internal/{observe,worker}: remove exp/event metrics

Switch to an experimental metrics package of my own.

Change-Id: I88cad487691787be5485b5773637e084317015ea
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/552655
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Tatiana Bradley <tatianabradley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>

go.mod

@@ -17,12 +17,13 @@ require (
 	github.com/google/go-github/v41 v41.0.0
 	github.com/google/osv-scanner v1.3.5
 	github.com/google/safehtml v0.1.0
+	github.com/jba/metrics v0.1.1
+	github.com/jba/metrics/otel v0.1.1
 	github.com/jba/templatecheck v0.7.0
 	github.com/lib/pq v1.10.9
 	github.com/shurcooL/githubv4 v0.0.0-20231126234147-1cffa1f02456
 	go.opentelemetry.io/otel v1.21.0
 	go.opentelemetry.io/otel/sdk v1.21.0
-	go.opentelemetry.io/otel/sdk/metric v1.21.0
 	golang.org/x/exp v0.0.0-20231219180239-dc181d75b848
 	golang.org/x/exp/event v0.0.0-20231219180239-dc181d75b848
 	golang.org/x/mod v0.14.0
@@ -75,6 +76,7 @@ require (
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.46.1 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.46.1 // indirect
 	go.opentelemetry.io/otel/metric v1.21.0 // indirect
+	go.opentelemetry.io/otel/sdk/metric v1.21.0 // indirect
 	go.opentelemetry.io/otel/trace v1.21.0 // indirect
 	golang.org/x/crypto v0.16.0 // indirect
 	golang.org/x/exp/typeparams v0.0.0-20221208152030-732eee02a75a // indirect

go.sum

@@ -136,6 +136,10 @@ github.com/googleapis/gax-go/v2 v2.12.0 h1:A+gCJKdRfqXkr+BIRGtZLibNXf0m1f9E4HG56
 github.com/googleapis/gax-go/v2 v2.12.0/go.mod h1:y+aIqrI5eb1YGMVJfuV3185Ts/D7qKpsEkdD5+I6QGU=
 github.com/imdario/mergo v0.3.15 h1:M8XP7IuFNsqUx6VPK2P9OSmsYsI/YFaGil0uD21V3dM=
 github.com/imdario/mergo v0.3.15/go.mod h1:WBLT9ZmE3lPoWsEzCh9LPo3TiwVN+ZKEjmz+hD27ysY=
+github.com/jba/metrics v0.1.1 h1:hkqa7RZwPxi7No2IOxPZSeZKW0tCVyAQ5V9L4DosJFk=
+github.com/jba/metrics v0.1.1/go.mod h1:8YE9o3xYiRMg6G4WFrSCV30NhTQFcGgodbVgTJ5waqs=
+github.com/jba/metrics/otel v0.1.1 h1:nJNBGBiv+WPx2AiqYXP9Iqpnk1Lcq6rOSBAgPXAvNwA=
+github.com/jba/metrics/otel v0.1.1/go.mod h1:ZlrAUyEXGcvJ5US085SnVuTPXlX+Oy76jNYUNTAbkKM=
 github.com/jba/templatecheck v0.7.0 h1:wjTb/VhGgSFeim5zjWVePBdaMo28X74bGLSABZV+zIA=
 github.com/jba/templatecheck v0.7.0/go.mod h1:n1Etw+Rrw1mDDD8dDRsEKTwMZsJ98EkktgNJC6wLUGo=
 github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 h1:BQSFePA1RWJOlocH6Fxy8MmwDt+yVQYULKfN0RoTN8A=

internal/observe/observe.go

@@ -9,6 +9,7 @@ package observe
 import (
 	"context"
 	"net/http"
+	"strings"
 
 	"golang.org/x/exp/event"
 	"golang.org/x/vulndb/internal/derrors"
@@ -16,8 +17,9 @@ import (
 	mexporter "github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/metric"
 	texporter "github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/trace"
 	gcppropagator "github.com/GoogleCloudPlatform/opentelemetry-operations-go/propagator"
+	"github.com/jba/metrics/otel"
 	"go.opentelemetry.io/otel/propagation"
-	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	eotel "golang.org/x/exp/event/otel"
 )
@@ -27,7 +29,6 @@ type Observer struct {
 	ctx            context.Context
 	tracerProvider *sdktrace.TracerProvider
 	traceHandler   *eotel.TraceHandler
-	metricHandler  *eotel.MetricHandler
 	propagator     propagation.TextMapPropagator
 
 	// LogHandlerFunc is invoked in [Observer.Observe] to obtain an
@@ -53,10 +54,12 @@ func NewObserver(ctx context.Context, projectID, serverName string) (_ *Observer
 	if err != nil {
 		return nil, err
 	}
-	// Initialize a MeterProvider with that periodically exports to the GCP exporter.
-	provider := sdkmetric.NewMeterProvider(
-		sdkmetric.WithReader(sdkmetric.NewPeriodicReader(mex)),
-	)
+	// Export all registered metrics except the runtime metrics.
+	scope := instrumentation.Scope{Name: "vulndb/worker"}
+	otel.Export(scope, mex, 0, func(name string) bool {
+		return !strings.HasPrefix(name, "runtime/")
+	})
+
 	tp := sdktrace.NewTracerProvider(
 		// Enable tracing if there is no incoming request, or if the incoming
 		// request is sampled.
@@ -66,7 +69,6 @@ func NewObserver(ctx context.Context, projectID, serverName string) (_ *Observer
 		ctx:            ctx,
 		tracerProvider: tp,
 		traceHandler:   eotel.NewTraceHandler(tp.Tracer(serverName)),
-		metricHandler:  eotel.NewMetricHandler(provider.Meter(serverName)),
 		// The propagator extracts incoming trace IDs so that we can connect our trace spans
 		// to the incoming ones constructed by Cloud Run.
 		propagator: propagation.NewCompositeTextMapPropagator(
@@ -101,6 +103,5 @@ func (h eventHandler) Event(ctx context.Context, ev *event.Event) context.Contex
 	if h.eh != nil {
 		ctx = h.eh.Event(ctx, ev)
 	}
-	ctx = h.o.traceHandler.Event(ctx, ev)
-	return h.o.metricHandler.Event(ctx, ev)
+	return h.o.traceHandler.Event(ctx, ev)
 }

internal/worker/server.go

@@ -21,6 +21,7 @@ import (
 
 	"cloud.google.com/go/errorreporting"
 	"github.com/google/safehtml/template"
+	"github.com/jba/metrics"
 	"golang.org/x/exp/event"
 	"golang.org/x/sync/errgroup"
 	"golang.org/x/vulndb/internal/cvelistrepo"
@@ -286,9 +287,11 @@ func (s *Server) indexPage(w http.ResponseWriter, r *http.Request) error {
 	return renderPage(r.Context(), w, page, s.indexTemplate)
 }
 
-const metricNamespace = "vulndb/worker"
+type UpdateOutcome struct {
+	Success bool
+}
 
-var updateCounter = event.NewCounter("updates", &event.MetricOptions{Namespace: metricNamespace})
+var updateCounters = metrics.NewCounterGroup[int64, UpdateOutcome]("updates", "calls to handleUpdate")
 
 func (s *Server) handleUpdate(w http.ResponseWriter, r *http.Request) error {
 	err := s.doUpdate(r)
@@ -301,7 +304,7 @@ func (s *Server) handleUpdate(w http.ResponseWriter, r *http.Request) error {
 func (s *Server) doUpdate(r *http.Request) (err error) {
 	defer func() {
 		success := err == nil
-		updateCounter.Record(r.Context(), 1, event.Bool("success", success))
+		updateCounters.At(UpdateOutcome{success}).Add(1)
 		log.Debugf(r.Context(), "recorded one /update operation in counter (success=%t)", success)
 	}()