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/core/api/src/main/java/org/onosproject/net/driver/DeviceConnect.java b/core/api/src/main/java/org/onosproject/net/driver/DeviceConnect.java
index 433be71..ffb7deb 100644
--- a/core/api/src/main/java/org/onosproject/net/driver/DeviceConnect.java
+++ b/core/api/src/main/java/org/onosproject/net/driver/DeviceConnect.java
@@ -17,8 +17,6 @@
import com.google.common.annotations.Beta;
-import java.util.concurrent.CompletableFuture;
-
/**
* Abstraction of handler behaviour used to set-up and tear-down connections
* with a device. A connection is intended as the presence of state (e.g. a
@@ -31,22 +29,24 @@
/**
* Connects to the device, for example by opening the transport session that
* will be later used to send control messages. Returns true if the
- * connection was initiated successfully, false otherwise. The
- * implementation might require probing the device over the network to
- * initiate the connection.
+ * connection was created successfully, false otherwise.
+ * <p>
+ * The implementation should trigger without blocking any necessary
+ * handshake with the device to initialize the connection over the network,
+ * eventually generating a {@link org.onosproject.net.device.DeviceAgentEvent.Type#CHANNEL_OPEN}
+ * event when ready.
* <p>
* When calling this method while a connection to the device already exists,
* the behavior is not defined. For example, some implementations might
* require to first call {@link #disconnect()}, while other might behave as
* a no-op.
*
- * @return CompletableFuture eventually true if a connection was created
- * successfully, false otherwise
+ * @return true if a connection was created successfully, false otherwise
* @throws IllegalStateException if a connection already exists and the
* implementation requires to call {@link
* #disconnect()} first.
*/
- CompletableFuture<Boolean> connect() throws IllegalStateException;
+ boolean connect() throws IllegalStateException;
/**
* Returns true if a connection to the device exists, false otherwise. This
@@ -61,14 +61,19 @@
*
* @return true if the connection is open, false otherwise
*/
- boolean isConnected();
+ boolean hasConnection();
/**
- * Disconnects from the device, for example closing the transport session
+ * Disconnects from the device, for example closing any transport session
* previously opened.
* <p>
* Calling multiple times this method while a connection to the device is
* already closed should result in a no-op.
+ * <p>
+ * If a connection to the device existed and it was open, the implementation
+ * is expected to generate a
+ * {@link org.onosproject.net.device.DeviceAgentEvent.Type#CHANNEL_CLOSED}
+ * event.
*/
void disconnect();
}