feat: add 24-hour traffic and capacity trend charts to dashboard and node detail pages

- Implemented TrendChart component for visualizing traffic and capacity trends.
- Enhanced DashboardOverview and NodeDetailPage components to display 24-hour request and capacity trends.
- Updated types to include traffic and capacity trend data structures.
- Created observability trends service to aggregate traffic and capacity data.
- Added tests for traffic report generation and trend data handling.
- Introduced new dependencies for charting (echarts and echarts-for-react).

atsf_agent/internal/observability/traffic.go

@@ -0,0 +1,202 @@
+package observability
+
+import (
+	"atsflare-agent/internal/config"
+	"atsflare-agent/internal/protocol"
+	"atsflare-agent/internal/state"
+	"bufio"
+	"encoding/json"
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type accessLogRecord struct {
+	Timestamp  string `json:"ts"`
+	Host       string `json:"host"`
+	RemoteAddr string `json:"remote_addr"`
+	Status     int    `json:"status"`
+}
+
+type trafficAggregate struct {
+	windowStartedAt time.Time
+	windowEndedAt   time.Time
+	requestCount    int64
+	errorCount      int64
+	statusCodes     map[string]int64
+	topDomains      map[string]int64
+	visitors        map[string]struct{}
+}
+
+func BuildTrafficReport(cfg *config.Config, stateStore *state.Store) *protocol.NodeTrafficReport {
+	if cfg == nil || stateStore == nil {
+		return nil
+	}
+
+	snapshot, err := stateStore.Load()
+	if err != nil {
+		return nil
+	}
+
+	logPath := managedAccessLogPath(cfg)
+	file, err := os.Open(logPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			if snapshot.AccessLogOffset != 0 {
+				snapshot.AccessLogOffset = 0
+				_ = stateStore.Save(snapshot)
+			}
+			return nil
+		}
+		return nil
+	}
+	defer file.Close()
+
+	info, err := file.Stat()
+	if err != nil {
+		return nil
+	}
+
+	offset := snapshot.AccessLogOffset
+	if offset < 0 || offset > info.Size() {
+		offset = 0
+	}
+	if _, err = file.Seek(offset, io.SeekStart); err != nil {
+		return nil
+	}
+
+	reader := bufio.NewReader(file)
+	currentOffset := offset
+	aggregate := newTrafficAggregate()
+
+	for {
+		line, readErr := reader.ReadBytes('\n')
+		if len(line) > 0 {
+			currentOffset += int64(len(line))
+			aggregate.consume(line)
+		}
+		if errors.Is(readErr, io.EOF) {
+			break
+		}
+		if readErr != nil {
+			return nil
+		}
+	}
+
+	snapshot.AccessLogOffset = currentOffset
+	_ = stateStore.Save(snapshot)
+
+	return aggregate.report()
+}
+
+func managedAccessLogPath(cfg *config.Config) string {
+	if cfg == nil || strings.TrimSpace(cfg.RouteConfigPath) == "" {
+		return ""
+	}
+	return filepath.Join(filepath.Dir(cfg.RouteConfigPath), "atsflare_access.log")
+}
+
+func newTrafficAggregate() *trafficAggregate {
+	return &trafficAggregate{
+		statusCodes: make(map[string]int64),
+		topDomains:  make(map[string]int64),
+		visitors:    make(map[string]struct{}),
+	}
+}
+
+func (aggregate *trafficAggregate) consume(line []byte) {
+	trimmed := strings.TrimSpace(string(line))
+	if trimmed == "" {
+		return
+	}
+
+	var record accessLogRecord
+	if err := json.Unmarshal([]byte(trimmed), &record); err != nil {
+		return
+	}
+
+	timestamp, err := parseAccessLogTime(record.Timestamp)
+	if err != nil {
+		return
+	}
+
+	if aggregate.windowStartedAt.IsZero() || timestamp.Before(aggregate.windowStartedAt) {
+		aggregate.windowStartedAt = timestamp
+	}
+	if aggregate.windowEndedAt.IsZero() || timestamp.After(aggregate.windowEndedAt) {
+		aggregate.windowEndedAt = timestamp
+	}
+
+	aggregate.requestCount++
+	if record.Status >= 500 {
+		aggregate.errorCount++
+	}
+	if record.Status > 0 {
+		aggregate.statusCodes[strconv.Itoa(record.Status)]++
+	}
+	if host := strings.TrimSpace(record.Host); host != "" {
+		aggregate.topDomains[host]++
+	}
+	if remoteAddr := strings.TrimSpace(record.RemoteAddr); remoteAddr != "" {
+		aggregate.visitors[remoteAddr] = struct{}{}
+	}
+}
+
+func (aggregate *trafficAggregate) report() *protocol.NodeTrafficReport {
+	if aggregate.requestCount == 0 || aggregate.windowStartedAt.IsZero() || aggregate.windowEndedAt.IsZero() {
+		return nil
+	}
+
+	return &protocol.NodeTrafficReport{
+		WindowStartedAtUnix: aggregate.windowStartedAt.Unix(),
+		WindowEndedAtUnix:   aggregate.windowEndedAt.Unix(),
+		RequestCount:        aggregate.requestCount,
+		ErrorCount:          aggregate.errorCount,
+		UniqueVisitorCount:  int64(len(aggregate.visitors)),
+		StatusCodes:         cloneTrafficCounts(aggregate.statusCodes, 0),
+		TopDomains:          topCounts(aggregate.topDomains, 8),
+		SourceCountries:     map[string]int64{},
+	}
+}
+
+func parseAccessLogTime(value string) (time.Time, error) {
+	return time.Parse(time.RFC3339, strings.TrimSpace(value))
+}
+
+func cloneTrafficCounts(values map[string]int64, limit int) map[string]int64 {
+	if len(values) == 0 {
+		return map[string]int64{}
+	}
+	items := make([]trafficCountItem, 0, len(values))
+	for key, value := range values {
+		items = append(items, trafficCountItem{key: key, value: value})
+	}
+	sort.Slice(items, func(i int, j int) bool {
+		if items[i].value == items[j].value {
+			return items[i].key < items[j].key
+		}
+		return items[i].value > items[j].value
+	})
+	if limit > 0 && len(items) > limit {
+		items = items[:limit]
+	}
+	result := make(map[string]int64, len(items))
+	for _, item := range items {
+		result[item.key] = item.value
+	}
+	return result
+}
+
+type trafficCountItem struct {
+	key   string
+	value int64
+}
+
+func topCounts(values map[string]int64, limit int) map[string]int64 {
+	return cloneTrafficCounts(values, limit)
+}