feature/featuretags: make clientmetrics optional

Saves 57 KB

Updates #12614

Change-Id: If7eebec12b3cb30ae6264171d36a258c04b05a70
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

util/clientmetric/clientmetric.go

@@ -1,6 +1,8 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
+//go:build !ts_omit_clientmetrics
+
 // Package clientmetric provides client-side metrics whose values
 // get occasionally logged.
 package clientmetric

util/clientmetric/omit.go

@@ -0,0 +1,24 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build ts_omit_clientmetrics
+
+package clientmetric
+
+type Metric struct{}
+
+func (*Metric) Add(int64)              {}
+func (*Metric) Set(int64)              {}
+func (*Metric) Value() int64           { return 0 }
+func (*Metric) Register(expvarInt any) {}
+func (*Metric) UnregisterAll()         {}
+
+func HasPublished(string) bool            { panic("unreachable") }
+func EncodeLogTailMetricsDelta() string   { return "" }
+func WritePrometheusExpositionFormat(any) {}
+
+var zeroMetric Metric
+
+func NewCounter(string) *Metric          { return &zeroMetric }
+func NewGauge(string) *Metric            { return &zeroMetric }
+func NewAggregateCounter(string) *Metric { return &zeroMetric }