feat: disk usage add cache

disk_usage.go

@@ -0,0 +1,51 @@
+package acp
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/samuelncui/godf"
+)
+
+const (
+	defaultDiskUsageFreshInterval = 1024 * 1024 * 1024 * 2
+)
+
+type diskUsageCache struct {
+	mountPoint    string
+	freshInterval int64
+
+	lock      sync.Mutex
+	freeSpace int64
+	used      int64
+}
+
+func newDiskUsageCache(mountPoint string, freshInterval int64) *diskUsageCache {
+	return &diskUsageCache{
+		mountPoint:    mountPoint,
+		freshInterval: freshInterval,
+	}
+}
+
+func (m *diskUsageCache) check(need int64) error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	m.used += need
+	if m.used <= m.freeSpace && m.used < m.freshInterval {
+		return nil
+	}
+
+	usage, err := godf.NewDiskUsage(m.mountPoint)
+	if err != nil {
+		return fmt.Errorf("get disk usage fail, mount_point= %s", m.mountPoint)
+	}
+
+	m.freeSpace = int64(usage.Available())
+	m.used = need
+	if m.used > m.freeSpace {
+		return fmt.Errorf("%w, want= %d have= %d", ErrTargetNoSpace, m.used, m.freeSpace)
+	}
+
+	return nil
+}