funcExpvarDoHandler¶added inv1.74.0

func ExpvarDoHandler(expvarDoFunc func(f func(expvar.KeyValue))) func(http.ResponseWriter, *http.Request)

ExpvarDoHandler handler returns a Handler like above, but takes an optionalexpvar.Do func allow the usage of alternative containers of metrics, otherthan the global expvar.Map.

funcHandler¶

func Handler(whttp.ResponseWriter, r *http.Request)

Handler is an HTTP handler to write expvar values into theprometheus export format:

https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md

It makes the following assumptions:

• *expvar.Int are counters (unless marked as a gauge_; see below)
• a *tailscale/metrics.Set is descended into, joining keys withunderscores. So use underscores as your metric names.
• an expvar named starting with "gauge_" or "counter_" is of thatPrometheus type, and has that prefix stripped.
• anything else is untyped and thus not exported.
• expvar.Func can return an int or int64 (for now) and anything elseis not exported.

This will evolve over time, or perhaps be replaced.

funcStaticStringVar¶added inv1.78.0

func StaticStringVar(sstring)expvar.Var

StaticStringVar returns a new expvar.Var that always returns s.

funcUptime¶

func Uptime()time.Duration

funcWritePrometheusExpvar¶

func WritePrometheusExpvar(wio.Writer, kvexpvar.KeyValue)

WritePrometheusExpvar writes kv to w in Prometheus metrics format.

See VarzHandler for conventions. This is exported primarily forpeople to test their varz.

typePrometheusMetricsReflectRooter¶

type PrometheusMetricsReflectRooter interface {expvar.Var// PrometheusMetricsReflectRoot returns the struct or struct pointer to walk.PrometheusMetricsReflectRoot()any}

PrometheusMetricsReflectRooter is an optional interface that expvar.Var implementationscan implement to indicate that they should be walked recursively with reflect to findsets of fields to export.

typePrometheusWriter¶added inv1.64.0

type PrometheusWriter interface {WritePrometheus(wio.Writer, namestring)}

PrometheusWriter is the interface implemented by metrics that can writethemselves into Prometheus exposition format.

As of 2024-03-25, this is only *metrics.MultiLabelMap.