MusicBrainz Light

A high-performance Rust implementation for creating and maintaining MusicBrainz database mirrors with automatic schema updates.

This project is a modernized clone of mbslave that provides significant performance improvements and automatic schema update capabilities, eliminating the need for manual schema migrations.

Features

• 🚀 High Performance: Written in Rust with async/await for optimal performance
• 🔄 Automatic Schema Updates: Handles schema changes automatically without manual intervention
• 📦 Easy Setup: Simple configuration and Docker support
• 🎯 Selective Sync: Configure which schemas and tables to replicate
• 📊 Progress Tracking: Built-in progress bars for long-running operations
• 🔧 Flexible Configuration: Support for TOML files and environment variables
• 🐳 Docker Ready: Includes Docker Compose setup for easy deployment

Improvements over mbslave

• Automatic Schema Updates: No more manual schema upgrade scripts
• Better Performance: Rust implementation with optimized database operations
• Modern Tooling: Built with modern async Rust ecosystem
• Simplified Maintenance: Reduced operational overhead
• Enhanced Error Handling: Better error messages and recovery

Installation

From Source

git clone https://github.com/oknozor/musicbrainz-light
cd musicbrainz-light
cargo install --path .

The binary will be available at target/release/mbpg-light.

Using cargo

cargo install musicbrainz-light

Configuration

Configuration File

Create a config.toml file in your project directory or /etc/mblight/config.toml:

[db]
user = "musicbrainz"
password = "musicbrainz"
host = "localhost"
port = 5432
name = "musicbrainz"

[musicbrainz]
url = "https://data.musicbrainz.org"
token = "your-musicbrainz-token"

[tables]
# Optional: specify which tables to keep (empty = keep all)
keep_only = []

[schema]
# Optional: specify which schemas to keep (empty = keep all)
keep_only = []

Getting a MusicBrainz Token

1. Visit MetaBrainz website
2. Create an account or log in
3. Generate an API token for database replication

Usage

Initialize Database

To create a new MusicBrainz mirror from scratch:

mbpg-light init

This command will:

1. Download the latest MusicBrainz SQL dump
2. Create database schemas
3. Import all data
4. Set up replication control
5. Apply indexes and constraints

Sync Database

To keep your database up-to-date with incremental changes:

# Sync once and exit when caught up
mbpg-light sync

# Sync continuously, waiting for new replication packets
mbpg-light sync --loop

This command will:

1. Download and apply replication packets
2. Automatically handle schema updates
3. Process pending data changes
4. Continue until all updates are applied (or loop infinitely with --loop)

Logging

Configure logging levels using the RUST_LOG environment variable:

# Info level (default)
export RUST_LOG=mbpg_light=info,musicbrainz_light=info

# Debug level
export RUST_LOG=mbpg_light=debug,musicbrainz_light=debug

Selective Replication

You can configure which schemas and tables to replicate by modifying your config.toml:

[schema]
keep_only = ["musicbrainz", "cover_art_archive"]

[tables]
keep_only = ["artist", "release", "recording", "work"]

This is useful for:

• Reducing database size
• Focusing on specific data subsets
• Testing with smaller datasets

Using as a library

You can use musicbrainz-light as a library in your Rust projects for programmatic access to MusicBrainz database operations.

Add Dependency

Add to your Cargo.toml:

[dependencies]
musicbrainz-light = "0.1"
tokio = { version = "1", features = ["rt-multi-thread"] }
sqlx = { version = "0.8", features = ["postgres", "runtime-tokio"] }

Feature Flags

The library supports several optional features:

• progress (default): Enables progress bars during operations
• cli: Command-line interface dependencies (not needed for library usage)

# Minimal library usage without CLI dependencies
[dependencies]
musicbrainz-light = { version = "0.1", default-features = false }

# With progress bars
[dependencies]
musicbrainz-light = { version = "0.1", default-features = false, features = ["progress"] }

Basic Usage

use musicbrainz_light::{MbLight, settings::Settings, MbLightError};

#[tokio::main]
async fn main() -> Result<(), MbLightError> {
    // Load configuration
    let config = Settings::get()?;

    // Create MbLight instance
    let mut mb_light = MbLight::try_new(config, config.db_url()).await?;

    // Initialize database (first time setup)
    mb_light.init().await?;

    // Or sync with existing database (sync once)
    mb_light.sync(false).await?;

    // Or sync infinitely
    mb_light.sync(true).await?;

    Ok(())
}

Configuration Options

Using Default Settings

The default Settings struct loads configuration from:

1. Environment variables with METADADA__ prefix
2. /etc/mblight/config.toml
3. config.toml in current directory

use musicbrainz_light::settings::Settings;

let settings = Settings::get()?;

Custom Settings Implementation

You can implement your own configuration by implementing the MbLightSettingsExt trait:

use musicbrainz_light::settings::MbLightSettingsExt;

struct MyCustomSettings {
    db_host: String,
    db_user: String,
    // ... other fields
}

impl MbLightSettingsExt for MyCustomSettings {
    fn db_user(&self) -> &str { &self.db_user }
    fn db_password(&self) -> &str { "my_password" }
    fn db_host(&self) -> &str { &self.db_host }
    fn db_port(&self) -> u16 { 5432 }
    fn db_name(&self) -> &str { "musicbrainz" }
    fn table_keep_only(&self) -> &Vec<String> { &vec![] }
    fn schema_keep_only(&self) -> &Vec<String> { &vec![] }
    fn musicbrainz_url(&self) -> &str { "https://data.musicbrainz.org" }
    fn musicbrainz_token(&self) -> &str { "your_token" }
    fn should_skip_table(&self, _table: &str) -> bool { false }
    fn should_skip_schema(&self, _schema: &str) -> bool { false }
}

// Use with MbLight
let custom_config = MyCustomSettings { /* ... */ };
let mb_light = MbLight::try_new(custom_config, db_url).await?;

With Notifications

When building MbLight with a mpsc::Sender , you can receive notifications when replication reaches the latest packet:

use tokio::sync::mpsc;

async fn with_notifications() -> Result<(), MbLightError> {
    let config = Settings::get()?;

    // Create notification channel
    let (tx, mut rx) = mpsc::channel(10);

    // Create MbLight instance and add notification sender
    let mb_light = MbLight::try_new(config, config.db_url()).await?.with_sender(tx);

    // Spawn sync task
    let sync_handle = tokio::spawn(async move {
        mb_light.sync(true).await  // Use infinite sync
    });

    // Listen for reindex notifications
    tokio::spawn(async move {
        while let Some(_) = rx.recv().await {
            println!("Replication caught up - time to reindex!");
            // Trigger your reindexing logic here
        }
    });

    sync_handle.await??;
    Ok(())
}

Utility Methods

Check if a table has data:

let has_artists = mb_light.has_data("musicbrainz", "artist").await?;
if has_artists {
    println!("Artist table contains data");
}

Development

Prerequisites

• Rust 1.75+ (2024 edition)
• PostgreSQL 12+
• Git

Building

# Debug build
cargo build

# Release build
cargo build --release

# Run tests
cargo test

# Check formatting and linting
cargo fmt --check
cargo clippy -- -D warnings

Features

The project supports several feature flags:

• cli (default): Command-line interface with colored output
• progress (default): Progress bars for long operations

# Build without CLI features
cargo build --no-default-features

# Build with specific features
cargo build --features "progress"

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.

Acknowledgments

• Original mbslave project by Lukáš Lalinský
• MusicBrainz for providing the database and replication infrastructure
• The Rust community for excellent async and database libraries

Support

• Open an issue for bug reports or feature requests
• Check existing issues before creating new ones
• Provide detailed information including configuration and logs

Changelog

See CHANGELOG.md for version history and changes.