Function tracing

datafusion-examples/examples/execution_monitoring/tracing.rs:68–95

Demonstrates the tracing injection feature for the DataFusion runtime

()

/// Demonstrates the tracing injection feature for the DataFusion runtime
pub async fn tracing() -> Result<()> {
    // Initialize tracing subscriber with thread info.
    tracing_subscriber::fmt()
        .with_thread_ids(true)
        .with_thread_names(true)
        .with_max_level(Level::DEBUG)
        .init();

    // Run query WITHOUT tracer injection.
    info!("***** RUNNING WITHOUT INJECTED TRACER *****");
    run_instrumented_query().await?;
    info!(
        "***** WITHOUT tracer: `tokio-runtime-worker` tasks did NOT inherit the `run_instrumented_query` span *****"
    );

    // Inject custom tracer so tasks run in the current span.
    info!("Injecting custom tracer...");
    set_join_set_tracer(&SpanTracer).expect("Failed to set tracer");

    // Run query WITH tracer injection.
    info!("***** RUNNING WITH INJECTED TRACER *****");
    run_instrumented_query().await?;
    info!(
        "***** WITH tracer: `tokio-runtime-worker` tasks DID inherit the `run_instrumented_query` span *****"
    );

    Ok(())
}

/// A simple tracer that ensures any spawned task or blocking closure
/// inherits the current span via `in_current_span`.