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https://github.com/elichai/log-derive
A procedural macro for auto logging output of functions
https://github.com/elichai/log-derive
logging metaprogramming proc-macro rust
Last synced: about 10 hours ago
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A procedural macro for auto logging output of functions
- Host: GitHub
- URL: https://github.com/elichai/log-derive
- Owner: elichai
- License: apache-2.0
- Created: 2019-01-31T10:37:44.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2021-11-03T13:53:59.000Z (about 3 years ago)
- Last Synced: 2024-10-09T22:11:06.384Z (4 months ago)
- Topics: logging, metaprogramming, proc-macro, rust
- Language: Rust
- Homepage: https://docs.rs/log-derive
- Size: 89.8 KB
- Stars: 188
- Watchers: 3
- Forks: 12
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- License: LICENSE-APACHE
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README
# log-derive
[](https://travis-ci.org/elichai/log-derive)
[](https://crates.io/crates/log-derive)
[](https://docs.rs/log-derive)
[](https://deps.rs/repo/github/elichai/log-derive)
A Rust macro to part of the [log](https://crates.io/crates/log) facade that auto generates loggings for functions output.
* [Documentation](https://docs.rs/log-derive)
## Usage
Add this to your `Cargo.toml`:
```toml
[dependencies]
log-derive = "0.3"
log = "0.4"
```
and for Rust Edition 2015 add this to your crate root:
```rust
#[macro_use]
extern crate log_derive;
extern crate log;
```
In Rust Edition 2018 you can simply do:
```rust
use log_derive::logfn;
```
After that all you need is to add the according macro above a function that,
either returns an output or receive an input that implements the `Debug` trait.
# Examples
```rust
#[logfn(Err = "Error", fmt = "Failed Sending Packet: {:?}")]
fn send_hi(addr: SocketAddr) -> Result<(), io::Error> {
let mut stream = TcpStream::connect(addr)?;
stream.write(b"Hi!")?;
Ok( () )
}
```
```rust
#[logfn(Trace)]
#[logfn_inputs(Info)]
fn test_log(a: u8) -> String {
(a*2).to_string()
}
```
```rust
#[logfn(Trace, fmt = "testing the num: {:?}")]
fn test_log(a: u8) -> String {
(a*2).to_string()
}
```
# Output
The output of the [fibonacci](./examples/fibonacci.rs) example:
```
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 5)
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 4)
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 3)
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 2)
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 1)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 0)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [ INFO] fibonacci() -> 2
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 1)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [ INFO] fibonacci() -> 3
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 2)
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 1)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 0)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [ INFO] fibonacci() -> 2
17:15:24 [ INFO] fibonacci() -> 5
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 3)
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 2)
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 1)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 0)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [ INFO] fibonacci() -> 2
17:15:24 [TRACE] (1) fibonacci: [examples/fibonacci.rs:16] fibonacci(n: 1)
17:15:24 [ INFO] fibonacci() -> 1
17:15:24 [ INFO] fibonacci() -> 3
17:15:24 [ INFO] fibonacci() -> 8
```
If you expand the output of the `#[logfn]` macro the resulting code will look something like this:
```rust
fn fibonacci(n: u32) -> u32 {
let result = (move || match n {
0 => 1,
1 => 1,
_ => fibonacci(n - 1) + fibonacci(n - 2),
})();
log::log!(log::Level::Info, "fibonacci() -> {}", result);
result
}
```
If the function returns a `Result` it will match through it to split between the `Ok` LogLevel and the `Err` LogLevel
The expansion of the `#[logfn_inputs]` macro will look something like this:
```rust
fn fibonacci(n: u32) -> u32 {
log::log!(log::Level::Info, "fibonacci(n: {:?})", n);
match n {
0 => 1,
1 => 1,
_ => fibonacci(n - 1) + fibonacci(n - 2),
}
}
```
Of course the `log!` macro will be expanded too and it will be a bit more messy.
## Note
The `log_ts` feature will fail your compilation in a `no-std` enviroment.
it can only be used where `std` is available. (as it uses `std::time::Instant`)