open-nomad/command/agent/metrics_endpoint.go
James Rasell 782350bd19
agent: return req error if prometheus metrics are disabled.
If the user has disabled Prometheus metrics and a request is
sent to the metrics endpoint requesting Prometheus formatted
metrics, then the request should fail.
2021-03-09 15:28:58 +01:00

50 lines
1.3 KiB
Go

package agent
import (
"net/http"
"sync"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
var (
// Only create the prometheus handler once
promHandler http.Handler
promOnce sync.Once
)
// MetricsRequest returns metrics for the agent. Metrics are JSON by default
// but Prometheus is an optional format.
func (s *HTTPServer) MetricsRequest(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
if req.Method != "GET" {
return nil, CodedError(405, ErrInvalidMethod)
}
if format := req.URL.Query().Get("format"); format == "prometheus" {
// Only return Prometheus formatted metrics if the user has enabled
// this functionality.
if !s.agent.config.Telemetry.PrometheusMetrics {
return nil, CodedError(http.StatusUnsupportedMediaType, "Prometheus is not enabled")
}
s.prometheusHandler().ServeHTTP(resp, req)
return nil, nil
}
return s.agent.InmemSink.DisplayMetrics(resp, req)
}
func (s *HTTPServer) prometheusHandler() http.Handler {
promOnce.Do(func() {
handlerOptions := promhttp.HandlerOpts{
ErrorLog: s.logger.Named("prometheus_handler").StandardLogger(nil),
ErrorHandling: promhttp.ContinueOnError,
DisableCompression: true,
}
promHandler = promhttp.HandlerFor(prometheus.DefaultGatherer, handlerOptions)
})
return promHandler
}