add: log management module (compressor, manager, retention)

internal/log/retention.go

@@ -0,0 +1,95 @@
+package log
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+type RetentionPolicy string
+
+const (
+	RetentionThisWeek  RetentionPolicy = "this_week"
+	RetentionThisMonth RetentionPolicy = "this_month"
+	RetentionNMonths   RetentionPolicy = "n_months"
+	RetentionForever   RetentionPolicy = "forever"
+)
+
+func applyRetention(logDir string, policy RetentionPolicy, months int) {
+	switch policy {
+	case RetentionForever:
+		return
+	case RetentionThisWeek:
+		cleanupExceptCurrentWeek(logDir)
+	case RetentionThisMonth:
+		cleanupExceptCurrentMonth(logDir)
+	case RetentionNMonths:
+		cleanupBeforeMonths(logDir, months)
+	}
+}
+
+func cleanupExceptCurrentWeek(logDir string) {
+	now := time.Now()
+	keep := lastWeekKey(now)
+	for _, f := range listArchives(logDir, "week_") {
+		if !strings.HasPrefix(f, "week_"+keep) {
+			os.Remove(filepath.Join(logDir, f))
+		}
+	}
+	cleanupAll(logDir, "month_")
+	cleanupAll(logDir, "year_")
+}
+
+func cleanupExceptCurrentMonth(logDir string) {
+	now := time.Now()
+	keep := lastMonthKey(now)
+	for _, f := range listArchives(logDir, "month_") {
+		if !strings.HasPrefix(f, "month_"+keep) {
+			os.Remove(filepath.Join(logDir, f))
+		}
+	}
+	cleanupAll(logDir, "year_")
+}
+
+func cleanupBeforeMonths(logDir string, months int) {
+	cutoff := time.Now().AddDate(0, -months, 0)
+	for _, f := range listArchives(logDir, "month_") {
+		// month_2006-01.tar.gz
+		if len(f) < 15 {
+			continue
+		}
+		dateStr := f[6:13]
+		t, err := time.Parse("2006-01", dateStr)
+		if err != nil {
+			continue
+		}
+		if t.Before(cutoff) {
+			os.Remove(filepath.Join(logDir, f))
+		}
+	}
+	for _, f := range listArchives(logDir, "year_") {
+		if len(f) < 12 {
+			continue
+		}
+		yearStr := f[5:9]
+		y, err := time.Parse("2006", yearStr)
+		if err != nil {
+			continue
+		}
+		if y.Before(cutoff) {
+			os.Remove(filepath.Join(logDir, f))
+		}
+	}
+}
+
+func cleanupAll(logDir, prefix string) {
+	for _, f := range listArchives(logDir, prefix) {
+		if err := os.Remove(filepath.Join(logDir, f)); err != nil {
+			log.Printf("[log retention] remove %s: %v", f, err)
+		}
+	}
+}
+
+