Merge pull request #117295 from aojea/transport_cache_metrics

add new metric for the internal client-go cache size

Kubernetes-commit: 64af2d93e5b97e41bb078e2fa81923fda6681154

go.mod

@@ -24,7 +24,7 @@ require (
 	golang.org/x/time v0.3.0
 	google.golang.org/protobuf v1.30.0
 	k8s.io/api v0.0.0-20230506223117-f3a0f2ed177a
-	k8s.io/apimachinery v0.0.0-20230508165628-e7958c5fe270
+	k8s.io/apimachinery v0.0.0-20230510175910-f3f375c6bf8b
 	k8s.io/klog/v2 v2.100.1
 	k8s.io/kube-openapi v0.0.0-20230501164219-8b0f38b5fd1f
 	k8s.io/utils v0.0.0-20230209194617-a36077c30491
@@ -60,5 +60,5 @@ require (
 
 replace (
 	k8s.io/api => k8s.io/api v0.0.0-20230506223117-f3a0f2ed177a
-	k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20230508165628-e7958c5fe270
+	k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20230510175910-f3f375c6bf8b
 )

go.sum

@@ -480,8 +480,8 @@ honnef.co/go/tools v0.0.1-2020.1.3/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9
 honnef.co/go/tools v0.0.1-2020.1.4/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
 k8s.io/api v0.0.0-20230506223117-f3a0f2ed177a h1:8sUE9zRxWwhC0FmKr0+Jtm6wgnL3ljlVJOT94jSVsO4=
 k8s.io/api v0.0.0-20230506223117-f3a0f2ed177a/go.mod h1:/fu24lnfAhrloAI7EhcGTa0fXXQH5r4rUqEQMW9endY=
-k8s.io/apimachinery v0.0.0-20230508165628-e7958c5fe270 h1:0kz1rv3L87V/4KNEVPlst7yhT5RfAC+5JqeXR3rBXVc=
+k8s.io/apimachinery v0.0.0-20230510175910-f3f375c6bf8b h1:WdIXsJtB+R/npU8V6XSRtCtBx0qSDvyrUhCQnHg/Fhw=
-k8s.io/apimachinery v0.0.0-20230508165628-e7958c5fe270/go.mod h1:jF849JXyKVKRC0O62ZBSygt6qOSEYju8i90sKd1mx4g=
+k8s.io/apimachinery v0.0.0-20230510175910-f3f375c6bf8b/go.mod h1:jF849JXyKVKRC0O62ZBSygt6qOSEYju8i90sKd1mx4g=
 k8s.io/klog/v2 v2.100.1 h1:7WCHKK6K8fNhTqfBhISHQ97KrnJNFZMcQvKp7gP/tmg=
 k8s.io/klog/v2 v2.100.1/go.mod h1:y1WjHnz7Dj687irZUWR/WLkLc5N1YHtjLdmgWjndZn0=
 k8s.io/kube-openapi v0.0.0-20230501164219-8b0f38b5fd1f h1:2kWPakN3i/k81b0gvD5C5FJ2kxm1WrQFanWchyKuqGg=

tools/metrics/metrics.go

@@ -64,6 +64,17 @@ type RetryMetric interface {
 	IncrementRetry(ctx context.Context, code string, method string, host string)
 }
 
+// TransportCacheMetric shows the number of entries in the internal transport cache
+type TransportCacheMetric interface {
+	Observe(value int)
+}
+
+// TransportCreateCallsMetric counts the number of times a transport is created
+// partitioned by the result of the cache: hit, miss, uncacheable
+type TransportCreateCallsMetric interface {
+	Increment(result string)
+}
+
 var (
 	// ClientCertExpiry is the expiry time of a client certificate
 	ClientCertExpiry ExpiryMetric = noopExpiry{}
@@ -85,6 +96,12 @@ var (
 	// RequestRetry is the retry metric that tracks the number of
 	// retries sent to the server.
 	RequestRetry RetryMetric = noopRetry{}
+	// TransportCacheEntries is the metric that tracks the number of entries in the
+	// internal transport cache.
+	TransportCacheEntries TransportCacheMetric = noopTransportCache{}
+	// TransportCreateCalls is the metric that counts the number of times a new transport
+	// is created
+	TransportCreateCalls TransportCreateCallsMetric = noopTransportCreateCalls{}
 )
 
 // RegisterOpts contains all the metrics to register. Metrics may be nil.
@@ -98,6 +115,8 @@ type RegisterOpts struct {
 	RequestResult         ResultMetric
 	ExecPluginCalls       CallsMetric
 	RequestRetry          RetryMetric
+	TransportCacheEntries TransportCacheMetric
+	TransportCreateCalls  TransportCreateCallsMetric
 }
 
 // Register registers metrics for the rest client to use. This can
@@ -131,6 +150,12 @@ func Register(opts RegisterOpts) {
 		if opts.RequestRetry != nil {
 			RequestRetry = opts.RequestRetry
 		}
+		if opts.TransportCacheEntries != nil {
+			TransportCacheEntries = opts.TransportCacheEntries
+		}
+		if opts.TransportCreateCalls != nil {
+			TransportCreateCalls = opts.TransportCreateCalls
+		}
 	})
 }
 
@@ -161,3 +186,11 @@ func (noopCalls) Increment(int, string) {}
 type noopRetry struct{}
 
 func (noopRetry) IncrementRetry(context.Context, string, string, string) {}
+
+type noopTransportCache struct{}
+
+func (noopTransportCache) Observe(int) {}
+
+type noopTransportCreateCalls struct{}
+
+func (noopTransportCreateCalls) Increment(string) {}

transport/cache.go

@@ -27,6 +27,7 @@ import (
 
 	utilnet "k8s.io/apimachinery/pkg/util/net"
 	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/tools/metrics"
 )
 
 // TlsTransportCache caches TLS http.RoundTrippers different configurations. The
@@ -80,11 +81,16 @@ func (c *tlsTransportCache) get(config *Config) (http.RoundTripper, error) {
 		// Ensure we only create a single transport for the given TLS options
 		c.mu.Lock()
 		defer c.mu.Unlock()
+		defer metrics.TransportCacheEntries.Observe(len(c.transports))
 
 		// See if we already have a custom transport for this config
 		if t, ok := c.transports[key]; ok {
+			metrics.TransportCreateCalls.Increment("hit")
 			return t, nil
 		}
+		metrics.TransportCreateCalls.Increment("miss")
+	} else {
+		metrics.TransportCreateCalls.Increment("uncacheable")
 	}
 
 	// Get the TLS options for this client config