Newer
Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
# Substrate Node Template
[](https://playground.substrate.dev/?deploy=node-template)
A fresh FRAME-based [Substrate](https://www.substrate.io/) node, ready for hacking :rocket:
## Getting Started
Follow the steps below to get started with the Node Template, or get it up and running right from your browser
in just a few clicks using [Playground](https://playground.substrate.dev/) :hammer_and_wrench:
### Using Nix
Install [nix](https://nixos.org/) and optionally [direnv](https://github.com/direnv/direnv) and [lorri](https://github.com/target/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`.
### Rust Setup
First, complete the [basic Rust setup instructions](./docs/rust-setup.md).
### Run
Use Rust's native `cargo` command to build and launch the template node:
```sh
cargo run --release -- --dev --tmp
```
### Build
The `cargo run` command will perform an initial build. Use the following command to build the node
without launching it:
```sh
cargo build --release
```
### Embedded Docs
Once the project has been built, the following command can be used to explore all parameters and
subcommands:
```sh
./target/release/node-template -h
```
## Run
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.
### Single-Node Development Chain
This command will start the single-node development chain with persistent state:
```bash
./target/release/node-template --dev
```
Purge the development chain's state:
```bash
./target/release/node-template purge-chain --dev
```
Start the development chain with detailed logging:
```bash
RUST_LOG=debug RUST_BACKTRACE=1 ./target/release/node-template -lruntime=debug --dev
```
### Connect with Polkadot-JS Apps Front-end
Once the node template is running locally, you can connect it with **Polkadot-JS Apps** front-end
to interact with your chain. [Click here](https://polkadot.js.org/apps/#/explorer?rpc=ws://localhost:9944) connecting the Apps to your local node template.
### Multi-Node Local Testnet
If you want to see the multi-node consensus algorithm in action, refer to
[our Start a Private Network tutorial](https://substrate.dev/docs/en/tutorials/start-a-private-network/).
## Template Structure
A Substrate project such as this consists of a number of components that are spread across a few
directories.
### Node
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`](https://libp2p.io/) networking stack to allow the
nodes in the network to communicate with one another.
- Consensus: Blockchains must have a way to come to
[consensus](https://substrate.dev/docs/en/knowledgebase/advanced/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](https://research.web3.foundation/en/latest/polkadot/NPoS/index.html).
- 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`](./node/src/chain_spec.rs): A
[chain specification](https://substrate.dev/docs/en/knowledgebase/integrate/chain-spec) 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 the `development_config` and `testnet_genesis` functions, which
are used to define the genesis state for the local development chain configuration. These
functions identify some
[well-known accounts](https://substrate.dev/docs/en/knowledgebase/integrate/subkey#well-known-keys)
and use them to configure the blockchain's initial state.
- [`service.rs`](./node/src/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](https://substrate.dev/docs/en/knowledgebase/advanced/consensus#longest-chain-rule),
the [Aura](https://substrate.dev/docs/en/knowledgebase/advanced/consensus#aura) block authoring
mechanism and the
[GRANDPA](https://substrate.dev/docs/en/knowledgebase/advanced/consensus#grandpa) finality
gadget.
After the node has been [built](#build), refer to the embedded documentation to learn more about the
capabilities and configuration parameters that it exposes:
```shell
./target/release/node-template --help
```
### Runtime
In Substrate, the terms
"[runtime](https://substrate.dev/docs/en/knowledgebase/getting-started/glossary#runtime)" and
"[state transition function](https://substrate.dev/docs/en/knowledgebase/getting-started/glossary#stf-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](https://substrate.dev/docs/en/knowledgebase/runtime/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](https://substrate.dev/docs/en/knowledgebase/runtime/macros) that makes it easy to
create pallets and flexibly compose them to create blockchains that can address
[a variety of needs](https://www.substrate.io/substrate-users/).
Review the [FRAME runtime implementation](./runtime/src/lib.rs) 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!`](https://crates.parity.io/frame_support/macro.construct_runtime.html)
macro, which is part of the core
[FRAME Support](https://substrate.dev/docs/en/knowledgebase/runtime/frame#support-library)
library.
### Pallets
The runtime in this project is constructed using many FRAME pallets that ship with the
[core Substrate repository](https://github.com/paritytech/substrate/tree/master/frame) and a
template pallet that is [defined in the `pallets`](./pallets/template/src/lib.rs) directory.
A FRAME pallet is compromised of a number of blockchain primitives:
- Storage: FRAME defines a rich set of powerful
[storage abstractions](https://substrate.dev/docs/en/knowledgebase/runtime/storage) 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](https://substrate.dev/docs/en/knowledgebase/runtime/events) to
notify users of important changes in the runtime.
- 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.
### Run in Docker
First, install [Docker](https://docs.docker.com/get-docker/) and
[Docker Compose](https://docs.docker.com/compose/install/).
Then run the following command to start a single node development chain.
```bash
./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.
```bash
# 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
# Check whether the code is compilable
./scripts/docker_run.sh cargo check
```