first commit

internal/metrics/exporter.go

@@ -0,0 +1,191 @@
+/*
+© Copyright IBM Corporation 2018, 2019
+
+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 metrics contains code to provide metrics for the queue manager
+package metrics
+
+import (
+	"github.com/ibm-messaging/mq-container/pkg/logger"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	namespace    = "ibmmq"
+	qmgrPrefix   = "qmgr"
+	qmgrLabel    = "qmgr"
+	objectPrefix = "object"
+	objectLabel  = "object"
+)
+
+type exporter struct {
+	qmName       string
+	gaugeMap     map[string]*prometheus.GaugeVec
+	counterMap   map[string]*prometheus.CounterVec
+	firstCollect bool
+	log          *logger.Logger
+}
+
+func newExporter(qmName string, log *logger.Logger) *exporter {
+	return &exporter{
+		qmName:       qmName,
+		gaugeMap:     make(map[string]*prometheus.GaugeVec),
+		counterMap:   make(map[string]*prometheus.CounterVec),
+		firstCollect: true,
+		log:          log,
+	}
+}
+
+// Describe provides details of all available metrics
+func (e *exporter) Describe(ch chan<- *prometheus.Desc) {
+
+	requestChannel <- false
+	response := <-responseChannel
+
+	for key, metric := range response {
+
+		if metric.isDelta {
+			// For delta type metrics - allocate a Prometheus Counter
+			counterVec := createCounterVec(metric.name, metric.description, metric.objectType)
+			e.counterMap[key] = counterVec
+
+			// Describe metric
+			counterVec.Describe(ch)
+
+		} else {
+			// For non-delta type metrics - allocate a Prometheus Gauge
+			gaugeVec := createGaugeVec(metric.name, metric.description, metric.objectType)
+			e.gaugeMap[key] = gaugeVec
+
+			// Describe metric
+			gaugeVec.Describe(ch)
+		}
+	}
+}
+
+// Collect is called at regular intervals to provide the current metric data
+func (e *exporter) Collect(ch chan<- prometheus.Metric) {
+
+	requestChannel <- true
+	response := <-responseChannel
+
+	for key, metric := range response {
+
+		if metric.isDelta {
+			// For delta type metrics - update their Prometheus Counter
+			counterVec := e.counterMap[key]
+
+			// Populate Prometheus Counter with metric values
+			// - Skip on first collect to avoid build-up of accumulated values
+			if !e.firstCollect {
+				for label, value := range metric.values {
+					var err error
+					var counter prometheus.Counter
+
+					if label == qmgrLabelValue {
+						counter, err = counterVec.GetMetricWithLabelValues(e.qmName)
+					} else {
+						counter, err = counterVec.GetMetricWithLabelValues(label, e.qmName)
+					}
+					if err == nil {
+						counter.Add(value)
+					} else {
+						e.log.Errorf("Metrics Error: %s", err.Error())
+					}
+				}
+			}
+
+			// Collect metric
+			counterVec.Collect(ch)
+
+		} else {
+			// For non-delta type metrics - reset their Prometheus Gauge
+			gaugeVec := e.gaugeMap[key]
+			gaugeVec.Reset()
+
+			// Populate Prometheus Gauge with metric values
+			// - Skip on first collect to avoid build-up of accumulated values
+			if !e.firstCollect {
+				for label, value := range metric.values {
+					var err error
+					var gauge prometheus.Gauge
+
+					if label == qmgrLabelValue {
+						gauge, err = gaugeVec.GetMetricWithLabelValues(e.qmName)
+					} else {
+						gauge, err = gaugeVec.GetMetricWithLabelValues(label, e.qmName)
+					}
+					if err == nil {
+						gauge.Set(value)
+					} else {
+						e.log.Errorf("Metrics Error: %s", err.Error())
+					}
+				}
+			}
+
+			// Collect metric
+			gaugeVec.Collect(ch)
+		}
+	}
+
+	if e.firstCollect {
+		e.firstCollect = false
+	}
+}
+
+// createCounterVec returns a Prometheus CounterVec populated with metric details
+func createCounterVec(name, description string, objectType bool) *prometheus.CounterVec {
+
+	prefix, labels := getVecDetails(objectType)
+
+	counterVec := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Name:      prefix + "_" + name,
+			Help:      description,
+		},
+		labels,
+	)
+	return counterVec
+}
+
+// createGaugeVec returns a Prometheus GaugeVec populated with metric details
+func createGaugeVec(name, description string, objectType bool) *prometheus.GaugeVec {
+
+	prefix, labels := getVecDetails(objectType)
+
+	gaugeVec := prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      prefix + "_" + name,
+			Help:      description,
+		},
+		labels,
+	)
+	return gaugeVec
+}
+
+// getVecDetails returns the required prefix and labels for a metric
+func getVecDetails(objectType bool) (prefix string, labels []string) {
+
+	prefix = qmgrPrefix
+	labels = []string{qmgrLabel}
+
+	if objectType {
+		prefix = objectPrefix
+		labels = []string{objectLabel, qmgrLabel}
+	}
+	return prefix, labels
+}