src/tools/logrotate.rs

   1 use std::path::{Path, PathBuf};
   2 use std::fs::{File, rename};
   3 use std::os::unix::io::FromRawFd;
   4 use std::io::Read;
   5
   6 use anyhow::{bail, Error};
   7 use nix::unistd;
   8
   9 use proxmox::tools::fs::{CreateOptions, make_tmp_file};
  10
  11 /// Used for rotating log files and iterating over them
  12 pub struct LogRotate {
  13     base_path: PathBuf,
  14     compress: bool,
  15 }
  16
  17 impl LogRotate {
  18     /// Creates a new instance if the path given is a valid file name
  19     /// (iow. does not end with ..)
  20     /// 'compress' decides if compresses files will be created on
  21     /// rotation, and if it will search '.zst' files when iterating
  22     pub fn new<P: AsRef<Path>>(path: P, compress: bool) -> Option<Self> {
  23         if path.as_ref().file_name().is_some() {
  24             Some(Self {
  25                 base_path: path.as_ref().to_path_buf(),
  26                 compress,
  27             })
  28         } else {
  29             None
  30         }
  31     }
  32
  33     /// Returns an iterator over the logrotated file names that exist
  34     pub fn file_names(&self) -> LogRotateFileNames {
  35         LogRotateFileNames {
  36             base_path: self.base_path.clone(),
  37             count: 0,
  38             compress: self.compress
  39         }
  40     }
  41
  42     /// Returns an iterator over the logrotated file handles
  43     pub fn files(&self) -> LogRotateFiles {
  44         LogRotateFiles {
  45             file_names: self.file_names(),
  46         }
  47     }
  48
  49     fn compress(file: &PathBuf, options: &CreateOptions) -> Result<(), Error> {
  50         let mut source = File::open(file)?;
  51         let (fd, tmp_path) = make_tmp_file(file, options.clone())?;
  52         let target = unsafe { File::from_raw_fd(fd) };
  53         let mut encoder = match zstd::stream::write::Encoder::new(target, 0) {
  54             Ok(encoder) => encoder,
  55             Err(err) => {
  56                 let _ = unistd::unlink(&tmp_path);
  57                 bail!("creating zstd encoder failed - {}", err);
  58             }
  59         };
  60
  61         if let Err(err) = std::io::copy(&mut source, &mut encoder) {
  62             let _ = unistd::unlink(&tmp_path);
  63             bail!("zstd encoding failed for file {:?} - {}", file, err);
  64         }
  65
  66         if let Err(err) = encoder.finish() {
  67             let _ = unistd::unlink(&tmp_path);
  68             bail!("zstd finish failed for file {:?} - {}", file, err);
  69         }
  70
  71         if let Err(err) = rename(&tmp_path, file) {
  72             let _ = unistd::unlink(&tmp_path);
  73             bail!("rename failed for file {:?} - {}", file, err);
  74         }
  75         Ok(())
  76     }
  77
  78     /// Rotates the files up to 'max_files'
  79     /// if the 'compress' option was given it will compress the newest file
  80     ///
  81     /// e.g. rotates
  82     /// foo.2.zst => foo.3.zst
  83     /// foo.1.zst => foo.2.zst
  84     /// foo       => foo.1.zst
  85     ///           => foo
  86     pub fn rotate(&mut self, options: CreateOptions, max_files: Option<usize>) -> Result<(), Error> {
  87         let mut filenames: Vec<PathBuf> = self.file_names().collect();
  88         if filenames.is_empty() {
  89             return Ok(()); // no file means nothing to rotate
  90         }
  91
  92         let mut next_filename = self.base_path.clone().canonicalize()?.into_os_string();
  93
  94         if self.compress {
  95             next_filename.push(format!(".{}.zst", filenames.len()));
  96         } else {
  97             next_filename.push(format!(".{}", filenames.len()));
  98         }
  99
 100         filenames.push(PathBuf::from(next_filename));
 101         let count = filenames.len();
 102
 103         for i in (0..count-1).rev() {
 104             rename(&filenames[i], &filenames[i+1])?;
 105         }
 106
 107         if self.compress {
 108             for i in 2..count-1 {
 109                 if filenames[i].extension().unwrap_or(std::ffi::OsStr::new("")) != "zst" {
 110                     Self::compress(&filenames[i], &options)?;
 111                 }
 112             }
 113         }
 114
 115         if let Some(max_files) = max_files {
 116             // delete all files > max_files
 117             for file in filenames.iter().skip(max_files) {
 118                 if let Err(err) = unistd::unlink(file) {
 119                     eprintln!("could not remove {:?}: {}", &file, err);
 120                 }
 121             }
 122         }
 123
 124         Ok(())
 125     }
 126 }
 127
 128 /// Iterator over logrotated file names
 129 pub struct LogRotateFileNames {
 130     base_path: PathBuf,
 131     count: usize,
 132     compress: bool,
 133 }
 134
 135 impl Iterator for LogRotateFileNames {
 136     type Item = PathBuf;
 137
 138     fn next(&mut self) -> Option<Self::Item> {
 139         if self.count > 0 {
 140             let mut path: std::ffi::OsString = self.base_path.clone().into();
 141
 142             path.push(format!(".{}", self.count));
 143             self.count += 1;
 144
 145             if Path::new(&path).is_file() {
 146                 Some(path.into())
 147             } else if self.compress {
 148                 path.push(".zst");
 149                 if Path::new(&path).is_file() {
 150                     Some(path.into())
 151                 } else {
 152                     None
 153                 }
 154             } else {
 155                 None
 156             }
 157         } else if self.base_path.is_file() {
 158             self.count += 1;
 159             Some(self.base_path.to_path_buf())
 160         } else {
 161             None
 162         }
 163     }
 164 }
 165
 166 /// Iterator over logrotated files by returning a boxed reader
 167 pub struct LogRotateFiles {
 168     file_names: LogRotateFileNames,
 169 }
 170
 171 impl Iterator for LogRotateFiles {
 172     type Item = Box<dyn Read + Send>;
 173
 174     fn next(&mut self) -> Option<Self::Item> {
 175         let filename = self.file_names.next()?;
 176         let file = File::open(&filename).ok()?;
 177
 178         if filename.extension().unwrap_or(std::ffi::OsStr::new("")) == "zst" {
 179             let encoder = zstd::stream::read::Decoder::new(file).ok()?;
 180             return Some(Box::new(encoder));
 181         }
 182
 183         Some(Box::new(file))
 184     }
 185 }