122 lines
3.0 KiB
Go
122 lines
3.0 KiB
Go
/*
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© Copyright IBM Corporation 2018, 2022
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Package metrics contains code to provide metrics for the queue manager
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package metrics
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import (
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"context"
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"fmt"
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"net/http"
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"time"
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"github.com/ibm-messaging/mq-container/internal/ready"
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"github.com/ibm-messaging/mq-container/pkg/logger"
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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 (
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defaultPort = "9157"
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)
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var (
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metricsEnabled = false
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metricsServer = &http.Server{Addr: ":" + defaultPort}
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)
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// GatherMetrics gathers metrics for the queue manager
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func GatherMetrics(qmName string, log *logger.Logger) {
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// If running in standby mode - wait until the queue manager becomes active
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for {
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active, _ := ready.IsRunningAsActiveQM(context.Background(), qmName)
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if active {
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break
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}
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time.Sleep(requestTimeout * time.Second)
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}
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metricsEnabled = true
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err := startMetricsGathering(qmName, log)
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if err != nil {
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log.Errorf("Metrics Error: %s", err.Error())
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StopMetricsGathering(log)
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}
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}
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// startMetricsGathering starts gathering metrics for the queue manager
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func startMetricsGathering(qmName string, log *logger.Logger) error {
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defer func() {
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if r := recover(); r != nil {
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log.Errorf("Metrics Error: %v", r)
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}
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}()
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log.Println("Starting metrics gathering")
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// Start processing metrics
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go processMetrics(log, qmName)
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// Wait for metrics to be ready before starting the Prometheus handler
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<-startChannel
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// Register metrics
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metricsExporter := newExporter(qmName, log)
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err := prometheus.Register(metricsExporter)
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if err != nil {
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return fmt.Errorf("Failed to register metrics: %v", err)
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}
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// Setup HTTP server to handle requests from Prometheus
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http.Handle("/metrics", promhttp.Handler())
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http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
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w.WriteHeader(200)
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// #nosec G104
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w.Write([]byte("Status: METRICS ACTIVE"))
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})
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go func() {
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err = metricsServer.ListenAndServe()
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if err != nil && err != http.ErrServerClosed {
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log.Errorf("Metrics Error: Failed to handle metrics request: %v", err)
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StopMetricsGathering(log)
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}
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}()
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return nil
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}
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// StopMetricsGathering stops gathering metrics for the queue manager
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func StopMetricsGathering(log *logger.Logger) {
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if metricsEnabled {
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// Stop processing metrics
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stopChannel <- true
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// Shutdown HTTP server
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timeout, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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err := metricsServer.Shutdown(timeout)
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if err != nil {
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log.Errorf("Failed to shutdown metrics server: %v", err)
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}
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}
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}
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