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.
Setup a logger through the log crate. Then:
rust
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:
rust
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.
The log target is futures_log.
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.
MIT