fix get docker host panic when dind replica is 0

Signed-off-by: Patrick Zhao <zhaoyu@koderover.com>

Author: PetrusZ

pkg/microservice/aslan/core/common/service/workflowcontroller/jobcontroller/job_freestyle.go

@@ -150,8 +150,10 @@ func (c *FreestyleJobCtl) run(ctx context.Context) error {
 
 	// decide which docker host to use.
 	// TODO: do not use code in warpdrive moudule, should move to a public place
-	dockerhosts := dockerhost.NewDockerHosts(hubServerAddr, c.logger)
-	c.jobTaskSpec.Properties.DockerHost = dockerhosts.GetBestHost(dockerhost.ClusterID(c.jobTaskSpec.Properties.ClusterID), fmt.Sprintf("%v", c.workflowCtx.TaskID))
+	if !c.jobTaskSpec.Properties.UseHostDockerDaemon {
+		dockerhosts := dockerhost.NewDockerHosts(hubServerAddr, c.logger)
+		c.jobTaskSpec.Properties.DockerHost = dockerhosts.GetBestHost(dockerhost.ClusterID(c.jobTaskSpec.Properties.ClusterID), fmt.Sprintf("%v", c.workflowCtx.TaskID))
+	}
 
 	// not local cluster
 	var (

pkg/tool/dockerhost/docker_host.go

@@ -100,8 +100,12 @@ func (d *dockerhosts) GetBestHost(clusterID ClusterID, key string) string {
 		d.initClusterInfo(clusterID)
 	}
 
-	// round-robin
 	members := d.store[clusterID].GetMembers()
+	if len(members) == 0 {
+		return ""
+	}
+
+	// round-robin
 	index := d.GetBestHostIndex(clusterID)
 	index = (index + 1) % len(members)
 	member := members[index]