improvement: Add WithDisableConnectionMetrics() to skip high-cardinality TLS metrics

changelog/@unreleased/pr-342.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Add WithDisableConnectionMetrics() to skip high-cardinality TLS metrics
+  links:
+  - https://github.com/palantir/conjure-go-runtime/pull/342

conjure-go-client/httpclient/client_builder.go

@@ -68,6 +68,7 @@ type httpClientBuilder struct {
 	Middlewares     []Middleware
 
 	DisableMetrics      refreshable.Bool
+	DisableConnMetrics  bool
 	MetricsTagProviders []TagsProvider
 
 	// These middleware options are not refreshed anywhere because they are not in ClientConfig,
@@ -92,7 +93,7 @@ func (b *httpClientBuilder) Build(ctx context.Context, params ...HTTPClientParam
 		Dialer:         refreshingclient.NewRefreshableDialer(ctx, b.DialerParams),
 	}
 	transport := refreshingclient.NewRefreshableTransport(ctx, b.TransportParams, b.TLSConfig, dialer)
-	transport = wrapTransport(transport, newMetricsMiddleware(b.ServiceNameTag, b.MetricsTagProviders, b.DisableMetrics))
+	transport = wrapTransport(transport, newMetricsMiddleware(b.ServiceNameTag, b.MetricsTagProviders, b.DisableMetrics, b.DisableConnMetrics))
 	transport = wrapTransport(transport, traceMiddleware{
 		ServiceName:       b.ServiceNameTag.Value(),
 		CreateRequestSpan: b.CreateRequestSpan,

conjure-go-client/httpclient/client_params.go

@@ -169,6 +169,14 @@ func WithMetrics(tagProviders ...TagsProvider) ClientOrHTTPClientParam {
 	})
 }
 
+// WithDisableConnectionMetrics disables detailed metrics about the TLS connection(s) created by the client.
+func WithDisableConnectionMetrics() ClientOrHTTPClientParam {
+	return clientOrHTTPClientParamFunc(func(b *httpClientBuilder) error {
+		b.DisableConnMetrics = true
+		return nil
+	})
+}
+
 // WithBytesBufferPool stores a bytes buffer pool on the client for use in encoding request bodies.
 // This prevents allocating a new byte buffer for every request.
 func WithBytesBufferPool(pool bytesbuffers.Pool) ClientParam {

conjure-go-client/httpclient/metrics.go

@@ -98,10 +98,10 @@ func MetricsMiddleware(serviceName string, tagProviders ...TagsProvider) (Middle
 	if err != nil {
 		return nil, werror.Wrap(err, "failed to construct service-name metric tag", werror.SafeParam("serviceName", serviceName))
 	}
-	return newMetricsMiddleware(serviceNameTag, tagProviders, nil), nil
+	return newMetricsMiddleware(serviceNameTag, tagProviders, nil, false), nil
 }
 
-func newMetricsMiddleware(serviceNameTag metrics.Tag, tagProviders []TagsProvider, disabled refreshable.Bool) Middleware {
+func newMetricsMiddleware(serviceNameTag metrics.Tag, tagProviders []TagsProvider, disabled refreshable.Bool, disableConnMetrics bool) Middleware {
 	return &metricsMiddleware{
 		Disabled:       disabled,
 		ServiceNameTag: serviceNameTag,
@@ -112,13 +112,15 @@ func newMetricsMiddleware(serviceNameTag metrics.Tag, tagProviders []TagsProvide
 			TagsProviderFunc(tagRequestMethodName),
 			StaticTagsProvider(metrics.Tags{serviceNameTag}),
 		),
+		disableConnMetrics: disableConnMetrics,
 	}
 }
 
 type metricsMiddleware struct {
-	Disabled       refreshable.Bool
-	ServiceNameTag metrics.Tag
-	Tags           []TagsProvider
+	Disabled           refreshable.Bool
+	ServiceNameTag     metrics.Tag
+	Tags               []TagsProvider
+	disableConnMetrics bool
 }
 
 // RoundTrip will emit counter and timer metrics with the name 'mariner.k8sClient.request'
@@ -131,8 +133,11 @@ func (h *metricsMiddleware) RoundTrip(req *http.Request, next http.RoundTripper)
 
 	metrics.FromContext(req.Context()).Counter(MetricRequestInFlight, h.ServiceNameTag).Inc(1)
 	start := time.Now()
-	tlsMetricsContext := h.tlsTraceContext(req.Context())
-	resp, err := next.RoundTrip(req.WithContext(tlsMetricsContext))
+	ctx := req.Context()
+	if !h.disableConnMetrics {
+		ctx = h.tlsTraceContext(ctx)
+	}
+	resp, err := next.RoundTrip(req.WithContext(ctx))
 	duration := time.Since(start)
 	metrics.FromContext(req.Context()).Counter(MetricRequestInFlight, h.ServiceNameTag).Dec(1)