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rust.ephemeral_filesystem_write

Stability Medium

Detects file writes that will be lost in ephemeral container environments.

Why It Matters

Ephemeral filesystem writes:

Data loss — Files gone on container restart
Silent failures — Writes succeed but data vanishes
Debugging nightmare — Logs/state disappear

Example

// ❌ Before (writing to ephemeral filesystem)
fn save_report(report: &Report) -> Result<()> {
    std::fs::write("/tmp/report.json", serde_json::to_string(report)?)?;
    Ok(())
}

// ✅ After (use persistent storage)
use aws_sdk_s3::Client;

async fn save_report(s3: &Client, report: &Report) -> Result<()> {
    s3.put_object()
        .bucket("reports")
        .key(&format!("report-{}.json", report.id))
        .body(serde_json::to_vec(report)?.into())
        .send()
        .await?;
    Ok(())
}

What Unfault Detects

File writes in /tmp, /var/tmp paths
Local file storage for important data
Missing persistent volume patterns

Auto-Fix

Unfault suggests object storage or mounted volumes.