Expand description
§Log Derive
log-derive
provides a simple attribute macro that facilitates logs as part of the log
facade
Right now it contains two macros logfn
, logfn_inputs
these macros are only for functions but still have a lot of power.
§Use
The basic use of these macros is by putting one or both of them on top of the function like this: #[logfn(INFO)]
The logfn
macro is used to log the output of the function and logfn_inputs
is used to log the inputs.
Please notice, the arguments being logged must implement the Debug
trait.
(i.e. logfn
requires the output to be Debug
and logfn_inputs
require the inputs to be Debug
)
The macros will accept all log levels provided by the log
facade.
In logfn
if the function returns a Result
type the macro will accept the following additional attributes:
(ok = "LEVEL")
and (err = "LEVEL")
this can provide different log levels if the function failed or not.
By default the macro uses the following formatting to print the message:
logfn
: ("FUNCTION_NAME() => {:?}", return_val)
logfn_inputs
: "FUNCTION_NAME(a: {:?}, b: {:?})", a, b)
This can be easily changed using the fmt
attribute: #[logfn(LEVEL, fmt = "Important Result: {:}")
which will accept format strings similar to println!
.
§Examples
use log_derive::{logfn, logfn_inputs};
struct Error;
struct Success;
enum Status { Alive, Dead, Unknown }
#[logfn(Warn)]
#[logfn_inputs(Info, fmt = "Checking if {:?} is alive")]
fn is_alive(person: &Person) -> Status {
match person.ping() {
Pong => Status::Alive,
Timeout => if person.is_awake() {
Unknown
} else {
Dead
}
}
}
#[logfn_inputs(Info)]
#[logfn(ok = "TRACE", err = "ERROR")]
fn call_isan(num: &str) -> Result<Success, Error> {
if num.len() >= 10 && num.len() <= 15 {
Ok(Success)
} else {
Err(Error)
}
}
#[logfn(INFO, fmt = "a + b = {}")]
#[logfn_inputs(Trace, fmt = "adding a: {:?} and b: {:?}")]
fn addition(a: usize, b: usize) -> usize {
a + b
}
#[logfn_inputs(Info)]
#[logfn(ok = "TRACE", log_ts = true)]
fn time_this(num: &str) -> Result<Success, Error> {
if num.len() >= 10 && num.len() <= 15 {
std::thread::sleep(Duration::from_secs(1));
Ok(Success)
} else {
Err(Error)
}
}
Attribute Macros§
- Logs the result of the function it’s above.
- Logs the inputs of the function