Rust Tracing Practices

Rust Tracing Practices

Event Recording

• Use level-specific macros for appropriate visibility: info!, debug!, trace!, warn!, error!
• Provide structured data as named arguments to facilitate automated processing and filtering
• Format log messages consistently, beginning with verbs in present tense
• Include relevant context through key-value pairs:

tracing::info!(user_id = user.id, action = "login", "User logged in successfully");
tracing::error!(error = %e, user_id = user.id, "Failed to authenticate user");

Instrumentation

• Apply the #[tracing::instrument] attribute to functions to automatically create trace spans
• Include the err parameter to capture error returns in the span
• Exclude sensitive or large parameters using skip(password) or skip_all
• Add custom context fields with fields(request_id = req.id())

#[tracing::instrument(level = "debug", err, skip(password), fields(user_id = user.id))]
async fn authenticate_user(user: &User, password: &[u8]) -> Result<AuthToken, AuthError> {
    // Implementation
}