fixes after @xla review

- move prometheus metrics into internal packages
- *Option structs
- misc. format changes

consensus/metrics.go

@@ -3,6 +3,9 @@ package consensus
 import (
 	"github.com/go-kit/kit/metrics"
 	"github.com/go-kit/kit/metrics/discard"
+
+	prometheus "github.com/go-kit/kit/metrics/prometheus"
+	stdprometheus "github.com/prometheus/client_golang/prometheus"
 )
 
 // Metrics contains metrics exposed by this package.
@@ -37,6 +40,76 @@ type Metrics struct {
 	TotalTxs metrics.Gauge
 }
 
+// PrometheusMetrics returns Metrics build using Prometheus client library.
+func PrometheusMetrics() *Metrics {
+	return &Metrics{
+		Height: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "height",
+			Help:      "Height of the chain.",
+		}, []string{}),
+		Rounds: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "rounds",
+			Help:      "Number of rounds.",
+		}, []string{}),
+
+		Validators: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "validators",
+			Help:      "Number of validators.",
+		}, []string{}),
+		ValidatorsPower: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "validators_power",
+			Help:      "Total power of all validators.",
+		}, []string{}),
+		MissingValidators: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "missing_validators",
+			Help:      "Number of validators who did not sign.",
+		}, []string{}),
+		MissingValidatorsPower: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "missing_validators_power",
+			Help:      "Total power of the missing validators.",
+		}, []string{}),
+		ByzantineValidators: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "byzantine_validators",
+			Help:      "Number of validators who tried to double sign.",
+		}, []string{}),
+		ByzantineValidatorsPower: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "byzantine_validators_power",
+			Help:      "Total power of the byzantine validators.",
+		}, []string{}),
+
+		BlockIntervalSeconds: prometheus.NewHistogramFrom(stdprometheus.HistogramOpts{
+			Subsystem: "consensus",
+			Name:      "block_interval_seconds",
+			Help:      "Time between this and the last block.",
+			Buckets:   []float64{1, 2.5, 5, 10, 60},
+		}, []string{}),
+
+		NumTxs: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "num_txs",
+			Help:      "Number of transactions.",
+		}, []string{}),
+		BlockSizeBytes: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "block_size_bytes",
+			Help:      "Size of the block.",
+		}, []string{}),
+		TotalTxs: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+			Subsystem: "consensus",
+			Name:      "total_txs",
+			Help:      "Total number of transactions.",
+		}, []string{}),
+	}
+}
+
 // NopMetrics returns no-op Metrics.
 func NopMetrics() *Metrics {
 	return &Metrics{