Troubleshooting

When building a pipeline, things can go wrong. We provide several tools to help you debug and troubleshoot your pipeline.

By default, if any node fails, the pipeline will stop. This is to prevent cascading failures. You can change this behaviour by using filter_errors after any step, or using other available helpers.

The tracing crate

Tracing quickly became the standard for logging in Rust. We use it throughout the pipeline. When you run your pipeline, you can set the log level to debug or trace to get detailed logs of what is happening.

To enable tracing you need to configure add a subscriber.

cargo add tracing tracing-subscriber

Then in the entry point of your program, you can add the following code:

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    tracing_subscriber::fmt::init();
    ...
}

When you then set RUST_LOG=debug or RUST_LOG=trace you will get detailed logs. Depending on the size of the data, it might be a lot

OpenTelemetry support

Tracing has best-in-class opentelemetry support. See the tracing-opentelemetry crate for more information.

Note that currently the Node is attached to every transformation step. Beware of large amounts of tracing data.

Helpers and utility functions

There are several helpers and utility functions available on the pipeline to help you debug and handle errors.

• log_all Logs both passing and failed nodes
• log_errors Logs errors only
• log_nodes Logs nodes only
• filter_errors Filters out errors, only passing nodes
• filter Filter out Result<Node> based on a predicate