def _get_connection(self):
"""Context manager providing a netmiko SSH connection object.
This function hides the complexities of gracefully handling retrying
failed connection attempts.
"""
retry_exc_types = (paramiko.SSHException, EOFError)
# Use tenacity to handle retrying.
@tenacity.retry(
# Log a message after each failed attempt.
after=tenacity.after_log(LOG, logging.DEBUG),
# Reraise exceptions if our final attempt fails.
reraise=True,
# Retry on SSH connection errors.
retry=tenacity.retry_if_exception_type(retry_exc_types),
# Stop after the configured timeout.
stop=tenacity.stop_after_delay(
int(self.ngs_config['ngs_ssh_connect_timeout'])),
# Wait for the configured interval between attempts.
wait=tenacity.wait_fixed(
int(self.ngs_config['ngs_ssh_connect_interval'])),
)
def _create_connection():
return netmiko.ConnectHandler(**self.config)
# First, create a connection.
try:
net_connect = _create_connection()
except tenacity.RetryError as e:
LOG.error("Reached maximum SSH connection attempts, not retrying")
raise exc.GenericSwitchNetmikoConnectError(
config=device_utils.sanitise_config(self.config), error=e)
except Exception as e:
LOG.error("Unexpected exception during SSH connection")
raise exc.GenericSwitchNetmikoConnectError(
config=device_utils.sanitise_config(self.config), error=e)
# Now yield the connection to the caller.
with net_connect:
yield net_connect
def send_commands_to_device(self, cmd_set):
if not cmd_set:
LOG.debug("Nothing to execute")
return
try:
net_connect = netmiko.ConnectHandler(**self.config)
net_connect.enable()
output = net_connect.send_config_set(config_commands=cmd_set)
except Exception as e:
raise exc.GenericSwitchNetmikoConnectError(config=self.config,
error=e)
LOG.debug(output)
def show_port_list(self):
try:
with ngs_lock.PoolLock(self.locker, **self.lock_kwargs):
with self._get_connection() as net_connect:
net_connect.enable()
# output = net_connect.send_config_set(
# config_commands=cmd_set)
# NOTE (vsaienko) always save configuration
# when configuration is applied successfully.
if self.SHOW_PORT_LIST:
output = net_connect.send_command(self.SHOW_PORT_LIST)
except Exception as e:
raise exc.GenericSwitchNetmikoConnectError(config=self.config,
error=e)
return output
def send_commands_to_device(self, cmd_set):
if not cmd_set:
LOG.debug("Nothing to execute")
return
try:
with ngs_lock.PoolLock(self.locker, **self.lock_kwargs):
with self._get_connection() as net_connect:
net_connect.enable()
output = net_connect.send_config_set(
config_commands=cmd_set)
# NOTE (vsaienko) always save configuration
# when configuration is applied successfully.
if self.SAVE_CONFIGURATION:
net_connect.send_command(self.SAVE_CONFIGURATION)
except Exception as e:
raise exc.GenericSwitchNetmikoConnectError(config=self.config,
error=e)
LOG.debug(output)
return output
def send_commands_to_device(self, cmd_set):
if not cmd_set:
LOG.debug("Nothing to execute")
return
try:
with ngs_lock.PoolLock(self.locker, **self.lock_kwargs):
with self._get_connection() as net_connect:
output = self.send_config_set(net_connect, cmd_set)
# NOTE (vsaienko) always save configuration
# when configuration is applied successfully.
self.save_configuration(net_connect)
except exc.GenericSwitchException:
# Reraise without modification exceptions originating from this
# module.
raise
except Exception as e:
raise exc.GenericSwitchNetmikoConnectError(
config=device_utils.sanitise_config(self.config), error=e)
LOG.debug(output)
return output