rest-server: add cleanup_old_tasks

this is a helper that removes task log files that are not referenced
by the task archive anymore

it gets the oldest task archive file, gets the first endtime (the
oldest) and removes all files in the taskdir where the mtime is older
than that

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

proxmox-rest-server/src/worker_task.rs

@@ -5,6 +5,7 @@ use std::io::{Read, Write, BufRead, BufReader};
 use std::panic::UnwindSafe;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
+use std::time::{SystemTime, Duration};
 
 use anyhow::{bail, format_err, Error};
 use futures::*;
@@ -218,6 +219,63 @@ pub fn rotate_task_log_archive(size_threshold: u64, compress: bool, max_files: O
     logrotate.rotate(size_threshold, None, max_files)
 }
 
+/// removes all task logs that are older than the oldest task entry in the
+/// task archive
+pub fn cleanup_old_tasks(compressed: bool) -> Result<(), Error> {
+    let setup = worker_task_setup()?;
+
+    let _lock = setup.lock_task_list_files(true)?;
+
+    let logrotate = LogRotate::new(&setup.task_archive_fn, compressed)
+            .ok_or_else(|| format_err!("could not get archive file names"))?;
+
+    let mut timestamp = None;
+    if let Some(last_file) = logrotate.files().last() {
+        let reader = BufReader::new(last_file);
+        for line in reader.lines() {
+            let line = line?;
+            if let Ok((_, _, Some(state))) = parse_worker_status_line(&line) {
+                timestamp = Some(state.endtime());
+                break;
+            }
+        }
+    }
+
+    fn get_modified(entry: std::fs::DirEntry) -> Result<SystemTime, std::io::Error> {
+        entry.metadata()?.modified()
+    }
+
+    if let Some(timestamp) = timestamp {
+        let cutoff_time = if timestamp > 0 {
+            SystemTime::UNIX_EPOCH.checked_add(Duration::from_secs(timestamp as u64))
+        } else {
+            SystemTime::UNIX_EPOCH.checked_sub(Duration::from_secs(-timestamp as u64))
+        }.ok_or_else(|| format_err!("could not calculate cutoff time"))?;
+
+        for i in 0..256 {
+            let mut path = setup.taskdir.clone();
+            path.push(format!("{:02X}", i));
+            for file in std::fs::read_dir(path)? {
+                let file = file?;
+                let path = file.path();
+
+                let modified = get_modified(file)
+                    .map_err(|err| format_err!("error getting mtime for {:?}: {}", path, err))?;
+
+                if modified < cutoff_time {
+                    match std::fs::remove_file(path) {
+                        Ok(()) => {},
+                        Err(err) if err.kind() == std::io::ErrorKind::NotFound => {},
+                        Err(err) => bail!("could not remove file: {}", err),
+                    }
+                }
+            }
+        }
+    }
+
+    Ok(())
+}
+
 
 /// Path to the worker log file
 pub fn upid_log_path(upid: &UPID) -> Result<std::path::PathBuf, Error> {