cache clean implemented

internal/cache/clean.go

@@ -0,0 +1,115 @@
+package cache
+
+import (
+	"log/slog"
+	"path/filepath"
+	"slices"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/dustin/go-humanize"
+)
+
+type fileEntry struct {
+	path  string
+	size  int64
+	atime time.Time
+}
+
+func (c *Cache) Clean() error {
+	// age always triggers eviction
+	// if cache is still over max size after age eviction
+	// evict until size is sizeThreshold % of max size
+	sizeThreshold := c.cfg.MaxCacheSize * 3 / 4
+
+	cacheSize, cachedFiles, err := c.getCachedFiles()
+	if err != nil {
+		return err
+	}
+
+	// remove any pkgs over max age, update cache size while doing
+	evictBefore := time.Now().Add(-c.cfg.MaxCacheAge)
+	i := 0
+	rsize := int64(0)
+	for _, f := range cachedFiles {
+		if !f.atime.Before(evictBefore) {
+			break
+		}
+		if err := c.cr.Remove(f.path); err != nil {
+			slog.Error("failed to remove file: %v", "file", f.path, "err", err)
+			continue
+		}
+		cacheSize -= f.size
+		rsize += f.size
+		i++
+	}
+	cachedFiles = cachedFiles[i:]
+	slog.Info("evicted aged out pkgs", "num", i, "size", humanize.Bytes(uint64(rsize)))
+
+	// if cache size < max size we're done
+	if cacheSize < c.cfg.MaxCacheSize {
+		return nil
+	}
+
+	// remove oldest files until cache size < threshold
+	i = 0
+	rsize = 0
+	for i < len(cachedFiles) && cacheSize > sizeThreshold {
+		f := cachedFiles[i]
+		if err := c.cr.Remove(f.path); err != nil {
+			slog.Error("failed to remove file: %v", "file", f.path, "err", err)
+			continue
+		}
+		cacheSize -= f.size
+		rsize += f.size
+		i++
+	}
+	slog.Info("evicted aged out pkgs", "num", i, "size", humanize.Bytes(uint64(rsize)))
+
+	return nil
+}
+
+func (c *Cache) getCachedFiles() (int64, []fileEntry, error) {
+	// returns total cache size and sorted slice, oldest first,
+	// of all fileEntry where name is the relative path
+	// from the cacheroot
+	cacheSize := int64(0)
+	cachedFiles := []fileEntry{}
+	for _, repo := range c.cfg.mirroredRepos {
+		relPath := filepath.Join(repo, "os/x86_64")
+		f, err := c.cr.Open(relPath)
+		files, err := f.ReadDir(-1)
+		if err != nil {
+			return 0, nil, err
+		}
+		if err := f.Close(); err != nil {
+			return 0, nil, err
+		}
+		for _, f := range files {
+			fInfo, err := f.Info()
+			if err != nil {
+				return 0, nil, err
+			}
+			if strings.HasSuffix(f.Name(), ".gz") || strings.HasSuffix(f.Name(), ".db") {
+				continue
+			}
+			name := filepath.Join(repo, repoArch, f.Name())
+			size := fInfo.Size()
+			stat_t := fInfo.Sys().(*syscall.Stat_t)
+			atime := time.Unix(stat_t.Atim.Sec, stat_t.Atim.Nsec)
+			entry := fileEntry{
+				path:  name,
+				size:  size,
+				atime: atime,
+			}
+			cachedFiles = append(cachedFiles, entry)
+			cacheSize += size
+
+		}
+	}
+	slices.SortFunc(cachedFiles, func(a, b fileEntry) int {
+		return a.atime.Compare(b.atime)
+	})
+	return cacheSize, cachedFiles, nil
+}