Add support for multiple subscribers to CRI container events

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/cri/server/service.go

@@ -23,6 +23,7 @@ import (
 	"net/http"
 	"sync"
 	"sync/atomic"
+	"time"
 
 	"github.com/containerd/go-cni"
 	"github.com/containerd/log"
@@ -32,6 +33,7 @@ import (
 
 	containerd "github.com/containerd/containerd/v2/client"
 	"github.com/containerd/containerd/v2/core/sandbox"
+	"github.com/containerd/containerd/v2/internal/eventq"
 	"github.com/containerd/containerd/v2/internal/registrar"
 	criconfig "github.com/containerd/containerd/v2/pkg/cri/config"
 	"github.com/containerd/containerd/v2/pkg/cri/nri"
@@ -118,9 +120,9 @@ type criService struct {
 	// allCaps is the list of the capabilities.
 	// When nil, parsed from CapEff of /proc/self/status.
 	allCaps []string //nolint:nolintlint,unused // Ignore on non-Linux
-	// containerEventsChan is used to capture container events and send them
-	// to the caller of GetContainerEvents.
-	containerEventsChan chan runtime.ContainerEventResponse
+	// containerEventsQ is used to capture container events and send them
+	// to the callers of GetContainerEvents.
+	containerEventsQ eventq.EventQueue[runtime.ContainerEventResponse]
 	// nri is used to hook NRI into CRI request processing.
 	nri *nri.API
 	// sandboxService is the sandbox related service for CRI
@@ -165,8 +167,15 @@ func NewCRIService(config criconfig.Config, options *CRIServiceOptions) (CRIServ
 		sandboxService:     newCriSandboxService(&config, options.Client),
 	}
 
-	// TODO: figure out a proper channel size.
-	c.containerEventsChan = make(chan runtime.ContainerEventResponse, 1000)
+	// TODO: Make discard time configurable
+	c.containerEventsQ = eventq.New[runtime.ContainerEventResponse](5*time.Minute, func(event runtime.ContainerEventResponse) {
+		containerEventsDroppedCount.Inc()
+		log.L.WithFields(
+			log.Fields{
+				"container": event.ContainerId,
+				"type":      event.ContainerEventType,
+			}).Warn("container event discarded")
+	})
 
 	if err := c.initPlatform(); err != nil {
 		return nil, nil, fmt.Errorf("initialize platform: %w", err)