tidb-pool

tidb-pool is a Rust crate that simplifies the creation of a MySQL connection pool for TiDB using a configuration file in TOML format. It provides a flexible, efficient, and configurable way to connect to TiDB, leveraging connection pooling for optimal performance in both lazy and immediate connection modes. This crate is built on top of the popular sqlx library for managing database connections in an asynchronous environment.

Features

• TOML-based Configuration: Easily configure the connection options via a .toml file.
• MySQL Connection Pool: Creates a connection pool for TiDB using the MySQL protocol.
• SSL Support: Optional SSL support for secure database connections.
• Lazy vs Immediate Connections: Choose between lazy connection initialization or establishing connections immediately.
• Customizable Pooling Options: Fine-tune connection pooling with options like max/min connections, timeouts, and more.

Installation

Add the following to your Cargo.toml:

[dependencies]
tidb-pool = "0.1.3"

Then, include the crate in your project:

use tidb_pool::build_pool_from_config;

Usage

This crate is designed to work with a TOML configuration file that specifies the connection details and pool options. Here's how you can use it to create a connection pool for TiDB:

1. Create a TOML Configuration File

Create a file config.toml with the necessary configuration settings for connecting to your TiDB database:

[tidb]
host = "127.0.0.1"
port = 4000
username = "root"
password = "secret"
databaseName = "test_db"

[tidb.pool_options]
maxConnections = 10
minConnections = 5
acquireTimeout = 30
idleTimeout = 300
maxLifetime = 3600
isLazy = true

# Optional: Uncomment to use SSL
# ssl_ca = "/path/to/ca-cert.pem"

2. Load the Configuration and Create the Pool

Now, you can load the configuration and build the connection pool using tidb-pool:

use tidb_pool::build_pool_from_config;
use sqlx::MySqlPool;
use std::fs;

#[tokio::main]
async fn main() -> Result<(), sqlx::Error> {
    // Load the configuration from the TOML file
    let config_content = fs::read_to_string("config.toml").expect("Failed to read config file");
    let config: TiDBConfig = toml::from_str(&config_content).expect("Invalid TOML configuration");

    // Build the connection pool
    let pool: MySqlPool = build_pool_from_config(config).await?;
    
    // Use the pool (e.g., execute queries)

    Ok(())
}

3. Configuration Fields

Here are the available fields in the TOML configuration:

• TiDB Section:

  • host: Hostname or IP address of the TiDB server.
  • port: Port number for the TiDB server (defaults to 4000).
  • username: Username for authentication.
  • password: Password for authentication.
  • databaseName: Name of the TiDB database to connect to.
  • ssl_ca: (Optional) Path to the CA certificate for SSL verification.

• Pool Options Section:

  • maxConnections: Maximum number of connections in the pool.
  • minConnections: Minimum number of connections maintained in the pool.
  • acquireTimeout: Timeout (in seconds) for acquiring a connection from the pool.
  • idleTimeout: Timeout (in seconds) for closing idle connections.
  • maxLifetime: Maximum lifetime (in seconds) for connections in the pool.
  • isLazy: Whether to lazily initialize connections (true) or establish them immediately (false).

Lazy vs Immediate Connections

The isLazy field in the configuration controls whether connections are established lazily or immediately:

• Lazy Connections (isLazy = true): Connections are only created when they are actually requested.
• Immediate Connections (isLazy = false): Connections are established as soon as the pool is created.

Example TOML Configuration

[tidb]
host = "127.0.0.1"
port = 4000
username = "admin"
password = "mypassword"
databaseName = "example_db"

[tidb.pool_options]
maxConnections = 15
minConnections = 5
acquireTimeout = 30
idleTimeout = 300
maxLifetime = 1800
isLazy = false

# Optional: Uncomment if you use SSL
# ssl_ca = "/path/to/ca-cert.pem"

Example

use tidb_pool::{build_pool_from_config, TiDBConfig};
use std::fs;
use sqlx::MySqlPool;

#[tokio::main]
async fn main() -> Result<(), sqlx::Error> {
    // Load the TiDB configuration from a TOML file
    let config_content = fs::read_to_string("config.toml").expect("Failed to read config file");
    let config: TiDBConfig = toml::from_str(&config_content).expect("Invalid TOML format");

    // Build the connection pool using the configuration
    let pool: MySqlPool = build_pool_from_config(config).await?;

    // Now you can use `pool` to execute queries, transactions, etc.
    
    Ok(())
}

Error Handling

The build_pool_from_config function returns a Result<MySqlPool, sqlx::Error>. If there is an error in creating the pool, it logs the issue and returns the error, allowing the caller to handle it gracefully.

License

This project is licensed under the MIT License.