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rust.missing_structured_logging

Observability Medium

Detects unstructured string logging instead of structured logs with fields.

Why It Matters

Unstructured logs:

Hard to query — Can’t filter by field values
No aggregation — Can’t count by error type
Poor metrics — Harder to build dashboards

Example

// ❌ Before (unstructured logging)
info!("User {} logged in from {}", user_id, ip_address);
error!("Failed to process order {}: {}", order_id, err);

// ✅ After (structured logging with tracing)
use tracing::{info, error};

info!(user_id = %user_id, ip = %ip_address, "User logged in");
error!(order_id = %order_id, error = ?err, "Failed to process order");

What Unfault Detects

Format strings with interpolated values
Missing structured fields in log macros
Debug prints in production paths

Auto-Fix

Unfault can convert to structured tracing macros with named fields.