Enable pluggable datalayer as experimental feature

cmd/epp/runner/runner.go

@@ -46,6 +46,8 @@ import (
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/common"
 	backendmetrics "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/backend/metrics"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/config/loader"
+	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/datalayer"
+	dlmetrics "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/datalayer/metrics"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/datastore"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/metrics"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/metrics/collectors"
@@ -245,40 +247,11 @@ func (r *Runner) Run(ctx context.Context) error {
 	}
 
 	// --- Setup Datastore ---
-	mapping, err := backendmetrics.NewMetricMapping(
-		*totalQueuedRequestsMetric,
-		*kvCacheUsagePercentageMetric,
-		*loraInfoMetric,
-	)
+	epf, err := r.setupMetricsCollection(setupLog)
 	if err != nil {
-		setupLog.Error(err, "Failed to create metric mapping from flags.")
 		return err
 	}
-	verifyMetricMapping(*mapping, setupLog)
-
-	var metricsHttpClient *http.Client
-	if *modelServerMetricsScheme == "https" {
-		metricsHttpClient = &http.Client{
-			Transport: &http.Transport{
-				TLSClientConfig: &tls.Config{
-					InsecureSkipVerify: *modelServerMetricsHttpsInsecureSkipVerify,
-				},
-			},
-		}
-	} else {
-		metricsHttpClient = http.DefaultClient
-	}
-
-	pmf := backendmetrics.NewPodMetricsFactory(&backendmetrics.PodMetricsClientImpl{
-		MetricMapping:            mapping,
-		ModelServerMetricsPort:   int32(*modelServerMetricsPort),
-		ModelServerMetricsPath:   *modelServerMetricsPath,
-		ModelServerMetricsScheme: *modelServerMetricsScheme,
-		Client:                   metricsHttpClient,
-	},
-		*refreshMetricsInterval)
-
-	datastore := datastore.NewDatastore(ctx, pmf)
+	datastore := datastore.NewDatastore(ctx, epf)
 
 	// --- Setup Metrics Server ---
 	customCollectors := []prometheus.Collector{collectors.NewInferencePoolMetricsCollector(datastore)}
@@ -446,6 +419,82 @@ func (r *Runner) parsePluginsConfiguration(ctx context.Context) error {
 	return nil
 }
 
+func (r *Runner) setupMetricsCollection(setupLog logr.Logger) (datalayer.EndpointFactory, error) {
+	if datalayer.Enabled(setupLog) {
+		return setupDatalayer(setupLog)
+	}
+
+	if len(datalayer.GetSources()) != 0 {
+		setupLog.Info("data sources registered but pluggable datalayer is disabled")
+	}
+	return setupMetricsV1(setupLog)
+}
+
+func setupMetricsV1(setupLog logr.Logger) (datalayer.EndpointFactory, error) {
+	mapping, err := backendmetrics.NewMetricMapping(
+		*totalQueuedRequestsMetric,
+		*kvCacheUsagePercentageMetric,
+		*loraInfoMetric,
+	)
+	if err != nil {
+		setupLog.Error(err, "Failed to create metric mapping from flags.")
+		return nil, err
+	}
+	verifyMetricMapping(*mapping, setupLog)
+
+	var metricsHttpClient *http.Client
+	if *modelServerMetricsScheme == "https" {
+		metricsHttpClient = &http.Client{
+			Transport: &http.Transport{
+				TLSClientConfig: &tls.Config{
+					InsecureSkipVerify: *modelServerMetricsHttpsInsecureSkipVerify,
+				},
+			},
+		}
+	} else {
+		metricsHttpClient = http.DefaultClient
+	}
+
+	pmf := backendmetrics.NewPodMetricsFactory(&backendmetrics.PodMetricsClientImpl{
+		MetricMapping:            mapping,
+		ModelServerMetricsPort:   int32(*modelServerMetricsPort),
+		ModelServerMetricsPath:   *modelServerMetricsPath,
+		ModelServerMetricsScheme: *modelServerMetricsScheme,
+		Client:                   metricsHttpClient,
+	},
+		*refreshMetricsInterval)
+	return pmf, nil
+}
+
+func setupDatalayer(setupLog logr.Logger) (datalayer.EndpointFactory, error) {
+	// create and register a metrics data source and extractor. In the future,
+	// data sources and extractors might be configured via a file. Once done,
+	// this (and registering the sources with the endpoint factory) should
+	// be moved accordingly.
+	source := dlmetrics.NewDataSource(*modelServerMetricsScheme,
+		int32(*modelServerMetricsPort),
+		*modelServerMetricsPath,
+		*modelServerMetricsHttpsInsecureSkipVerify,
+		nil)
+	extractor, err := dlmetrics.NewExtractor(*totalQueuedRequestsMetric,
+		*kvCacheUsagePercentageMetric,
+		*loraInfoMetric)
+
+	if err != nil {
+		return nil, err
+	}
+	if err := source.AddExtractor(extractor); err != nil {
+		return nil, err
+	}
+	if err := datalayer.RegisterSource(source); err != nil {
+		return nil, err
+	}
+
+	factory := datalayer.NewEndpointFactory(setupLog, *refreshMetricsInterval)
+	factory.SetSources(datalayer.GetSources())
+	return factory, nil
+}
+
 func initLogging(opts *zap.Options) {
 	// Unless -zap-log-level is explicitly set, use -v
 	useV := true

pkg/epp/datalayer/collector.go

@@ -22,6 +22,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/go-logr/logr"
 	"sigs.k8s.io/controller-runtime/pkg/log"
 
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/util/logging"
@@ -73,6 +74,8 @@ type Collector struct {
 	startOnce sync.Once
 	stopOnce  sync.Once
 
+	logger logr.Logger
+
 	// TODO: optional metrics tracking collection (e.g., errors, invocations, ...)
 }
 
@@ -82,11 +85,13 @@ func NewCollector() *Collector {
 }
 
 // Start initiates data source collection for the endpoint.
+// TODO: pass PoolInfo for backward compatibility
 func (c *Collector) Start(ctx context.Context, ticker Ticker, ep Endpoint, sources []DataSource) error {
 	var ready chan struct{}
 	started := false
 
 	c.startOnce.Do(func() {
+		c.logger = log.FromContext(ctx)
 		c.ctx, c.cancel = context.WithCancel(ctx)
 		started = true
 		ready = make(chan struct{})
@@ -107,6 +112,7 @@ func (c *Collector) Start(ctx context.Context, ticker Ticker, ep Endpoint, sourc
 				case <-c.ctx.Done(): // per endpoint context cancelled
 					return
 				case <-ticker.Channel():
+					// TODO: do not collect if there's no pool specified?
 					for _, src := range sources {
 						ctx, cancel := context.WithTimeout(c.ctx, defaultCollectionTimeout)
 						_ = src.Collect(ctx, endpoint) // TODO: track errors per collector?

pkg/epp/datalayer/enabled.go

@@ -0,0 +1,31 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package datalayer
+
+import (
+	"github.com/go-logr/logr"
+
+	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/util/env"
+)
+
+const (
+	EnableExperimentalDatalayerV2 = "ENABLE_EXPERIMENTAL_DATALAYER_V2"
+)
+
+func Enabled(logger logr.Logger) bool {
+	return env.GetEnvBool(EnableExperimentalDatalayerV2, false, logger)
+}

pkg/epp/datalayer/factory.go

@@ -18,9 +18,14 @@ package datalayer
 
 import (
 	"context"
+	"sync"
+	"time"
 
+	"github.com/go-logr/logr"
 	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
 
+	"sigs.k8s.io/controller-runtime/pkg/log"
 	v1 "sigs.k8s.io/gateway-api-inference-extension/api/v1"
 )
 
@@ -44,3 +49,83 @@ type EndpointFactory interface {
 	NewEndpoint(parent context.Context, inpod *corev1.Pod, poolinfo PoolInfo) Endpoint
 	ReleaseEndpoint(ep Endpoint)
 }
+
+// EndpointLifecycle manages the life cycle (creation and termination) of
+// endpoints.
+type EndpointLifecycle struct {
+	sources         []DataSource  // data sources for collectors
+	collectors      sync.Map      // collectors map. key: Pod namespaced name, value: *Collector
+	refreshInterval time.Duration // metrics refresh interval
+}
+
+// NewEndpointFactory returns a new endpoint for factory, managing collectors for
+// its endpoints.
+// TODO: consider making a config object? Only caveat is that sources might not be
+// known at creation time (e.g., loaded from configuration file).
+func NewEndpointFactory(log logr.Logger, refreshMetricsInterval time.Duration) *EndpointLifecycle {
+	return &EndpointLifecycle{
+		sources:         []DataSource{},
+		collectors:      sync.Map{},
+		refreshInterval: refreshMetricsInterval,
+	}
+}
+
+// NewEndpoint implements EndpointFactory.NewEndpoint.
+// Creates a new endpoint and starts its associated collector with its own ticker.
+// Guards against multiple concurrent calls for the same endpoint.
+func (lc *EndpointLifecycle) NewEndpoint(parent context.Context, inpod *corev1.Pod, _ PoolInfo) Endpoint {
+	key := types.NamespacedName{Namespace: inpod.Namespace, Name: inpod.Name}
+	logger := log.FromContext(parent).WithValues("pod", key)
+
+	if _, ok := lc.collectors.Load(key); ok {
+		logger.Info("collector already running for endpoint", "endpoint", key)
+		return nil
+	}
+
+	endpoint := NewEndpoint()
+	endpoint.UpdatePod(inpod)
+	collector := NewCollector() // for full backward compatibility, set the logger and poolinfo
+
+	if _, loaded := lc.collectors.LoadOrStore(key, collector); loaded {
+		// another goroutine already created and stored a collector for this endpoint.
+		// No need to start the new collector.
+		logger.Info("collector already running for endpoint", "endpoint", key)
+		return nil
+	}
+
+	ticker := NewTimeTicker(lc.refreshInterval)
+	if err := collector.Start(parent, ticker, endpoint, lc.sources); err != nil {
+		logger.Error(err, "failed to start collector for endpoint", "endpoint", key)
+		lc.collectors.Delete(key)
+	}
+
+	return endpoint
+}
+
+// ReleaseEndpoint implements EndpointFactory.ReleaseEndpoint
+// Stops the collector and cleans up resources for the endpoint
+func (lc *EndpointLifecycle) ReleaseEndpoint(ep Endpoint) {
+	key := ep.GetPod().GetNamespacedName()
+
+	if value, ok := lc.collectors.LoadAndDelete(key); ok {
+		collector := value.(*Collector)
+		_ = collector.Stop()
+	}
+}
+
+// Shutdown gracefully stops all collectors and cleans up all resources.
+func (lc *EndpointLifecycle) Shutdown() {
+	lc.collectors.Range(func(key, value interface{}) bool {
+		collector := value.(*Collector)
+		_ = collector.Stop()
+		lc.collectors.Delete(key)
+		return true
+	})
+}
+
+// SetSources configures the data sources available for collection.
+// This should be called after all data sources have been configured and before
+// any endpoint is created.
+func (lc *EndpointLifecycle) SetSources(sources []DataSource) {
+	_ = copy(lc.sources, sources)
+}

pkg/epp/datalayer/metrics/client.go

@@ -41,14 +41,15 @@ const (
 )
 
 var (
+	baseTransport = &http.Transport{
+		MaxIdleConns:        maxIdleConnections,
+		MaxIdleConnsPerHost: 4, // host is defined as scheme://host:port
+		// TODO: set additional timeouts, transport options, etc.
+	}
 	defaultClient = &client{
 		Client: http.Client{
-			Timeout: timeout,
-			Transport: &http.Transport{
-				MaxIdleConns:        maxIdleConnections,
-				MaxIdleConnsPerHost: 4, // host is defined as scheme://host:port
-			},
-			// TODO: set additional timeouts, transport options, etc.
+			Timeout:   timeout,
+			Transport: baseTransport,
 		},
 	}
 )

pkg/epp/datalayer/metrics/datasource.go

@@ -18,6 +18,7 @@ package metrics
 
 import (
 	"context"
+	"crypto/tls"
 	"errors"
 	"fmt"
 	"net"
@@ -30,7 +31,7 @@ import (
 )
 
 const (
-	dataSourceName = "metrics-data-source"
+	DataSourceName = "metrics-data-source"
 )
 
 // DataSource is a Model Server Protocol (MSP) compliant metrics data source,
@@ -46,7 +47,15 @@ type DataSource struct {
 
 // NewDataSource returns a new MSP compliant metrics data source, configured with the provided
 // client factory. If ClientFactory is nil, a default factory is used.
-func NewDataSource(metricsScheme string, metricsPort int32, metricsPath string, cl Client) *DataSource {
+func NewDataSource(metricsScheme string, metricsPort int32, metricsPath string, skipCertVerification bool, cl Client) *DataSource {
+	if metricsScheme == "https" {
+		httpsTransport := baseTransport.Clone()
+		httpsTransport.TLSClientConfig = &tls.Config{
+			InsecureSkipVerify: skipCertVerification,
+		}
+		defaultClient.Transport = httpsTransport
+	}
+
 	if cl == nil {
 		cl = defaultClient
 	}
@@ -68,7 +77,7 @@ func (dataSrc *DataSource) SetPort(metricsPort int32) {
 
 // Name returns the metrics data source name.
 func (dataSrc *DataSource) Name() string {
-	return dataSourceName
+	return DataSourceName
 }
 
 // AddExtractor adds an extractor to the data source, validating it can process