forked from electricdusk/rushlink
84 lines
2.5 KiB
Go
84 lines
2.5 KiB
Go
package rushlink
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import (
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"log"
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"net/http"
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"time"
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"gitea.hashru.nl/dsprenkels/rushlink/internal/db"
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"github.com/gorilla/mux"
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"github.com/pkg/errors"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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)
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const metricNamespace = "rushlink"
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// metricURLsTotalGauge counts the number of requests that are handled by
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// the application, partitioned by status code and HTTP method.
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//
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// This counter is updated by throughout the application.
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var metricRequestsTotalCounter = prometheus.NewCounterVec(
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prometheus.CounterOpts{
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Namespace: metricNamespace,
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Subsystem: "http",
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Name: "requests_total",
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Help: "How many HTTP requests processed, partitioned by status code and HTTP method.",
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}, []string{"code", "method"})
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// metricURLsTotalGauge measures the amount of pastes stored in the database,
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// partitioned by type and state.
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//
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// Its values are computed on the fly by updateMetrics().
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var metricURLsTotalGauge = prometheus.NewGaugeVec(
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prometheus.GaugeOpts{
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Namespace: metricNamespace,
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Subsystem: "pastes",
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Name: "urls_total",
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Help: "The current amount of pastes in the database, partitioned by state and type.",
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}, []string{"state", "type"})
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// StartMetricsServer starts sering Prometheus metrics exports on addr
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func StartMetricsServer(addr string, database *db.Database, fs *db.FileStore) {
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prometheus.MustRegister(metricRequestsTotalCounter)
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prometheus.MustRegister(metricURLsTotalGauge)
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router := mux.NewRouter()
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router.Handle("/metrics", &MetricsHandler{database}).Methods("GET")
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srv := &http.Server{
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Handler: router,
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Addr: addr,
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WriteTimeout: 15 * time.Second,
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ReadTimeout: 15 * time.Second,
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}
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log.Fatal(srv.ListenAndServe())
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}
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type MetricsHandler struct {
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db *db.Database
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}
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func (mh *MetricsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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mh.updateMetrics()
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promhttp.Handler().ServeHTTP(w, r)
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}
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func (mh *MetricsHandler) updateMetrics() {
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// Update metricURLsTotalGauge
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for state := db.PasteStateUndef; state <= db.PasteStateDeleted; state++ {
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for ty := db.PasteTypeUndef; ty <= db.PasteTypeFileUpload; ty++ {
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var count int64
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query := mh.db.Unscoped().Model(&db.Paste{}).Where("type = ? AND state = ?", ty, state).Count(&count)
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if err := query.Error; err != nil {
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log.Printf("error: %v", errors.Wrap(err, "fetching pastes_total metric"))
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return
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}
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labels := map[string]string{
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"state": state.String(),
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"type": ty.String(),
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}
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metricURLsTotalGauge.With(labels).Set(float64(count))
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}
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}
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}
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