Add gNMI device state subscriber

Change-Id: I20cb5e130f4e416bf8678aab2e5268faf24ad06b
diff --git a/providers/general/BUILD b/providers/general/BUILD
index 0f4654f..2ac73a0 100644
--- a/providers/general/BUILD
+++ b/providers/general/BUILD
@@ -7,7 +7,7 @@
     category = "Provider",
     description = "General device southbound providers.",
     included_bundles = BUNDLES,
-    required_apps = [],
+    required_apps = ["org.onosproject.protocols.gnmi"],
     title = "General Device Provider",
     url = "http://onosproject.org",
 )
diff --git a/providers/general/device/BUILD b/providers/general/device/BUILD
index 2807457..40957b1 100644
--- a/providers/general/device/BUILD
+++ b/providers/general/device/BUILD
@@ -1,4 +1,9 @@
-COMPILE_DEPS = CORE_DEPS + JACKSON
+COMPILE_DEPS = CORE_DEPS + JACKSON + [
+    "//protocols/gnmi/stub:onos-protocols-gnmi-stub",
+    "//protocols/gnmi/api:onos-protocols-gnmi-api",
+    "@com_google_protobuf//:protobuf_java",
+    "//protocols/grpc/api:onos-protocols-grpc-api",
+]
 
 osgi_jar_with_tests(
     test_deps = TEST_ADAPTERS,
diff --git a/providers/general/device/src/main/java/org/onosproject/provider/general/device/impl/GeneralDeviceProvider.java b/providers/general/device/src/main/java/org/onosproject/provider/general/device/impl/GeneralDeviceProvider.java
index 3ca56ee..bbf71f2 100644
--- a/providers/general/device/src/main/java/org/onosproject/provider/general/device/impl/GeneralDeviceProvider.java
+++ b/providers/general/device/src/main/java/org/onosproject/provider/general/device/impl/GeneralDeviceProvider.java
@@ -25,6 +25,7 @@
 import org.onlab.util.Tools;
 import org.onosproject.cfg.ComponentConfigService;
 import org.onosproject.core.CoreService;
+import org.onosproject.gnmi.api.GnmiController;
 import org.onosproject.mastership.MastershipService;
 import org.onosproject.net.AnnotationKeys;
 import org.onosproject.net.DefaultAnnotations;
@@ -169,6 +170,16 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
     private PiPipeconfWatchdogService pipeconfWatchdogService;
 
+    // FIXME: no longer general if we add a dependency to a protocol-specific
+    // service. Possible solutions are: rename this provider to
+    // StratumDeviceProvider, find a way to allow this provider to register for
+    // protocol specific events (e.g. port events) via drivers (similar to
+    // DeviceAgentListener).
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    private GnmiController gnmiController;
+
+    private GnmiDeviceStateSubscriber gnmiDeviceStateSubscriber;
+
     /**
      * Configure poll frequency for port status and statistics; default is 10 sec.
      */
@@ -228,6 +239,9 @@
         pipeconfWatchdogService.addListener(pipeconfWatchdogListener);
         rescheduleProbeTask(false);
         modified(context);
+        gnmiDeviceStateSubscriber = new GnmiDeviceStateSubscriber(gnmiController,
+                deviceService, mastershipService, providerService);
+        gnmiDeviceStateSubscriber.activate();
         log.info("Started");
     }
 
@@ -316,6 +330,8 @@
         providerRegistry.unregister(this);
         providerService = null;
         cfgService.unregisterConfigFactory(factory);
+        gnmiDeviceStateSubscriber.deactivate();
+        gnmiDeviceStateSubscriber = null;
         log.info("Stopped");
     }
 
diff --git a/providers/general/device/src/main/java/org/onosproject/provider/general/device/impl/GnmiDeviceStateSubscriber.java b/providers/general/device/src/main/java/org/onosproject/provider/general/device/impl/GnmiDeviceStateSubscriber.java
new file mode 100644
index 0000000..b253f3e
--- /dev/null
+++ b/providers/general/device/src/main/java/org/onosproject/provider/general/device/impl/GnmiDeviceStateSubscriber.java
@@ -0,0 +1,281 @@
+/*
+ * Copyright 2018-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.provider.general.device.impl;
+
+import com.google.common.annotations.Beta;
+import com.google.common.collect.Sets;
+import com.google.common.util.concurrent.Striped;
+import gnmi.Gnmi.Notification;
+import gnmi.Gnmi.Path;
+import gnmi.Gnmi.PathElem;
+import gnmi.Gnmi.SubscribeRequest;
+import gnmi.Gnmi.Subscription;
+import gnmi.Gnmi.SubscriptionList;
+import gnmi.Gnmi.SubscriptionMode;
+import gnmi.Gnmi.Update;
+import org.onlab.util.SharedExecutors;
+import org.onosproject.gnmi.api.GnmiClient;
+import org.onosproject.gnmi.api.GnmiController;
+import org.onosproject.gnmi.api.GnmiEvent;
+import org.onosproject.gnmi.api.GnmiEventListener;
+import org.onosproject.gnmi.api.GnmiUpdate;
+import org.onosproject.gnmi.api.GnmiUtils;
+import org.onosproject.mastership.MastershipEvent;
+import org.onosproject.mastership.MastershipListener;
+import org.onosproject.mastership.MastershipService;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Port;
+import org.onosproject.net.SparseAnnotations;
+import org.onosproject.net.device.DefaultPortDescription;
+import org.onosproject.net.device.DeviceEvent;
+import org.onosproject.net.device.DeviceListener;
+import org.onosproject.net.device.DeviceProviderService;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.device.PortDescription;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.locks.Lock;
+
+/**
+ * Entity that manages gNMI subscription for devices using OpenConfig models and
+ * that reports relevant events to the core.
+ */
+@Beta
+class GnmiDeviceStateSubscriber {
+
+    private static Logger log = LoggerFactory.getLogger(GnmiDeviceStateSubscriber.class);
+
+    private final GnmiController gnmiController;
+    private final DeviceService deviceService;
+    private final DeviceProviderService providerService;
+    private final MastershipService mastershipService;
+
+    private final ExecutorService executorService = SharedExecutors.getPoolThreadExecutor();
+
+    private final InternalGnmiEventListener gnmiEventListener = new InternalGnmiEventListener();
+    private final InternalDeviceListener deviceEventListener = new InternalDeviceListener();
+    private final InternalMastershipListener mastershipListener = new InternalMastershipListener();
+    private final Collection<DeviceId> deviceSubscribed = Sets.newHashSet();
+
+    private final Striped<Lock> deviceLocks = Striped.lock(30);
+
+    GnmiDeviceStateSubscriber(GnmiController gnmiController, DeviceService deviceService,
+                              MastershipService mastershipService,
+                              DeviceProviderService providerService) {
+        this.gnmiController = gnmiController;
+        this.deviceService = deviceService;
+        this.mastershipService = mastershipService;
+        this.providerService = providerService;
+    }
+
+    public void activate() {
+        deviceService.addListener(deviceEventListener);
+        mastershipService.addListener(mastershipListener);
+        gnmiController.addListener(gnmiEventListener);
+        // Subscribe to existing devices.
+        deviceService.getDevices().forEach(d -> executorService.execute(
+                () -> checkDeviceSubscription(d.id())));
+    }
+
+    public void deactivate() {
+        deviceSubscribed.forEach(this::unsubscribeIfNeeded);
+        deviceService.removeListener(deviceEventListener);
+        mastershipService.removeListener(mastershipListener);
+        gnmiController.removeListener(gnmiEventListener);
+    }
+
+    private void checkDeviceSubscription(DeviceId deviceId) {
+        deviceLocks.get(deviceId).lock();
+        try {
+            if (!deviceService.isAvailable(deviceId)
+                    || deviceService.getDevice(deviceId) == null
+                    || !mastershipService.isLocalMaster(deviceId)) {
+                // Device not available/removed or this instance is no longer
+                // master.
+                unsubscribeIfNeeded(deviceId);
+            } else {
+                subscribeIfNeeded(deviceId);
+            }
+        } finally {
+            deviceLocks.get(deviceId).unlock();
+        }
+    }
+
+    private Path interfaceOperStatusPath(String interfaceName) {
+        return Path.newBuilder()
+                .addElem(PathElem.newBuilder().setName("interfaces").build())
+                .addElem(PathElem.newBuilder()
+                                 .setName("interface").putKey("name", interfaceName).build())
+                .addElem(PathElem.newBuilder().setName("state").build())
+                .addElem(PathElem.newBuilder().setName("oper-status").build())
+                .build();
+    }
+
+    private void unsubscribeIfNeeded(DeviceId deviceId) {
+        if (!deviceSubscribed.contains(deviceId)) {
+            // Not subscribed.
+            return;
+        }
+        GnmiClient client = gnmiController.getClient(deviceId);
+        if (client == null) {
+            log.debug("Cannot find gNMI client for device {}", deviceId);
+        } else {
+            client.terminateSubscriptionChannel();
+        }
+        deviceSubscribed.remove(deviceId);
+    }
+
+    private void subscribeIfNeeded(DeviceId deviceId) {
+        if (deviceSubscribed.contains(deviceId)) {
+            // Already subscribed.
+            // FIXME: if a new port is added after the first subscription we are
+            // not subscribing to the new port.
+            return;
+        }
+
+        GnmiClient client = gnmiController.getClient(deviceId);
+        if (client == null) {
+            log.warn("Cannot find gNMI client for device {}", deviceId);
+            return;
+        }
+
+        List<Port> ports = deviceService.getPorts(deviceId);
+        SubscriptionList.Builder subscriptionList = SubscriptionList.newBuilder();
+        subscriptionList.setMode(SubscriptionList.Mode.STREAM);
+        subscriptionList.setUpdatesOnly(true);
+
+        ports.forEach(port -> {
+            String portName = port.number().name();
+            // Subscribe /interface/interface[name=port-name]/state/oper-status
+            Path subscribePath = interfaceOperStatusPath(portName);
+            Subscription interfaceOperStatusSub =
+                    Subscription.newBuilder()
+                            .setPath(subscribePath)
+                            .setMode(SubscriptionMode.ON_CHANGE)
+                            .build();
+            // TODO: more state subscription
+            subscriptionList.addSubscription(interfaceOperStatusSub);
+        });
+
+        SubscribeRequest subscribeRequest = SubscribeRequest.newBuilder()
+                .setSubscribe(subscriptionList.build())
+                .build();
+
+        client.subscribe(subscribeRequest);
+
+        deviceSubscribed.add(deviceId);
+    }
+
+    private void handleGnmiUpdate(GnmiUpdate eventSubject) {
+        Notification notification = eventSubject.update();
+        if (notification == null) {
+            log.warn("Cannot handle gNMI event without update data, abort");
+            log.debug("gNMI update:\n{}", eventSubject);
+            return;
+        }
+
+        List<Update> updateList = notification.getUpdateList();
+        updateList.forEach(update -> {
+            Path path = update.getPath();
+            PathElem lastElem = path.getElem(path.getElemCount() - 1);
+
+            // Use last element to identify which state updated
+            if ("oper-status".equals(lastElem.getName())) {
+                handleOperStatusUpdate(eventSubject.deviceId(), update);
+            } else {
+                log.debug("Unrecognized update {}", GnmiUtils.pathToString(path));
+            }
+        });
+    }
+
+    private void handleOperStatusUpdate(DeviceId deviceId, Update update) {
+        Path path = update.getPath();
+        // first element should be "interface"
+        String interfaceName = path.getElem(1).getKeyOrDefault("name", null);
+        if (interfaceName == null) {
+            log.error("No interface present in gNMI update, abort");
+            log.debug("gNMI update:\n{}", update);
+            return;
+        }
+
+        List<Port> portsFromDevice = deviceService.getPorts(deviceId);
+        portsFromDevice.forEach(port -> {
+            if (!port.number().name().equals(interfaceName)) {
+                return;
+            }
+
+            // Port/Interface name is identical in OpenConfig model, but not in ONOS
+            // This might cause some problem if we use one name to different port
+            PortDescription portDescription = DefaultPortDescription.builder()
+                    .portSpeed(port.portSpeed())
+                    .withPortNumber(port.number())
+                    .isEnabled(update.getVal().getStringVal().equals("UP"))
+                    .type(port.type())
+                    .annotations((SparseAnnotations) port.annotations())
+                    .build();
+            providerService.portStatusChanged(deviceId, portDescription);
+        });
+    }
+
+    class InternalGnmiEventListener implements GnmiEventListener {
+
+        @Override
+        public void event(GnmiEvent event) {
+            if (!deviceSubscribed.contains(event.subject().deviceId())) {
+                log.warn("Received gNMI event from {}, but we are not subscribed to it",
+                         event.subject().deviceId());
+            }
+            log.debug("Received gNMI event {}", event.toString());
+            if (event.type() == GnmiEvent.Type.UPDATE) {
+                executorService.execute(
+                        () -> handleGnmiUpdate((GnmiUpdate) event.subject()));
+            } else {
+                log.debug("Unsupported gNMI event type: {}", event.type());
+            }
+        }
+    }
+
+    class InternalMastershipListener implements MastershipListener {
+
+        @Override
+        public void event(MastershipEvent event) {
+            executorService.execute(() -> checkDeviceSubscription(event.subject()));
+        }
+    }
+
+    class InternalDeviceListener implements DeviceListener {
+
+        @Override
+        public void event(DeviceEvent event) {
+            switch (event.type()) {
+                case DEVICE_ADDED:
+                case DEVICE_AVAILABILITY_CHANGED:
+                case DEVICE_UPDATED:
+                case DEVICE_REMOVED:
+                    executorService.execute(
+                            () -> checkDeviceSubscription(event.subject().id()));
+                    break;
+                default:
+                    break;
+            }
+        }
+    }
+}