Retry fetching Docker container info

pkg/plugin/dhcp_manager.go

@@ -215,7 +215,7 @@ func (m *dhcpManager) Start(ctx context.Context) error {
 		return util.ErrNoContainer
 	}
 
-	ctr, err := m.docker.ContainerInspect(ctx, ctrID)
+	ctr, err := util.AwaitContainerInspect(ctx, m.docker, ctrID, pollTime)
 	if err != nil {
 		return fmt.Errorf("failed to get Docker container info: %w", err)
 	}

pkg/util/docker.go

@@ -1,5 +1,42 @@
 package util
 
+import (
+	"context"
+	"time"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/client"
+	log "github.com/sirupsen/logrus"
+)
+
 const (
 	OptionsKeyGeneric = "com.docker.network.generic"
 )
+
+func AwaitContainerInspect(ctx context.Context, docker *client.Client, id string, interval time.Duration) (types.ContainerJSON, error) {
+	var err error
+	ctrChan := make(chan types.ContainerJSON)
+	go func() {
+		for {
+			var ctr types.ContainerJSON
+			ctr, err = docker.ContainerInspect(ctx, id)
+			if err == nil {
+				ctrChan <- ctr
+				return
+			}
+
+			time.Sleep(interval)
+		}
+	}()
+
+	var dummy types.ContainerJSON
+	select {
+	case link := <-ctrChan:
+		return link, nil
+	case <-ctx.Done():
+		if err != nil {
+			log.WithError(err).WithField("id", id).Error("Failed to await container by index")
+		}
+		return dummy, ctx.Err()
+	}
+}