Add GetProcessedMetrics method to Prometheus helper

CHANGELOG.asciidoc

@@ -39,6 +39,7 @@ https://github.com/elastic/beats/compare/v6.0.0-beta2...master[Check the HEAD di
 - Add config option for windows/perfmon metricset to ignore non existent counters. {pull}6432[6432]
 - Refactor docker CPU calculations to be more consistent with `docker stats`. {pull}6608[6608]
 - Update logstash.node_stats metricset to write data under `logstash.node.stats.*`. {pull}6714[6714]
+- Fixed typo in values for `state_container` `status.phase`, from `terminate` to `terminated`. {pull}6916[6916]
 
 *Packetbeat*
 
@@ -223,6 +224,9 @@ https://github.com/elastic/beats/compare/v6.0.0-beta2...master[Check the HEAD di
 
 *Metricbeat*
 
+- Kubernetes `state_container` `cpu.limit.nanocores` and `cpu.request.nanocores` have been
+deprecated in favor of `cpu.*.cores`. {pull}6916[6916]
+
 *Packetbeat*
 
 *Winlogbeat*

metricbeat/docs/fields.asciidoc

@@ -7307,6 +7307,26 @@ Container restarts count
 --
 
 
+*`kubernetes.container.cpu.limit.cores`*::
++
+--
+type: long
+
+Container CPU cores limit
+
+
+--
+
+*`kubernetes.container.cpu.request.cores`*::
++
+--
+type: long
+
+Container CPU requested cores
+
+
+--
+
 *`kubernetes.container.cpu.limit.nanocores`*::
 +
 --

metricbeat/helper/prometheus/label.go

@@ -0,0 +1,42 @@
+package prometheus
+
+// LabelMap defines the mapping from Prometheus label to a Metricbeat field
+type LabelMap interface {
+	// GetField returns the resulting field name
+	GetField() string
+
+	// IsKey returns true if the label is a key label
+	IsKey() bool
+}
+
+// Label maps a Prometheus label to a Metricbeat field
+func Label(field string) LabelMap {
+	return &commonLabel{
+		field: field,
+		key:   false,
+	}
+}
+
+// KeyLabel maps a Prometheus label to a Metricbeat field. The label is flagged as key.
+// Metrics with the same tuple of key labels will be grouped in the same event.
+func KeyLabel(field string) LabelMap {
+	return &commonLabel{
+		field: field,
+		key:   true,
+	}
+}
+
+type commonLabel struct {
+	field string
+	key   bool
+}
+
+// GetField returns the resulting field name
+func (l *commonLabel) GetField() string {
+	return l.field
+}
+
+// IsKey returns true if the label is a key label
+func (l *commonLabel) IsKey() bool {
+	return l.key
+}

metricbeat/helper/prometheus/metric.go

@@ -0,0 +1,126 @@
+package prometheus
+
+import (
+	"strings"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// MetricMap defines the mapping from Prometheus metric to a Metricbeat field
+type MetricMap interface {
+	// GetField returns the resulting field name
+	GetField() string
+
+	// GetValue returns the resulting value
+	GetValue(m *dto.Metric) interface{}
+}
+
+// Metric directly maps a Prometheus metric to a Metricbeat field
+func Metric(field string) MetricMap {
+	return &commonMetric{
+		field: field,
+	}
+}
+
+// KeywordMetric maps a Prometheus metric to a Metricbeat field, stores the
+// given keyword when source metric value is 1
+func KeywordMetric(field, keyword string) MetricMap {
+	return &keywordMetric{
+		commonMetric{
+			field: field,
+		},
+		keyword,
+	}
+}
+
+// BooleanMetric maps a Prometheus metric to a Metricbeat field of bool type
+func BooleanMetric(field string) MetricMap {
+	return &booleanMetric{
+		commonMetric{
+			field: field,
+		},
+	}
+}
+
+// LabelMetric maps a Prometheus metric to a Metricbeat field, stores the value
+// of a given label on it if the gauge value is 1
+func LabelMetric(field, label string) MetricMap {
+	return &labelMetric{
+		commonMetric{
+			field: field,
+		},
+		label,
+	}
+}
+
+type commonMetric struct {
+	field string
+}
+
+// GetField returns the resulting field name
+func (m *commonMetric) GetField() string {
+	return m.field
+}
+
+// GetValue returns the resulting value
+func (m *commonMetric) GetValue(metric *dto.Metric) interface{} {
+	counter := metric.GetCounter()
+	if counter != nil {
+		return int64(counter.GetValue())
+	}
+
+	gauge := metric.GetGauge()
+	if gauge != nil {
+		return gauge.GetValue()
+	}
+
+	// Other types are not supported here
+	return nil
+}
+
+type keywordMetric struct {
+	commonMetric
+	keyword string
+}
+
+// GetValue returns the resulting value
+func (m *keywordMetric) GetValue(metric *dto.Metric) interface{} {
+	if gauge := metric.GetGauge(); gauge != nil && gauge.GetValue() == 1 {
+		return m.keyword
+	}
+	return nil
+}
+
+type booleanMetric struct {
+	commonMetric
+}
+
+// GetValue returns the resulting value
+func (m *booleanMetric) GetValue(metric *dto.Metric) interface{} {
+	if gauge := metric.GetGauge(); gauge != nil {
+		return gauge.GetValue() == 1
+	}
+	return nil
+}
+
+type labelMetric struct {
+	commonMetric
+	label string
+}
+
+// GetValue returns the resulting value
+func (m *labelMetric) GetValue(metric *dto.Metric) interface{} {
+	if gauge := metric.GetGauge(); gauge != nil && gauge.GetValue() == 1 {
+		return strings.ToLower(getLabel(metric, m.label))
+	}
+	return nil
+}
+
+func getLabel(metric *dto.Metric, name string) string {
+	for _, label := range metric.GetLabel() {
+		if label.GetName() == name {
+			return label.GetValue()
+		}
+	}
+	return ""
+}