PLEX-1843: add node balances to beholder

Author: fernandezlautaro

metrics/balance.go

@@ -1,8 +1,15 @@
 package metrics
 
 import (
+	"context"
+	"fmt"
+
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+
+	"github.com/smartcontractkit/chainlink-common/pkg/beholder"
 )
 
 var (
@@ -11,3 +18,36 @@ var (
 		[]string{"account", "chainID", "chainFamily"},
 	)
 )
+
+type GenericBalanceMetrics interface {
+	RecordNodeBalance(ctx context.Context, account string, balance float64)
+}
+
+var _ GenericBalanceMetrics = &balanceMetrics{}
+
+type balanceMetrics struct {
+	network     string
+	chainID     string
+	nodeBalance metric.Float64Gauge
+}
+
+func NewGenericBalanceMetrics(network string, chainID string) (GenericBalanceMetrics, error) {
+	nodeBalance, err := beholder.GetMeter().Float64Gauge("node_balance")
+	if err != nil {
+		return nil, fmt.Errorf("failed to register node balance metric: %w", err)
+	}
+
+	return &balanceMetrics{
+		network:     network,
+		chainID:     chainID,
+		nodeBalance: nodeBalance,
+	}, nil
+}
+
+func (m *balanceMetrics) RecordNodeBalance(ctx context.Context, account string, balance float64) {
+	NodeBalance.WithLabelValues(account, m.chainID, m.network).Set(balance)
+	m.nodeBalance.Record(ctx, balance, metric.WithAttributes(
+		attribute.String("network", m.network),
+		attribute.String("chainID", m.chainID),
+		attribute.String("account", account)))
+}

metrics/balance_test.go

@@ -0,0 +1,24 @@
+package metrics
+
+import (
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func setupTestBalanceMetrics(t *testing.T) GenericBalanceMetrics {
+	m, err := NewGenericBalanceMetrics("test-network", "1")
+	require.NoError(t, err)
+	return m
+}
+
+func TestBalanceMetrics_RecordNodeBalance(t *testing.T) {
+	m := setupTestBalanceMetrics(t)
+	m.RecordNodeBalance(t.Context(), "account", 5.5)
+	require.InEpsilon(t,
+		5.5,
+		testutil.ToFloat64(NodeBalance.WithLabelValues("account", "1", "test-network")),
+		0.001,
+	)
+}