/
metrics_server.go
87 lines (77 loc) · 2.32 KB
/
metrics_server.go
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/*
* Copyright 2020 National Library of Norway.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package telemetry
import (
"context"
"fmt"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/collectors"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/rs/zerolog/log"
"net/http"
"sync"
"time"
)
var once sync.Once
// MetricsServer is the Prometheus metrics endpoint for the Browser Controller
type MetricsServer struct {
addr string
path string
server *http.Server
}
// NewMetricsServer returns a new instance of MetricsServer listening on the given port
func NewMetricsServer(listenInterface string, listenPort int, path string) *MetricsServer {
a := &MetricsServer{
addr: fmt.Sprintf("%s:%d", listenInterface, listenPort),
path: path,
}
once.Do(func() {
prometheus.MustRegister(
CanonicalizationsTotal,
ScopechecksTotal,
ScopecheckResponseTotal,
CompileScriptSeconds,
ExecuteScriptSeconds,
collectors.NewBuildInfoCollector(),
)
})
return a
}
func (a *MetricsServer) Start() error {
router := http.NewServeMux()
router.Handle(a.path, promhttp.Handler())
a.server = &http.Server{
Addr: a.addr,
Handler: router,
ReadTimeout: 5 * time.Second,
WriteTimeout: 5 * time.Second,
IdleTimeout: 5 * time.Second,
}
log.Info().Msgf("Metrics server listening on address: %s", a.addr)
err := a.server.ListenAndServe()
if err != nil && !errors.Is(err, http.ErrServerClosed) {
return fmt.Errorf("failed to listen on %s: %w", a.addr, err)
}
return nil
}
func (a *MetricsServer) Close() {
log.Info().Msgf("Shutting down Metrics server")
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
a.server.SetKeepAlivesEnabled(false)
_ = a.server.Shutdown(ctx)
}