chore: publish pxmon v0.2.0

internal/history/capacity_store.go

@@ -0,0 +1,102 @@
+package history
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+type CapacityDiskPoint struct {
+	Mount      string `json:"mount"`
+	UsedBytes  uint64 `json:"used_bytes"`
+	TotalBytes uint64 `json:"total_bytes"`
+}
+
+type CapacitySnapshot struct {
+	Timestamp time.Time           `json:"timestamp"`
+	Disks     []CapacityDiskPoint `json:"disks,omitempty"`
+}
+
+type CapacityStore struct {
+	dir string
+}
+
+func NewCapacityStore(baseDir string) *CapacityStore {
+	if strings.TrimSpace(baseDir) == "" {
+		baseDir = "."
+	}
+	return &CapacityStore{dir: filepath.Join(baseDir, "history", "capacity")}
+}
+
+func (s *CapacityStore) Path(clusterID string) string {
+	return filepath.Join(s.dir, sanitizeClusterID(clusterID)+".jsonl")
+}
+
+func (s *CapacityStore) Append(clusterID string, snap CapacitySnapshot) error {
+	if strings.TrimSpace(clusterID) == "" {
+		return errors.New("empty cluster id")
+	}
+	if snap.Timestamp.IsZero() {
+		snap.Timestamp = time.Now().UTC()
+	}
+	if len(snap.Disks) == 0 {
+		return nil
+	}
+	if err := os.MkdirAll(s.dir, 0o700); err != nil {
+		return err
+	}
+	f, err := os.OpenFile(s.Path(clusterID), os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o600)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	b, err := json.Marshal(snap)
+	if err != nil {
+		return err
+	}
+	_, err = f.Write(append(b, '\n'))
+	return err
+}
+
+func (s *CapacityStore) Load(clusterID string, since time.Time) ([]CapacitySnapshot, error) {
+	if strings.TrimSpace(clusterID) == "" {
+		return nil, errors.New("empty cluster id")
+	}
+	f, err := os.Open(s.Path(clusterID))
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return []CapacitySnapshot{}, nil
+		}
+		return nil, err
+	}
+	defer f.Close()
+	sc := bufio.NewScanner(f)
+	sc.Buffer(make([]byte, 0, 64*1024), 8*1024*1024)
+	out := make([]CapacitySnapshot, 0, 512)
+	for sc.Scan() {
+		line := strings.TrimSpace(sc.Text())
+		if line == "" {
+			continue
+		}
+		var snap CapacitySnapshot
+		if err := json.Unmarshal([]byte(line), &snap); err != nil {
+			continue
+		}
+		if !since.IsZero() && snap.Timestamp.Before(since) {
+			continue
+		}
+		if len(snap.Disks) == 0 {
+			continue
+		}
+		out = append(out, snap)
+	}
+	if err := sc.Err(); err != nil {
+		return nil, fmt.Errorf("scan capacity: %w", err)
+	}
+	return out, nil
+}