logwatcher/src/lib.rs
Kenan Sulayman c08f460021
Use closures
2016-11-04 02:24:17 +01:00

106 lines
3.2 KiB
Rust

use std::fs::File;
use std::io::SeekFrom;
use std::io::BufReader;
use std::io::prelude::*;
use std::io;
use std::thread::sleep;
use std::time::Duration;
use std::os::unix::fs::MetadataExt;
use std::io::ErrorKind;
pub struct LogWatcher{
filename: String,
inode: u64,
pos: u64,
reader: BufReader<File>,
finish: bool
}
impl LogWatcher {
pub fn register(filename: String) -> Result<LogWatcher, io::Error> {
let f = match File::open(filename.clone()) {
Ok(x) => x,
Err(err) => return Err(err)
};
let metadata = match f.metadata() {
Ok(x) => x,
Err(err) => return Err(err)
};
let mut reader = BufReader::new(f);
let pos = metadata.len();
reader.seek(SeekFrom::Start(pos)).unwrap();
Ok(LogWatcher{filename: filename,
inode: metadata.ino(),
pos: pos,
reader: reader,
finish: false})
}
fn reopen_if_log_rotated<F: ?Sized>(&mut self, callback: &F)
where F: Fn(String) {
loop {
match File::open(self.filename.clone()) {
Ok(x) => {
let f = x;
let metadata = match f.metadata() {
Ok(m) => m,
Err(_) => {
sleep(Duration::new(1, 0));
continue;
}
};
if metadata.ino() != self.inode{
self.finish = true;
self.watch(callback);
self.finish = false;
println!("reloading log file");
self.reader = BufReader::new(f);
self.pos = 0;
self.inode = metadata.ino();
}
else{
sleep(Duration::new(1, 0));
}
break;
},
Err(err) => {
if err.kind() == ErrorKind::NotFound{
sleep(Duration::new(1, 0));
continue;
}
}
};
}
}
pub fn watch<F: ?Sized>(&mut self, callback: &F)
where F: Fn(String) {
loop{
let mut line = String::new();
let resp = self.reader.read_line(&mut line);
match resp{
Ok(len) => {
if len > 0{
self.pos += len as u64;
self.reader.seek(SeekFrom::Start(self.pos)).unwrap();
callback(line.replace("\n", ""));
line.clear();
}else {
if self.finish{
break;
}
else{
self.reopen_if_log_rotated(callback);
self.reader.seek(SeekFrom::Start(self.pos)).unwrap();
}
}
},
Err(err) => {
println!("{}", err);
}
}
}
}
}