windows_exporter/pkg/collector/handler.go

84 lines
2.5 KiB
Go

//go:build windows
package collector
import (
"fmt"
stdlog "log"
"net/http"
"strconv"
"time"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/collectors"
"github.com/prometheus/client_golang/prometheus/collectors/version"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
func (c *Collectors) BuildServeHTTP(disableExporterMetrics bool, timeoutMargin float64) http.HandlerFunc {
collectorFactory := func(timeout time.Duration, requestedCollectors []string) (error, *Prometheus) {
filteredCollectors := make(map[string]Collector)
// scrape all enabled collectors if no collector is requested
if len(requestedCollectors) == 0 {
filteredCollectors = c.collectors
}
for _, name := range requestedCollectors {
col, exists := c.collectors[name]
if !exists {
return fmt.Errorf("unavailable collector: %s", name), nil
}
filteredCollectors[name] = col
}
filtered := Collectors{
logger: c.logger,
collectors: filteredCollectors,
perfCounterQuery: c.perfCounterQuery,
}
return nil, NewPrometheus(timeout, &filtered, c.logger)
}
return func(w http.ResponseWriter, r *http.Request) {
const defaultTimeout = 10.0
var timeoutSeconds float64
if v := r.Header.Get("X-Prometheus-Scrape-Timeout-Seconds"); v != "" {
var err error
timeoutSeconds, err = strconv.ParseFloat(v, 64)
if err != nil {
_ = level.Warn(c.logger).Log("msg", fmt.Sprintf("Couldn't parse X-Prometheus-Scrape-Timeout-Seconds: %q. Defaulting timeout to %f", v, defaultTimeout))
}
}
if timeoutSeconds == 0 {
timeoutSeconds = defaultTimeout
}
timeoutSeconds -= timeoutMargin
reg := prometheus.NewRegistry()
err, wc := collectorFactory(time.Duration(timeoutSeconds*float64(time.Second)), r.URL.Query()["collect[]"])
if err != nil {
_ = level.Warn(c.logger).Log("msg", "Couldn't create filtered metrics handler", "err", err)
w.WriteHeader(http.StatusBadRequest)
w.Write([]byte(fmt.Sprintf("Couldn't create filtered metrics handler: %s", err))) //nolint:errcheck
return
}
reg.MustRegister(wc)
if !disableExporterMetrics {
reg.MustRegister(
collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}),
collectors.NewGoCollector(),
version.NewCollector("windows_exporter"),
)
}
h := promhttp.HandlerFor(reg, promhttp.HandlerOpts{
ErrorLog: stdlog.New(log.NewStdlibAdapter(level.Error(c.logger)), "", stdlog.Lshortfile),
})
h.ServeHTTP(w, r)
}
}