Allow sharing the same gRPC channel between clients
This change introduces a refactoring of the gRPC protocol subsystem that
allows the creation of a gRPC chanel independently of the client, while
allowing multiple clients to share the same channel (e.g. as in Stratum
where we use 3 clients).
Moreover, we refactor the P4RuntimeClient API to support multiple
P4Runtime-internal device ID using the same client. While before the
client was associated to one of such ID.
Finally, we provide an abstract implementation for gRPC-based driver
behaviors, reducing code duplication in P4Runtime, gNMI and gNOI drivers.
Change-Id: I1a46352bbbef1e0d24042f169ae8ba580202944f
diff --git a/protocols/grpc/api/src/main/java/org/onosproject/grpc/api/GrpcClientController.java b/protocols/grpc/api/src/main/java/org/onosproject/grpc/api/GrpcClientController.java
index b47d499..3edb36d 100644
--- a/protocols/grpc/api/src/main/java/org/onosproject/grpc/api/GrpcClientController.java
+++ b/protocols/grpc/api/src/main/java/org/onosproject/grpc/api/GrpcClientController.java
@@ -17,6 +17,7 @@
package org.onosproject.grpc.api;
import com.google.common.annotations.Beta;
+import io.grpc.ManagedChannel;
import org.onosproject.net.DeviceId;
import org.onosproject.net.device.DeviceAgentListener;
import org.onosproject.net.provider.ProviderId;
@@ -24,76 +25,54 @@
/**
* Abstraction of controller that manages gRPC clients.
*
- * @param <K> the gRPC client key
* @param <C> the gRPC client type
*/
@Beta
-public interface GrpcClientController<K extends GrpcClientKey, C extends GrpcClient> {
+public interface GrpcClientController<C extends GrpcClient> {
/**
- * Instantiates a new client to operate on a gRPC server identified by the
- * given information. As a result of this method, a client can be later
- * obtained by invoking {@link #getClient(DeviceId)}.
+ * Instantiates a new client to operate on the given gRPC channel. Returns
+ * true if the client was created successfully, false otherwise. Clients
+ * are identified by device IDs and once created they can be obtained by
+ * invoking {@link #get(DeviceId)}.
* <p>
- * Upon creation, a connection to the server is automatically started, which
- * blocks execution. If the connection is successful, the client is created
- * and this method returns true, otherwise (e.g., socket error) any state
- * associated with this client is destroyed and returns false.
- * <p>
- * Only one client can exist for the same device ID. Calls to this method
- * are idempotent fot the same client key, i.e. returns true if such client
- * already exists. Otherwise, if a client for the same device ID but
- * different client key already exists, throws an exception.
+ * Only one client can exist for the same device ID. If a client for the
+ * given device ID already exists, throws an exception.
*
- * @param clientKey the client key
- * @return true if the client was created and the channel to the server is
- * open; false otherwise
- * @throws IllegalArgumentException if a client for the same device ID but
- * different client key already exists.
+ * @param deviceId device ID
+ * @param channel gRPC managed channel
+ * @return true if the client was created, false otherwise
+ * @throws IllegalArgumentException if a client for the same device ID
+ * already exists.
*/
- boolean createClient(K clientKey);
+ boolean create(DeviceId deviceId, ManagedChannel channel);
/**
- * Returns the gRPC client previously created for the given device, or null
- * if such client does not exist.
- *
- * @param deviceId the device identifier
- * @return the gRPC client of the device if exists; null otherwise
- */
- C getClient(DeviceId deviceId);
-
- /**
- * Returns the gRPC client previously created for the given client key, or
+ * Returns the gRPC client previously created for the given device ID, or
* null if such client does not exist.
*
- * @param clientKey client key
+ * @param deviceId the device ID
* @return the gRPC client of the device if exists; null otherwise
*/
- C getClient(K clientKey);
+ C get(DeviceId deviceId);
/**
* Removes the gRPC client for the given device and any gRPC channel state
* associated to it. If no client exists for the given device, the result is
* a no-op.
*
- * @param deviceId the device identifier
+ * @param deviceId the device ID
*/
- void removeClient(DeviceId deviceId);
+ void remove(DeviceId deviceId);
/**
- * Similar to {@link #removeClient(DeviceId)} but uses the client key to
- * identify the client to remove.
+ * Adds a listener for device agent events for the given provider. If a
+ * listener already exists for the given device ID and provider ID, then it
+ * will be replaced by the new one.
*
- * @param clientKey the client key
- */
- void removeClient(K clientKey);
-
- /**
- * Adds a listener for device agent events for the given provider.
- *
- * @param deviceId device identifier
+ * @param deviceId device ID
* @param providerId provider ID
- * @param listener the device agent listener
+ * @param listener the device agent listener
*/
void addDeviceAgentListener(DeviceId deviceId, ProviderId providerId,
DeviceAgentListener listener);
@@ -102,7 +81,7 @@
* Removes the listener for device agent events that was previously
* registered for the given provider.
*
- * @param deviceId device identifier
+ * @param deviceId device ID
* @param providerId the provider ID
*/
void removeDeviceAgentListener(DeviceId deviceId, ProviderId providerId);