MCPX MCP Gateway

package metrics import ( "context" "fmt" "lunar/toolkit-core/haproxy" "github.com/rs/zerolog/log" "go.opentelemetry.io/otel/attribute" "go.opentelemetry.io/otel/metric" ) const haproxySocketPath = "/var/run/haproxy/haproxy.sock" type remainingConnectionsMetricManager struct { haproxy *haproxy.Stats observer metric.Int64ObservableGauge attributes []attribute.KeyValue } func newRemainingConnectionsMetricManager( meter metric.Meter, ) (*remainingConnectionsMetricManager, error) { mng := &remainingConnectionsMetricManager{ attributes: []attribute.KeyValue{}, } if err := mng.init(meter); err != nil { return nil, fmt.Errorf("failed to initialize remaining connections metric manager: %w", err) } log.Debug().Msg("Remaining connections metric manager created successfully") return mng, nil } func (m *remainingConnectionsMetricManager) remainingConnectionsCallback( _ context.Context, observer metric.Int64Observer, ) error { remainingConns, err := m.haproxy.QueryRemainingConnections() if err != nil { return err } observer.Observe( int64(remainingConns), metric.WithAttributes(m.attributes...), ) return nil } func (m *remainingConnectionsMetricManager) init(meter metric.Meter) error { haproxyClient, err := haproxy.NewHAProxyStatsClient(haproxySocketPath) if err != nil { return fmt.Errorf("failed to create HAProxy stats client: %w", err) } m.haproxy = haproxyClient m.attributes = appendGatewayIDAttribute(m.attributes...) m.observer, err = meter.Int64ObservableGauge( MetricPrefix+string(RemainingConnectionsMetric), metric.WithDescription("The number of remaining connections in the pool"), metric.WithInt64Callback(m.remainingConnectionsCallback), ) if err != nil { return err } log.Debug().Msg("Remaining connections metric manager initialized successfully") return nil }