boxlite 0.9.3

Embeddable virtual machine runtime for secure, isolated code execution
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//! DNS configuration for containers.
//!
//! Deprecated: DNS is now handled by the guest agent via bind-mount
//! (matching Docker/containerd). This module is kept for test coverage only.

#[cfg(test)]
pub fn configure_container_dns(
    rootfs: &std::path::Path,
) -> boxlite_shared::errors::BoxliteResult<()> {
    use boxlite_shared::errors::BoxliteError;
    use std::fs;
    tracing::debug!("Configuring DNS for container at {:?}", rootfs);

    // Ensure /etc directory exists in rootfs
    let etc_dir = rootfs.join("etc");
    fs::create_dir_all(&etc_dir).map_err(|e| {
        BoxliteError::Storage(format!("Failed to create /etc directory in rootfs: {}", e))
    })?;

    // Create /etc/resolv.conf with gateway as DNS server
    let resolv_conf = etc_dir.join("resolv.conf");
    let content = format!(
        "# Generated by BoxLite\n# DNS queries forwarded to gateway\nnameserver {}\nsearch localdomain\n",
        crate::net::constants::DNS_SERVER_IP
    );

    fs::write(&resolv_conf, content)
        .map_err(|e| BoxliteError::Storage(format!("Failed to write /etc/resolv.conf: {}", e)))?;

    tracing::info!("Created /etc/resolv.conf in container rootfs");
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use tempfile::TempDir;

    #[test]
    fn test_configure_dns_creates_file() {
        let tmp = TempDir::new().unwrap();
        let rootfs = tmp.path();

        configure_container_dns(rootfs).unwrap();

        // File should exist
        let resolv_conf = rootfs.join("etc/resolv.conf");
        assert!(resolv_conf.exists());
    }

    #[test]
    fn test_configure_dns_content() {
        let tmp = TempDir::new().unwrap();
        let rootfs = tmp.path();

        configure_container_dns(rootfs).unwrap();

        // Read and verify content
        let content = fs::read_to_string(rootfs.join("etc/resolv.conf")).unwrap();
        assert!(content.contains(&format!(
            "nameserver {}",
            crate::net::constants::DNS_SERVER_IP
        )));
        assert!(content.contains("search localdomain"));
        assert!(content.contains("Generated by BoxLite"));
    }

    #[test]
    fn test_configure_dns_creates_etc_dir() {
        let tmp = TempDir::new().unwrap();
        let rootfs = tmp.path();

        // /etc should not exist initially
        assert!(!rootfs.join("etc").exists());

        configure_container_dns(rootfs).unwrap();

        // /etc should be created
        assert!(rootfs.join("etc").exists());
        assert!(rootfs.join("etc").is_dir());
    }

    #[test]
    fn test_configure_dns_idempotent() {
        let tmp = TempDir::new().unwrap();
        let rootfs = tmp.path();

        // Call twice
        configure_container_dns(rootfs).unwrap();
        configure_container_dns(rootfs).unwrap();

        // Should still work and have correct content
        let content = fs::read_to_string(rootfs.join("etc/resolv.conf")).unwrap();
        assert!(content.contains(&format!(
            "nameserver {}",
            crate::net::constants::DNS_SERVER_IP
        )));
    }
}