pod: add a in-memory pod list

It tracks all existing pods in the current runtime. If the runtime
calls multiple APIs, it can reuse existing pod data structure instead
of re-construct it in every API call.

Signed-off-by: Peng Tao <bergwolf@gmail.com>

virtcontainers/pod.go

@@ -642,23 +642,37 @@ func newPod(podConfig PodConfig) (*Pod, error) {
 		wg:              &sync.WaitGroup{},
 	}
 
-	if err := p.storage.createAllResources(*p); err != nil {
+	if err = globalPodList.addPod(p); err != nil {
 		return nil, err
 	}
 
-	if err := p.hypervisor.init(p); err != nil {
-		p.storage.deletePodResources(p.id, nil)
+	defer func() {
+		if err != nil {
+			p.Logger().WithError(err).WithField("podid", p.id).Error("Create new pod failed")
+			globalPodList.removePod(p.id)
+		}
+	}()
+
+	if err = p.storage.createAllResources(*p); err != nil {
 		return nil, err
 	}
 
-	if err := p.hypervisor.createPod(podConfig); err != nil {
+	defer func() {
+		if err != nil {
 			p.storage.deletePodResources(p.id, nil)
+		}
+	}()
+
+	if err = p.hypervisor.init(p); err != nil {
+		return nil, err
+	}
+
+	if err = p.hypervisor.createPod(podConfig); err != nil {
 		return nil, err
 	}
 
 	agentConfig := newAgentConfig(podConfig)
-	if err := p.agent.init(p, agentConfig); err != nil {
-		p.storage.deletePodResources(p.id, nil)
+	if err = p.agent.init(p, agentConfig); err != nil {
 		return nil, err
 	}
 
@@ -688,6 +702,11 @@ func fetchPod(podID string) (pod *Pod, err error) {
 		return nil, errNeedPodID
 	}
 
+	pod, err = globalPodList.lookupPod(podID)
+	if pod != nil && err == nil {
+		return pod, err
+	}
+
 	fs := filesystem{}
 	config, err := fs.fetchPodConfig(podID)
 	if err != nil {
@@ -766,6 +785,8 @@ func (p *Pod) delete() error {
 		}
 	}
 
+	globalPodList.removePod(p.id)
+
 	return p.storage.deletePodResources(p.id, nil)
 }
 

virtcontainers/podlist.go

@@ -0,0 +1,60 @@
+//
+// Copyright (c) 2018 HyperHQ Inc.
+//
+// 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 virtcontainers
+
+import (
+	"fmt"
+	"sync"
+)
+
+type podList struct {
+	lock sync.RWMutex
+	pods map[string]*Pod
+}
+
+// globalPodList tracks pods globally
+var globalPodList = &podList{pods: make(map[string]*Pod)}
+
+func (p *podList) addPod(pod *Pod) (err error) {
+	if pod == nil {
+		return nil
+	}
+
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	if p.pods[pod.id] == nil {
+		p.pods[pod.id] = pod
+	} else {
+		err = fmt.Errorf("pod %s exists", pod.id)
+	}
+	return err
+}
+
+func (p *podList) removePod(id string) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	delete(p.pods, id)
+}
+
+func (p *podList) lookupPod(id string) (*Pod, error) {
+	p.lock.RLock()
+	defer p.lock.RUnlock()
+	if p.pods[id] != nil {
+		return p.pods[id], nil
+	}
+	return nil, fmt.Errorf("pod %s does not exist", id)
+}