism for running and registering a parachain.
Once the project has been built, the following command can be used to explore all parameters and subcommands:
./target/release/node-template -h
The provided cargo run
command will launch a temporary node and its state will be discarded after
you terminate the process. After the project has been built, there are other ways to launch the
node.
This command will start the single-node development chain with persistent state:
./target/release/node-template --dev
We need n + 1 full validator nodes running on a relay chain to accept n parachain / parathread connections. Here we will start two relay chain nodes so we can have one parachain node connecting in later.
From the Polkadot working directory:
./target/release/node-template purge-chain --dev
Start the development chain with detailed logging:
RUST_LOG=debug RUST_BACKTRACE=1 ./target/release/node-template -lruntime=debug --dev
To connect to a relay chain, you must first _reserve a ParaId
for your parathread that will
become a parachain. To do this, you will need sufficient amount of currency on the network account
to reserve the ID.
If you want to see the multi-node consensus algorithm in action, refer to our Start a Private Network tutorial.
A Substrate project such as this consists of a number of components that are spread across a few directories.
A blockchain node is an application that allows users to participate in a blockchain network. Substrate-based blockchain nodes expose a number of capabilities:
- Networking: Substrate nodes use the
libp2p
networking stack to allow the nodes in the network to communicate with one another. - Consensus: Blockchains must have a way to come to consensus on the state of the network. Substrate makes it possible to supply custom consensus engines and also ships with several consensus mechanisms that have been built on top of Web3 Foundation research.
- RPC Server: A remote procedure call (RPC) server is used to interact with Substrate nodes.
There are several files in the node
directory - take special note of the following:
chain_spec.rs
: A chain specification is a source code file that defines a Substrate chain's initial (genesis) state. Chain specifications are useful for development and testing, and critical when architecting the launch of a production chain. Take note of thedevelopment_config
andtestnet_genesis
functions, which are used to define the genesis state for the local development chain configuration. These functions identify some well-known accounts and use them to configure the blockchain's initial state.service.rs
: This file defines the node implementation. Take note of the libraries that this file imports and the names of the functions it invokes. In particular, there are references to consensus-related topics, such as the longest chain rule, the Aura block authoring mechanism and the GRANDPA finality gadget.
After the node has been built, refer to the embedded documentation to learn more about the capabilities and configuration parameters that it exposes:
./target/release/node-template --help
In Substrate, the terms "runtime" and "state transition function" are analogous - they refer to the core logic of the blockchain that is responsible for validating blocks and executing the state changes they define. The Substrate project in this repository uses the FRAME framework to construct a blockchain runtime. FRAME allows runtime developers to declare domain-specific logic in modules called "pallets". At the heart of FRAME is a helpful macro language that makes it easy to create pallets and flexibly compose them to create blockchains that can address a variety of needs.
Review the FRAME runtime implementation included in this template and note the following:
- This file configures several pallets to include in the runtime. Each pallet configuration is
defined by a code block that begins with
impl $PALLET_NAME::Config for Runtime
. - The pallets are composed into a single runtime by way of the
construct_runtime!
macro, which is part of the core FRAME Support library.
The runtime in this project is constructed using many FRAME pallets that ship with the
core Substrate repository and a
template pallet that is defined in the pallets
directory.
A FRAME pallet is compromised of a number of blockchain primitives:
- Storage: FRAME defines a rich set of powerful storage abstractions that makes it easy to use Substrate's efficient key-value database to manage the evolving state of a blockchain.
- Dispatchables: FRAME pallets define special types of functions that can be invoked (dispatched) from outside of the runtime in order to update its state.
- Events: Substrate uses events to notify users of important changes in the runtime.b
- Errors: When a dispatchable fails, it returns an error.
- Config: The
Config
configuration interface is used to define the types and parameters upon which a FRAME pallet depends.
First, install Docker and Docker Compose.
Then run the following command to start a single node development chain.
./scripts/docker_run.sh
This command will firstly compile your code, and then start a local development network. You can
also replace the default command (cargo build --release && ./target/release/node-template --dev --ws-external
)
by appending your own. A few useful ones are as follow.
# Run Substrate node without re-compiling
./scripts/docker_run.sh ./target/release/node-template --dev --ws-external
# Purge the local dev chain
./scripts/docker_run.sh ./target/release/node-template purge-chain --dev
Now that you have two relay chain nodes, and a parachain node accompanied with a relay chain light
client running, the next step is to register the parachain in the relay chain with the following
steps (for detail, refer to the [Substrate Cumulus Worship](https://substrate.dev/cumulus-workshop/#/en/3-parachains/2-register)):
- Goto [Polkadot Apps UI](https://polkadot.js.org/apps/#/explorer), connecting to your relay chain.
- Execute a sudo extrinsic on the relay chain by going to `Developer` -> `sudo` page.
- Pick `paraSudoWrapper` -> `sudoScheduleParaInitialize(id, genesis)` as the extrinsic type,
shown below.
![Polkadot Apps UI](docs/assets/ss01.png)
- Set the `id: ParaId` to 2,000 (or whatever ParaId you used above), and set the `parachain: Bool`
option to **Yes**.
- For the `genesisHead`, drag the genesis state file exported above, `para-2000-genesis`, in.
- For the `validationCode`, drag the genesis wasm file exported above, `para-2000-wasm`, in.
> **Note**: When registering to the public Rococo testnet, ensure you set a **unique** `paraId`
> larger than 1,000. Values below 1,000 are reserved _exclusively_ for system parachains.
### Restart the Parachain (Collator)
The collator node may need to be restarted to get it functioning as expected. After a
[new epoch](https://wiki.polkadot.network/docs/en/glossary#epoch) starts on the relay chain,
your parachain will come online. Once this happens, you should see the collator start
reporting _parachain_ blocks:
```bash
# Notice the relay epoch change! Only then do we start parachain collating!
#
2021-05-30 17:00:04 [Relaychain] 💤 Idle (2 peers), best: #30 (0xfc02…2a2a), finalized #28 (0x10ff…6539), ⬇ 1.0kiB/s ⬆ 0.3kiB/s
2021-05-30 17:00:04 [Parachain] 💤 Idle (0 peers), best: #0 (0xd42b…f271), finalized #0 (0xd42b…f271), ⬇ 0 ⬆ 0
2021-05-30 17:00:06 [Relaychain] 👶 New epoch 3 launching at block 0x68bc…0605 (block slot 270402601 >= start slot 270402601).
2021-05-30 17:00:06 [Relaychain] 👶 Next epoch starts at slot 270402611
2021-05-30 17:00:06 [Relaychain] ✨ Imported #31 (0x68bc…0605)
2021-05-30 17:00:06 [Parachain] Starting collation. relay_parent=0x68bcc93d24a31a2c89800a56c7a2b275fe9ca7bd63f829b64588ae0d99280605 at=0xd42bb78354bc21770e3f0930ed45c7377558d2d8e81ca4d457e573128aabf271
2021-05-30 17:00:06 [Parachain] 🙌 Starting consensus session on top of parent 0xd42bb78354bc21770e3f0930ed45c7377558d2d8e81ca4d457e573128aabf271
2021-05-30 17:00:06 [Parachain] 🎁 Prepared block for proposing at 1 [hash: 0xf6507812bf60bf53af1311f775aac03869be870df6b0406b2969784d0935cb92; parent_hash: 0xd42b…f271; extrinsics (2): [0x1bf5…1d76, 0x7c9b…4e23]]
2021-05-30 17:00:06 [Parachain] 🔖 Pre-sealed block for proposal at 1. Hash now 0x80fc151d7ccf228b802525022b6de257e42388ec7dc3c1dd7de491313650ccae, previously 0xf6507812bf60bf53af1311f775aac03869be870df6b0406b2969784d0935cb92.
2021-05-30 17:00:06 [Parachain] ✨ Imported #1 (0x80fc…ccae)
2021-05-30 17:00:06 [Parachain] Produced proof-of-validity candidate. block_hash=0x80fc151d7ccf228b802525022b6de257e42388ec7dc3c1dd7de491313650ccae
2021-05-30 17:00:09 [Relaychain] 💤 Idle (2 peers), best: #31 (0x68bc…0605), finalized #29 (0xa6fa…9e16), ⬇ 1.2kiB/s ⬆ 129.9kiB/s
2021-05-30 17:00:09 [Parachain] 💤 Idle (0 peers), best: #0 (0xd42b…f271), finalized #0 (0xd42b…f271), ⬇ 0 ⬆ 0
2021-05-30 17:00:12 [Relaychain] ✨ Imported #32 (0x5e92…ba30)
2021-05-30 17:00:12 [Relaychain] Moving approval window from session 0..=2 to 0..=3
2021-05-30 17:00:12 [Relaychain] ✨ Imported #32 (0x8144…74eb)
2021-05-30 17:00:14 [Relaychain] 💤 Idle (2 peers), best: #32 (0x5e92…ba30), finalized #29 (0xa6fa…9e16), ⬇ 1.4kiB/s ⬆ 0.2kiB/s
2021-05-30 17:00:14 [Parachain] 💤 Idle (0 peers), best: #0 (0xd42b…f271), finalized #0 (0xd42b…f271), ⬇ 0 ⬆ 0
2021-05-30 17:00:18 [Relaychain] ✨ Imported #33 (0x8c30…9ccd)
2021-05-30 17:00:18 [Parachain] Starting collation. relay_parent=0x8c30ce9e6e9867824eb2aff40148ac1ed64cf464f51c5f2574013b44b20f9ccd at=0x80fc151d7ccf228b802525022b6de257e42388ec7dc3c1dd7de491313650ccae
2021-05-30 17:00:19 [Relaychain] 💤 Idle (2 peers), best: #33 (0x8c30…9ccd), finalized #30 (0xfc02…2a2a), ⬇ 0.7kiB/s ⬆ 0.4kiB/s
2021-05-30 17:00:19 [Parachain] 💤 Idle (0 peers), best: #1 (0x80fc…ccae), finalized #0 (0xd42b…f271), ⬇ 0 ⬆ 0
2021-05-30 17:00:22 [Relaychain] 👴 Applying authority set change scheduled at block #31
2021-05-30 17:00:22 [Relaychain] 👴 Applying GRANDPA set change to new set [(Public(88dc3417d5058ec4b4503e0c12ea1a0a89be200fe98922423d4334014fa6b0ee (5FA9nQDV...)), 1), (Public(d17c2d7823ebf260fd138f2d7e27d114c0145d968b5ff5006125f2414fadae69 (5GoNkf6W...)), 1)]
2021-05-30 17:00:22 [Relaychain] 👴 Imported justification for block #31 that triggers command Changing authorities, signaling voter.
2021-05-30 17:00:24 [Relaychain] ✨ Imported #34 (0x211b…febf)
2021-05-30 17:00:24 [Parachain] Starting collation. relay_parent=0x211b3c53bebeff8af05e8f283d59fe171b7f91a5bf9c4669d88943f5a42bfebf at=0x80fc151d7ccf228b802525022b6de257e42388ec7dc3c1dd7de491313650ccae
2021-05-30 17:00:24 [Parachain] 🙌 Starting consensus session on top of parent 0x80fc151d7ccf228b802525022b6de257e42388ec7dc3c1dd7de491313650ccae
2021-05-30 17:00:24 [Parachain] 🎁 Prepared block for proposing at 2 [hash: 0x10fcb3180e966729c842d1b0c4d8d2c4028cfa8bef02b909af5ef787e6a6a694; parent_hash: 0x80fc…ccae; extrinsics (2): [0x4a6c…1fc6, 0x6b84…7cea]]
2021-05-30 17:00:24 [Parachain] 🔖 Pre-sealed block for proposal at 2. Hash now 0x5087fd06b1b73d90cfc3ad175df8495b378fffbb02fea212cc9e49a00fd8b5a0, previously 0x10fcb3180e966729c842d1b0c4d8d2c4028cfa8bef02b909af5ef787e6a6a694.
2021-05-30 17:00:24 [Parachain] ✨ Imported #2 (0x5087…b5a0)
2021-05-30 17:00:24 [Parachain] Produced proof-of-validity candidate. block_hash=0x5087fd06b1b73d90cfc3ad175df8495b378fffbb02fea212cc9e49a00fd8b5a0
2021-05-30 17:00:24 [Relaychain] 💤 Idle (2 peers), best: #34 (0x211b…febf), finalized #31 (0x68bc…0605), ⬇ 1.0kiB/s ⬆ 130.1kiB/s
2021-05-30 17:00:24 [Parachain] 💤 Idle (0 peers), best: #1 (0x80fc…ccae), finalized #0 (0xd42b…f271), ⬇ 0 ⬆ 0
2021-05-30 17:00:29 [Relaychain] 💤 Idle (2 peers), best: #34 (0x211b…febf), finalized #32 (0x5e92…ba30), ⬇ 0.2kiB/s ⬆ 0.1kiB/s
2021-05-30 17:00:29 [Parachain] 💤 Idle (0 peers), best: #1 (0x80fc…ccae), finalized #0 (0xd42b…f271), ⬇ 0 ⬆ 0
2021-05-30 17:00:30 [Relaychain] ✨ Imported #35 (0xee07…38a0)
2021-05-30 17:00:34 [Relaychain] 💤 Idle (2 peers), best: #35 (0xee07…38a0), finalized #33 (0x8c30…9ccd), ⬇ 0.9kiB/s ⬆ 0.3kiB/s
2021-05-30 17:00:34 [Parachain] 💤 Idle (0 peers), best: #1 (0x80fc…ccae), finalized #1 (0x80fc…ccae), ⬇ 0 ⬆ 0
2021-05-30 17:00:36 [Relaychain] ✨ Imported #36 (0xe8ce…4af6)
2021-05-30 17:00:36 [Parachain] Starting collation. relay_parent=0xe8cec8015c0c7bf508bf3f2f82b1696e9cca078e814b0f6671f0b0d5dfe84af6 at=0x5087fd06b1b73d90cfc3ad175df8495b378fffbb02fea212cc9e49a00fd8b5a0
2021-05-30 17:00:39 [Relaychain] 💤 Idle (2 peers), best: #36 (0xe8ce…4af6), finalized #33 (0x8c30…9ccd), ⬇ 0.6kiB/s ⬆ 0.1kiB/s
2021-05-30 17:00:39 [Parachain] 💤 Idle (0 peers), best: #2 (0x5087…b5a0), finalized #1 (0x80fc…ccae), ⬇ 0 ⬆ 0
Note the delay here! It may take some time for your relay chain to enter a new epoch.
Is this Cumulus Parachain Template Rococo & Westend testnets compatible? Yes!
- Rococo is the testnet of Kusama (join the Rococo Faucet to get testing funds).
- Westend is the testnet of Polkadot (join the Westend Faucet to get testing funds).
See the Cumulus Workshop for the latest instructions to register a parathread/parachain on a relay chain.
NOTE: When running the relay chain and parachain, you must use the same tagged version of Polkadot and Cumulus so the collator would register successfully to the relay chain. You should test locally registering your parachain successfully before attempting to connect to any running relay chain network!
Find chainspec
files to connect to live networks here.
You want to be sure to use the correct git release tag in these files, as they change from time
to time and must match the live network!
These networks are under constant development - so please follow the progress and update of your parachains in lock step with the testnet changes if you wish to connect to the network. Do join the Parachain Technical matrix chat room to ask questions and connect with the parachain building teams.
- More detailed instructions to use Cumulus parachains are found in the Cumulus Workshop.
- Refer to the upstream Substrate Node Template to learn more about the structure of this project, the capabilities it encapsulates and the way in which those capabilities are implemented.
- Learn more about how a parachain block is added to a finalized chain here.