trackable
provides functionalities to define trackable objects and track those.
Below code is an example that tracks failure of an I/O operation:
#[macro_use]
extern crate trackable;
use trackable::error::Failure;
fn foo() -> Result<(), Failure> {
track!(std::fs::File::open("/path/to/non_existent_file").map_err(Failure::from_error))?;
Ok(())
}
fn bar() -> Result<(), Failure> {
track!(foo())?;
Ok(())
}
fn baz() -> Result<(), Failure> {
track!(bar())?;
Ok(())
}
fn main() {
let result = baz();
assert!(result.is_err());
let error = result.err().unwrap();
assert_eq!(format!("\r{}", error), r#"
Failed (cause; No such file or directory)
HISTORY:
[0] at rust_out:<anon>:7
[1] at rust_out:<anon>:12
[2] at rust_out:<anon>:16
"#);
}
This example used the built-in Failure
type, but you can easily define your own trackable error types.
See the documentaion of error module for more details.