metrics: implement uptime and system metrics

internal/metrics/period/handler.go

@@ -0,0 +1,82 @@
+package period
+
+import (
+	"errors"
+	"net/http"
+	"time"
+
+	"github.com/coder/websocket"
+	"github.com/coder/websocket/wsjson"
+	metricsutils "github.com/yusing/go-proxy/internal/metrics/utils"
+	"github.com/yusing/go-proxy/internal/net/gphttp"
+	"github.com/yusing/go-proxy/internal/net/gphttp/gpwebsocket"
+	"github.com/yusing/go-proxy/internal/net/gphttp/httpheaders"
+)
+
+// ServeHTTP serves the data for the given period.
+//
+// If the period is not specified, it serves the last result.
+//
+// If the period is specified, it serves the data for the given period.
+//
+// If the period is invalid, it returns a 400 error.
+//
+// If the data is not found, it returns a 204 error.
+//
+// If the request is a websocket request, it serves the data for the given period for every interval.
+func (p *Poller[T, AggregateT]) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	query := r.URL.Query()
+
+	if httpheaders.IsWebsocket(r.Header) {
+		interval := metricsutils.QueryDuration(query, "interval", 0)
+
+		minInterval := 1 * time.Second
+		if interval == 0 {
+			interval = pollInterval
+		}
+		if interval < minInterval {
+			interval = minInterval
+		}
+		gpwebsocket.Periodic(w, r, interval, func(conn *websocket.Conn) error {
+			data, err := p.getRespData(r)
+			if err != nil {
+				return err
+			}
+			if data == nil {
+				return nil
+			}
+			return wsjson.Write(r.Context(), conn, data)
+		})
+	} else {
+		data, err := p.getRespData(r)
+		if err != nil {
+			gphttp.ServerError(w, r, err)
+			return
+		}
+		if data == nil {
+			http.Error(w, "no data", http.StatusNoContent)
+			return
+		}
+		gphttp.RespondJSON(w, r, data)
+	}
+}
+
+func (p *Poller[T, AggregateT]) getRespData(r *http.Request) (any, error) {
+	query := r.URL.Query()
+	period := query.Get("period")
+	if period == "" {
+		return p.GetLastResult(), nil
+	}
+	rangeData, ok := p.Get(Filter(period))
+	if !ok {
+		return nil, errors.New("invalid period")
+	}
+	total, aggregated := p.aggregate(rangeData, query)
+	if total == -1 {
+		return nil, errors.New("bad request")
+	}
+	return map[string]any{
+		"total": total,
+		"data":  aggregated,
+	}, nil
+}