Fix for not reusable http client leading to connection leaks in Jolokia module

CHANGELOG.next.asciidoc

@@ -181,6 +181,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Fix issue with `elasticsearch/node_stats` metricset (x-pack) not indexing `source_node` field. {pull}10639[10639]
 - Migrate docker autodiscover to ECS. {issue}10757[10757] {pull}10862[10862]
 - Fix issue in kubernetes module preventing usage percentages to be properly calculated. {pull}10946[10946]
+- Fix for not reusable http client leading to connection leaks in Jolokia module {pull}11014[11014]
 
 *Packetbeat*
 

metricbeat/module/jolokia/jmx/config.go

@@ -29,7 +29,6 @@ import (
 
 	"github.com/elastic/beats/libbeat/common"
 	"github.com/elastic/beats/libbeat/logp"
-	"github.com/elastic/beats/metricbeat/helper"
 )
 
 type JMXMapping struct {
@@ -355,20 +354,17 @@ func (pc *JolokiaHTTPGetFetcher) Fetch(m *MetricSet) ([]common.MapStr, error) {
 	}
 
 	for _, r := range httpReqs {
+		m.http.SetMethod(r.HTTPMethod)
+		m.http.SetURI(m.BaseMetricSet.HostData().SanitizedURI + r.URI)
 
-		http, err := helper.NewHTTP(m.BaseMetricSet)
-
-		http.SetMethod(r.HTTPMethod)
-		http.SetURI(m.BaseMetricSet.HostData().SanitizedURI + r.URI)
-
-		resBody, err := http.FetchContent()
+		resBody, err := m.http.FetchContent()
 		if err != nil {
 			return nil, err
 		}
 
 		if logp.IsDebug(metricsetName) {
 			m.log.Debugw("Jolokia response body",
-				"host", m.HostData().Host, "uri", http.GetURI(), "body", string(resBody), "type", "response")
+				"host", m.HostData().Host, "uri", m.http.GetURI(), "body", string(resBody), "type", "response")
 		}
 
 		// Map response to Metricbeat events
@@ -491,19 +487,17 @@ func (pc *JolokiaHTTPPostFetcher) Fetch(m *MetricSet) ([]common.MapStr, error) {
 		}
 	}
 
-	http, err := helper.NewHTTP(m.BaseMetricSet)
-
-	http.SetMethod(httpReqs[0].HTTPMethod)
-	http.SetBody(httpReqs[0].Body)
+	m.http.SetMethod(httpReqs[0].HTTPMethod)
+	m.http.SetBody(httpReqs[0].Body)
 
-	resBody, err := http.FetchContent()
+	resBody, err := m.http.FetchContent()
 	if err != nil {
 		return nil, err
 	}
 
 	if logp.IsDebug(metricsetName) {
 		m.log.Debugw("Jolokia response body",
-			"host", m.HostData().Host, "uri", http.GetURI(), "body", string(resBody), "type", "response")
+			"host", m.HostData().Host, "uri", m.http.GetURI(), "body", string(resBody), "type", "response")
 	}
 
 	// Map response to Metricbeat events

metricbeat/module/jolokia/jmx/jmx.go

@@ -20,6 +20,8 @@ package jmx
 import (
 	"github.com/joeshaw/multierror"
 
+	"github.com/elastic/beats/metricbeat/helper"
+
 	"github.com/elastic/beats/libbeat/common"
 	"github.com/elastic/beats/libbeat/logp"
 	"github.com/elastic/beats/metricbeat/mb"
@@ -55,8 +57,9 @@ type MetricSet struct {
 	mb.BaseMetricSet
 	mapping   []JMXMapping
 	namespace string
-	http      JolokiaHTTPRequestFetcher
+	jolokia   JolokiaHTTPRequestFetcher
 	log       *logp.Logger
+	http      *helper.HTTP
 }
 
 // New create a new instance of the MetricSet
@@ -71,16 +74,22 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 		return nil, err
 	}
 
-	jolokiaHTTPBuild := NewJolokiaHTTPRequestFetcher(config.HTTPMethod)
+	jolokiaFetcher := NewJolokiaHTTPRequestFetcher(config.HTTPMethod)
 
 	log := logp.NewLogger(metricsetName).With("host", base.HostData().Host)
 
+	http, err := helper.NewHTTP(base)
+	if err != nil {
+		return nil, err
+	}
+
 	return &MetricSet{
 		BaseMetricSet: base,
 		mapping:       config.Mappings,
 		namespace:     config.Namespace,
-		http:          jolokiaHTTPBuild,
+		jolokia:       jolokiaFetcher,
 		log:           log,
+		http:          http,
 	}, nil
 }
 
@@ -89,7 +98,7 @@ func (m *MetricSet) Fetch() ([]common.MapStr, error) {
 
 	var allEvents []common.MapStr
 
-	allEvents, err := m.http.Fetch(m)
+	allEvents, err := m.jolokia.Fetch(m)
 	if err != nil {
 		return nil, err
 	}