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// Copyright (C) 2018 Mateusz Makowski // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with this program. If not, see <https://www.gnu.org/licenses/>. //! A minimal logging library. //! //! This is a tiny library used to write stuff happening in your program to a file. //! //! Changelog for current version can be found in the [repository](https://github.com/makos/rlog). #![doc(html_root_url = "https://docs.rs/rlog/1.0.0")] use std::fs::OpenOptions; use std::io::Write; extern crate chrono; /// Main structure. /// /// ```` /// pub struct Logger { /// path: String, /// format: String, /// } /// ```` /// /// * `path`: filepath to the log file you want to use, can be relative. /// * `format`: timestamp in [ISO8061](https://en.wikipedia.org/wiki/ISO_8601) format. /// /// Please note that the log file isn't created after creating a new instance of Logger struct, /// but rather after the first call to `log()` method. That is also the time when filepath given is validated. /// /// # Examples /// /// ## Default timestamp formatting /// /// ```` /// extern crate rlog; /// use rlog::Logger; /// # use std::fs::remove_file; /// /// let log = Logger::new("my.log", ""); // Note the empty string literal as second parameter. /// // Method log() returns a bool to signal succes or failure. /// assert!(log.log("Just testing")); /// assert!(log.log("Another test")); /// # remove_file("my.log").unwrap(); /// ```` /// /// Result is in file `my.log` in the root directory of your crate: /// /// ````ignore /// 10.08.2018 09:06.33 Just testing /// 10.08.2018 09:06.34 Another test /// ```` /// /// ## Custom formatting /// /// rlog supports (thanks to [chrono](https://crates.io/crates/chrono)) [ISO 8061](https://en.wikipedia.org/wiki/ISO_8601) timestamp formatting. /// /// ```` /// extern crate rlog; /// use rlog::Logger; /// # use std::fs::remove_file; /// /// let log = Logger::new("my.log", "%d-%m %H:%M"); /// /// assert!(log.log("Custom format test")); /// # remove_file("my.log").unwrap(); /// ```` /// /// Output: /// /// `my.log` /// ````ignore /// 10-08 10:46 Custom format test /// ```` pub struct Logger { path: String, format: String, } impl Logger { /// Create new instance. /// /// # Example /// /// ```` /// extern crate rlog; /// use rlog::Logger; /// /// let log = Logger::new("test.log", "%a %H:%M"); /// ```` pub fn new(path: &str, format: &str) -> Logger { let mut _format = "%d-%m-%Y %a %H:%M.%S"; if format != "" { _format = format; } Logger { path: path.to_owned(), format: _format.to_owned(), } } /// Format setter method. pub fn fmt(&mut self, fmt: &str) { self.format = fmt.to_owned(); } /// Format getter method. pub fn get_fmt(&self) -> &str { &self.format } /// Path setter method. pub fn path(&mut self, path: &str) { self.path = path.to_owned(); } /// Path getter method. pub fn get_path(&self) -> &str { &self.path } /// Log message `msg` to file. /// /// This method will create the log file if it does not exist. /// /// # Errors /// /// If there are problems opening a file, the method returns `false` and prints error to stderr. /// `Result<T, Err>` isn't used for the sake of simplicity. /// /// # Example /// /// ```` /// extern crate rlog; /// use rlog::Logger; /// # use std::fs::remove_file; /// /// let log = Logger::new("my.log", ""); /// assert!(log.log("Just testing")); /// # remove_file("my.log").unwrap(); /// ```` pub fn log(&self, msg: &str) -> bool { match OpenOptions::new() .append(true) .create(true) .open(&self.path) { Ok(mut file) => { let final_msg = self.parse_format(msg); match file.write(final_msg.as_bytes()) { Ok(_) => true, Err(e) => { eprintln!("Logger::log() write error:\n{}\n", e); false } } } Err(e) => { eprintln!("Logger::log() open error:\n{}\n", e); false } } } fn parse_format(&self, msg: &str) -> String { let now = chrono::Local::now(); now.format(&self.format).to_string() + " " + msg + "\n" } }