add 'namespace' to allow parallel tests

add failing test case which shows old metrics are not cleared

code cleanup

code cleanup

assure new gagues are exported properly

recreate gauges on each scrape to clear stale values

include tests for stale metrics of all types

clear containers as well

containers.go

@@ -18,12 +18,14 @@ const (
 )
 
 type CounterContainer struct {
- counters map[string]*prometheus.CounterVec
+ counters map[string]*prometheus.CounterVec
+ namespace string
 }
 
-func NewCounterContainer() *CounterContainer {
+func NewCounterContainer(namespace string) *CounterContainer {
  return &CounterContainer{
- counters: make(map[string]*prometheus.CounterVec),
+ counters: make(map[string]*prometheus.CounterVec),
+ namespace: namespace,
  }
 }
 
@@ -33,7 +35,7 @@ func (c *CounterContainer) Fetch(name, help string, labels ...string) (*promethe
 
  if !exists {
  counter = prometheus.NewCounterVec(prometheus.CounterOpts{
- Namespace: namespace,
+ Namespace: c.namespace,
  Name: name,
  Help: help,
  }, labels)
@@ -45,12 +47,14 @@ func (c *CounterContainer) Fetch(name, help string, labels ...string) (*promethe
 }
 
 type GaugeContainer struct {
- gauges map[string]*prometheus.GaugeVec
+ gauges map[string]*prometheus.GaugeVec
+ namespace string
 }
 
-func NewGaugeContainer() *GaugeContainer {
+func NewGaugeContainer(namespace string) *GaugeContainer {
  return &GaugeContainer{
- gauges: make(map[string]*prometheus.GaugeVec),
+ gauges: make(map[string]*prometheus.GaugeVec),
+ namespace: namespace,
  }
 }
 
@@ -60,7 +64,7 @@ func (c *GaugeContainer) Fetch(name, help string, labels ...string) (*prometheus
 
  if !exists {
  gauge = prometheus.NewGaugeVec(prometheus.GaugeOpts{
- Namespace: namespace,
+ Namespace: c.namespace,
  Name: name,
  Help: help,
  }, labels)

containers_test.go

@@ -32,7 +32,7 @@ func Test_container_key(t *testing.T) {
 }
 
 func Test_container_fetch_counter(t *testing.T) {
- container := NewCounterContainer()
+ container := NewCounterContainer("marathon")
  _, new := container.Fetch("foo", "")
 
  if !new {
@@ -52,7 +52,7 @@ func Test_container_fetch_counter(t *testing.T) {
 }
 
 func Test_container_fetch_gauge(t *testing.T) {
- container := NewGaugeContainer()
+ container := NewGaugeContainer("marathon")
  _, new := container.Fetch("foo", "")
 
  if !new {

exporter.go

@@ -12,7 +12,7 @@ import (
  "github.com/prometheus/common/log"
 )
 
-const namespace = "marathon"
+const defaultNamespace = "marathon"
 
 type Exporter struct {
  scraper Scraper
@@ -71,6 +71,9 @@ func (e *Exporter) scrape(ch chan<- prometheus.Metric) {
  }
  }(time.Now())
 
+ // Rebuild gauges & coutners to avoid stale values
+ e.Gauges = NewGaugeContainer(e.Gauges.namespace)
+ e.Counters = NewCounterContainer(e.Counters.namespace)
  if err = e.exportApps(ch); err != nil {
  return
  }
@@ -422,11 +425,11 @@ func (e *Exporter) scrapeTimer(key string, json *gabs.Container) (bool, error) {
  return new, nil
 }
 
-func NewExporter(s Scraper) *Exporter {
+func NewExporter(s Scraper, namespace string) *Exporter {
  return &Exporter{
  scraper: s,
- Counters: NewCounterContainer(),
- Gauges: NewGaugeContainer(),
+ Counters: NewCounterContainer(namespace),
+ Gauges: NewGaugeContainer(namespace),
  duration: prometheus.NewGauge(prometheus.GaugeOpts{
  Namespace: namespace,
  Subsystem: "exporter",