README.md

Futures Poll Log

This crate adds a "inspect" method to all futures, allowing you to tag futures with a name and see all poll calls to them logged.

Usage

Setup a logger through the log crate. Then use the extension trait:

extern crate futures_poll_log;
use futures_poll_log::LoggingExt;

let _: Result<i32, _> =futures::future::ok(3)
        .inspect("immeditate future")
        .map(|i| {
            i*2
        })
        .inspect("mapped future")
        .and_then(|_| {
            Err("ooops".to_string())
        })
        .inspect("failing future")
        .wait();

This will log:

DEBUG - Polling future `failing future'
DEBUG - Polling future `mapped future'
DEBUG - Polling future `immeditate future'
DEBUG - Future `immeditate future' polled: Ok(Ready(3))
DEBUG - Future `mapped future' polled: Ok(Ready(6))
DEBUG - Future `failing future' polled: Err("ooops")

Note that it logs the Async state.

Log target

The log target is futures_log.

Silence

Building the crate with the feature "silence" makes the effect completely vanish, including the intermediate futures. The library also stops binding to log lib.

This allows you to keep the tagging around for future debugging sessions.

License

MIT