[ONOS-8012] Implement kubernetes network policy store and manager

Change-Id: I0386f1103046f69f5f06586229fb2ac5a0926c15
diff --git a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sNetworkPolicyWatcher.java b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sNetworkPolicyWatcher.java
new file mode 100644
index 0000000..1f8c4a3
--- /dev/null
+++ b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sNetworkPolicyWatcher.java
@@ -0,0 +1,207 @@
+/*
+ * Copyright 2019-present Open Networking Foundation
+ *
+ * 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 org.onosproject.k8snetworking.impl;
+
+import io.fabric8.kubernetes.api.model.networking.NetworkPolicy;
+import io.fabric8.kubernetes.client.KubernetesClient;
+import io.fabric8.kubernetes.client.KubernetesClientException;
+import io.fabric8.kubernetes.client.Watcher;
+import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.LeadershipService;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreService;
+import org.onosproject.k8snetworking.api.K8sNetworkPolicyAdminService;
+import org.onosproject.k8snode.api.K8sApiConfigEvent;
+import org.onosproject.k8snode.api.K8sApiConfigListener;
+import org.onosproject.k8snode.api.K8sApiConfigService;
+import org.onosproject.mastership.MastershipService;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Deactivate;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.component.annotations.ReferenceCardinality;
+import org.slf4j.Logger;
+
+import java.util.Objects;
+import java.util.concurrent.ExecutorService;
+
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+import static org.onlab.util.Tools.groupedThreads;
+import static org.onosproject.k8snetworking.api.Constants.K8S_NETWORKING_APP_ID;
+import static org.onosproject.k8snetworking.util.K8sNetworkingUtil.k8sClient;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Kubernetes network policy watcher used for feeding network policy information.
+ */
+@Component(immediate = true)
+public class K8sNetworkPolicyWatcher {
+
+    private final Logger log = getLogger(getClass());
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected CoreService coreService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected MastershipService mastershipService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected ClusterService clusterService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected LeadershipService leadershipService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected K8sNetworkPolicyAdminService k8sNetworkPolicyAdminService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected K8sApiConfigService k8sApiConfigService;
+
+    private final ExecutorService eventExecutor = newSingleThreadExecutor(
+            groupedThreads(this.getClass().getSimpleName(), "event-handler"));
+
+    private final InternalK8sNetworkPolicyWatcher
+            internalK8sNetworkPolicyWatcher = new InternalK8sNetworkPolicyWatcher();
+    private final InternalK8sApiConfigListener
+            internalK8sApiConfigListener = new InternalK8sApiConfigListener();
+
+    private ApplicationId appId;
+    private NodeId localNodeId;
+
+    @Activate
+    protected void activate() {
+        appId = coreService.registerApplication(K8S_NETWORKING_APP_ID);
+        localNodeId = clusterService.getLocalNode().id();
+        leadershipService.runForLeadership(appId.name());
+        k8sApiConfigService.addListener(internalK8sApiConfigListener);
+
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        k8sApiConfigService.removeListener(internalK8sApiConfigListener);
+        leadershipService.withdraw(appId.name());
+        eventExecutor.shutdown();
+
+        log.info("Stopped");
+    }
+
+    private class InternalK8sApiConfigListener implements K8sApiConfigListener {
+
+        private boolean isRelevantHelper() {
+            return Objects.equals(localNodeId, leadershipService.getLeader(appId.name()));
+        }
+
+        @Override
+        public void event(K8sApiConfigEvent event) {
+
+            switch (event.type()) {
+                case K8S_API_CONFIG_UPDATED:
+                    eventExecutor.execute(this::processConfigUpdating);
+                    break;
+                case K8S_API_CONFIG_CREATED:
+                case K8S_API_CONFIG_REMOVED:
+                default:
+                    // do nothing
+                    break;
+            }
+        }
+
+        private void processConfigUpdating() {
+            if (!isRelevantHelper()) {
+                return;
+            }
+
+            KubernetesClient client = k8sClient(k8sApiConfigService);
+
+            if (client != null) {
+                client.network().networkPolicies().inAnyNamespace().watch(
+                        internalK8sNetworkPolicyWatcher);
+            }
+        }
+    }
+
+    private class InternalK8sNetworkPolicyWatcher implements Watcher<NetworkPolicy> {
+
+        @Override
+        public void eventReceived(Action action, NetworkPolicy service) {
+            switch (action) {
+                case ADDED:
+                    eventExecutor.execute(() -> processAddition(service));
+                    break;
+                case MODIFIED:
+                    eventExecutor.execute(() -> processModification(service));
+                    break;
+                case DELETED:
+                    eventExecutor.execute(() -> processDeletion(service));
+                    break;
+                case ERROR:
+                    log.warn("Failures processing network policy manipulation.");
+                    break;
+                default:
+                    // do nothing
+                    break;
+            }
+        }
+
+        @Override
+        public void onClose(KubernetesClientException e) {
+            log.info("Network policy watcher OnClose: {}" + e);
+        }
+
+        private void processAddition(NetworkPolicy networkPolicy) {
+            if (!isMaster()) {
+                return;
+            }
+
+            log.trace("Process network policy {} creating event from API server.",
+                    networkPolicy.getMetadata().getName());
+
+            k8sNetworkPolicyAdminService.createNetworkPolicy(networkPolicy);
+        }
+
+        private void processModification(NetworkPolicy networkPolicy) {
+            if (!isMaster()) {
+                return;
+            }
+
+            log.trace("Process network policy {} updating event from API server.",
+                    networkPolicy.getMetadata().getName());
+
+            if (k8sNetworkPolicyAdminService.networkPolicy(
+                    networkPolicy.getMetadata().getUid()) != null) {
+                k8sNetworkPolicyAdminService.updateNetworkPolicy(networkPolicy);
+            }
+        }
+
+        private void processDeletion(NetworkPolicy networkPolicy) {
+            if (!isMaster()) {
+                return;
+            }
+
+            log.trace("Process network policy {} removal event from API server.",
+                    networkPolicy.getMetadata().getName());
+
+            k8sNetworkPolicyAdminService.removeNetworkPolicy(networkPolicy.getMetadata().getUid());
+        }
+
+        private boolean isMaster() {
+            return Objects.equals(localNodeId, leadershipService.getLeader(appId.name()));
+        }
+    }
+}