How to emit metrics in Go
To emit metrics from the Temporal Client in Go, create a metrics handler from the Client Options and specify a listener address to be used by Prometheus.
client.Options{
        MetricsHandler: sdktally.NewMetricsHandler(newPrometheusScope(prometheus.Configuration{
            ListenAddress: "0.0.0.0:9090",
            TimerType:     "histogram",
        }
The Go SDK currently supports the Tally library; however, Tally offers extensible custom metrics reporting, which is exposed through the WithCustomMetricsReporter API.
For more information, see the Go sample for metrics.