Set up otel metrics reporting to prometheus

Register otel collector bridging to the default prometheus registry so
that F3 metrics (which use the newer otel APIs for metrics) get included
in Lotus metrics.

CHANGELOG.md

@@ -9,6 +9,7 @@
 - https://github.com/filecoin-project/lotus/pull/12276: chore: deps: Update GST, Filecoin-FFI and Actors to final versions NV23
 - https://github.com/filecoin-project/lotus/pull/12278: chore: Set Mainnet upgrade epoch for NV23.
 - https://github.com/filecoin-project/lotus/pull/12269 Fix `logIndex` ordering in `EthGetTransactionReceipt` by using the EventIndex to fetch logs
+- https://github.com/filecoin-project/lotus/pull/12285 Set up OpenTelemetry metrics reporting to prometheus
 
 ## ☢️ Upgrade Warnings ☢️
 

chain/lf3/f3.go

@@ -10,6 +10,9 @@ import (
 	logging "github.com/ipfs/go-log/v2"
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	"github.com/libp2p/go-libp2p/core/host"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/prometheus"
+	"go.opentelemetry.io/otel/sdk/metric"
 	"go.uber.org/fx"
 	"golang.org/x/xerrors"
 
@@ -50,6 +53,20 @@ type F3Params struct {
 
 var log = logging.Logger("f3")
 
+func init() {
+	// Set up otel to prometheus reporting so that F3 metrics are reported via lotus
+	// prometheus metrics. This bridge eventually gets picked up by opencensus
+	// exporter as HTTP handler. This by default registers an otel collector against
+	// the global prometheus registry. In the future, we should clean up metrics in
+	// Lotus and move it all to use otel. For now, bridge away.
+	if bridge, err := prometheus.New(); err != nil {
+		log.Errorf("could not create the otel prometheus exporter: %v", err)
+	} else {
+		provider := metric.NewMeterProvider(metric.WithReader(bridge))
+		otel.SetMeterProvider(provider)
+	}
+}
+
 func New(mctx helpers.MetricsCtx, lc fx.Lifecycle, params F3Params) (*F3, error) {
 
 	ds := namespace.Wrap(params.Datastore, datastore.NewKey("/f3"))

go.mod

@@ -144,7 +144,9 @@ require (
 	go.opentelemetry.io/otel v1.28.0
 	go.opentelemetry.io/otel/bridge/opencensus v1.28.0
 	go.opentelemetry.io/otel/exporters/jaeger v1.14.0
+	go.opentelemetry.io/otel/exporters/prometheus v0.50.0
 	go.opentelemetry.io/otel/sdk v1.28.0
+	go.opentelemetry.io/otel/sdk/metric v1.28.0
 	go.uber.org/atomic v1.11.0
 	go.uber.org/fx v1.22.1
 	go.uber.org/multierr v1.11.0
@@ -316,7 +318,6 @@ require (
 	github.com/zondax/hid v0.9.2 // indirect
 	github.com/zondax/ledger-go v0.14.3 // indirect
 	go.opentelemetry.io/otel/metric v1.28.0 // indirect
-	go.opentelemetry.io/otel/sdk/metric v1.28.0 // indirect
 	go.opentelemetry.io/otel/trace v1.28.0 // indirect
 	go.uber.org/dig v1.17.1 // indirect
 	go.uber.org/mock v0.4.0 // indirect

go.sum

@@ -1387,6 +1387,8 @@ go.opentelemetry.io/otel/bridge/opencensus v1.28.0 h1:/BcyAV1bUJjSVxoeKwTQL9cS4X
 go.opentelemetry.io/otel/bridge/opencensus v1.28.0/go.mod h1:FZp2xE+46yAyp3DfLFALze58nY0iIE8zs+mCgkPAzq0=
 go.opentelemetry.io/otel/exporters/jaeger v1.14.0 h1:CjbUNd4iN2hHmWekmOqZ+zSCU+dzZppG8XsV+A3oc8Q=
 go.opentelemetry.io/otel/exporters/jaeger v1.14.0/go.mod h1:4Ay9kk5vELRrbg5z4cpP9EtmQRFap2Wb0woPG4lujZA=
+go.opentelemetry.io/otel/exporters/prometheus v0.50.0 h1:2Ewsda6hejmbhGFyUvWZjUThC98Cf8Zy6g0zkIimOng=
+go.opentelemetry.io/otel/exporters/prometheus v0.50.0/go.mod h1:pMm5PkUo5YwbLiuEf7t2xg4wbP0/eSJrMxIMxKosynY=
 go.opentelemetry.io/otel/metric v1.28.0 h1:f0HGvSl1KRAU1DLgLGFjrwVyismPlnuU6JD6bOeuA5Q=
 go.opentelemetry.io/otel/metric v1.28.0/go.mod h1:Fb1eVBFZmLVTMb6PPohq3TO9IIhUisDsbJoL/+uQW4s=
 go.opentelemetry.io/otel/sdk v1.28.0 h1:b9d7hIry8yZsgtbmM0DKyPWMMUMlK9NEKuIG4aBqWyE=