proxmox-sys: imported pbs-tools/src/logrotate.rs (with various cleanups)

- new: CreateOption s instead of owner string
- new: returns Result instead of Option
- new: add max_files  option
- remove new_with_user()

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>

proxmox-sys/Cargo.toml

@@ -13,5 +13,6 @@ anyhow = "1.0"
 base64 = "0.12"
 libc = "0.2.107"
 nix = "0.19.1"
+zstd = { version = "0.6", features = [ "bindgen" ] }
 
 proxmox = { path = "../proxmox", version = "0.15", default-features = false }

proxmox-sys/debian/changelog

@@ -4,6 +4,8 @@ rust-proxmox-sys (0.1.0) unstable; urgency=medium
 
   * imported pbs-tools/src/process_locker.rs
 
+  * imported pbs-tools/src/logrotate.rs (with various cleanups)
+
   * initial release
 
  -- Proxmox Support Team <support@proxmox.com>  Fri, 19 Nov 2021 07:19:19 +0100

proxmox-sys/src/lib.rs

@@ -1,2 +1,3 @@
 pub mod crypt;
+pub mod logrotate;
 pub mod process_locker;

proxmox-sys/src/logrotate.rs

@@ -0,0 +1,215 @@
+use std::path::{Path, PathBuf};
+use std::fs::{File, rename};
+use std::os::unix::io::{FromRawFd, IntoRawFd};
+use std::io::Read;
+
+use anyhow::{bail, Error};
+use nix::unistd;
+
+use proxmox::tools::fs::{CreateOptions, make_tmp_file};
+
+/// Used for rotating log files and iterating over them
+pub struct LogRotate {
+    base_path: PathBuf,
+    compress: bool,
+    max_files: Option<usize>,
+    /// User logs should be reowned to.
+    options: CreateOptions,
+}
+
+impl LogRotate {
+    /// Creates a new instance if the path given is a valid file name (iow. does not end with ..)
+    /// 'compress' decides if compresses files will be created on rotation, and if it will search
+    /// '.zst' files when iterating
+    ///
+    /// 'options' is used for newly created compressed files.
+    pub fn new<P: AsRef<Path>>(
+        path: P,
+        compress: bool,
+        max_files: Option<usize>,
+        options: Option<CreateOptions>,
+    ) -> Result<Self, Error> {
+        if path.as_ref().file_name().is_some() {
+            bail!("logrotate path does not contain a file name");
+        }
+        Ok(Self {
+            base_path: path.as_ref().to_path_buf(),
+            options: options.unwrap_or(CreateOptions::new()),
+            compress,
+            max_files,
+        })
+    }
+
+    /// Returns an iterator over the logrotated file names that exist
+    pub fn file_names(&self) -> LogRotateFileNames {
+        LogRotateFileNames {
+            base_path: self.base_path.clone(),
+            count: 0,
+            compress: self.compress
+        }
+    }
+
+    /// Returns an iterator over the logrotated file handles
+    pub fn files(&self) -> LogRotateFiles {
+        LogRotateFiles {
+            file_names: self.file_names(),
+        }
+    }
+
+    fn compress(source_path: &PathBuf, target_path: &PathBuf, options: &CreateOptions) -> Result<(), Error> {
+        let mut source = File::open(source_path)?;
+        let (fd, tmp_path) = make_tmp_file(target_path, options.clone())?;
+        let target = unsafe { File::from_raw_fd(fd.into_raw_fd()) };
+        let mut encoder = match zstd::stream::write::Encoder::new(target, 0) {
+            Ok(encoder) => encoder,
+            Err(err) => {
+                let _ = unistd::unlink(&tmp_path);
+                bail!("creating zstd encoder failed - {}", err);
+            }
+        };
+
+        if let Err(err) = std::io::copy(&mut source, &mut encoder) {
+            let _ = unistd::unlink(&tmp_path);
+            bail!("zstd encoding failed for file {:?} - {}", target_path, err);
+        }
+
+        if let Err(err) = encoder.finish() {
+            let _ = unistd::unlink(&tmp_path);
+            bail!("zstd finish failed for file {:?} - {}", target_path, err);
+        }
+
+        if let Err(err) = rename(&tmp_path, target_path) {
+            let _ = unistd::unlink(&tmp_path);
+            bail!("rename failed for file {:?} - {}", target_path, err);
+        }
+
+        if let Err(err) = unistd::unlink(source_path) {
+            bail!("unlink failed for file {:?} - {}", source_path, err);
+        }
+
+        Ok(())
+    }
+
+    /// Rotates the files
+    /// if the 'compress' option was given it will compress the newest file
+    ///
+    /// e.g. rotates
+    /// foo.2.zst => foo.3.zst
+    /// foo.1     => foo.2.zst
+    /// foo       => foo.1
+    pub fn do_rotate(&mut self) -> Result<(), Error> {
+        let mut filenames: Vec<PathBuf> = self.file_names().collect();
+        if filenames.is_empty() {
+            return Ok(()); // no file means nothing to rotate
+        }
+        let count = filenames.len() + 1;
+
+        let mut next_filename = self.base_path.clone().canonicalize()?.into_os_string();
+        next_filename.push(format!(".{}", filenames.len()));
+        if self.compress && count > 2 {
+            next_filename.push(".zst");
+        }
+
+        filenames.push(PathBuf::from(next_filename));
+
+        for i in (0..count-1).rev() {
+            if self.compress
+                && filenames[i].extension() != Some(std::ffi::OsStr::new("zst"))
+                && filenames[i+1].extension() == Some(std::ffi::OsStr::new("zst"))
+            {
+                Self::compress(&filenames[i], &filenames[i+1], &self.options)?;
+            } else {
+                rename(&filenames[i], &filenames[i+1])?;
+            }
+        }
+
+        if let Some(max_files) = self.max_files {
+            for file in filenames.iter().skip(max_files) {
+                if let Err(err) = unistd::unlink(file) {
+                    eprintln!("could not remove {:?}: {}", &file, err);
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Conditional rotate if file bigger than 'max_size'
+    pub fn rotate(
+        &mut self,
+        max_size: u64,
+    ) -> Result<bool, Error> {
+
+        let metadata = match self.base_path.metadata() {
+            Ok(metadata) => metadata,
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => return Ok(false),
+            Err(err) =>  bail!("unable to open {:?} - {}", self.base_path, err),
+        };
+
+        if metadata.len() > max_size {
+            self.do_rotate()?;
+            Ok(true)
+        } else {
+            Ok(false)
+        }
+    }
+}
+
+/// Iterator over logrotated file names
+pub struct LogRotateFileNames {
+    base_path: PathBuf,
+    count: usize,
+    compress: bool,
+}
+
+impl Iterator for LogRotateFileNames {
+    type Item = PathBuf;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.count > 0 {
+            let mut path: std::ffi::OsString = self.base_path.clone().into();
+
+            path.push(format!(".{}", self.count));
+            self.count += 1;
+
+            if Path::new(&path).is_file() {
+                Some(path.into())
+            } else if self.compress {
+                path.push(".zst");
+                if Path::new(&path).is_file() {
+                    Some(path.into())
+                } else {
+                    None
+                }
+            } else {
+                None
+            }
+        } else if self.base_path.is_file() {
+            self.count += 1;
+            Some(self.base_path.to_path_buf())
+        } else {
+            None
+        }
+    }
+}
+
+/// Iterator over logrotated files by returning a boxed reader
+pub struct LogRotateFiles {
+    file_names: LogRotateFileNames,
+}
+
+impl Iterator for LogRotateFiles {
+    type Item = Box<dyn Read + Send>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let filename = self.file_names.next()?;
+        let file = File::open(&filename).ok()?;
+
+        if filename.extension() == Some(std::ffi::OsStr::new("zst")) {
+            let encoder = zstd::stream::read::Decoder::new(file).ok()?;
+            return Some(Box::new(encoder));
+        }
+
+        Some(Box::new(file))
+    }
+}