Martino Ferrari
107 lines
4.0 KiB
Go
107 lines
4.0 KiB
Go
// Package metrics provides in-process Prometheus-format instrumentation.
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// All counters and gauges use atomic operations and are safe for concurrent use.
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package metrics
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import (
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"fmt"
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"net/http"
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"sync/atomic"
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"time"
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)
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var startTime = time.Now()
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// Counters and gauges — updated by callers in ws.go and api.go.
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var (
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wsConns atomic.Int64 // current open WebSocket connections (gauge)
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msgIn atomic.Int64 // total WS messages received (counter)
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msgOut atomic.Int64 // total WS messages sent (counter)
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writeOps atomic.Int64 // total signal write operations (counter)
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historyReqs atomic.Int64 // total history requests served (counter)
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)
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// IncWsConns increments the active WebSocket connection gauge.
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func IncWsConns() { wsConns.Add(1) }
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// DecWsConns decrements the active WebSocket connection gauge.
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func DecWsConns() { wsConns.Add(-1) }
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// IncMsgIn increments the total inbound WS message counter.
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func IncMsgIn() { msgIn.Add(1) }
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// IncMsgOut increments the total outbound WS message counter.
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func IncMsgOut() { msgOut.Add(1) }
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// IncWrites increments the signal write operation counter.
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func IncWrites() { writeOps.Add(1) }
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// IncHistoryReqs increments the history request counter.
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func IncHistoryReqs() { historyReqs.Add(1) }
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// Stats is a point-in-time snapshot of the in-process counters, for rendering
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// as JSON in the admin pane (the Prometheus Handler renders the same data as
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// text).
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type Stats struct {
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UptimeSeconds float64 `json:"uptimeSeconds"`
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WsConnections int64 `json:"wsConnections"`
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MsgIn int64 `json:"msgIn"`
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MsgOut int64 `json:"msgOut"`
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WriteOps int64 `json:"writeOps"`
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HistoryReqs int64 `json:"historyReqs"`
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}
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// Snapshot returns the current values of all counters and gauges.
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func Snapshot() Stats {
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return Stats{
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UptimeSeconds: time.Since(startTime).Seconds(),
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WsConnections: wsConns.Load(),
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MsgIn: msgIn.Load(),
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MsgOut: msgOut.Load(),
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WriteOps: writeOps.Load(),
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HistoryReqs: historyReqs.Load(),
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}
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}
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// Handler returns an http.HandlerFunc that renders Prometheus-format metrics.
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// activeSubs is called each request to read the current number of unique signal
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// subscriptions from the broker; pass nil to omit the metric.
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func Handler(activeSubs func() int) http.HandlerFunc {
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return func(w http.ResponseWriter, _ *http.Request) {
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w.Header().Set("Content-Type", "text/plain; version=0.0.4; charset=utf-8")
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uptime := time.Since(startTime).Seconds()
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subs := 0
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if activeSubs != nil {
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subs = activeSubs()
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}
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fmt.Fprintf(w, "# HELP uopi_uptime_seconds Seconds elapsed since the server started\n")
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fmt.Fprintf(w, "# TYPE uopi_uptime_seconds counter\n")
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fmt.Fprintf(w, "uopi_uptime_seconds %.3f\n\n", uptime)
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fmt.Fprintf(w, "# HELP uopi_ws_connections Current number of open WebSocket connections\n")
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fmt.Fprintf(w, "# TYPE uopi_ws_connections gauge\n")
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fmt.Fprintf(w, "uopi_ws_connections %d\n\n", wsConns.Load())
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fmt.Fprintf(w, "# HELP uopi_signal_subscriptions Current number of unique upstream signal subscriptions\n")
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fmt.Fprintf(w, "# TYPE uopi_signal_subscriptions gauge\n")
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fmt.Fprintf(w, "uopi_signal_subscriptions %d\n\n", subs)
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fmt.Fprintf(w, "# HELP uopi_ws_messages_in_total Total WebSocket messages received from clients\n")
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fmt.Fprintf(w, "# TYPE uopi_ws_messages_in_total counter\n")
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fmt.Fprintf(w, "uopi_ws_messages_in_total %d\n\n", msgIn.Load())
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fmt.Fprintf(w, "# HELP uopi_ws_messages_out_total Total WebSocket messages sent to clients\n")
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fmt.Fprintf(w, "# TYPE uopi_ws_messages_out_total counter\n")
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fmt.Fprintf(w, "uopi_ws_messages_out_total %d\n\n", msgOut.Load())
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fmt.Fprintf(w, "# HELP uopi_write_ops_total Total signal write operations\n")
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fmt.Fprintf(w, "# TYPE uopi_write_ops_total counter\n")
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fmt.Fprintf(w, "uopi_write_ops_total %d\n\n", writeOps.Load())
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fmt.Fprintf(w, "# HELP uopi_history_requests_total Total historical data requests served\n")
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fmt.Fprintf(w, "# TYPE uopi_history_requests_total counter\n")
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fmt.Fprintf(w, "uopi_history_requests_total %d\n\n", historyReqs.Load())
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}
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}
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