Linera Manual

https://linera.dev
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The Linera Manual is the reference documentation for Linera, a decentralized protocol for real-time...
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### Linera Server Output Example (Bash)

Source: https://linera.dev/operators/testnets/manual-installation

This example shows the output of the `linera-server generate` command, including the successful writing of the server configuration and the generated public and account keys.

```bash
$ linera-server generate --validators /path/to/validator/configuration.toml
2024-07-01T16:51:32.881519Z  INFO linera_server: Wrote server config server.json
02a580bbda90f0ab10f015422d450b3e873166703af05abd77d8880852a3504e4d,009b2ecc5d39645e81ff01cfe4ceeca5ec207d822762f43b35ef77b2367666a7f8
```

--------------------------------

### Install Node.js on Ubuntu

Source: https://linera.dev/developers/frontend/setup

This command installs Node.js on an Ubuntu system, which is a prerequisite for using tools like `http-server` for serving web content.

```bash
sudo apt install nodejs
```

--------------------------------

### Linera Devnet Wallet and Storage Configuration

Source: https://linera.dev/operators/devnets/kind

Example environment variables provided after launching the devnet, which are used to configure the Linera wallet and storage for interacting with the local network.

```Shell
export LINERA_WALLET="/tmp/.tmpIOelqk/wallet_0.json"
export LINERA_STORAGE="rocksdb:/tmp/.tmpIOelqk/client_0.db"
```

--------------------------------

### Clone Linera Protocol Repository

Source: https://linera.dev/developers/getting_started/installation

Clones the official Linera Protocol repository from GitHub and checks out the specified release branch (`testnet_conway`).

```Shell
git clone https://github.com/linera-io/linera-protocol.git
cd linera-protocol
git checkout -t origin/testnet_conway  # Current release branch
```

--------------------------------

### Start Local Development Network with Faucet

Source: https://linera.dev/developers/getting_started/hello_linera

Starts a local Linera validator network with a default number of shards and a faucet service running on port 8080. This command is used to set up a private testing environment.

```bash
linera net up --with-faucet --faucet-port 8080
```

--------------------------------

### Install Linera Toolchain from Source using Cargo

Source: https://linera.dev/developers/getting_started/installation

Installs the Linera toolchain locally from source code using Cargo. This method is useful for development and debugging purposes.

```Shell
cargo install --locked --path linera-storage-service
cargo install --locked --path linera-service
```

--------------------------------

### Start Linera Service Mode

Source: https://linera.dev/developers/getting_started/hello_linera

Starts the Linera client in service mode, exposing a GraphQL API on port 8080. This allows interaction with deployed applications and network state.

```bash
linera service --port 8080
```

--------------------------------

### Install Linera Binaries using Cargo

Source: https://linera.dev/developers/getting_started/installation

Installs the `linera-storage-service` and `linera-service` binaries using Cargo, the Rust package manager. These binaries are essential for operating Linera.

```Shell
cargo install --locked linera-storage-service@0.15.0
cargo install --locked linera-service@0.15.0
```

--------------------------------

### Install Linera Client via npm

Source: https://linera.dev/developers/frontend/setup

This command installs a specific version of the Linera client library from the Node package repository into the project's `node_modules` directory.

```bash
npm install @linera/client@0.14.0
```

--------------------------------

### Install Protobuf Compiler (Protoc) on Linux

Source: https://linera.dev/developers/getting_started/installation

Downloads and installs the Protocol Buffers compiler (protoc) for Linux x86_64. Protoc is used for compiling .proto files into code for various languages.

```Shell
curl -LO https://github.com/protocolbuffers/protobuf/releases/download/v21.11/protoc-21.11-linux-x86_64.zip
unzip protoc-21.11-linux-x86_64.zip -d $HOME/.local
export PATH="$HOME/.local/bin:$PATH"
```

--------------------------------

### Launch Linera Devnet with Kind

Source: https://linera.dev/operators/devnets/kind

Starts a local Linera development network using Kind and Kubernetes. This command builds Docker images from the Linera source and sets up the cluster.

```Shell
linera net up --kubernetes
```

--------------------------------

### Install Protobuf Compiler (Protoc)

Source: https://linera.dev/operators/devnets/kind

Downloads and installs the Protocol Buffers compiler (protoc) for Linux x86_64, which is required for handling Protocol Buffers definitions used by Linera.

```Shell
curl -LO https://github.com/protocolbuffers/protobuf/releases/download/v21.11/protoc-21.11-linux-x86_64.zip
unzip protoc-21.11-linux-x86_64.zip -d $HOME/.local
export PATH="$PATH:$HOME/.local/bin"
```

--------------------------------

### Install Linera from Source

Source: https://linera.dev/print

Installs the Linera storage service and Linera service locally from the cloned source code using Cargo. This is an alternative to installing pre-compiled binaries.

```bash
cargo install --locked --path linera-storage-service
cargo install --locked --path linera-service
```

--------------------------------

### Install Rust and Wasm

Source: https://linera.dev/operators/devnets/kind

Installs the Rust programming language toolchain and the WebAssembly target, which are prerequisites for building and running Linera components.

```Shell
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add wasm32-unknown-unknown
```

--------------------------------

### Linera Devnet Wallet and Storage Configuration

Source: https://linera.dev/print

Example environment variables provided after starting the devnet, which configure the Linera wallet and storage backend for interacting with the local network.

```Shell
export LINERA_WALLET="/tmp/.tmpIOelqk/wallet_0.json"
export LINERA_STORAGE="rocksdb:/tmp/.tmpIOelqk/client_0.db"
```

--------------------------------

### Interact with Linera Devnet (Sync Balance)

Source: https://linera.dev/operators/devnets/kind

Demonstrates interacting with the local Linera devnet by synchronizing chain information and querying the balance. It also notes a deprecated command and suggests an alternative.

```Shell
$linera sync-balance
2024-05-21T22:30:12.061199Z  INFO linera: Synchronizing chain information and querying the local balance
2024-05-21T22:30:12.061218Z  WARN linera: This command is deprecated. Use `linera sync && linera query-balance` instead.
2024-05-21T22:30:12.065787Z  INFO linera::client_context: Saved user chain states
2024-05-21T22:30:12.065792Z  INFO linera: Operation confirmed after 4 ms
1000000.
```

--------------------------------

### Initialize Wallet and Request Chain from Testnet

Source: https://linera.dev/developers/getting_started/hello_linera

Initializes a Linera developer wallet and requests a new microchain from the specified Testnet faucet. Ensure your Linera toolchain is compatible with the Testnet.

```bash
linera wallet init --faucet https://faucet.testnet-conway.linera.net
linera wallet request-chain --faucet https://faucet.testnet-conway.linera.net
```

--------------------------------

### Configure Rust Toolchain for Linera

Source: https://linera.dev/developers/getting_started/installation

Specifies the Rust toolchain version, components (clippy, rustfmt, rust-src), and targets (wasm32-unknown-unknown) required for Linera development.

```TOML
[toolchain]
channel = "1.86.0"
components = [ "clippy", "rustfmt", "rust-src" ]
targets = [ "wasm32-unknown-unknown" ]
profile = "minimal"
```

--------------------------------

### Start Linera Validator with Docker Compose (Bash)

Source: https://linera.dev/operators/testnets/manual-installation

This command starts the Linera validator deployment using Docker Compose in detached mode. It assumes the genesis and server configurations are available in the `docker` directory.

```bash
cd docker && docker compose up -d
```

--------------------------------

### Install Linera Service with Kubernetes Feature

Source: https://linera.dev/operators/devnets/kind

Installs the Linera service using Cargo, enabling the 'kubernetes' feature, which is necessary for running Linera with Kind.

```Shell
cargo install --locked --path linera-service --features kubernetes
```

--------------------------------

### Start Local Linera Development Network

Source: https://linera.dev/print

Starts a local Linera development network with a validator, default shards, and a faucet service running on port 8080.

```bash
linera net up --with-faucet --faucet-port 8080
```

--------------------------------

### Add Linera SDK as a Library using Cargo

Source: https://linera.dev/developers/getting_started/installation

Adds the `linera-sdk` crate as a dependency to your Rust project using Cargo. This allows you to use the Linera SDK for building applications.

```Shell
cargo add linera-sdk@0.15.0
```

--------------------------------

### Build Counter Application

Source: https://linera.dev/print

Compiles the 'counter' application example from the Linera protocol repository using Cargo in release mode, targeting the Wasm 32-unknown-unknown platform.

```bash
cd examples/counter && cargo build --release --target wasm32-unknown-unknown
```

--------------------------------

### Start Local Devnet with Kind

Source: https://linera.dev/print

Launches a local development network using 'kind' and Kubernetes. This command builds Docker images from the Linera source and sets up the cluster.

```Shell
linera net up --kubernetes
```

--------------------------------

### Interact with Linera Devnet (Query Balance)

Source: https://linera.dev/print

Demonstrates querying the balance of an account on a local Linera devnet using the `linera` binary. It includes example output showing the synchronization and balance retrieval process.

```Bash
linera --wallet wallet.json --storage rocksdb:linera.db query-balance
```

--------------------------------

### Query Deployed Applications (GraphQL)

Source: https://linera.dev/developers/getting_started/hello_linera

Uses GraphQL to query the list of applications deployed on a specific chain ID. Replace '...' with your actual chain ID obtained from `linera wallet show`.

```graphql
query {
  applications(chainId: "...") {
    id
    description
    link
  }
}
```

--------------------------------

### Install Linera Binaries

Source: https://linera.dev/print

Installs the Linera storage service and Linera service binaries from crates.io using Cargo. It specifies version 0.15.0 for compatibility with the current Testnet.

```bash
cargo install --locked linera-storage-service@0.15.0
cargo install --locked linera-service@0.15.0
```

--------------------------------

### Request a New Chain from Faucet

Source: https://linera.dev/print

Initializes a wallet and requests a new chain directly from the faucet, simplifying the setup process on test networks.

```bash
linera --wallet wallet2.json --storage rocksdb:linera2.db wallet init --faucet $FAUCET_URL
linera --wallet wallet2.json --storage rocksdb:linera2.db wallet request-chain --faucet $FAUCET_URL
```

--------------------------------

### Query Counter Application Value (GraphQL)

Source: https://linera.dev/developers/getting_started/hello_linera

Queries the current value of the counter application. This assumes the application has been deployed and initialized with a value, typically '42' in this example.

```graphql
query {
  value
}
```

--------------------------------

### Set PATH for Debug Binaries

Source: https://linera.dev/developers/getting_started/installation

Configures the system's PATH environment variable to include the directory containing locally compiled debug binaries for Linera.

```Shell
export PATH="$PWD/target/debug:$PATH"
```

--------------------------------

### Install Protoc on Linux

Source: https://linera.dev/print

Steps to download and install the Protobuf compiler (protoc) on a Linux system, a required dependency for the Linera toolchain.

```Shell
curl -LO https://github.com/protocolbuffers/protobuf/releases/download/v21.11/protoc-21.11-linux-x86_64.zip
unzip protoc-21.11-linux-x86_64.zip -d $HOME/.local
export PATH="$HOME/.local/bin:$PATH"
```

--------------------------------

### Clone Linera Repository and Checkout Branch

Source: https://linera.dev/operators/devnets/kind

Clones the Linera protocol repository from GitHub and checks out a specific release branch ('testnet_conway') for development.

```Shell
git clone https://github.com/linera-io/linera-protocol.git
cd linera-protocol
git checkout -t origin/testnet_conway  # Current release branch
```

--------------------------------

### Start Linera Node Service

Source: https://linera.dev/print

Starts the Linera node service, which executes blocks, exposes a GraphQL API and IDE, and listens for validator notifications.

```bash
linera service
```

--------------------------------

### Install Node.js on Ubuntu

Source: https://linera.dev/print

This command installs Node.js on an Ubuntu system, which is a prerequisite for using tools like `http-server` for serving web applications.

```bash
sudo apt install nodejs

```

--------------------------------

### Install Linera Toolchain with Kubernetes Feature

Source: https://linera.dev/print

Installs the Linera toolchain using Cargo, enabling the 'kubernetes' feature. This command should be run from the root of the cloned linera-protocol repository.

```Shell
cargo install --locked --path linera-service --features kubernetes
```

--------------------------------

### Verify Linera Validator Installation

Source: https://linera.dev/print

Verifies the Linera validator installation by initializing a wallet, requesting a chain from the faucet, and querying the validator's RPC API. It checks the API hashes and the genesis configuration hash.

```shell
$ linera wallet init --faucet https://faucet.testnet-conway.linera.net
$ linera wallet request-chain --faucet https://faucet.testnet-conway.linera.net
$ linera query-validator grpcs:my-domain.com:443
```

--------------------------------

### Initialize Linera Wallet and Request Chain

Source: https://linera.dev/operators/testnets/verify-installation

Initializes a Linera wallet and requests a chain from a specified faucet. This is a prerequisite for interacting with the Linera network.

```bash
$ linera wallet init --faucet https://faucet.testnet-conway.linera.net
$ linera wallet request-chain --faucet https://faucet.testnet-conway.linera.net
```

--------------------------------

### Synchronize Chain and Query Balance

Source: https://linera.dev/developers/getting_started/hello_linera

Synchronizes the local chain with the network and displays the current balance of the default chain. A positive balance indicates successful synchronization.

```bash
linera sync
linera query-balance
```

--------------------------------

### Download Genesis Configuration (Bash)

Source: https://linera.dev/operators/testnets/manual-installation

This command downloads the genesis configuration file required for validators to function. The genesis file defines the initial network state, including the committee of validators and chains.

```bash
wget "https://storage.googleapis.com/linera-io-dev-public/testnet-conway/genesis.json"
```

--------------------------------

### Initialize Linera Wallet and Request Chain

Source: https://linera.dev/developers/core_concepts/wallets

Initializes a Linera wallet and requests a new chain from a specified faucet URL. This is the first step for developers to start interacting with the Linera network.

```bash
linera wallet init --faucet $FAUCET_URL
linera wallet request-chain --faucet $FAUCET_URL
```

--------------------------------

### Install Rust and Wasm

Source: https://linera.dev/developers/getting_started/installation

Installs the Rust programming language and the WebAssembly target for cross-compilation. This is a prerequisite for developing Linera applications.

```Shell
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add wasm32-unknown-unknown
```

--------------------------------

### Initialize Linera Client

Source: https://linera.dev/print

This snippet shows the initialization of the Linera client, which involves downloading the WebAssembly binary, creating memory, and initializing it.

```javascript
await linera.default();
```

--------------------------------

### Vite Configuration for Linera Client and Web Workers

Source: https://linera.dev/print

This Vite configuration example demonstrates how to set up a project that uses the Linera client library. It specifies multiple entry points for the build (`index.html` and `@linera/client`), preserves entry point signatures for correct Web Worker referencing, and excludes the Linera client from dependency optimization.

```typescript
export default defineConfig({
  build: {
    rollupOptions: {
      input: {
        index: 'index.html',
        linera: '@linera/client',
      },
      preserveEntrySignatures: 'strict',
    },
  },
  optimizeDeps: {
    exclude: [
      '@linera/client',
    ],
  },
})

```

--------------------------------

### Initialize a New Linera Wallet

Source: https://linera.dev/print

Initializes a new Linera wallet using a specified JSON file and storage backend, optionally connecting to a faucet.

```bash
linera --wallet wallet2.json --storage rocksdb:linera2.db wallet init --faucet $FAUCET_URL
```

--------------------------------

### Create Wallet and Request Chain from Faucet (Linera CLI)

Source: https://linera.dev/developers/core_concepts/wallets

A shortcut for test networks to create a new wallet and request a chain directly from the faucet.

```bash
linera --wallet wallet2.json --storage rocksdb:linera2.db wallet init --faucet $FAUCET_URL
linera --wallet wallet2.json --storage rocksdb:linera2.db wallet request-chain --faucet $FAUCET_URL
```

--------------------------------

### Create New Linera Project

Source: https://linera.dev/print

Initializes a new Linera project with the necessary scaffolding and files for building a Web3 application. This command sets up the project structure, including configuration files and source code directories.

```Shell
linera project new my-counter
```

--------------------------------

### Vite Configuration for Linera Client

Source: https://linera.dev/developers/frontend/setup

This JavaScript configuration is for Vite, a build tool. It defines multiple entry points for the build (`index.html` and `@linera/client`), ensures entry point signatures are preserved, and excludes the Linera client from dependency optimization to correctly handle its integration.

```javascript
export default defineConfig({
  build: {
    rollupOptions: {
      input: {
        index: 'index.html',
        linera: '@linera/client',
      },
      preserveEntrySignatures: 'strict',
    },
  },
  optimizeDeps: {
    exclude: [
      '@linera/client',
    ],
  },
})
```

--------------------------------

### Linera Service Trait Implementation - Parameters

Source: https://linera.dev/developers/backend/service

Implements the `Service` trait for `CounterService`, specifying the `Parameters` associated type. In this example, the unit type `()` is used as the parameters are not utilized.

```rust
impl Service for CounterService {
    type Parameters = ();

    // ...
}
```

--------------------------------

### Publish and Create Counter Application

Source: https://linera.dev/developers/getting_started/hello_linera

Publishes the compiled Wasm bytecode for the counter application's contract and service, and creates an instance of the application on the network. It takes the bytecode locations and JSON-encoded initialization arguments.

```bash
linera publish-and-create \
  ../target/wasm32-unknown-unknown/release/counter_{contract,service}.wasm \
  --json-argument "42"
```

--------------------------------

### Configure Linera Validator (TOML)

Source: https://linera.dev/operators/testnets/manual-installation

This TOML file configures a Linera validator, specifying server details, ports, and shard configurations. It serves as the primary input for validator setup.

```toml
server_config_path = "server.json"
host = "<your-host>" # e.g. my-subdomain.my-domain.net
port = 19100
metrics_host = "proxy"
metrics_port = 21100
internal_host = "proxy"
internal_port = 20100
[external_protocol]
Grpc = "ClearText" # Depending on your load balancer you may need "Tls" here.
[internal_protocol]
Grpc = "ClearText"

# Adjust depending on the number of shards you have
[[shards]]
host = "docker-shard-1"
port = 19100
metrics_port = 21100

[[shards]]
host = "docker-shard-2"
port = 19100
metrics_port = 21100

[[shards]]
host = "docker-shard-3"
port = 19100
metrics_port = 21100

[[shards]]
host = "docker-shard-4"
port = 19100
metrics_port = 21100
```

--------------------------------

### Create Linera Project

Source: https://linera.dev/developers/backend/creating_a_project

Initializes a new Linera project with the specified name. This command generates the project's directory structure and essential configuration files, including the manifest, application ABI, state, contract, and service definitions.

```bash
linera project new my-counter
```

--------------------------------

### Caddy Configuration for Linera Validator

Source: https://linera.dev/operators/testnets/requirements

This Caddy configuration forwards requests to a Linera validator running on localhost:19100. It utilizes HTTP/2 for communication and sets appropriate timeouts for read and write operations. The configuration also includes the 'Access-Control-Allow-Origin' header to enable cross-origin requests.

```caddy
example.com {
  reverse_proxy localhost:19100 {
    transport http {
      versions h2c
      read_timeout 10m
      write_timeout 10m
    }

    header Access-Control-Allow-Origin *
  }
}

```

--------------------------------

### ScyllaDB Kernel Parameter Tuning

Source: https://linera.dev/operators/testnets/requirements

These commands adjust the maximum number of asynchronous I/O events allowed in kernel contexts, a requirement for optimal ScyllaDB performance. The first command applies the setting temporarily, while the second makes it persistent across reboots by modifying sysctl configuration.

```bash
echo 1048576 > /proc/sys/fs/aio-max-nr
```

```bash
sudo sysctl -p /etc/sysctl.conf
```

--------------------------------

### Nginx Configuration for Linera Validator

Source: https://linera.dev/operators/testnets/requirements

This Nginx configuration is designed to proxy gRPC traffic to a Linera validator running on port 19100. It supports HTTP/2, TLS termination, and includes necessary headers for web client compatibility, including CORS. The configuration also sets timeouts for gRPC and client connections.

```nginx
server {
        listen 80 http2;

        location / {
                grpc_pass grpc://127.0.0.1:19100;
        }
}

server {
    listen 443 ssl http2;
    server_name <hostname>; # e.g. my-subdomain.my-domain.net

    # SSL certificates
    ssl_certificate <ssl-cert-path>; # e.g. /etc/letsencrypt/live/my-subdomain.my-domain.net/fullchain.pem
    ssl_certificate_key <ssl-key-path>; # e.g. /etc/letsencrypt/live/my-subdomain.my-domain.net/privkey.pem;

    # Proxy traffic to the service running on port 19100.
    location / {
        grpc_pass grpc://127.0.0.1:19100;

        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Access-Control-Allow-Origin *;
    }

    keepalive_timeout 10m 60s;
    grpc_read_timeout 10m;
    grpc_send_timeout 10m;

    client_header_timeout 10m;
    client_body_timeout 10m;
}

```

--------------------------------

### Start Linera Validator with Docker Compose

Source: https://linera.dev/print

Starts the Linera validator deployment using Docker Compose. This command should be run from the `docker` directory and starts the services in detached mode.

```shell
cd docker && docker compose up -d
```

--------------------------------

### Switch Linera Wallets and Storage

Source: https://linera.dev/print

Demonstrates how to switch between different Linera wallets and storage configurations using command-line options or environment variables. This allows managing multiple wallet states and database backends.

```bash
linera --wallet wallet2.json --storage rocksdb:linera2.db
export LINERA_STORAGE=$PWD/wallet2.json
export LINERA_WALLET=$PWD/wallet2.json
linera --with-wallet $I
```

--------------------------------

### Install Rust and Wasm

Source: https://linera.dev/print

Commands to install the Rust programming language and the WebAssembly target, which are prerequisites for the Linera toolchain.

```Shell
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add wasm32-unknown-unknown
```

--------------------------------

### Install Protoc on Linux

Source: https://linera.dev/print

Downloads and installs the Protobuf compiler (protoc) for Linux x86_64. This is required for protocol buffer compilation.

```Shell
curl -LO https://github.com/protocolbuffers/protobuf/releases/download/v21.11/protoc-21.11-linux-x86_64.zip
unzip protoc-21.11-linux-x86_64.zip -d $HOME/.local
export PATH="$PATH:$HOME/.local/bin"
```

--------------------------------

### Install Rust and Wasm

Source: https://linera.dev/print

Installs Rust and the WebAssembly target using the official Rustup script. This is a prerequisite for the Linera toolchain.

```Shell
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add wasm32-unknown-unknown
```

--------------------------------

### Initialize Developer Wallet and Request Chain (Testnet)

Source: https://linera.dev/print

Initializes a Linera developer wallet and requests a new microchain with tokens from the Testnet's faucet service. Requires a compatible Linera toolchain.

```bash
linera wallet init --faucet https://faucet.testnet-conway.linera.net
linera wallet request-chain --faucet https://faucet.testnet-conway.linera.net
```

--------------------------------

### Basic HTML UI for Linera Counter

Source: https://linera.dev/developers/frontend/setup

This HTML file sets up the basic user interface for the Linera counter application, including elements to display the chain ID, the click count, and a button to increment the count.

```html
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Counter</title>
  </head>
  <body>
    <p>Chain: <span id="chain-id">requesting chain…</span></p>
    <p>Clicks: <span id="count">0</span></p>
    <button id="increment">Click me!</button>
  </body>
</html>
```

--------------------------------

### Initialize Linera Wallet and Request Chain

Source: https://linera.dev/print

This snippet shows the basic commands to initialize a Linera wallet and request a new chain using the `linera` CLI. It requires a faucet URL to be set as an environment variable.

```bash
linera wallet init --faucet $FAUCET_URL
linera wallet request-chain --faucet $FAUCET_URL
```

--------------------------------

### Interact with Linera Devnet (Sync)

Source: https://linera.dev/print

Shows how to synchronize chain information with a local Linera devnet using the `linera` binary. It specifies the wallet and storage configuration.

```Bash
linera --wallet wallet.json --storage rocksdb:linera.db sync
```

--------------------------------

### Initialize Wallet for Local Network

Source: https://linera.dev/developers/getting_started/hello_linera

Initializes a Linera developer wallet and requests a new microchain from the local faucet service running at http://localhost:8080. Note that wallets are network-specific and may need re-creation upon restarting the local network.

```bash
linera wallet init --faucet http://localhost:8080
linera wallet request-chain --faucet http://localhost:8080
```

--------------------------------

### Start Linera Service

Source: https://linera.dev/print

Starts the Linera client service on port 8080 to expose local APIs for interacting with applications on the network. This is a prerequisite for querying application state.

```bash
linera service --port 8080
```

--------------------------------

### Bash Initialize Linera Wallet for Testnet

Source: https://linera.dev/print

Commands to initialize a Linera wallet for a testnet and request a new chain from the faucet.

```bash
linera wallet init --faucet https://faucet.testnet-conway.linera.net
linera wallet request-chain --faucet https://faucet.testnet-conway.linera.net
```

--------------------------------

### Install Linera Client Package

Source: https://linera.dev/print

This command installs a specific version of the Linera client library from the Node Package Repository (npm). This library provides the JavaScript API to interact with Linera applications.

```bash
npm install @linera/client@0.14.0

```

--------------------------------

### Initialize Linera Client

Source: https://linera.dev/developers/frontend/interactivity

This code initializes the Linera client by downloading the WebAssembly binary, creating memory, and initializing it. This is a prerequisite for interacting with the Linera network.

```javascript
await linera.default();
```

--------------------------------

### Pledge Mutation in GraphQL

Source: https://linera.dev/developers/backend/composition

An example GraphQL mutation to pledge tokens to a crowd-funding application. It specifies the owner and the amount to be pledged.

```graphql
mutation { pledge(owner: "User:841…6c0", amount: "10") }
```

--------------------------------

### Get Application Backend

Source: https://linera.dev/print

This snippet shows how to obtain an object representing the application backend by calling the `client.frontend().application()` method with the application ID.

```javascript
const backend = await client.frontend().application(COUNTER_APP_ID);
```

--------------------------------

### Create Wallet and Claim Chain

Source: https://linera.dev/developers/frontend/interactivity

This snippet demonstrates how to create a new Linera wallet using the testnet faucet, claim a new chain, and initialize a client with this wallet. It also updates a UI element with the new chain ID.

```javascript
const faucet = await new linera.Faucet(
  'https://faucet.testnet-conway.linera.net',
);
const wallet = await faucet.createWallet();
const client = await new linera.Client(wallet);
document.getElementById('chain-id').innerText = await faucet.claimChain(client);
```
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