mocra 0.3.0

A distributed, event-driven crawling and data collection framework
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use crate::common::state::State;
use crate::queue::compensation::Compensator;
use chrono::{DateTime, Utc};
use log::{error, info, warn};
use sea_orm::{ConnectionTrait, Statement, TransactionTrait};
use std::sync::Arc;
use tokio::time::{Duration, sleep};

/// Starts a periodic cleaner for stale `Running` tasks.
///
/// Every minute, the cleaner marks rows as `Failed` when `updated_at` is older
/// than `now - zombie_threshold_secs`.
pub async fn start_zombie_cleaner(
    state: Arc<State>,
    zombie_threshold_secs: i64,
    compensator: Option<Arc<dyn Compensator>>,
) {
    info!(
        "ZombieTaskCleaner started with threshold {}s",
        zombie_threshold_secs
    );

    loop {
        sleep(Duration::from_secs(60)).await;

        let threshold_time = Utc::now() - chrono::Duration::seconds(zombie_threshold_secs);

        match clean_zombies(&state, threshold_time, &compensator).await {
            Ok(count) => {
                if count > 0 {
                    warn!("Cleaned up {} zombie tasks", count);
                }
            }
            Err(e) => {
                error!("Failed to clean zombie tasks: {}", e);
            }
        }
    }
}

async fn clean_zombies(
    state: &State,
    threshold_time: DateTime<Utc>,
    compensator: &Option<Arc<dyn Compensator>>,
) -> Result<u64, sea_orm::DbErr> {
    let formatted_time = threshold_time.format("%Y-%m-%d %H:%M:%S").to_string();
    let backend = state.db.get_database_backend();

    let txn = state.db.begin().await?;

    // Mark zombie tasks as Failed inside the transaction.
    let update_sql = format!(
        "UPDATE base.task_result SET status = 'Failed', error = 'Zombie Task Detected (Timeout)' WHERE status = 'Running' AND updated_at < '{}'",
        formatted_time
    );
    let res = txn
        .execute(Statement::from_string(backend, update_sql))
        .await?;
    let affected = res.rows_affected();

    // Remove compensation records only for rows actually transitioned.
    if affected > 0
        && let Some(comp) = compensator
    {
        let select_sql = format!(
            "SELECT id FROM base.task_result WHERE status = 'Failed' AND error = 'Zombie Task Detected (Timeout)' AND updated_at < '{}'",
            formatted_time
        );
        if let Ok(rows) = txn
            .query_all(Statement::from_string(backend, select_sql))
            .await
        {
            for row in &rows {
                if let Ok(id) = row.try_get::<String>("", "id") {
                    let _ = comp.remove_task("task", &id).await;
                }
            }
        }
    }

    txn.commit().await?;

    Ok(affected)
}