use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

vendor/k8s.io/component-base/metrics/registry.go

@@ -0,0 +1,161 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+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
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"github.com/blang/semver"
+	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
+
+	apimachineryversion "k8s.io/apimachinery/pkg/version"
+	"k8s.io/component-base/version"
+)
+
+var (
+	showHiddenOnce sync.Once
+	showHidden     atomic.Value
+)
+
+// SetShowHidden will enable showing hidden metrics. This will no-opt
+// after the initial call
+func SetShowHidden() {
+	showHiddenOnce.Do(func() {
+		showHidden.Store(true)
+	})
+}
+
+// ShouldShowHidden returns whether showing hidden deprecated metrics
+// is enabled. While the primary usecase for this is internal (to determine
+// registration behavior) this can also be used to introspect
+func ShouldShowHidden() bool {
+	return showHidden.Load() != nil && showHidden.Load().(bool)
+}
+
+// Registerable is an interface for a collector metric which we
+// will register with KubeRegistry.
+type Registerable interface {
+	prometheus.Collector
+	Create(version *semver.Version) bool
+}
+
+// KubeRegistry is an interface which implements a subset of prometheus.Registerer and
+// prometheus.Gatherer interfaces
+type KubeRegistry interface {
+	// Deprecated
+	RawRegister(prometheus.Collector) error
+	// Deprecated
+	RawMustRegister(...prometheus.Collector)
+	Register(Registerable) error
+	MustRegister(...Registerable)
+	Unregister(Registerable) bool
+	Gather() ([]*dto.MetricFamily, error)
+}
+
+// kubeRegistry is a wrapper around a prometheus registry-type object. Upon initialization
+// the kubernetes binary version information is loaded into the registry object, so that
+// automatic behavior can be configured for metric versioning.
+type kubeRegistry struct {
+	PromRegistry
+	version semver.Version
+}
+
+// Register registers a new Collector to be included in metrics
+// collection. It returns an error if the descriptors provided by the
+// Collector are invalid or if they — in combination with descriptors of
+// already registered Collectors — do not fulfill the consistency and
+// uniqueness criteria described in the documentation of metric.Desc.
+func (kr *kubeRegistry) Register(c Registerable) error {
+	if c.Create(&kr.version) {
+		return kr.PromRegistry.Register(c)
+	}
+	return nil
+}
+
+// MustRegister works like Register but registers any number of
+// Collectors and panics upon the first registration that causes an
+// error.
+func (kr *kubeRegistry) MustRegister(cs ...Registerable) {
+	metrics := make([]prometheus.Collector, 0, len(cs))
+	for _, c := range cs {
+		if c.Create(&kr.version) {
+			metrics = append(metrics, c)
+		}
+	}
+	kr.PromRegistry.MustRegister(metrics...)
+}
+
+// RawRegister takes a native prometheus.Collector and registers the collector
+// to the registry. This bypasses metrics safety checks, so should only be used
+// to register custom prometheus collectors.
+//
+// Deprecated
+func (kr *kubeRegistry) RawRegister(c prometheus.Collector) error {
+	return kr.PromRegistry.Register(c)
+}
+
+// RawMustRegister takes a native prometheus.Collector and registers the collector
+// to the registry. This bypasses metrics safety checks, so should only be used
+// to register custom prometheus collectors.
+//
+// Deprecated
+func (kr *kubeRegistry) RawMustRegister(cs ...prometheus.Collector) {
+	kr.PromRegistry.MustRegister(cs...)
+}
+
+// Unregister unregisters the Collector that equals the Collector passed
+// in as an argument.  (Two Collectors are considered equal if their
+// Describe method yields the same set of descriptors.) The function
+// returns whether a Collector was unregistered. Note that an unchecked
+// Collector cannot be unregistered (as its Describe method does not
+// yield any descriptor).
+func (kr *kubeRegistry) Unregister(collector Registerable) bool {
+	return kr.PromRegistry.Unregister(collector)
+}
+
+// Gather calls the Collect method of the registered Collectors and then
+// gathers the collected metrics into a lexicographically sorted slice
+// of uniquely named MetricFamily protobufs. Gather ensures that the
+// returned slice is valid and self-consistent so that it can be used
+// for valid exposition. As an exception to the strict consistency
+// requirements described for metric.Desc, Gather will tolerate
+// different sets of label names for metrics of the same metric family.
+func (kr *kubeRegistry) Gather() ([]*dto.MetricFamily, error) {
+	return kr.PromRegistry.Gather()
+}
+
+func newKubeRegistry(v apimachineryversion.Info) *kubeRegistry {
+	r := &kubeRegistry{
+		PromRegistry: prometheus.NewRegistry(),
+		version:      parseVersion(v),
+	}
+	return r
+}
+
+func registerMetadataMetrics(r *kubeRegistry) {
+	RegisterBuildInfo(r)
+}
+
+// NewKubeRegistry creates a new vanilla Registry without any Collectors
+// pre-registered.
+func NewKubeRegistry() KubeRegistry {
+	r := newKubeRegistry(version.Get())
+	registerMetadataMetrics(r)
+	return r
+}