Component drivers connect and provide interfaces to various components in the OpenFlow/SDN topology.
The three main methods of a component driver are connect, disconnect, and execute. While writing a custom driver, overriding an existing component method may be used in favor of writing a new method that contains similar logic.
The Mininet driver may be used as a reference to writing a custom driver.
In this example, the Mininet driver inherits from the abstract Emulator driver which inherits from the CLI driver. The Mininet driver reuses the execute and disconnect API from the CLI driver. The connect API is the only API that is redefined.
class MininetCliDriver( Emulator ): def __init__( self ): super( MininetCliDriver, self ).__init__() self.handle = self def connect( self, user_name, ip_address, pwd, options ): self.handle = super( MininetCliDriver, self ).connect( user_name, ip_address, pwd )
Here the connect will call the inherited connect() method from CLI driver (via Emulator class).
Driver specific methods/functions can be specified using the simple execute command in mininetclidriver.
def pingall( self, timeout=300 ): """ Verifies the reachability of the hosts using pingall command. Optional parameter timeout allows you to specify how long to wait for pingall to complete Returns: main.TRUE if pingall completes with no pings dropped otherwise main.FALSE""" if self.handle: main.log.info( self.name + ": Checking reachabilty to the hosts using pingall" ) try: response = self.execute( cmd="pingall", prompt="mininet>", timeout=int( timeout ) )
The cluster driver combines the CLI, REST, and Bench components as a cluster. This allows the use of a function or variable from another driver without the need to specify that specific driver. For example,
main.Cluster.active( 0 ).devices()
can be used instead of
and keeps the same context as the former. This can be helpful in tests where the number of ONOS nodes is not static throughout the test.
However, if the function name is similar across more than one driver, the driver name will need to be specified. For example, in
main.Cluster.active( 0 ).CLI.sendline( "roles" )
"CLI" must be specified to avoid ambiguity.
NOTE: More documentation for writing drivers will be added in the future.
Email us if you’re stuck, think you’ve found a bug, or just want to send some feedback. Please have a look at the guidelines to learn how to efficiently submit a bug report.