src/tools/file_logger.rs

   1 use failure::*;
   2 use chrono::{TimeZone, Local};
   3 use std::io::Write;
   4
   5 /// Log messages with timestamps into files
   6 ///
   7 /// Logs messages to file, and optionaly to standart output.
   8 ///
   9 ///
  10 /// #### Example:
  11 /// ```
  12 /// #[macro_use] extern crate proxmox_backup;
  13 /// # use failure::*;
  14 /// use proxmox_backup::tools::FileLogger;
  15 ///
  16 /// let mut log = FileLogger::new("test.log", true).unwrap();
  17 /// flog!(log, "A simple log: {}", "Hello!");
  18 /// ```
  19
  20
  21 #[derive(Debug)]
  22 pub struct FileLogger {
  23     file: std::fs::File,
  24     to_stdout: bool,
  25 }
  26
  27 /// Log messages to [FileLogger](tools/struct.FileLogger.html)
  28 #[macro_export]
  29 macro_rules! flog {
  30     ($log:expr, $($arg:tt)*) => ({
  31         $log.log(format!($($arg)*));
  32     })
  33 }
  34
  35 impl FileLogger {
  36
  37     pub fn new<P: AsRef<std::path::Path>>(file_name: P, to_stdout: bool) -> Result<Self, Error> {
  38
  39         let file = std::fs::OpenOptions::new()
  40             .read(true)
  41             .write(true)
  42             .create_new(true)
  43             .open(file_name)?;
  44
  45         Ok(Self { file , to_stdout })
  46     }
  47
  48     pub fn log<S: AsRef<str>>(&mut self, msg: S) {
  49
  50         let msg = msg.as_ref();
  51
  52         let mut stdout = std::io::stdout();
  53         if self.to_stdout {
  54             stdout.write(msg.as_bytes()).unwrap();
  55             stdout.write(b"\n").unwrap();
  56         }
  57
  58         let line = format!("{}: {}\n", Local.timestamp(Local::now().timestamp(), 0).to_rfc3339(), msg);
  59         self.file.write(line.as_bytes()).unwrap();
  60     }
  61 }
  62
  63 impl std::io::Write for FileLogger {
  64     fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
  65         if self.to_stdout { let _ = std::io::stdout().write(buf); }
  66         self.file.write(buf)
  67     }
  68
  69     fn flush(&mut self) -> Result<(), std::io::Error> {
  70         if self.to_stdout { let _ = std::io::stdout().flush(); }
  71         self.file.flush()
  72     }
  73 }