RPyC Memory Connect

RpycMemConnect is a wrapper around rpyc.connect to connect with RpycMemService. RpycMemConnect performs some basic error recovery and validations.

import rpyc

from rpyc_mem.connect import RpycMemConnect

"""
Assuming RpycMemService running on localhost:18813

Defaults: max_retry=4
          retry_delay=3
          ignore_version=False
"""
rc = RpycMemConnect('localhost', 18813)

print(rc.rpyc_version())    # (5, 1, 0)
print(rpyc.__version__ == rc.rpyc_version())    # True
print(rc.root.memoize == rc.memoize)    # True
print(rc.is_memoized('not_memoized'))    # False

RPyC warns against having different versions for client and server; when the ignore_version is False, having different versions will raise an exception during __init__. The attributes that are not defined by RpycMemConnect are searched in the underlying RPyC connection object, Ex: rc.root will invoke getattr(self.rpyc_conn, 'root'). The RpycMemService attributes can be accessed as if they were defined under RpycMemConnect namespace, Ex: rc.memoize == rc.root.memoize

RpycMemConnect performs some basic error recovery as configured by max_retry and retry_delay. If you want to bypass this you can work with raw connection object rc.rpyc_conn. RpycMemConnect has these additional attributes:

• rc.setup_rmem_conn() - Re-setup the connection (attempt-close and open).

• rc.rmem_except_handler() - Function decorator for handling the connection errors when working with raw connection object

• rc.close() - Close the underlying RPyC connection. Connection errors are no more handled (until the connection is re-setup)

The following snippet shows their usage:

from rpyc_mem.connect import RpycMemConnect

rc = RpycMemConnect('localhost', 18813, max_retry=1)
rc.close()

# Working with raw connection object
try:
    rc.rpyc_conn.root.rpyc_version()
except EOFError:
    rc.setup_rmem_conn()    # Re-setup the connection ([attempt] close and open)
    print(rc.rpyc_conn.root.rpyc_version())

# Recovery from connection failures
rc.rpyc_conn.close()   # With rc.close() connection errors are no more handled
print(rc.rpyc_version())

# Using exception handlers when working with raw connection object
rc.rpyc_conn.close()

def reconnect_hook():
    print('re-connected')

@rc.rmem_except_handler(on_reconnect=reconnect_hook)
def rmem_fn():
    """Function that uses rpyc connection object"""
    print(rc.rpyc_conn.root.is_memoized('not_memoized'))

rmem_fn()

"""
Output:
(5, 1, 0)
(5, 1, 0)
re-connected
False
"""