Рыба проекта. Минимальная функциональность

pkg/adapters/retention/retention.go

@@ -0,0 +1,109 @@
+// Package retention prunes old encrypted Postgres dump files from a backup
+// directory based on their modification time.
+// Package retention prunes old encrypted Postgres dump files from a backup
+// directory based on their modification time.
+package retention
+
+import (
+	"context"
+	"io/fs"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// DumpGlob matches only encrypted Postgres dump artefacts produced by the
+// backupper: synapse-<timestamp>.dump.pqenc. The pattern is intentionally
+// strict — any deviation in prefix, middle, or extension is preserved.
+const DumpGlob = "synapse-*.dump.pqenc"
+
+// PruneByAge removes every file in dir matching DumpGlob whose modification
+// time is older than retentionDays relative to now. It returns the basenames
+// of the files it removed.
+//
+// retentionDays == 0 disables pruning entirely (opt-out): the function
+// returns a nil slice and a nil error without touching the directory.
+//
+// Subdirectories, non-matching files, and the root dir itself are never
+// removed or followed.
+func PruneByAge(
+	ctx context.Context,
+	dir string,
+	retentionDays int,
+	now time.Time,
+) (
+	[]string,
+	error,
+) {
+	if retentionDays == 0 {
+		return nil, nil
+	}
+
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+
+	if _, err := os.Stat(dir); err != nil {
+		return nil, err
+	}
+
+	cutoff := now.Add(-time.Duration(retentionDays) * 24 * time.Hour)
+
+	logger := slog.Default()
+	var pruned []string
+
+	walkErr := fs.WalkDir(os.DirFS(dir), ".", func(walkPath string, entry fs.DirEntry, walkErrIn error) error {
+		if walkErrIn != nil {
+			return walkErrIn
+		}
+
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+
+		if entry.IsDir() {
+			return nil
+		}
+
+		name := filepath.Base(walkPath)
+
+		matched, err := filepath.Match(DumpGlob, name)
+		if err != nil {
+			return err
+		}
+		if !matched {
+			return nil
+		}
+
+		full := filepath.Join(dir, walkPath)
+		info, err := os.Stat(full)
+		if err != nil {
+			return err
+		}
+
+		if !info.ModTime().Before(cutoff) {
+			return nil
+		}
+
+		age := now.Sub(info.ModTime())
+		if err := os.Remove(full); err != nil {
+			return err
+		}
+
+		logger.Info(
+			"prune retention: removed old dump",
+			slog.String("file", name),
+			slog.Float64("age_seconds", age.Seconds()),
+		)
+
+		pruned = append(pruned, name)
+
+		return nil
+	})
+	if walkErr != nil {
+		return pruned, walkErr
+	}
+
+	return pruned, nil
+}