minco-sqlx-postgres 0.1.1

Bounded SQLx PostgreSQL pools and migrations for Minco local and serverless runtimes
Documentation 
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//! Bounded `SQLx` `PostgreSQL` pools for local servers and serverless runtimes.
#![forbid(unsafe_code)]

use serde::{Deserialize, Serialize};
pub use sqlx::PgPool;
use sqlx::postgres::PgPoolOptions;
use std::{path::Path, time::Duration};
use thiserror::Error;

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct PostgresPoolConfig {
    pub url: String,
    pub max_connections: u32,
    pub acquire_timeout_seconds: u64,
    pub idle_timeout_seconds: u64,
}

impl PostgresPoolConfig {
    pub fn serverless(url: impl Into<String>) -> Self {
        Self {
            url: url.into(),
            max_connections: 2,
            acquire_timeout_seconds: 5,
            idle_timeout_seconds: 60,
        }
    }
    pub fn validate(&self) -> Result<(), PostgresError> {
        if self.url.trim().is_empty() {
            return Err(PostgresError::InvalidConfig("database URL is empty".into()));
        }
        if self.max_connections == 0 {
            return Err(PostgresError::InvalidConfig(
                "max_connections must be at least 1".into(),
            ));
        }
        Ok(())
    }
}

pub async fn connect(config: &PostgresPoolConfig) -> Result<PgPool, PostgresError> {
    config.validate()?;
    Ok(PgPoolOptions::new()
        .min_connections(0)
        .max_connections(config.max_connections)
        .acquire_timeout(Duration::from_secs(config.acquire_timeout_seconds))
        .idle_timeout(Some(Duration::from_secs(config.idle_timeout_seconds)))
        .connect(&config.url)
        .await?)
}

pub fn connect_lazy(config: &PostgresPoolConfig) -> Result<PgPool, PostgresError> {
    config.validate()?;
    Ok(PgPoolOptions::new()
        .min_connections(0)
        .max_connections(config.max_connections)
        .acquire_timeout(Duration::from_secs(config.acquire_timeout_seconds))
        .idle_timeout(Some(Duration::from_secs(config.idle_timeout_seconds)))
        .connect_lazy(&config.url)?)
}

pub async fn migrate(pool: &PgPool, path: impl AsRef<Path>) -> Result<(), PostgresError> {
    let migrator = sqlx::migrate::Migrator::new(path.as_ref()).await?;
    migrator.run(pool).await?;
    Ok(())
}

pub async fn ready(pool: &PgPool) -> bool {
    matches!(
        sqlx::query_scalar::<_, i32>("SELECT 1")
            .fetch_one(pool)
            .await,
        Ok(1)
    )
}

#[derive(Debug, Error)]
pub enum PostgresError {
    #[error("invalid PostgreSQL configuration: {0}")]
    InvalidConfig(String),
    #[error("PostgreSQL error: {0}")]
    Sqlx(#[from] sqlx::Error),
    #[error("PostgreSQL migration error: {0}")]
    Migration(#[from] sqlx::migrate::MigrateError),
}

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn serverless_defaults_bound_connection_pressure() {
        let config = PostgresPoolConfig::serverless("postgres://example.invalid/db");
        assert_eq!(config.max_connections, 2);
        assert_eq!(config.acquire_timeout_seconds, 5);
    }
}