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 /// # std::fs::remove_file("test.log");
  17 /// let mut log = FileLogger::new("test.log", true).unwrap();
  18 /// flog!(log, "A simple log: {}", "Hello!");
  19 /// ```
  20
  21
  22 #[derive(Debug)]
  23 pub struct FileLogger {
  24     file: std::fs::File,
  25     to_stdout: bool,
  26 }
  27
  28 /// Log messages to [FileLogger](tools/struct.FileLogger.html)
  29 #[macro_export]
  30 macro_rules! flog {
  31     ($log:expr, $($arg:tt)*) => ({
  32         $log.log(format!($($arg)*));
  33     })
  34 }
  35
  36 impl FileLogger {
  37
  38     pub fn new<P: AsRef<std::path::Path>>(file_name: P, to_stdout: bool) -> Result<Self, Error> {
  39
  40         let file = std::fs::OpenOptions::new()
  41             .read(true)
  42             .write(true)
  43             .create_new(true)
  44             .open(file_name)?;
  45
  46         Ok(Self { file , to_stdout })
  47     }
  48
  49     pub fn log<S: AsRef<str>>(&mut self, msg: S) {
  50
  51         let msg = msg.as_ref();
  52
  53         let mut stdout = std::io::stdout();
  54         if self.to_stdout {
  55             stdout.write_all(msg.as_bytes()).unwrap();
  56             stdout.write_all(b"\n").unwrap();
  57         }
  58
  59         let line = format!("{}: {}\n", Local.timestamp(Local::now().timestamp(), 0).to_rfc3339(), msg);
  60         self.file.write_all(line.as_bytes()).unwrap();
  61     }
  62 }
  63
  64 impl std::io::Write for FileLogger {
  65     fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
  66         if self.to_stdout { let _ = std::io::stdout().write(buf); }
  67         self.file.write(buf)
  68     }
  69
  70     fn flush(&mut self) -> Result<(), std::io::Error> {
  71         if self.to_stdout { let _ = std::io::stdout().flush(); }
  72         self.file.flush()
  73     }
  74 }