20 lines of code with 0 deps.
info!("{line_count} lines.");
.[src/main.rs 15:5]
.cargo run --release
.
You can modify the code to disable this.log
crate. As the project grows, it is possible
to migrate to an advanced logger (using the log
crate facade)
without changing the code.stderr
or file
).Download the examples below:
sh
git clone https://github.com/vglinka/nolog
```rust
cargo run --example base
cargo run --example to-stderr
cargo run --example to-file
cargo run --example to-file-debug-plus-release
cargo run --example to-file-debug-plus-release --release
sh
cd ./nolog-no-dep-to-stdout/
cargo run
sh
cd ./nolog-as-dep-to-stdout/
cargo run
```
If you want to log to a file and are going to use nolog
as a dependency,
then use nolog-plain crate (а non-colored version of nolog).
Characters used for text coloring will not be saved to the file.
Example using nolog-plain
crate:
sh
cd ./examples/nolog-plain-as-dep-to-file/
cargo run
Create a logger.rs
with the following content (this is the complete
library code):
```rust /* ---------------------------------------------------------------------------- MIT License
Copyright (c) 2022 Vadim Glinka
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ---------------------------------------------------------------------------- */
trace { ( $($msg:expr),* ) => { writelog!(formatargs!("\x1B[34mTRCE:\x1B[0m {} [{} {}:{}]", formatargs!($($msg),*), file!(), line!(), column!())) } }
debug { ( $($msg:expr),* ) => { writelog!(formatargs!("\x1B[36mDEBG:\x1B[0m {} [{} {}:{}]", formatargs!($($msg),*), file!(), line!(), column!())) } }
info { ( $($msg:expr),* ) => { writelog!(formatargs!("\x1B[32mINFO:\x1B[0m {} [{} {}:{}]", formatargs!($($msg),*), file!(), line!(), column!())) } }
warn { ( $($msg:expr),* ) => { writelog!(formatargs!("\x1B[33mWARN:\x1B[0m {} [{} {}:{}]", formatargs!($($msg),*), file!(), line!(), column!())) } }
error { ( $($msg:expr),* ) => { writelog!(formatargs!("\x1B[31mERRO:\x1B[0m {} [{} {}:{}]", formatargs!($($msg),*), file!(), line!(), column!())) } }
crit { ( $($msg:expr),* ) => { writelog!(formatargs!("\x1B[35mCRIT:\x1B[0m {} [{} {}:{}]", formatargs!($($msg),*), file!(), line!(), column!())) } }
writelog { ( $msg:expr ) => { println!("{}", $msg) } } ```
main.rs
could be like this:
```rust
mod logger; // ^^^^^^ // Must go higher in the list than the modules // in which it will be used. // Macro import in modules below is not needed. mod other;
fn main() { let a = 42; trace!("text {a},{a},{a}"); debug!("text {a},{},{}", a, 24); info!("text {},{},{}", a, 24, "42"); warn!("text {a},{},{}", 'a', "422"); error!("text {a},{a},{}", a); crit!("text {a},{a},{a}");
/* Output:
TRCE: text 42,42,42 [examples/to-stderr.rs 55:5]
DEBG: text 42,42,24 [examples/to-stderr.rs 56:5]
INFO: text 42,24,42 [examples/to-stderr.rs 57:5]
WARN: text 42,a,422 [examples/to-stderr.rs 58:5]
ERRO: text 42,42,42 [examples/to-stderr.rs 59:5]
CRIT: text 42,42,42 [examples/to-stderr.rs 60:5]
*/
} ``` Now you have a logger and no new dependencies.
To redirect output to stderr
you need to add a single 'e' character
to the writelog
macro so that instead of println!()
it becomes eprintln!()
. See full example.
Write log to file: See full example.
Although this logger was created to be used directly in small projects, you can also use it as a dependency.
In Cargo.toml
:
toml
nolog = "0.2.0"
In main.rs
:
rust
use nolog::*;
OR
rust
use nolog::{crit, debug, error, info, trace, warn, writelog};
OR
```rust
pub extern crate nolog; ```
The last option with extern
is the preferred option. You don't have
to import macros in every module, they will work without imports.
See example.
If you want to log to a file and are going to use nolog
as a dependency,
then use nolog-plain crate.
Characters used for text coloring will not be saved to the file.
This will make the code even shorter. See example.
format!()
have been replaced with
invocation format_args!()
because format_args!()
avoids heap
allocations. All examples have been updated. The use of format_args!()
has affected the code for writing to a file. Now std::fmt::Arguments
is used instead of String
.
See example.README.md
and examples.README.md
and examples.README.md